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Sample records for resistance welding machine

  1. Testing and Modeling of Machine Properties in Resistance Welding

    DEFF Research Database (Denmark)

    Wu, Pei

    The objective of this work has been to test and model the machine properties including the mechanical properties and the electrical properties in resistance welding. The results are used to simulate the welding process more accurately. The state of the art in testing and modeling machine properties...... as real projection welding tests, is easy to realize in industry, since tests may be performed in situ. In part II, an approach of characterizing the electrical properties of AC resistance welding machines is presented, involving testing and mathematical modelling of the weld current, the firing angle...... in resistance welding has been described based on a comprehensive literature study. The present thesis has been subdivided into two parts: Part I: Mechanical properties of resistance welding machines. Part II: Electrical properties of resistance welding machines. In part I, the electrode force in the squeeze...

  2. Identification of Mechanical parameters for Resistance Welding Machines

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    2003-01-01

    Mechanical dynamic responses of resistance welding machine have a significant influence on weld quality and electrode service life, it must be considered when the real welding production is carried out or the welding process is simulated. The mathematical models for characterizing the mechanical...

  3. Control system of power supply for resistance welding machine

    Directory of Open Access Journals (Sweden)

    Світлана Костянтинівна Поднебенна

    2017-06-01

    Full Text Available This article describes the existing methods of heat energy stabilizing, which are realized in thyristor power supplies for resistance welding machines. The advantages and features of thyristor power supplies have been described. A control system of power supply for resistance welding machine with stabilization of heat energy in a welding spot has been developed. Measurements are performed in primary winding of a welding transformer. Weld spot heating energy is calculated as the difference between the energy, consumed from the mains, and the energy losses in the primary and secondary circuits of the welding transformer as well as the energy losses in the transformer core. Algorithms of digital signal processing of the developed control system are described in the article. All measurements and calculations are preformed automatically in real-time. Input signals to the control system are: transformer primary voltage and current, temperature of the welding circuit. The designed control system ensures control of the welding heat energy and is not influenced by the supply voltage and impedance changes caused by insertion of the ferromagnetic mass in the welding circuit, the temperature change during the welding process. The developed control system for resistance welding machine makes it possible to improve the quality of welded joints, increase the efficiency of the resistance welding machine

  4. Characterisation of Dynamic Mechanical Properties of Resistance Welding Machines

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    2005-01-01

    characterizing the dynamic mechanical characteristics of resistance welding machines is suggested, and a test set-up is designed determining the basic, independent machine parameters required in the model. The model is verified by performing a series of mechanical tests as well as real projection welds.......The dynamic mechanical properties of a resistance welding machine have significant influence on weld quality, which must be considered when simulating the welding process numerically. However, due to the complexity of the machine structure and the mutual coupling of components of the machine system......, it is very difficult to measure or calculate the basic, independent machine parameters required in a mathematical model of the machine dynamics, and no test method has so far been presented in literature, which can be applied directly in an industrial environment. In this paper, a mathematical model...

  5. Testing and Modeling of Mechanical Characteristics of Resistance Welding Machines

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    2003-01-01

    for both upper and lower electrode systems. This has laid a foundation for modeling the welding process and selecting the welding parameters considering the machine factors. The method is straightforward and easy to be applied in industry since the whole procedure is based on tests with no requirements......The dynamic mechanical response of resistance welding machine is very important to the weld quality in resistance welding especially in projection welding when collapse or deformation of work piece occurs. It is mainly governed by the mechanical parameters of machine. In this paper, a mathematical...... model for characterizing the dynamic mechanical responses of machine and a special test set-up called breaking test set-up are developed. Based on the model and the test results, the mechanical parameters of machine are determined, including the equivalent mass, damping coefficient, and stiffness...

  6. Resistance seam welding

    International Nuclear Information System (INIS)

    Schueler, A.W.

    1977-01-01

    The advantages and disadvantages of the resistance seam welding process are presented. Types of seam welds, types of seam welding machines, seam welding power supplies, resistance seam welding parameters and seam welding characteristics of various metals

  7. A Method for Identifying the Mechanical Parameters in Resistance Spot Welding Machines

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    2003-01-01

    Mechanical dynamic responses of resistance welding machine have a significant influence on weld quality and electrode service life, it must be considered when the real welding production is carried out or the welding process is stimulated. The mathematical models for characterizing the mechanical...

  8. Resistance welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.

    2003-01-01

    Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...... this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical modelling...

  9. Automatic welding machine for piping

    International Nuclear Information System (INIS)

    Yoshida, Kazuhiro; Koyama, Takaichi; Iizuka, Tomio; Ito, Yoshitoshi; Takami, Katsumi.

    1978-01-01

    A remotely controlled automatic special welding machine for piping was developed. This machine is utilized for long distance pipe lines, chemical plants, thermal power generating plants and nuclear power plants effectively from the viewpoint of good quality control, reduction of labor and good controllability. The function of this welding machine is to inspect the shape and dimensions of edge preparation before welding work by the sense of touch, to detect the temperature of melt pool, inspect the bead form by the sense of touch, and check the welding state by ITV during welding work, and to grind the bead surface and inspect the weld metal by ultrasonic test automatically after welding work. The construction of this welding system, the main specification of the apparatus, the welding procedure in detail, the electrical source of this welding machine, the cooling system, the structure and handling of guide ring, the central control system and the operating characteristics are explained. The working procedure and the effect by using this welding machine, and the application to nuclear power plants and the other industrial field are outlined. The HIDIC 08 is used as the controlling computer. This welding machine is useful for welding SUS piping as well as carbon steel piping. (Nakai, Y.)

  10. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors...

  11. Resistance welding equipment manufacturing capability for exports

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, V.S.; Raju, Y.S.; Somani, A.K.; Setty, D.S.; Rameswara Raw, A.; Hermantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderbad (India)

    2010-07-01

    Indian Pressurised Heavy Water Reactor (PHWR) fuel bundle is fully welded and is unique in its design. Appendage welding, end closure welding, and end plate welding is carried out using resistance welding technique. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. Nuclear Fuel Complex (NFC), an industrial unit is established in Hyderabad, under the aegis of the Dept of Atomic Energy to manufacture fuel for Pressurised Heavy Water Reactors. From inception, NFC has given importance for self-reliance and indigenization with respect to manufacturing process and equipment. Sintering furnaces, centreless grinders, appendage-welding machines, end-closure welding equipment and end-plate welding equipments, which were initially imported, are either indigenized or designed and manufactured in house. NFC has designed, manufactured a new appendage-welding machine for manufacturing 37 element fuel bundles. Recently NFC has bagged an order from IAEA through international bidding for design, manufacture, supply, erection and commissioning of end-closure welding equipment. The paper gives in detail the salient features of these welding equipment. (author)

  12. MFDC - technological improvement in resistance welding controls

    Energy Technology Data Exchange (ETDEWEB)

    Somani, A.K.; Naga Bhaskar, V.; Chandramouli, J.; Rameshwara Rao, A. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

    2008-07-01

    Among the various Resistance Welding operations carried out in the production line of a fuel bundle end plug welding is the most critical operation. Welding controllers play a very vital role in obtaining consistent weld quality by regulating and controlling the weld current. Conventional mains synchronized welding controllers are at best capable of controlling the weld current at a maximum speed of the mains frequency. In view of the very short welding durations involved in the various stages of a fuel bundle fabrication, a need was felt for superior welding controllers. Medium Frequency Welding Controllers offer a solution to these limitations in addition to offering other advantages. Medium Frequency power sources offer precise welding current control as they regulate and correct the welding current faster, typically twenty times faster when operated at 1000Hz. An MFDC was employed on one of the welding machines and its performance was studied. This paper discusses about the various advantages of MFDCs with other controllers employed at NFC to end plug welding operation. (author)

  13. Machine for welding solar cell connections

    Energy Technology Data Exchange (ETDEWEB)

    Lorans, D.Y.

    1977-08-09

    A machine for welding a connection wire over a solar cell electrode is described which comprises a base, a welding mount for the solar cell which is supported on the base, means for holding the solar cell on the welding mount, welding electrodes, means to lower the welding electrodes over the solar cell and the connection wire superimposed thereon, means for applying electric current pulses to said welding electrodes. It is characterized by the fact that it further comprises means for imparting to said mount an alternating transverse movement in relation to said base before and during the welding operation.

  14. Measurement of Dynamic Resistance in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    Through years, the dynamic resistance across the electrodes has been used for weld quality estimation and contact resistance measurement. However, the previous methods of determining the dynamic resistance were mostly based on measuring the voltage and current on the secondary side of the transfo......Through years, the dynamic resistance across the electrodes has been used for weld quality estimation and contact resistance measurement. However, the previous methods of determining the dynamic resistance were mostly based on measuring the voltage and current on the secondary side...... of the transformer in resistance welding machines, implying defects from induction noise and interference with the leads connected to the electrodes for measuring the voltage. In this study, the dynamic resistance is determined by measuring the voltage on the primary side and the current on the secondary side...

  15. Welding process automation in power machine building

    International Nuclear Information System (INIS)

    Mel'bard, S.N.; Shakhnov, A.F.; Shergov, I.V.

    1977-01-01

    The level of welding automation operations in power engineering and ways of its enhancement are highlighted. Used as the examples of comlex automation are an apparatus for the horizontal welding of turbine rotors, remotely controlled automatic machine for welding ring joint of large-sized vessels, equipment for the electron-beam welding of steam turbine assemblies of alloyed steels. The prospects of industrial robots are noted. The importance of the complex automation of technological process, including stocking, assemblying, transportation and auxiliary operations, is emphasized

  16. Resistance Spot Welding of dissimilar Steels

    Directory of Open Access Journals (Sweden)

    Ladislav Kolařík

    2012-01-01

    Full Text Available This paper presents an analysis of the properties of resistance spot welds between low carbon steel and austenitic CrNi stainless steel. The thickness of the welded dissimilar materials was 2 mm. A DeltaSpot welding gun with a process tape was used for welding the dissimilar steels. Resistance spot welds were produced with various welding parameters (welding currents ranging from 7 to 8 kA. Light microscopy, microhardness measurements across the welded joints, and EDX analysis were used to evaluate the quality of the resistance spot welds. The results confirm the applicability of DeltaSpot welding for this combination of materials.

  17. FSW of Aluminum Tailor Welded Blanks across Machine Platforms

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Upadhyay, Piyush; Carlson, Blair; Szymanski, Robert; Luzanski, Tom; Marshall, Dustin

    2015-02-16

    Development and characterization of friction stir welded aluminum tailor welded blanks was successfully carried out on three separate machine platforms. Each was a commercially available, gantry style, multi-axis machine designed specifically for friction stir welding. Weld parameters were developed to support high volume production of dissimilar thickness aluminum tailor welded blanks at speeds of 3 m/min and greater. Parameters originally developed on an ultra-high stiffness servo driven machine where first transferred to a high stiffness servo-hydraulic friction stir welding machine, and subsequently transferred to a purpose built machine designed to accommodate thin sheet aluminum welding. The inherent beam stiffness, bearing compliance, and control system for each machine were distinctly unique, which posed specific challenges in transferring welding parameters across machine platforms. This work documents the challenges imposed by successfully transferring weld parameters from machine to machine, produced from different manufacturers and with unique control systems and interfaces.

  18. Measurement of Dynamic Resistance in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Wu, Pei; Lu, J.; Zhang, Wenqi

    2007-01-01

    is influenced by inductive noise caused by the high welding current. In this study, the dynamic resistance is determined by measuring the voltage at primary side and current at secondary side. This increases the accuracy of measurement because of higher signal-noise ratio, and allows to apply to in-process......The conventional methods of determining the dynamic resistance were mostly done by measuring the voltage and current at secondary side of transformer in resistance welding machines, in which the measuring set-up normally interferes with the movement of electrode, and the measuring precision...

  19. An Experimental Study of the Electrical Contact Resistance in Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng; Zhang, Wenqi; Bay, Niels

    2005-01-01

    Electrical contact resistance is of critical importance in resistance welding. In this article, the contact resistance is experimentally investigated for welding mild steel, stainless steel, and aluminum to themselves. A parametric study was carried out on a Gleeble® machine, investigating...

  20. Thermomechanical Modelling of Resistance Welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi

    2007-01-01

    The present paper describes a generic programme for analysis, optimization and development of resistance spot and projection welding. The programme includes an electrical model determining electric current and voltage distribution as well as heat generation, a thermal model calculating heat...

  1. 29 CFR 1910.255 - Resistance welding.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Resistance welding. 1910.255 Section 1910.255 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Welding, Cutting and Brazing § 1910.255 Resistance welding. (a.... Ignitron tubes used in resistance welding equipment shall be equipped with a thermal protection switch. (3...

  2. Modular Power Supply for Micro Resistance Welding

    Directory of Open Access Journals (Sweden)

    Bondarenko Oleksandr

    2017-07-01

    Full Text Available The study is devoted to the important issue of enhancing the circuitry and characteristics of power supplies for micro resistance welding machines. The aim of the research is to provide high quality input current and to increase the energy efficiency of the output pulse generator by means of improving the circuit topologies of the power supply main blocks. In study, the principle of constructing the power supply for micro resistance welding, which provides high values of output welding current and high accuracy of welding pulse formation, makes it possible to reduce energy losses, and provides high quality of consumed input current, is represented. The multiphase topology of the charger with power factor correction based on SEPIC converters is suggested as the most efficient for charging the supercapacitor storage module. The multicell topology of the supercapacitor energy storage with voltage equalizing is presented. The parameters of the converter cells are evaluated. The calculations of energy efficiency of the power supply’s input and output converters based on suggested topologies are carried out and verified in MATLAB Simulink. The power factor value greater than 99 % is derived.

  3. Reliability of copper based alloys for electric resistance spot welding

    International Nuclear Information System (INIS)

    Jovanovicj, M.; Mihajlovicj, A.; Sherbedzhija, B.

    1977-01-01

    Durability of copper based alloys (B-5 and B-6) for electric resistance spot-welding was examined. The total amount of Be, Ni and Zr was up to 2 and 1 wt.% respectively. Good durability and satisfactory quality of welded spots were obtained in previous laboratory experiments carried out on the fixed spot-welding machine of an industrial type (only B-5 alloy was examined). Electrodes made of both B-5 and B-6 alloy were tested on spot-welding grips and fixed spot-welding machines in Tvornica automobila Sarajevo (TAS). The obtained results suggest that the durability of electrodes made of B-5 and B-6 alloys is more than twice better than of that used in TAS

  4. Three-dimensional simulations of resistance spot welding

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Zhang, Wenqi; Perret, William

    2014-01-01

    This paper draws from the fundamentals of electro-thermo-mechanical coupling to the main aspects of finite element implementation and three-dimensional modelling of resistance welding. A new simulation environment is proposed in order to perform three-dimensional simulations and optimization...... of resistance welding together with the simulations of conventional and special-purpose quasi-static mechanical tests. Three-dimensional simulations of resistance welding consider the electrical, thermal, mechanical and metallurgical characteristics of the material as well as the operating conditions...... of the welding machines. Simulations of the mechanical tests take into account material softening due to the accumulation of ductile damage and cover conventional tests, such as tensile–shear tests, cross-tension test and peel tests, as well as the possibility of special-purpose tests designed by the users...

  5. FRICTION - WELDING MACHINE AUTOMATIC CONTROL CIRCUIT DESIGN AND APPLICATION

    OpenAIRE

    Hakan ATEŞ; Ramazan BAYINDIR

    2003-01-01

    In this work, automatic controllability of a laboratory-sized friction-welding machine has been investigated. The laboratory-sized friction-welding machine was composed of motor, brake, rotary and constant samples late pliers, and hydraulic unit. In automatic method, welding parameters such as friction time, friction pressure, forge time and forge pressure can be applied sensitively using time relays and contactors. At the end of the experimental study it's observed that automatic control sys...

  6. Numerical methods in simulation of resistance welding

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Martins, Paulo A.F.; Zhang, Wenqi

    2015-01-01

    Finite element simulation of resistance welding requires coupling betweenmechanical, thermal and electrical models. This paper presents the numerical models and theircouplings that are utilized in the computer program SORPAS. A mechanical model based onthe irreducible flow formulation is utilized...... a resistance welding point of view, the most essential coupling between the above mentioned models is the heat generation by electrical current due to Joule heating. The interaction between multiple objects is anothercritical feature of the numerical simulation of resistance welding because it influences...... thecontact area and the distribution of contact pressure. The numerical simulation of resistancewelding is illustrated by a spot welding example that includes subsequent tensile shear testing...

  7. Computerised weld strength testing machine for PHWR fuel elements with a versatile control system

    International Nuclear Information System (INIS)

    Gupta, U.C.; Sastry, V.S.; Rasheed, Jawad; Bibawe, S.R.

    1994-01-01

    Spacer pads and bearing pads are resistance spot welded on PHWR fuel elements to ensure inter-element gap for coolant flow. These welds are subjected to destructive tests as per SQC specifications while qualifying a machine and during production. The testing machine used earlier over the years was tedious involving manual operations of clamping, tool actuation, increasing and decreasing the pressure, referring to charts and statistical calculations. To carry out the destructive testing of the welds conveniently and reliably, an automatic machine is developed in-house in which are incorporated a quartz force transducer and a computerized data-acquisition and processing system together with a very versatile electronic control system based on a single-chip microcomputer. This paper describes the salient features of the machine and the control system. (author). 4 figs

  8. In-Space Friction Stir Welding Machine, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Longhurst Engineering, PLC, and Vanderbilt University propose an in-space friction stir welding (FSW) machine for joining complex structural aluminum components. The...

  9. FRICTION - WELDING MACHINE AUTOMATIC CONTROL CIRCUIT DESIGN AND APPLICATION

    Directory of Open Access Journals (Sweden)

    Hakan ATEŞ

    2003-02-01

    Full Text Available In this work, automatic controllability of a laboratory-sized friction-welding machine has been investigated. The laboratory-sized friction-welding machine was composed of motor, brake, rotary and constant samples late pliers, and hydraulic unit. In automatic method, welding parameters such as friction time, friction pressure, forge time and forge pressure can be applied sensitively using time relays and contactors. At the end of the experimental study it's observed that automatic control system has been worked successfully.

  10. Visualization of Spot- welding Resistance

    Directory of Open Access Journals (Sweden)

    Michal Černý

    2016-01-01

    Full Text Available This contribution devotes to monitoring of processes running during joining of steel sheets by incadescent so called point welding using non-destructive trial method – acoustic emission (AE. The joining process is detailed described within experimental measuring from the point of view of metallurgic effects runnig during weld creation (records obtained by means of AE method. It takes into consideration quality of joined steels within welding data of steel producer. Steel welding (determined by chemical composition during mechanical verification and firmness of welds consider results of measurement AE and fracture effect of point joints. The measurement also demonstrates conclusion about connection of metallurgic processes with material wave effects (AE measurement and their impact on firmness of joint at steel with guaranteed welding, difficult welding and at their potential combination.

  11. SORPAS – The Professional Software for Simulation of Resistance Welding

    DEFF Research Database (Denmark)

    Zhang, Wenqi

    2002-01-01

    and easily operate and utilize the software. With the user-friendly facilities for flexible geometric design of work pieces and electrodes as well as process parameter settings similar to real machine parameter settings, the software has been readily applied in industry for supporting product development...... applied in industries including automotive, electronics and other metal processing industries as well as welding equipment manufacturers....... directly usable by engineers and technicians in industry, all of the important parameters in resistance welding are considered and automatically implemented into the software. With the specially designed graphic user interface for Windows, engineers (even without prior knowledge of FEM) can quickly learn...

  12. Research Activities at IPT, DTU on Resistance Projection Welding

    DEFF Research Database (Denmark)

    Bay, Niels

    2000-01-01

    Resistance welding processes and among these especially the resistance projection welding is considered an industrially strategic process with increasing applications as alternative to other welding processes, soldering, brazing and mechanical assembling. This is due to increasing requirements...... as regards quality assurance and the special possibilities of joining complex metal combinations and geometries using resistance projection welding....

  13. Performance of indigenous resistance welding equipment for PHWR fuel fabrication in NFC

    International Nuclear Information System (INIS)

    Hemantha Rao, G.V.S.; Jayaraj, R.N.; Prakash, M.S.; Gupta, U.C.; Ganguly, C.

    1999-01-01

    Indigenisation of critical equipment for manufacturing of PHWR fuel and automation in the production line have been the main thrust in NFC in recent years. As part of this endeavour, resistance welding equipment for end plug welding of Zircaloy-4 clad Uranium Oxide fuel pin and end plates of 19-element fuel bundles have been developed. The paper discusses the equipment design features, critical operating parameters and performance of these indigenous welding machines. (author)

  14. Improving resistance welding of aluminum sheets by addition of metal powder

    DEFF Research Database (Denmark)

    Al Naimi, Ihsan K.; Al-Saadi, Moneer H.; Daws, Kasim M.

    2015-01-01

    . The improvement obtained is shown to be due to the development of a secondary bond in the joint beside the weld nugget increasing the total weld area. The application of powder additive is especially feasible, when using welding machines with insufficient current capacity for producing the required nugget size......In order to ensure good quality joints between aluminum sheets by resistance spot welding, a new approach involving the addition of metal powder to the faying surfaces before resistance heating is proposed. Three different metal powders (pure aluminum and two powders corresponding to the alloys AA....... In such cases the best results are obtained with pure aluminum powder....

  15. Neural network monitoring of resistive welding

    International Nuclear Information System (INIS)

    Quero, J.M.; Millan, R.L.; Franquelo, L.G.; Canas, J.

    1994-01-01

    Supervision of welding processes is one of the most important and complicated tasks in production lines. Artificial Neural Networks have been applied for modeling and control of ph physical processes. In our paper we propose the use of a neural network classifier for on-line non-destructive testing. This system has been developed and installed in a resistive welding station. Results confirm the validity of this novel approach. (Author) 6 refs

  16. The Effect of Vibration during Friction Stir Welding on Corrosion Behavior, Mechanical Properties, and Machining Characteristics of Stir Zone

    Directory of Open Access Journals (Sweden)

    Sajad Fouladi

    2017-10-01

    Full Text Available Different methods have been applied to refine various characteristics of the zone (or nugget obtained by friction stir welding (FSW. In the current research, joining components are vibrated normal to the weld line during FSW to refine the zone microstructure. This process is described as friction stir vibration welding (FSVW. The effect of FSVW on mechanical properties, corrosion behavior, and machining characteristics of the zone are investigated. Al5052 alloy specimens are welded using FSW and FSVW processes and their different characteristics are compared and discussed. The results show that the strength and ductility of the welded parts increase when the vibration is applied. The outcomes also show that corrosion resistance of the nugget for FSV-welded specimens is lower than FS welded samples, and machining force of the former specimens is higher than the latter ones. These are related to smaller grain size in the zone of FSV-welded specimens compared to FS welded parts. Smaller grain size leads to a greater volume fraction of grain boundaries and, correspondingly, higher strength and hardness, as well as lower corrosion resistance.

  17. Welding and brazing of the JET machine components

    International Nuclear Information System (INIS)

    Walravens, M.J.

    1985-10-01

    The report covers the techniques used for joining the various parts of the machine. The difficulties encountered during the welding and brazing of similar and dissimilar metals are underlined and the solutions adopted to solve them are indicated. The vast experience gained by those involved in the processes of joining the various parts of the JET machine components, and the lessons learnt are summarized in this report. (author)

  18. Corrosion resistance of copper canister weld material

    International Nuclear Information System (INIS)

    Gubner, Rolf; Andersson, Urban

    2007-03-01

    The proposed design for a final repository for spent fuel and other long-lived residues is based on the multi-barrier principle. The waste will be encapsulated in sealed cylindrical canisters, which will be placed in granite bedrock and surrounded by compacted bentonite clay. The canister design is based on a thick cast iron insert fitted inside a copper canister. SKB has since several years developed manufacturing processes for the canister components using a network of manufacturers. For the encapsulation process SKB has built the Canister Laboratory to demonstrate and develop the encapsulation technique in full scale. The critical part of the encapsulation of spent fuel is the sealing of the canister which is done by welding the copper lid to the cylindrical part of the canister. Two welding techniques have been developed in parallel, Electron Beam Welding (EBW) and Friction Stir Welding (FSW). During the past two decades, SKB has developed the technology EBW at The Welding Institute (TWI) in Cambridge, UK. The development work at the Canister Laboratory began in 1999. In electron beam welding, a gun is used to generate the electron beam which is aimed at the joint. The beam heats up the material to the melting point allowing a fusion weld to be formed. The gun was developed by TWI and has a unique design for use at reduced pressure. The system has gone through a number of improvements under the last couple of years including implementation of a beam oscillation system. However, during fabrication of the outer copper canisters there will be some unavoidable grain growth in the welded areas. As grains grow they will tend to concentrate impurities at the new grain boundaries that might pose adverse effects on the corrosion resistance of welds. As a new method for joining, SKB has been developing friction stir welding (FSW) for sealing copper canisters for spent nuclear fuel in cooperation with TWI since 1997. FSW was invented in 1991 at TWI and is a thermo

  19. Corrosion resistance of copper canister weld material

    Energy Technology Data Exchange (ETDEWEB)

    Gubner, Rolf; Andersson, Urban [Corrosion and Metals Research Institute, Sto ckholm (Sweden)

    2007-03-15

    The proposed design for a final repository for spent fuel and other long-lived residues is based on the multi-barrier principle. The waste will be encapsulated in sealed cylindrical canisters, which will be placed in granite bedrock and surrounded by compacted bentonite clay. The canister design is based on a thick cast iron insert fitted inside a copper canister. SKB has since several years developed manufacturing processes for the canister components using a network of manufacturers. For the encapsulation process SKB has built the Canister Laboratory to demonstrate and develop the encapsulation technique in full scale. The critical part of the encapsulation of spent fuel is the sealing of the canister which is done by welding the copper lid to the cylindrical part of the canister. Two welding techniques have been developed in parallel, Electron Beam Welding (EBW) and Friction Stir Welding (FSW). During the past two decades, SKB has developed the technology EBW at The Welding Institute (TWI) in Cambridge, UK. The development work at the Canister Laboratory began in 1999. In electron beam welding, a gun is used to generate the electron beam which is aimed at the joint. The beam heats up the material to the melting point allowing a fusion weld to be formed. The gun was developed by TWI and has a unique design for use at reduced pressure. The system has gone through a number of improvements under the last couple of years including implementation of a beam oscillation system. However, during fabrication of the outer copper canisters there will be some unavoidable grain growth in the welded areas. As grains grow they will tend to concentrate impurities at the new grain boundaries that might pose adverse effects on the corrosion resistance of welds. As a new method for joining, SKB has been developing friction stir welding (FSW) for sealing copper canisters for spent nuclear fuel in cooperation with TWI since 1997. FSW was invented in 1991 at TWI and is a thermo

  20. Wear Resistance Analysis of A359/SiC/20p Advanced Composite Joints Welded by Friction Stir Welding

    Directory of Open Access Journals (Sweden)

    O. Cuevas Mata

    Full Text Available Abstract Advancement in automotive part development demands new cost-effective materials with higher mechanical properties and improved wear resistance as compared to existing materials. For instance, Aluminum Matrix Composites (AMC shows improved mechanical properties as wear and abrasion resistance, high strength, chemical and dimensional stability. Automotive industry has focused in AMC for a variety of applications in automotive parts in order to improve the fuel economy, minimize vehicle emissions, improve design options, and increase the performance. Wear resistance is one of the most important factors in useful life of the automotive components, overall in those components submitted to mechanical systems like automotive brakes and suspensions. Friction Stir Welding (FSW rises as the most capable process to joining AMC, principally for the capacity to weld without compromising their ceramic reinforcement. The aim of this study is focused on the analysis of wear characteristics of the friction-stir welded joint of aluminum matrix reinforced with 20 percent in weight silicon carbide composite (A359/SiC/20p. The experimental procedure consisted in cut samples into small plates and perform three welds on these with a FSW machine using a tool with 20 mm shoulder diameter and 8 mm pin diameter. The wear features of the three welded joints and parent metal were analyzed at constant load applying 5 N and a rotational speed of 100 rpm employing a Pin-on - Disk wear testing apparatus, using a sapphire steel ball with 6 mm diameter. The experimental results indicate that the three welded joints had low friction coefficient compared with the parent metal. The results determine that the FSW process parameters affect the wear resistance of the welded joints owing to different microstructural modifications during welding that causes a low wear resistance on the welded zone.

  1. Evaluating the SCC resistance of underwater welds in sodium tetrathionate

    International Nuclear Information System (INIS)

    White, R.A.; Angeliu, T.M.

    1997-01-01

    The susceptibility of welds to stress corrosion cracking (SCC) is enhanced by the surface residual tensile stresses generated by the typical welding process. However, underwater plasma transferred arc (PTA) welding has been shown to produce compressive surface residual stresses, an encouraging result if repairs of cracked boiling water reactor (BWR) components are to be made without further endangering them to SCC. This program was designed to verify that underwater PTA welds are resistant to SCC and to determine if underwater PTA welding could mitigate SCC in potentially susceptible welds. This was achieved by exposing various welds on solution annealed (SA) and SA + thermally sensitized 304 stainless steel at 25 C in a solution of 1.5 gm/liter of sodium sulfide added to 0.05M sodium tetrathionate, titrated to a pH of 1.25 with H 2 SO 4 . The autogeneous welds were produced using gas tungsten arc (GTA) and plasma transferred arc (PTA) welding under atmospheric conditions, and PTA welding underwater. After 1 hour of sodium tetrathionate exposure, GTA and air PTA welds exhibited SCC while the underwater PTA weld heat affected zones were more resistant. Underwater PTA welds bisecting a GTA weld eliminated the cracking in the GTA weld heat affected zone under certain conditions. The lack of IG cracking in the region influenced by the underwater PTA weld is consistent with the measurement of compressive surface residual stresses inherent to the underwater welding process

  2. Metallography of Battery Resistance Spot Welds

    Science.gov (United States)

    Martinez, J. E.; Johannes, L. B.; Gonzalez, D.; Yayathi, S.; Figuered, J. M.; Darcy, E. C.; Bilc, Z. M.

    2015-01-01

    Li-ion cells provide an energy dense solution for systems that require rechargeable electrical power. However, these cells can undergo thermal runaway, the point at which the cell becomes thermally unstable and results in hot gas, flame, electrolyte leakage, and in some cases explosion. The heat and fire associated with this type of event is generally violent and can subsequently cause damage to the surrounding system or present a dangerous risk to the personnel nearby. The space flight environment is especially sensitive to risks particularly when it involves potential for fire within the habitable volume of the International Space Station (ISS). In larger battery packs such as Robonaut 2 (R2), numerous Li-ion cells are placed in parallel-series configurations to obtain the required stack voltage and desired run-time or to meet specific power requirements. This raises a second and less obvious concern for batteries that undergo certification for space flight use: the joining quality at the resistance spot weld of battery cells to component wires/leads and battery tabs, bus bars or other electronic components and assemblies. Resistance spot welds undergo materials evaluation, visual inspection, conductivity (resistivity) testing, destructive peel testing, and metallurgical examination in accordance with applicable NASA Process Specifications. Welded components are cross-sectioned to ensure they are free of cracks or voids open to any exterior surface. Pore and voids contained within the weld zone but not open to an exterior surface, and are not determined to have sharp notch like characteristics, shall be acceptable. Depending on requirements, some battery cells are constructed of aluminum canisters while others are constructed of steel. Process specific weld schedules must be developed and certified for each possible joining combination. The aluminum canisters' positive terminals were particularly difficult to weld due to a bi-metal strip that comes ultrasonically

  3. Resistance projection welding small pins in vacuum tube feedthrough assembly

    International Nuclear Information System (INIS)

    Kuncz, F. Jr.

    1980-01-01

    Resistance projection welding of two stainless steel pins to a cup is successfully accomplished by specially designed electrodes and by forming domes on the pin ends. Details of electrode and pin construction are given, as well as welding parameters

  4. Estimation of weld nugget temperature by thermography method in resistance projection welding process

    International Nuclear Information System (INIS)

    Setty, D.S.; Rameswara Roa, A.; Hemantha Rao, G.V.S.; Jaya Raj, R.N.

    2008-01-01

    In the Pressurized Heavy Water Reactor (PHWR) fuel manufacturing, zirconium alloy appendages like spacer and bearing pads are welded to the thin wall zirconium alloy fuel tubes by using resistance projection welding process. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. In the fuel assembly, spacer pads are used to get the required inter-element spacing and Bearing pads are used to get the required load-bearing surface for the fuel assembly. Performance of the fuel assembly in the reactor is greatly influenced by these weld joint's quality. Phase transformation from α to β phase is not acceptable while welding these tiny appendages. At present only destructive metallography test is available for this purpose. This can also be achieved by measuring weld nugget temperature where in the phase transformation temperature for zirconium alloy material is 853 o C. The temperature distribution during resistance welding of tiny parts cannot be measured by conventional methods due to very small space and short weld times involved in the process. Shear strength, dimensional accuracy and weld microstructures are some of the key parameters used to measure the quality of appendage weld joints. Weld parameters were optimized with the help of industrial experimentation methodology. Individual projection welding by split electrode concept, and during welding on empty tube firm support is achieved on inner side of the tube by using expandable pneumatic mandrel. In the present paper, an attempt was made to measure the weld nugget temperature by thermography technique and is correlated with standard microstructures of zirconium alloy material. The temperature profiles in the welding process are presented for different welding conditions. This technique has helped in measuring the weld nugget temperature more accurately. It was observed that in the present appendage welding

  5. Resistance Spot Welding with Middelfrequency-Inverter Weling Gun

    DEFF Research Database (Denmark)

    Rasmussen, Mogens H.

    The paper presents the results of investigations concerning the process stability and weldability lobes for uncoated sheets of 1.0 mm thickness when performing resistance spot welding with a middlefrequency-inverter welding gun......The paper presents the results of investigations concerning the process stability and weldability lobes for uncoated sheets of 1.0 mm thickness when performing resistance spot welding with a middlefrequency-inverter welding gun...

  6. Investigation and control of factors influencing resistance upset butt welding.

    OpenAIRE

    Kerstens, N.F.H.

    2010-01-01

    The purpose of this work is to investigate the factors influencing the resistance upset butt welding process to obtain an understanding of the metal behaviour and welding process characteristics, so that new automotive steels can be welded with reduced development time and fewer failures in production. In principle the welding process is rather simple, the materials to be joined are clamped between two electrodes and pressed together. Because there is an interface present with a higher resist...

  7. Welding of heat-resistant 20% Cr-5% Al steels

    International Nuclear Information System (INIS)

    Tusek, J.; Arbi, D.; Kosmac, A.; Nartnik, U.

    2002-01-01

    The paper treats welding of heat-resistant ferritic stainless steels alloyed with approximately 20% Cr and 5% Al. The major part of the paper is dedicated to welding of 20% Cr-5% Al steel with 3 mm in thickness. Welding was carried out with five different welding processes, i. e., manual metal-arc, MIG, TIG, plasma arc, and laser beam welding processes, using a filler material and using no filler material, respectively. The welded joints obtained were subjected to mechanical tests and the analysis of microstructure in the weld metal and the transition zone. The investigations conducted showed that heat-resistant ferritic stainless 20% Cr-5% Al steel can be welded with fusion welding processes using a Ni-based filler material. (orig.)

  8. Present and future of laser welding machine; Laser yosetsuki no genjo to tenbo

    Energy Technology Data Exchange (ETDEWEB)

    Taniu, Y. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1998-04-01

    This paper describes recent trends of laser welding machine. For CO2 laser welding machine, seam weld of large diameter weld pipes using a 25 kW-class machine, and plate weld of steel plate using a 45 kW-class machine are reported. For YAG laser welding machine, high-output 5.5 kW-class machines are commercialized. Machines with slab structure of plate-like YAG chrystal have been developed which show high-oscillation efficiency and can be applied to cutting. Machines have been developed in which YAG laser output with slab structure is transmitted through GI fiber. High-speed welding of aluminum alloys can be realized by improving the converging performance. Efficiency of YAG laser can be enhanced through the time-divided utilization by switching the beam transmission path using fiber change-over switch. In the automobile industry, CO2 laser is mainly used, and a system combining CO laser with articulate robot is realized. TIG and MIG welding is often used for welding of aluminum for railway vehicles. It is required to reduce the welding strain. In the iron and steel industry, the productivity has been improved by the laser welding. YAG laser is put into practice for nuclear reactors. 5 refs., 8 figs., 1 tab.

  9. Single-purpose welding machines used in the manufacture of power equipment

    International Nuclear Information System (INIS)

    Bartak, J.

    1988-01-01

    A dedicated welding machine based on submerged arc welding with a wire electrode was developed for welding pipe sockets, spacers and other rotary parts to pressure vessel bodies. Two modifications of this apparatus were devised: one is designed for welding low-alloy carbon steels, where preheating is requisite, the other, for welding austenitic materials, requiring vigorous cooling. The single-purpose ADFS-1 device is designed for surfacing rings 200 to 1200 mm in diameter; it consists of a pillar with a drive, a rotary console, a collector, a horizontal support, a console with a vertical motor support, and a welding head with a feed equipment. Submerged arc welding using a 20x0.5 mm strip electrode is applied. Another dedicated welding machine employing submerged arc welding with a strip electrode was developed for the continuous welding of inner surfaces of pressure vessels in the sites of holes for flares. (Z.M.). 3 figs., 3 refs

  10. Microstructure and mechanical properties of resistance upset butt welded 304 austenitic stainless steel joints

    International Nuclear Information System (INIS)

    Sharifitabar, M.; Halvaee, A.; Khorshahian, S.

    2011-01-01

    Graphical abstract: Three different microstructural zones formed at different distances from the joint interface in resistance upset butt welding of 304 austenitic stainless steel. Highlights: → Evaluation of microstructure in resistance upset welding of 304 stainless steel. → Evaluation of welding parameters effects on mechanical properties of the joint. → Introducing the optimum welding condition for joining stainless steel bars. -- Abstract: Resistance upset welding (UW) is a widely used process for joining metal parts. In this process, current, time and upset pressure are three parameters that affect the quality of welded products. In the present research, resistance upset butt welding of 304 austenitic stainless steel and effect of welding power and upset pressure on microstructure, tensile strength and fatigue life of the joint were investigated. Microstructure of welds were studied using scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis was used to distinguish the phase(s) that formed at the joint interface and in heat affected zone (HAZ). Energy dispersive spectroscopy (EDS) linked to the SEM was used to determine chemical composition of phases formed at the joint interface. Fatigue tests were performed using a pull-push fatigue test machine and the fatigue properties were analyzed drawing stress-number of cycles to failure (S-N) curves. Also tensile strength tests were performed. Finally tensile and fatigue fracture surfaces were studied by SEM. Results showed that there were three different microstructural zones at different distances from the joint interface and delta ferrite phase has formed in these regions. There was no precipitation of chromium carbide at the joint interface and in the HAZ. Tensile and fatigue strengths of the joint decreased with welding power. Increasing of upset pressure has also considerable influence on tensile strength of the joint. Fractography of fractured samples showed that formation of hot spots at

  11. Investigation and control of factors influencing resistance upset butt welding.

    NARCIS (Netherlands)

    Kerstens, N.F.H.

    2010-01-01

    The purpose of this work is to investigate the factors influencing the resistance upset butt welding process to obtain an understanding of the metal behaviour and welding process characteristics, so that new automotive steels can be welded with reduced development time and fewer failures in

  12. EFFECTS OF ELECTRODE DEFORMATION OF RESISTANCE SPOT WELDING ON 304 AUSTENITIC STAINLESS STEEL WELD GEOMETRY

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2012-12-01

    Full Text Available The resistance spot welding process is accomplished by forcing huge amounts of current flow from the upper electrode tip through the base metals to the lower electrode tip, or vice versa or in both directions. A weld joint is established between the metal sheets through fusion, resulting in a strong bond between the sheets without occupying additional space. The growth of the weld nugget (bond between sheets is therefore determined from the welding current density; sufficient time for current delivery; reasonable electrode pressing force; and the area provided for current delivery (electrode tip. The welding current and weld time control the root penetration, while the electrode pressing force and electrode tips successfully accomplish the connection during the welding process. Although the welding current and weld time cause the heat generation at the areas concerned (electrode tip area, the electrode tips’ diameter and electrode pressing forces also directly influence the welding process. In this research truncated-electrode deformation and mushrooming effects are observed, which result in the welded areas being inconsistent due to the expulsion. The copper to chromium ratio is varied from the tip to the end of the electrode whilst the welding process is repeated. The welding heat affects the electrode and the electrode itself influences the shape of the weld geometry.

  13. Process for quality assurance of welded joints for electrical resistance point welding

    International Nuclear Information System (INIS)

    Schaefer, R.; Singh, S.

    1977-01-01

    In order to guarantee the reproducibility of welded joints of even quality (above all in the metal working industry), it is proposed that before starting resistance point welding, a preheating current should be allowed to flow at the site of the weld. A given reduction of the total resistance at the site of the weld should effect the time when the preheating current is switched over to welding current. This value is always predetermined empirically. Further possibilities of controlling the welding process are described, where the measurement of thermal expansion of the parts is used. A standard welding time is given. The rated course of electrode movement during the process can be predicted and a running comparison of nominal and actual values can be carried out. (RW) [de

  14. Design of reinforcement welding machine within steel framework for marine engineering

    Science.gov (United States)

    Wang, Gang; Wu, Jin

    2017-04-01

    In this project, a design scheme that reinforcement welding machine is added within the steel framework is proposed according to the double-side welding technology for box-beam structure in marine engineering. Then the design and development of circuit and transmission mechanism for new welding equipment are completed as well with one sample machine being made. Moreover, the trial running is finished finally. Main technical parameters of the equipment are: the working stroke: ≥1500mm, the welding speed: 8˜15cm/min and the welding sheet thickness: ≥20mm.

  15. Effects of heat input on the pitting resistance of Inconel 625 welds by overlay welding

    Science.gov (United States)

    Kim, Jun Seok; Park, Young IL; Lee, Hae Woo

    2015-03-01

    The objective of this study was to establish the relationship between the dilution ratio of the weld zone and pitting resistance depending on the heat input to welding of the Inconel alloy. Each specimen was produced by electroslag welding using Inconel 625 as the filler metal. In the weld zone of each specimen, dendrite grains were observed near the fusion line and equiaxed grains were observed on the surface. It was also observed that a melted zone with a high Fe content was formed around the fusion line, which became wider as the welding heat input increased. In order to evaluate the pitting resistance, potentiodynamic polarization tests and CPT tests were conducted. The results of these tests confirmed that there is no difference between the pitting resistances of each specimen, as the structures of the surfaces were identical despite the effect of the differences in the welding heat input for each specimen and the minor dilution effect on the surface.

  16. Weld nugget formation in resistance spot welding of new lightweight sandwich material

    DEFF Research Database (Denmark)

    Sagüés Tanco, J.; Nielsen, Chris Valentin; Chergui, Azeddine

    2015-01-01

    Weldability of a new lightweight sandwich material, LITECOR®, by resistance spot welding is analyzed by experiments and numerical simulations. The spot welding process is accommodated by a first pulse squeezing out the non-conductive polymer core of the sandwich material locally to allow metal......–metal contact. This is facilitated by the use of a shunt tool and is followed by a second pulse for the actual spot welding and nugget formation. A weldability lobe in the time-current space of the second pulse reveals a process window of acceptable size for automotive assembly lines. Weld growth curves...... with experimental results in the range of welding parameters leading to acceptable weld nugget sizes. The validated accuracy of the commercially available software proves the tool useful for assisting the choice of welding parameters....

  17. X-ray evaluation of residual stress distributions within surface machined layer generated by surface machining and sequential welding

    International Nuclear Information System (INIS)

    Taniguchi, Yuu; Okano, Shigetaka; Mochizuki, Masahito

    2017-01-01

    The excessive tensile residual stress generated by welding after surface machining may be an important factor to cause stress corrosion cracking (SCC) in nuclear power plants. Therefore we need to understand and control the residual stress distribution appropriately. In this study, residual stress distributions within surface machined layer generated by surface machining and sequential welding were evaluated by X-ray diffraction method. Depth directional distributions were also investigated by electrolytic polishing. In addition, to consider the effect of work hardened layer on the residual stress distributions, we also measured full width at half maximum (FWHM) obtained from X-ray diffraction. Testing material was a low-carbon austenitic stainless steel type SUS316L. Test specimens were prepared by surface machining with different cutting conditions. Then, bead-on-plate welding under the same welding condition was carried out on the test specimens with different surface machined layer. As a result, the tensile residual stress generated by surface machining increased with increasing cutting speed and showed nearly uniform distributions on the surface. Furthermore, the tensile residual stress drastically decreased with increasing measurement depth within surface machined layer. Then, the residual stress approached 0 MPa after the compressive value showed. FWHM also decreased drastically with increasing measurement depth and almost constant value from a certain depth, which was almost equal regardless of the machining condition, within surface machined layer in all specimens. After welding, the transverse distribution of the longitudinal residual stress varied in the area apart from the weld center according to machining conditions and had a maximum value in heat affected zone. The magnitude of the maximum residual stress was almost equal regardless of the machining condition and decreased with increasing measurement depth within surface machined layer. Finally, the

  18. Resistance projection welding of vacuum tube getter assembly

    International Nuclear Information System (INIS)

    Kuncz, F. Jr.

    1980-01-01

    Tungsten inert gas welding the leads to a vacuum tube getter assembly can result in fusion of gettering powder, lowering gas absorption capability. Using resistance projection welding with ball-ended leads, getter bodies were successfully bonded to the leads. Special electrodes were designed. Materials and methods are given for producing ball-ended leads, designating and building special electrodes, and for welding the leads to the body

  19. Applying of dilatometric effect for resistance welding automation

    Directory of Open Access Journals (Sweden)

    Bondarenko O. F.

    2017-06-01

    Full Text Available The important issue of resistance spot welding control to obtain high quality welded joints, especially in living tissue welding, is considered. The actual state of the issue is described and analyzed. In order to improve the quality of welded joints, the applying of dilatometric effect to control the resistance spot welding process, namely of shifting the welding electrodes, is suggested. To register the shifting, the use of modern inertial microelectromechanical sensors (MEMS is proposed. The experimental measuring system, which processes the MEMS-sensor signal and makes it suitable for use as a feedback signal, is developed. The structure and operational algorithm of the system are described. The abilities of measuring with MEMS-sensors the values of electrode shifting caused by dilatometric effect under resistance welding are assessed. These method and equipment are recommended for welding the metals, as well as for welding the living tissues. The results of preliminary studies prove the advisability and relevance of the suggested solutions.

  20. Microstructural evolution and mechanical performance of resistance spot welded DP1000 steel with single and double pulse welding

    NARCIS (Netherlands)

    Chabok, Ali; van der Aa, Ellen; De Hosson, Jeff; Pei, Yutao T.

    2017-01-01

    Two welding schemes of single and double pulse were used for the resistance spot welding of DP1000 dual phase steel. The changes in the mechanical performance and variant pairing of martensite under two different welding conditions were scrutinized. It is demonstrated that, although both welds fail

  1. Resistance Welding of Advanced Materials and Micro Components

    DEFF Research Database (Denmark)

    Friis, Kasper Storgaard

    With the use of the Finite Element Method it has become possible to analyse and better understand complex physical processes such as the resistance welding by numerical simulation. However, simulation of resistance welding is a very complex matter due to the strong interaction between mechanical......, thermal, electrical and metallurgical effects all signifcantly in uencing the process. Modelling is further complicated when down-scaling the process for welding micro components or when welding new advanced high strength steels in the automotive industry. The current project deals with three main themes...... aimed at improving the understanding of resistance welding for increasing the accuracy of numerical simulation of the process. Firstly methods for measuring and modelling mechanical and electrical properties at a wide range of temperatures is investigated, and especially the electrical contact...

  2. Welding quality evaluation of resistance spot welding using the time-varying inductive reactance signal

    Science.gov (United States)

    Zhang, Hongjie; Hou, Yanyan; Yang, Tao; Zhang, Qian; Zhao, Jian

    2018-05-01

    In the spot welding process, a high alternating current is applied, resulting in a time-varying electromagnetic field surrounding the welder. When measuring the welding voltage signal, the impedance of the measuring circuit consists of two parts: dynamic resistance relating to weld nugget nucleation event and inductive reactance caused by mutual inductance. The aim of this study is to develop a method to acquire the dynamic reactance signal and to discuss the possibility of using this signal to evaluate the weld quality. For this purpose, a series of experiments were carried out. The reactance signals under different welding conditions were compared and the results showed that the morphological feature of the reactance signal was closely related to the welding current and it was also significantly influenced by some abnormal welding conditions. Some features were extracted from the reactance signal and combined to construct weld nugget strength and diameter prediction models based on the radial basis function (RBF) neural network. In addition, several features were also used to monitor the expulsion in the welding process by using Fisher linear discriminant analysis. The results indicated that using the dynamic reactance signal to evaluate weld quality is possible and feasible.

  3. Resistance Element Welding of Magnesium Alloy/austenitic Stainless Steel

    Science.gov (United States)

    Manladan, S. M.; Yusof, F.; Ramesh, S.; Zhang, Y.; Luo, Z.; Ling, Z.

    2017-09-01

    Multi-material design is increasingly applied in the automotive and aerospace industries to reduce weight, improve crash-worthiness, and reduce environmental pollution. In the present study, a novel variant of resistance spot welding technique, known as resistance element welding was used to join AZ31 Mg alloy to 316 L austenitic stainless steel. The microstructure and mechanical properties of the joints were evaluated. It was found that the nugget consisted of two zones, including a peripheral fusion zone on the stainless steel side and the main fusion zone. The tensile shear properties of the joints are superior to those obtained by traditional resistance spot welding.

  4. Automatic reel controls filler wire in welding machines

    Science.gov (United States)

    Millett, A. V.

    1966-01-01

    Automatic reel on automatic welding equipment takes up slack in the reel-fed filler wire when welding operation is terminated. The reel maintains constant, adjustable tension on the wire during the welding operation and rewinds the wire from the wire feed unit when the welding is completed.

  5. A Shape Optimization Study for Tool Design in Resistance Welding

    DEFF Research Database (Denmark)

    Bogomolny, Michael; Bendsøe, Martin P.; Hattel, Jesper Henri

    2009-01-01

    The purpose of this study is to apply shape optimization tools for design of resistance welding electrodes. The numerical simulation of the welding process has been performed by a simplified FEM model implemented in COMSOL. The design process is formulated as an optimization problem where...... the objective is to prolong the life-time of the electrodes. Welding parameters like current, time and electrode shape parameters are selected to be the design variables while constraints are chosen to ensure a high quality of the welding. Surrogate models based on a Kriging approximation has been used in order...

  6. Comparative estimation of the properties of heat resisting nickel alloy welded joints made by electron-beam and arc welding

    International Nuclear Information System (INIS)

    Morochko, V.P.; Sorokin, L.I.; Yakushin, B.F.; Moryakov, V.F.

    1977-01-01

    As compared to argon arc welding of refractory nickel alloys at 15 m/hour rate, electron beam welding decreases energy consumption per unit length (from 4300 to 2070 cal/cm), the weld area (from 108 to 24 mm 2 ), and the length of the thermal effect zone (from 0.9-1.8 to 0.4-0.8 mm). Electron beam welding also provides for better resistance to hot cracking in the weld metal and in the near-weld zone, as compared to automatic argon arc welding and manual welding with addition of the basic metal. However, this advantage is observed only at welding rates less than 45 m/hour. Electron beam welded joints of refractory nickel alloys with intermetallide reinforcement have higher strength, plasticity and impact strength, and lower scattering of these properties than arc welded joints

  7. Corrosion resistance of «tube – tubesheet» weld joint obtained by friction welding

    Directory of Open Access Journals (Sweden)

    RIZVANOV Rif Garifovich

    2017-08-01

    Full Text Available Shell-and-tube heat exchangers are widely applied for implementation of various processes at ventures of fuel and energy complex. Cost of production and reliability of heat exchangers of this type is to a wide extent determined by corresponding characteristics of tube bundle, «tube – tubesheet» is its typical joint in particular when welding operations are used in order to attach tubes to tubesheet in addition to expansion. When manufacturing such equipment of heat-resistant chrome-bearing or chromium-molybdenum steels including steel 15H5M, the process of fixed joint manufacturing gets significantly more complicated and costly due to the necessity to use thermal treatment before, during and after welding (this problem is particularly applicable for manufacturing of large-size equipment. One of the options to exclude thermal treatment from manufacturing process is to use «non-arc» welding methods – laser welding, explosion welding as well as friction welding. Use of each of the welding methods mentioned above during production of heat-exchange equipment has its process challenges and peculiarities. This article gives a comparative analysis of weld structure and distribution of electrode potentials of welded joints and parent metal of the joints simulating welding of tube to tubesheet of steel 15H5M using the following welding methods: shielded manual arc welding, tungsten-arc inert-gas welding and friction welding. Comparative analysis of macro- and microstructures of specific zones of the studied welded joints showed that the joints produced by arc welding methods do not exhibit evident inhomogeneity of the structure after application of thermal treatment which is explained by the correctness of thermal treatment. Joints obtained via friction welding are characterized by structural inhomogeneity of the welded joint zone metal microstructure. The ultra-fine-grained structure obtained as a result of friction welding makes it possible to

  8. Galvanic corrosion resistance of welded dissimilar nickel-base alloys

    International Nuclear Information System (INIS)

    Corbett, R.A.; Morrison, W.S.; Snyder, R.J.

    1986-01-01

    A program for evaluating the corrosion resistance of various dissimilar welded nickel-base alloy combinations is outlined. Alloy combinations included ALLCORR, Hastelloy C-276, Inconel 72 and Inconel 690. The GTAW welding process involved both high and minimum heat in-put conditions. Samples were evaluated in the as-welded condition, as well as after having been aged at various condtions of time and temperature. These were judged to be most representative of process upset conditions which might be expected. Corrosion testing evaluated resistance to an oxidizing acid and a severe service environment in which the alloy combinations might be used. Mechanical properties are also discussed

  9. Stainless steel welding method with excellent nitric acid corrosion resistance

    International Nuclear Information System (INIS)

    Matsushita, Yukinobu; Inazumi, Toru; Hyakubo, Tamako; Masamura, Katsumi.

    1996-01-01

    The present invention concerns a welding method for a stainless steel used in a circumstance being in contact with a highly oxidizing nitric acid solution such as nuclear fuel reprocessing facilities, upon welding 316 type austenite steel containing Mo while giving excellent nitric acid resistance. A method of TIG welding using a filler metal having a composition of C, Si, Mn, P, S, Ni, Cr, Mo and Cu somewhat different from a stainless steel mother material in which C, Si, Mn, P, S, Ni, Cr and Mo are specified comprises a step of TIG-welding the surface of the mother material and a step of TIG-welding the rear face of the mother material, in which the welding conditions for the rear face of the mother material are such that the distance between the surface of the outermost welding metal layer on the side of the surface of the mother material and the bottom of the groove is not less than 5mm, and an amount of welding heat is made constant. As a result, even if the method is used in a circumstance being in contact with a highly corrosive solution such as nitric acid, corrosion resistance is not degraded. (N.H.)

  10. Experimental Study of Tensile Test in Resistance Spot Welding Process

    Directory of Open Access Journals (Sweden)

    Lebbal Habib

    Full Text Available Abstract Resistance spot welding (RSW is a widely used joining process for fabricating sheet metal assemblies in automobile industry .In comparison with other welding processes the RSW is faster and easier for automation. This process involves electrical, thermal and mechanical interactions. Resistance spot welding primarily takes place by localized melting spot at the interface of the sheets followed by its quick solidification under sequential control of pressure water-cooled electrode and flow of required electric current for certain duration. In this work the tensile tests were studied, the results obtained show that the type material, the overlap length, the angle of the rolling direction and the thickness of the sheet have an influence in resistance spot welding process.

  11. Weld-brazing - a new joining process. [combination resistance spot welding and brazing of titanium alloys

    Science.gov (United States)

    Bales, T. T.; Royster, D. M.; Arnold, W. E., Jr.

    1972-01-01

    A joining process designated weld brazing which combines resistance spot welding and brazing has been developed. Resistance spot welding is used to position and align the parts as well as to establish a suitable faying surface gap for brazing. Fabrication is then completed by capillary flow of the braze alloy into the joint. The process has been used successfully to fabricate Ti-6Al-4V titanium alloy joints using 3003 aluminum braze alloy. Test results obtained on single overlap and hat-stiffened structural specimens show that weld brazed joints are superior in tensile shear, stress rupture, fatigue, and buckling than joint fabricated by spotwelding or brazing. Another attractive feature of the process is that the brazed joints is hermetically sealed by the braze material.

  12. On the issue of particularities of design and simulation of welded constructions of machine's basic parts

    OpenAIRE

    Mihaylov, V.; Porhynov, S.

    2010-01-01

    In current conditions of machine industry competitive strength of firms effectively to make the process equipment has an essential value. It predetermines the necessity of wide application of welded constructions of machine tools basic parts. The solution of this task involves development o technique permitting to calculate and optimize the basic parts of machine tools depending on conditions in each case. In the present paper the results of research of deflected mode of machine tool basic pa...

  13. Process Simulation of Resistance Weld Bonding and Automotive Light-weight Materials

    DEFF Research Database (Denmark)

    Zhang, Wenqi; Chergui, Azeddine; Nielsen, Chris Valentin

    of mechanical, electrical, thermal and metallurgical processes, which are essential for simulation of resistance welding process to predict the welding results and evaluate the weldability of materials. These functions have been further extended with new functions for optimization of welding process parameters...... and predicting welding process window, for weld planning with optimal welding parameter settings, and for modeling microstructures and hardness distribution after welding. Latest developments have been made on simulation of resistance welding with nonconductive materials for applications in weld bonding......This paper presents the latest developments in numerical simulation of resistance welding especially with the new functions for simulation of microstructures, weld bonding and spot welding of new light-weight materials. The fundamental functions in SORPAS® are built on coupled modeling...

  14. Design and Implementation of Software for Resistance Welding Process Simulations

    DEFF Research Database (Denmark)

    Zhang, Wenqi

    2003-01-01

    Based on long time engineering research and dedicated collaborations with industry, a new welding software, SORPAS, has been developed for simulation of resistance projection and spot welding processes applying the powerful finite element method (FEM). In order to make the software directly usabl...... equipment manufacturers...... by engineers and technicians in industry, all of the important parameters in resistance welding are considered and automatically implemented into the software. With the specially designed graphic user interface for Windows, engineers (even without prior knowledge of FEM) can quickly learn and easily operate...... and utilize the software. All industrial users, including welding engineers from DaimlerChrysler, Volkswangen, PSA Peugeot Citroen, VOLVO, Siemens, ABB and so on, have started using the software just after taking a one-day training course. With the user-friendly facilities for flexible geometric design...

  15. Testing and Modeling of Contact Problems in Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    together two or three cylindrical parts as well as disc-ring pairs of dissimilar metals. The tests have demonstrated the effectiveness of the model. A theoretical and experimental study is performed on the contact resistance aiming at a more reliable model for numerical simulation of resistance welding......As a part of the efforts towards a professional and reliable numerical tool for resistance welding engineers, this Ph.D. project is dedicated to refining the numerical models related to the interface behavior. An FE algorithm for the contact problems in resistance welding has been developed...... for the formulation, and the interfaces are treated in a symmetric pattern. The frictional sliding contact is also solved employing the constant friction model. The algorithm is incorporated into the finite element code. Verification is carried out in some numerical tests as well as experiments such as upsetting...

  16. Determination of Ductile Tearing Resistance Curve in Weld Joints

    International Nuclear Information System (INIS)

    Marie, S.; Gilles, P.; Ould, P.

    2010-01-01

    Steels present in the ductile domain a tearing resistance which increase with the crack propagation up to the failure. This ductile tearing resistance is in general characterised with curves giving the variation of a global parameter (opening displacement at the crack tip delta, integral J) versus the crack extension Delta a. These global approaches depend more or less on the specimen geometry and on the type of the imposed loading. Local approaches based on the description of the ductile tearing mechanisms provide reliable solution to the transferability problem (from the lab specimen to the component) but are complex and costly to use and are not codified. These problems get worse in the case of a weld joint where no standard is available for the measurement of their ductile tearing resistance. But the welded joints are often the weak point of the structure because of greater risk of defects, the heterogeneity of the microstructure of the weld, deformation along the interface between two materials with different yield stress (mismatch).... After briefly recalling the problems of transferability of the ductile tearing resistance curves obtained on lab specimen to the case of components, this article identifies the factors complicating the determination of the toughness in the welded joints and gives recommendations for the experimental determination of ductile tearing resistance curves of welded joints

  17. Effectiveness of Podcasts as Laboratory Instructional Support: Learner Perceptions of Machine Shop and Welding Students

    Science.gov (United States)

    Lauritzen, Louis Dee

    2014-01-01

    Machine shop students face the daunting task of learning the operation of complex three-dimensional machine tools, and welding students must develop specific motor skills in addition to understanding the complexity of material types and characteristics. The use of consumer technology by the Millennial generation of vocational students, the…

  18. Resistance Spot Welding of Steel Sheets of the Same and Different Thickness

    Directory of Open Access Journals (Sweden)

    Milan Brožek

    2017-01-01

    Full Text Available Resistance welding ranks among progressive and in practice often used manufacturing techniques of rigid joints. It is applied in single‑part production, short‑run production as well as in mass production. The basis of this method is in the utilization of the Joulean heat, which arises at the passage of current through connected sheets at collective influence of compressive force. The aim of the carried out tests was the determination of the dependence between the rupture force of spot welds made using steel sheets of the same and different thickness for different welding conditions. For carrying out of this aim 360 assemblies were prepared. The sheets (a total of 720 pieces of dimensions 100 × 25 mm and thickness of 0.8 mm, 1.5 mm and 3.0 mm were made from low carbon steel. In the place determined for welding the test specimens were garnet blasted and then degreased with acetone. The welding of two specimens always of the same (0.8+0.8 mm, 1.5+1.5 mm a 3.0+3.0 mm and different (0.8 + 1.5 mm, 0.8+3.0 mm a 1.5+3.0 mm thickness was carried out using the welding machine type BV 2,5.21. At this type the welding current value is constant (Imax = 6.4 kA. The welding time (the time of the passage of the current was changed in the whole entirety, namely 0.10 s, 0.15 s, 0.20 s, 0.25 s, 0.3 s, 0.4 s, 0.6 s, 0.8 s, 1.0 s, 1.3 s, 1.6 s and 2.0 s. The compressive force was chosen according to the thickness of the connected sheets in the range from 0.8 to 2.4 kN. From the results of carried out tests it follows that using the working variables recommended by the producer we obtain the quality welds. But it we use the longer welding times, we can obtain stronger welds, namely up to 21 % compared to welds made using working variables recommended by the producer.

  19. Pressure Resistance Welding of High Temperature Metallic Materials

    International Nuclear Information System (INIS)

    Jerred, N.; Zirker, L.; Charit, I.; Cole, J.; Frary, M.; Butt, D.; Meyer, M.; Murty, K.L.

    2010-01-01

    Pressure Resistance Welding (PRW) is a solid state joining process used for various high temperature metallic materials (Oxide dispersion strengthened alloys of MA957, MA754; martensitic alloy HT-9, tungsten etc.) for advanced nuclear reactor applications. A new PRW machine has been installed at the Center for Advanced Energy Studies (CAES) in Idaho Falls for conducting joining research for nuclear applications. The key emphasis has been on understanding processing-microstructure-property relationships. Initial studies have shown that sound joints can be made between dissimilar materials such as MA957 alloy cladding tubes and HT-9 end plugs, and MA754 and HT-9 coupons. Limited burst testing of MA957/HT-9 joints carried out at various pressures up to 400 C has shown encouraging results in that the joint regions do not develop any cracking. Similar joint strength observations have also been made by performing simple bend tests. Detailed microstructural studies using SEM/EBSD tools and fatigue crack growth studies of MA754/HT-9 joints are ongoing.

  20. Argon-arc welding of heat resisting aluminium alloys

    International Nuclear Information System (INIS)

    Ryazantsev, V.I.; Fedoseev, V.A.

    1997-01-01

    Welding of aluminium heat resisting alloys of the Al-Cu-Mg system is studied. The hot-shortness of heat-resistant alloys M40, 1150 and 1151 are at the level of aluminium alloys 1201 and by 2-3 times lower as compared to the aluminium alloy AMg6. The M40, 1150 and 1151 alloys have unquestionable advantages against other know aluminium alloys only at temperatures of welded structures operation, beginning with 150-2000 deg C and especially at 250 deg C

  1. Prediction of residual stress distributions due to surface machining and welding and crack growth simulation under residual stress distribution

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Katsuyama, JInya; Onizawa, Kunio; Hashimoto, Tadafumi; Mikami, Yoshiki; Mochizuki, Masahito

    2011-01-01

    Research highlights: → Residual stress distributions due to welding and machining are evaluated by XRD and FEM. → Residual stress due to machining shows higher tensile stress than welding near the surface. → Crack growth analysis is performed using calculated residual stress. → Crack growth result is affected machining rather than welding. → Machining is an important factor for crack growth. - Abstract: In nuclear power plants, stress corrosion cracking (SCC) has been observed near the weld zone of the core shroud and primary loop recirculation (PLR) pipes made of low-carbon austenitic stainless steel Type 316L. The joining process of pipes usually includes surface machining and welding. Both processes induce residual stresses, and residual stresses are thus important factors in the occurrence and propagation of SCC. In this study, the finite element method (FEM) was used to estimate residual stress distributions generated by butt welding and surface machining. The thermoelastic-plastic analysis was performed for the welding simulation, and the thermo-mechanical coupled analysis based on the Johnson-Cook material model was performed for the surface machining simulation. In addition, a crack growth analysis based on the stress intensity factor (SIF) calculation was performed using the calculated residual stress distributions that are generated by welding and surface machining. The surface machining analysis showed that tensile residual stress due to surface machining only exists approximately 0.2 mm from the machined surface, and the surface residual stress increases with cutting speed. The crack growth analysis showed that the crack depth is affected by both surface machining and welding, and the crack length is more affected by surface machining than by welding.

  2. Analysis on Development of Transverse - Sectioned Weld Zone using FEM Verified with Multipulsed Resistance Seam Welding

    Directory of Open Access Journals (Sweden)

    N Muhammad

    2013-12-01

    Full Text Available This paper details an investigation, through an experimental study, of the development of weld nuggets and a heat-affected zone (HAZ in resistance seam welding(RSEW using a numerical simulation approach. SYSWELD software for the simulation of heat treatment, welding, and welding assembly was utilized for the simulation process. The integrated Spot Weld Advisor (SWA in SYSWELD was applied to simulate the RSEW model using a two-dimensional axis-symmetric FE model with customized electrode meshing. The thermal-mechanical-electrical characteristic and contact condition were taken into account throughout this study. The developed model comprised a transverse cross section for welding two layers of low carbon steel with a thickness of 1 mm. For the experimental verification, three-pulsed RSEW with two different current stages was carried out. It was discovered that this program code, Spotweld Advisor, when used with the meshing method, was capable of offering results that were in agreement with physical experiments.

  3. Effect of technological procedures on the crack resistance of nickel alloy welded joints under heat treatment

    International Nuclear Information System (INIS)

    Bagdasarov, Yu.S.; Sorokin, L.I.; Yakushin, B.F.; Moryashchev, S.F.

    1983-01-01

    Comparison of the efficiency of some technological procedures directed to the increase of crack resistance of KhN50MBKTYUR (EhP99) alloy welded joints under heat treatment was conducted. Welded joints were manufactured by the methods of electron beam welding, laser welding, automatic argon-arc welding. The latter was conducted by conventional technology as well as with electromagnetic mixing of liquid metal of welding bath, with compulsory cooling of weld matal, with pulse arc. It is shown that the high fracture resistance of welded joints, manufactured by electron beam and laser welding is achieved by combination of high mechanical properties of heat affected zone metal and reduced elastic potential energy margin of residual welding stresses (as compared to argon-arc welding)

  4. Optimizing friction stir weld parameters of aluminum and copper using conventional milling machine

    Science.gov (United States)

    Manisegaran, Lohappriya V.; Ahmad, Nurainaa Ayuni; Nazri, Nurnadhirah; Noor, Amirul Syafiq Mohd; Ramachandran, Vignesh; Ismail, Muhammad Tarmizizulfika; Ahmad, Ku Zarina Ku; Daruis, Dian Darina Indah

    2018-05-01

    The joining of two of any particular materials through friction stir welding (FSW) are done by a rotating tool and the work piece material that generates heat which causes the region near the FSW tool to soften. This in return will mechanically intermix the work pieces. The first objective of this study is to join aluminum plates and copper plates by means of friction stir welding process using self-fabricated tools and conventional milling machine. This study also aims to investigate the optimum process parameters to produce the optimum mechanical properties of the welding joints for Aluminum plates and Copper plates. A suitable tool bit and a fixture is to be fabricated for the welding process. A conventional milling machine will be used to weld the aluminum and copper. The most important parameters to enable the process are speed and pressure of the tool (or tool design and alignment of the tool onto the work piece). The study showed that the best surface finish was produced from speed of 1150 rpm and tool bit tilted to 3°. For a 200mm × 100mm Aluminum 6061 with plate thickness of 2 mm at a speed of 1 mm/s, the time taken to complete the welding is only 200 seconds or equivalent to 3 minutes and 20 seconds. The Copper plates was successfully welded using FSW with tool rotation speed of 500 rpm, 700 rpm, 900 rpm, 1150 rpm and 1440 rpm and with welding traverse rate of 30 mm/min, 60 mm/min and 90 mm/min. As the conclusion, FSW using milling machine can be done on both Aluminum and Copper plates, however the weld parameters are different for the two types of plates.

  5. 3D Modeling and Testing of Contact Problems in Resistance Welding

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin

    A generic, electro-thermo-mechanically coupled finite element program is developed for three-dimensional simulation of resistance welding. The developed computer program has reached a level of a complete standalone software that can be utilized as a tool in the analysis of resistance welding...... of resistance welding processes, which cover a wide range of spot welding and projection welding applications. Three-dimensional simulation of spot welding enables the analysis of critical effects like electrode misalignment and shunt effects between consecutive spots. A single-sided spot welding case involving...... three-dimensional contact is also presented. This case was suggested by and discussed with a German steel manufacturer. When it comes to projection welding, a natural need for three-dimensional analysis arises in many cases because of the involved geometries. Cross-wire welding and welding of square...

  6. Corrosion Resistant Cladding by YAG Laser Welding in Underwater Environment

    International Nuclear Information System (INIS)

    Tsutomi Kochi; Toshio Kojima; Suemi Hirata; Ichiro Morita; Katsura Ohwaki

    2002-01-01

    It is known that stress-corrosion cracking (SCC) will occur in nickel-base alloys used in Reactor Pressure Vessel (RPV) and Internals of nuclear power plants. A SCC sensitivity has been evaluated by IHI in each part of RPV and Internals. There are several water level instrumentation nozzles installed in domestic BWR RPV. In water level instrumentation nozzles, 182 type nickel-base alloys were used for the welding joint to RPV. It is estimated the SCC potential is high in this joint because of a higher residual stress than the yield strength (about 400 MPa). This report will describe a preventive maintenance method to these nozzles Heat Affected Zone (HAZ) and welds by a corrosion resistant cladding (CRC) by YAG Laser in underwater environment (without draining a reactor water). There are many kinds of countermeasures for SCC, for example, Induction Heating Stress Improvement (IHSI), Mechanical Stress Improvement Process (MSIP) and so on. A YAG laser CRC is one of them. In this technology a laser beam is used for heat source and irradiated through an optical fiber to a base metal and SCC resistant material is used for welding wires. After cladding the HAZ and welds are coated by the corrosion resistant materials so their surfaces are improved. A CRC by gas tungsten arc welding (GTAW) in an air environment had been developed and already applied to a couple of operating plants (16 Nozzles). This method was of course good but it spent much time to perform because of an installation of some water-proof working boxes to make a TIG-weldability environment. CRC by YAG laser welding in underwater environment has superior features comparing to this conventional TIG method as follows. At the viewpoint of underwater environment, (1) an outage term reduction (no drainage water). (2) a radioactive exposure dose reduction for personnel. At that of YAG laser welding, (1) A narrower HAZ. (2) A smaller distortion. (3) A few cladding layers. A YAG laser CRC test in underwater

  7. Effect of welding processes on the impression creep resistance of type 316 LN stainless steel weld joints

    International Nuclear Information System (INIS)

    Vasudevan, M.; Vasantharaja, P.; Sisira, P.; Divya, K.; Ganesh Sundara Raman, S.

    2016-01-01

    Type 316 LN stainless steel is the major structural material used in the construction of fast breeder reactors. Activated Tungsten Inert Gas (A-TIG) welding , a variant of the TIG welding process has been found to enhance the depth of penetration significantly during autogenous welding and also found to enhance the creep rupture life in stainless steels. The present study aims at comparing the effect of TIG and A-TIG welding processes on the impression creep resistance of type 316 LN stainless steel base metal, fusion zone and heat affected zone (HAZ) of weld joints. Optical and TEM have been used to correlate the microstructures with the observed creep rates of various zones of the weld joints. Finer microstructure and higher ferrite content was observed in the TIG weld joint fusion zone. Coarser grain structure was observed in the HAZ of the weld joints. Impression creep rate of A-TIG weld joint fusion zone was almost equal to that of the base metal and lower than that of the TIG weld joint fusion zone. A-TIG weld joint HAZ was found to have lower creep rate compared to that of conventional TIG weld joint HAZ due to higher grain size. HAZ of the both the weld joints exhibited lower creep rate than the base metal. (author)

  8. Resistance spot welding of a complicated joint in new advanced high strength steel

    NARCIS (Netherlands)

    Joop Pauwelussen; Nick den Uijl

    2015-01-01

    The goal of this article is to investigate resistance spot welding of a complicated welding configuration of three sheets of dissimilar steel sheet materials with shunt welds, using simulations. The configuration used resembles a case study of actual welds in automotive applications. One of the

  9. Remote machining and robotic welding in a proton cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, W; Mark, C

    1984-09-01

    Increasing residual radiation in the TRIUMF meson research facility cyclotron at the University of British Columbia has required development of a remotely operable industrial robot cutting and vacuum tight welding capabili

  10. Use of servo controlled weld head for end closure welding

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, S.K.; Setty, D.S.; Rameswara Rao, A.; Hemantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

    2010-07-01

    In the PHWR fuel fabrication line resistance welding processes are used for joining various zirconium based alloy components to fuel tube of similar material. The quality requirement of these welding processes is very stringent and has to meet all the product requirements. At present these welding processes are being carried out by using standard resistance welding machines. In the resistance welding process in addition to current and time, force is one of the critical and important parameter, which influences the weld quality. At present advanced feed back type fast response medium frequency weld controllers are being used. This has upslope/down slope, constant and repetitive weld pattern selection features makes this critical welding process more reliable. Compared to weld controllers, squeeze force application devices are limited and normally standard high response pneumatic cylinders are used in the welding process. With this type of devices the force is constant during welding process and cannot be varied during welding process as per the material deformation characteristics. Similarly due to non-availability of feed back systems in the squeeze force application systems restricts the accuracy and quality of the welding process. In the present paper the influence of squeeze force pattern on the weld quality using advanced feed back type servo based force control system was studied. Different squeeze forces were used during pre and post weld heat periods along with constant force and compared with the weld quality. (author)

  11. A reliability-based preventive maintenance methodology for the projection spot welding machine

    Directory of Open Access Journals (Sweden)

    Fayzimatov Ulugbek

    2018-06-01

    Full Text Available An effective operations of a projection spot welding (PSW machine is closely related to the effec-tiveness of the maintenance. Timely maintenance can prevent failures and improve reliability and maintainability of the machine. Therefore, establishing the maintenance frequency for the welding machine is one of the most important tasks for plant engineers. In this regard, reliability analysis of the welding machine can be used to establish preventive maintenance intervals (PMI and to identify the critical parts of the system. In this reliability and maintainability study, analysis of the PSW machine was carried out. The failure and repair data for analysis were obtained from automobile manufacturing company located in Uzbekistan. The machine was divided into three main sub-systems: electrical, pneumatic and hydraulic. Different distributions functions for all sub-systems was tested and their parameters tabulated. Based on estimated parameters of the analyzed distribu-tions, PMI for the PSW machines sub-systems at different reliability levels was calculated. Finally, preventive measures for enhancing the reliability of the PSW machine sub-systems are suggested.

  12. Study of electric arc welding of castings for nuclear power machine-building

    International Nuclear Information System (INIS)

    Rymkevich, A.I.; Korsunov, P.M.

    1977-01-01

    Mechanical and corrosion-resistance properties are studied of the welded joints of cast billets from steel 00Kh12N3DL by automatic submerged arc welding. It is shown by testing the joints made with preheating up to 100 deg C and subsequent tempering (620 deg C for 25 h + 640 deg C for 16 h) that in the temperature range of 20-350 deg C they possess fairly good strength, ductility, impact viscosity, and corrosion-resistance properties approximating the corresponding characteristics of the base metal. The welding technology developed can be used to make pump casings for atomic power equipment

  13. Matrix phased array (MPA) imaging technology for resistance spot welds

    Science.gov (United States)

    Na, Jeong K.; Gleeson, Sean T.

    2014-02-01

    A three-dimensional MPA probe has been incorporated with a high speed phased array electronic board to visualize nugget images of resistance spot welds. The primary application area of this battery operated portable MPA ultrasonic imaging system is in the automotive industry which a conventional destructive testing process is commonly adopted to check the quality of resistance spot welds in auto bodies. Considering an average of five-thousand spot welds in a medium size passenger vehicle, the amount of time and effort given to popping the welds and measuring nugget size are immeasurable in addition to the millions of dollars' worth of scrap metals recycled per plant per year. This wasteful labor intensive destructive testing process has become less reliable as auto body sheet metal has transitioned from thick and heavy mild steels to thin and light high strength steels. Consequently, the necessity of developing a non-destructive inspection methodology has become inevitable. In this paper, the fundamental aspects of the current 3-D probe design, data acquisition algorithms, and weld nugget imaging process are discussed.

  14. Matrix phased array (MPA) imaging technology for resistance spot welds

    International Nuclear Information System (INIS)

    Na, Jeong K.; Gleeson, Sean T.

    2014-01-01

    A three-dimensional MPA probe has been incorporated with a high speed phased array electronic board to visualize nugget images of resistance spot welds. The primary application area of this battery operated portable MPA ultrasonic imaging system is in the automotive industry which a conventional destructive testing process is commonly adopted to check the quality of resistance spot welds in auto bodies. Considering an average of five-thousand spot welds in a medium size passenger vehicle, the amount of time and effort given to popping the welds and measuring nugget size are immeasurable in addition to the millions of dollars' worth of scrap metals recycled per plant per year. This wasteful labor intensive destructive testing process has become less reliable as auto body sheet metal has transitioned from thick and heavy mild steels to thin and light high strength steels. Consequently, the necessity of developing a non-destructive inspection methodology has become inevitable. In this paper, the fundamental aspects of the current 3-D probe design, data acquisition algorithms, and weld nugget imaging process are discussed

  15. Matrix phased array (MPA) imaging technology for resistance spot welds

    Energy Technology Data Exchange (ETDEWEB)

    Na, Jeong K.; Gleeson, Sean T. [Edison Welding Institute, 1250 Arthur E. Adams Drive, Columbus, OH 43221 (United States)

    2014-02-18

    A three-dimensional MPA probe has been incorporated with a high speed phased array electronic board to visualize nugget images of resistance spot welds. The primary application area of this battery operated portable MPA ultrasonic imaging system is in the automotive industry which a conventional destructive testing process is commonly adopted to check the quality of resistance spot welds in auto bodies. Considering an average of five-thousand spot welds in a medium size passenger vehicle, the amount of time and effort given to popping the welds and measuring nugget size are immeasurable in addition to the millions of dollars' worth of scrap metals recycled per plant per year. This wasteful labor intensive destructive testing process has become less reliable as auto body sheet metal has transitioned from thick and heavy mild steels to thin and light high strength steels. Consequently, the necessity of developing a non-destructive inspection methodology has become inevitable. In this paper, the fundamental aspects of the current 3-D probe design, data acquisition algorithms, and weld nugget imaging process are discussed.

  16. Corrosion resistance of ERW (Electric Resistance Welded) seam welds as compared to metal base in API 5L steel pipes

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Velasquez, Jorge L.; Godinez Salcedo, Jesus G.; Lopez Fajardo, Pedro [Instituto Politecnico Nacional (IPN), Mexico D.F. (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE). Dept. de Ingenieria Metalurgica

    2009-07-01

    The corrosion resistance of ERW seam welds and the base metal in API 5L X70 steel pipes was evaluated by Tafel tests. The procedure was according to ASTM G3 standard. The study was completed with metallographic and chemical characterization of the tested zones, that is, the welded zone and the base metal away of the weld. All tests were made on the internal surface of the pipe in order to assess the internal corrosion of an in-service pipeline made of the API 5L X70 steel. The test solution was acid brine prepared according to NACE Publications 1D182 and 1D196. The results showed that the ERW seam weld corrodes as much as three times faster than the base material. This behavior is attributed to a more heterogeneous microstructure with higher internal energy in the ERW seam weld zone, as compared to the base metal, which is basically a ferrite pearlite microstructure in a normalized condition. This result also indicates that pipeline segments made of ERW steel pipe where the seam weld is located near or at the bottom of the pipe are prone to a highly localized attack that may form channels of metal loss if there is water accumulation at the bottom of the pipeline. (author)

  17. Contact Modelling in Resistance Welding, Part II: Experimental Validation

    DEFF Research Database (Denmark)

    Song, Quanfeng; Zhang, Wenqi; Bay, Niels

    2006-01-01

    Contact algorithms in resistance welding presented in the previous paper are experimentally validated in the present paper. In order to verify the mechanical contact algorithm, two types of experiments, i.e. sandwich upsetting of circular, cylindrical specimens and compression tests of discs...... with a solid ring projection towards a flat ring, are carried out at room temperature. The complete algorithm, involving not only the mechanical model but also the thermal and electrical models, is validated by projection welding experiments. The experimental results are in satisfactory agreement...

  18. Effect of processing conditions on residual stress distributions by bead-on-plate welding after surface machining

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Mochizuki, Masahito

    2014-01-01

    Residual stress is important factor for stress corrosion cracking (SCC) that has been observed near the welded zone in nuclear power plants. Especially, surface residual stress is significant for SCC initiation. In the joining processes of pipes, butt welding is conducted after surface machining. Residual stress is generated by both processes, and residual stress distribution due to surface machining is varied by the subsequent butt welding. In previous paper, authors reported that residual stress distribution generated by bead on plate welding after surface machining has a local maximum residual stress near the weld metal. The local maximum residual stress shows approximately 900 MPa that exceeds the stress threshold for SCC initiation. Therefore, for the safety improvement of nuclear power plants, a study on the local maximum residual stress is important. In this study, the effect of surface machining and welding conditions on residual stress distribution generated by welding after surface machining was investigated. Surface machining using lathe machine and bead on plate welding with tungsten inert gas (TIG) arc under various conditions were conducted for plate specimens made of SUS316L. Then, residual stress distributions were measured by X-ray diffraction method (XRD). As a result, residual stress distributions have the local maximum residual stress near the weld metal in all specimens. The values of the local maximum residual stresses are almost the same. The location of the local maximum residual stress is varied by welding condition. It could be consider that the local maximum residual stress is generated by same generation mechanism as welding residual stress in surface machined layer that has high yield stress. (author)

  19. Research on TIG weld machine of the upper side ring slot of Gd-rod technology reconstruct

    International Nuclear Information System (INIS)

    Fang Shixiang; Lan Zhibing; Cui Quhu

    2010-01-01

    The research on TIG weld machine of the upper side ring slot of Gd-rod existent matter: seal electrical source got up difficulty; control system had graveness aging; space between was adjusted precision lowness; welding torch lay mode and structure were not in reason. carried through all around technology reconstruct: had chosen the best of TIG weld machine; designed ignite arc device, designed optics imaging device, designed tungsten mighty axis direction auto conditioning, was provided with arc slot, adopted PLC to control the whole system and realization auto control. After TIG weld machine of the upper side ring slot of Gd-rod technology reconstruct research , provided with arc slot the first time in the Gd-rod of nuclear fuel, optimized the weld technics, improved welding line melt width and deep equality, stability, and great breadth advanced nuclear fuel product line technology and throughput. (authors)

  20. Effects of solidified microstructures on J-R fracture resistances of the surge line pipe welds

    International Nuclear Information System (INIS)

    Youn, J. H.; Lee, B. S.; Yoo, W.

    2003-01-01

    The cause of the difference in J-R fracture resistances of AISI Type 347 GTAW welds which had almost same amounts of chromium carbides were investigated by the microstructural observations. As a result, the difference in the fracture resistances with the morphologies of the retained δ-ferrites in Type 347 welds were observed. The fracture resistance of the weld which had mostly vermicular type δ-ferrites was inferior to the weld which has lacy and acicular mixed type δ-ferrites. Therefore, it was deduced that the morphology of δ-ferrites affected the J-R fracture resistances of Type 347 welds

  1. Remote machining and robotic welding in a proton cyclotron

    International Nuclear Information System (INIS)

    Cameron, W.; Mark, C.

    1984-01-01

    Increasing residual radiation in the TRIUMF meson research facility cyclotron at the University of British Columbia has required development of a remotely operable industrial robot cutting and vacuum tight welding capability for modification and updating of vacuum tank access ports, and for possible repairs of leaks or holes in the vacuum tank periphery

  2. Three-dimensional micro assembly of a hinged nickel micro device by magnetic lifting and micro resistance welding

    International Nuclear Information System (INIS)

    Chang, Chun-Wei; Hsu, Wensyang

    2009-01-01

    The three-dimensional micro assembly of hinged nickel micro devices by magnetic lifting and micro resistance welding is proposed here. By an electroplating-based surface machining process, the released nickel structure with the hinge mechanism can be fabricated. Lifting of the released micro structure to different tilted angles is accomplished by controlling the positions of a magnet beneath the device. An in situ electro-thermal actuator is used here to provide the pressing force in micro resistance welding for immobilizing the tilted structure. The proposed technique is shown to immobilize micro devices at controlled angles ranging from 14° to 90° with respect to the substrate. Design parameters such as the electro-thermal actuator and welding beam width are also investigated. It is found that there is a trade-off in beam width design between large contact pressure and low thermal deformation. Different dominated effects from resistivity enhancement and contact area enlargement during the welding process are also observed in the dynamic resistance curves. Finally, a lifted and immobilized electro-thermal bent-beam actuator is shown to displace upward about 27.7 µm with 0.56 W power input to demonstrate the capability of electrical transmission at welded joints by the proposed 3D micro assembly technique

  3. Fracture resistance of welded panel specimen with perpendicular crack in tensile

    International Nuclear Information System (INIS)

    Gochev, Todor; Adziev, Todor

    1998-01-01

    Defects caused by natural crack in welded joints of high-strength low-alloy (HSLA) steels are very often. Perpendicular crack in welded joints and its heat treatment after the welding has also an influence on the fracture resistance. The fracture resistance of welded joints by crack in tense panel specimens was investigated by crack mouse opening displesment (CMOD), the parameter of fracture mechanic. Crack propagation was analysed by using a metallographic analysis of fractured specimens after the test. (Author)

  4. Characteristics of Resistance Spot Welded Ti6Al4V Titanium Alloy Sheets

    Directory of Open Access Journals (Sweden)

    Xinge Zhang

    2017-10-01

    Full Text Available Ti6Al4V titanium alloy is applied extensively in the aviation, aerospace, jet engine, and marine industries owing to its strength-to-weight ratio, excellent high-temperature properties and corrosion resistance. In order to extend the application range, investigations on welding characteristics of Ti6Al4V alloy using more welding methods are required. In the present study, Ti6Al4V alloy sheets were joined using resistance spot welding, and the weld nugget formation, mechanical properties (including tensile strength and hardness, and microstructure features of the resistance spot-welded joints were analyzed and evaluated. The visible indentations on the weld nugget surfaces caused by the electrode force and the surface expulsion were severe due to the high welding current. The weld nugget width at the sheets’ faying surface was mainly affected by the welding current and welding time, and the welded joint height at weld nugget center was chiefly associated with electrode force. The maximum tensile load of welded joint was up to 14.3 kN in the pullout failure mode. The hardness of the weld nugget was the highest because of the coarse acicular α′ structure, and the hardness of the heat-affected zone increased in comparison to the base metal due to the transformation of the β phase to some fine acicular α′ phase.

  5. Design of parallel intersector weld/cut robot for machining processes in ITER vacuum vessel

    International Nuclear Information System (INIS)

    Wu Huapeng; Handroos, Heikki; Kovanen, Janne; Rouvinen, Asko; Hannukainen, Petri; Saira, Tanja; Jones, Lawrence

    2003-01-01

    This paper presents a new parallel robot Penta-WH, which has five degrees of freedom driven by hydraulic cylinders. The manipulator has a large, singularity-free workspace and high stiffness and it acts as a transport device for welding, machining and inspection end-effectors inside the ITER vacuum vessel. The presented kinematic structure of a parallel robot is particularly suitable for the ITER environment. Analysis of the machining process for ITER, such as the machining methods and forces are given, and the kinematic analyses, such as workspace and force capacity are discussed

  6. Weld Growth Mechanisms and Failure Behavior of Three-Sheet Resistance Spot Welds Made of 5052 Aluminum Alloy

    Science.gov (United States)

    Li, Yang; Yan, Fuyu; Luo, Zhen; Chao, Y. J.; Ao, Sansan; Cui, Xuetuan

    2015-06-01

    This paper investigates the weld nugget formation in three-sheet aluminum alloy resistance spot welding. The nugget formation process in three equal thickness sheets and three unequal thickness sheets of 5052 aluminum alloy were studied. The results showed that the nugget was initially formed at the workpiece/workpiece interfaces (i.e., both upper interface and lower interface). The two small nuggets then grew along the radial direction and axial direction (welding direction) as the welding time increased. Eventually, the two nuggets fused into one large nugget. During the welding process, the Peltier effect between the Cu-Al caused the shift of the nugget in the welding direction. In addition, the mechanical strength and fracture mode of the weld nuggets at the upper and lower interfaces were also studied using tensile shear specimen configuration. Three failure modes were identified, namely interfacial, mixed, and pullout. The critical welding time and critical nugget diameter corresponding to the transitions of these modes were investigated. Finally, an empirical failure load formula for three-sheet weld similar to two-sheet spot weld was developed.

  7. A study of dynamic resistance during small scale resistance spot welding of thin Ni sheets

    International Nuclear Information System (INIS)

    Tan, W; Zhou, Y; Kerr, H W; Lawson, S

    2004-01-01

    The dynamic resistance has been investigated during small scale resistance spot welding (SSRSW) of Ni sheets. Electrical measurements have been correlated with scanning electron microscope images of joint development. The results show that the dynamic resistance curve can be divided into the following stages based on physical change in the workpieces: asperity heating, surface breakdown, asperity softening, partial surface melting, nugget growth and expulsion. These results are also compared and contrasted with dynamic resistance behaviour in large scale RSW

  8. Magnetic property effect on transport processes in resistance spot welding

    Energy Technology Data Exchange (ETDEWEB)

    Wei, P S [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan 80424 (China); Wu, T H, E-mail: pswei@mail.nsysu.edu.tw, E-mail: wux0064@gmail.com [Department of Mechanical Engineering, Yung Ta Institute of Technology and Commerce, Pintong, Taiwan 909 (China)

    2011-08-17

    This study investigates the effects of the Curie temperature and magnetic permeability on transport variables, solute distribution and nugget shapes during resistance spot welding. The Curie temperature is the temperature below which a metal or alloy is ferromagnetic with a high magnetic permeability, and above which it is paramagnetic with a small magnetic permeability. The model proposed here accounts for electromagnetic force, heat generation and contact resistance at the faying surface and electrode-workpiece interfaces and bulk resistance in workpieces. Contact resistance includes constriction and film resistances, which are functions of hardness, temperature, electrode force and surface condition. The computed results show that transport variables and nugget shapes can be consistently interpreted from the delay of response time and jump of electric current density as a result of finite magnetic diffusion, rather than through the examination of the variations of dynamic electrical resistance with time. The molten nugget on the faying surface is initiated earlier with increasing magnetic permeability and Curie temperature. A high Curie temperature enhances convection and solute mixing, and readily melts through the workpiece surface near the electrode edge. Any means to reduce the Curie temperature or magnetic permeability, such as adjusting the solute content, can be a good way to control weld quality. This study can also be applied to interpret the contact problems encountered in various electronics and packaging technologies, and so on.

  9. Research of the Resistance of Contact Welding Joint of R65 Type Rail

    Directory of Open Access Journals (Sweden)

    Kęstutis Dauskurdis

    2015-03-01

    Full Text Available In the article the R65 type rail joints that were welded by resistance welding are analysed. Survey methodology of the research consists of the following parts: visual inspection of welded joint, ultrasonic rail inspection, hardness test of upper part of the rail, fusion area research, the measurement hardness test of heat-softened area, the measurement microhardness test, microstructure research of the welded joint, impact strength experiments, chemical analysis of welded joint, wheel-rail interaction research using the finite element method (FEM. The results of the research are analysed and the quality of weld is evaluated. The conclusion is based on the results of this research.

  10. Distribution of temperature and deformations during resistance butt welding of uranium rods with titanium

    International Nuclear Information System (INIS)

    Tatarinov, V.R.; Krasnorutskij, V.S.

    1977-01-01

    Results are described on studying time-temperature and deformation parameters for resistance welding of uranium rods with titanium. It is shown that in the first period of welding (approximately 2/3 tsub(wel.)) the maxima of weld temperature and weld deformation deviate to titanium, and in the final period uranium deformation reaches the level of maximum lateral deformation of titanium. For faying surfaces with minimum weld deformation the joint cleaning of contaminants and oxides is insufficient, which results in lower weld quality

  11. Fundamental studies on electron beam welding on heat resistant superalloys for nuclear plants, 6

    International Nuclear Information System (INIS)

    Susei, Syuzo; Shimizu, Sigeki; Nagai, Hiroyoshi; Aota, Toshikazu; Satoh, Keisuke

    1980-01-01

    In this report, base metal of superalloys for nuclear plants, its electron beam and TIG weld joints were compared with each other in the mechanical properties. Obtained conclusions are summarized as follows: 1) TIG weld joint is superior to electron beam weld joint and base metal in 0.2% proof stress irrespective of the material, and electron beam weld joint is also superior to base metal. There is an appreciable difference in tensile stress between base metal and weld joint regardless of the materials. Meanwhile, electron beam weld joint is superior to TIG weld joint in both elongation and reduction of area. 2) Electron beam weld joint has considerably higher low-cycle fatigue properties at elevated temperatures than TIG weld joint, and it is usually as high as base metal. 3) In the secondary creep rate, base metal of Hastelloy X (HAEM) has higher one than its weld joints. However, electron beam weld joint is nearly comparable to the base metal. 4) There is hardly any appreciable difference between base metal and weld joint in the creep rupture strength without distinction of the material. In the ductility, base metal is much superior and is followed by electron beam weld joint and TIG weld joint in the order of high ductility. However, electron beam weld joint is rather comparable to base metal. 5) In consideration of welded pipe with a circumferential joint, the weld joint should be evaluated in terms of secondary creep rate, elongation and rupture strength. As the weld joint of high creep rupture strength approaches the base metal in the secondary creep rate and the elongation, it seems to be more resistant against the fracture due to creep deformation. In this point of view, electron beam weld joint is far superior to TIG weld joint and nearly comparable to the base metal. (author)

  12. Neural Network-Based Resistance Spot Welding Control and Quality Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Allen, J.D., Jr.; Ivezic, N.D.; Zacharia, T.

    1999-07-10

    This paper describes the development and evaluation of neural network-based systems for industrial resistance spot welding process control and weld quality assessment. The developed systems utilize recurrent neural networks for process control and both recurrent networks and static networks for quality prediction. The first section describes a system capable of both welding process control and real-time weld quality assessment, The second describes the development and evaluation of a static neural network-based weld quality assessment system that relied on experimental design to limit the influence of environmental variability. Relevant data analysis methods are also discussed. The weld classifier resulting from the analysis successfldly balances predictive power and simplicity of interpretation. The results presented for both systems demonstrate clearly that neural networks can be employed to address two significant problems common to the resistance spot welding industry, control of the process itself, and non-destructive determination of resulting weld quality.

  13. Microstructure and fatigue properties of Mg-to-steel dissimilar resistance spot welds

    International Nuclear Information System (INIS)

    Liu, L.; Xiao, L.; Chen, D.L.; Feng, J.C.; Kim, S.; Zhou, Y.

    2013-01-01

    Highlights: ► Mg/steel dissimilar spot weld had the same fatigue strength as Mg/Mg similar weld. ► Crack propagation path of Mg/Mg and Mg/steel welds was the same. ► Penetration of Zn into the Mg base metal led to crack initiation of Mg/steel weld. ► HAZ weakening and stress concentration led to crack initiation of Mg/Mg weld. -- Abstract: The structural application of lightweight magnesium alloys in the automotive industry inevitably involves dissimilar welding with steels and the related durability issues. This study was aimed at evaluating the microstructural change and fatigue resistance of Mg/steel resistance spot welds, in comparison with Mg/Mg welds. The microstructure of Mg/Mg spot welds can be divided into: base metal, heat affected zone and fusion zone (nugget). However, the microstructure of Mg/steel dissimilar spot welds had three different regions along the joined interface: weld brazing, solid-state joining and soldering. The horizontal and vertical Mg hardness profiles of Mg/steel and Mg/Mg welds were similar. Both Mg/steel and Mg/Mg welds were observed to have an equivalent fatigue resistance due to similar crack propagation characteristics and failure mode. Both Mg/steel and Mg/Mg welds failed through thickness in the magnesium sheet under stress-controlled cyclic loading, but fatigue crack initiation of the two types of welds was different. The crack initiation of Mg/Mg welds was occurred due to a combined effect of stress concentration, grain growth in the heat affected zone (HAZ), and the presence of Al-rich phases at HAZ grain boundaries, while the penetration of small amounts of Zn coating into the Mg base metal stemming from the liquid metal induced embrittlement led to crack initiation in the Mg/steel welds.

  14. Estimation of work capacity of welded mounting joints of pipelines of heat resisting steel

    International Nuclear Information System (INIS)

    Gorynin, I.V.; Ignatov, V.A.; Timofeev, B.T.; Blyumin, A.A.

    1982-01-01

    The analysis of a work capacity of circular welds made for the Dsub(y)850 pipeline connection with high pressure vessels of heat resisting steel of the 15Kh1NMFA type has been carried out on the base of test results with small samples and real units. Welds were performed using the manual electric arc welding without the following heat treatment. It has been shown that residual stresses in such welds do not produce an essential effect on the resistance of weld metal and heat affected zone on the formation and developments of cracks

  15. One-step femtosecond laser welding and internal machining of three glass substrates

    Science.gov (United States)

    Tan, Hua; Duan, Ji'an

    2017-05-01

    In this paper, it demonstrated one-step femtosecond laser welding and internal machining of three fused silica substrates in the optical- and non-optical-contact regimes by focusing 1030-nm laser pulses at the middle of the second substrate. Focusing laser pulses within the second glass in optical-contact and non-optical-contact samples induces permanent internal structural modification, leading to the three glass substrates bonding together simultaneously. The bonding mechanism is based on the internal modification of glass, and this mechanism is different from that of ordinary glass welding at the interface. Welding-spot size is affected by not only the gap distance (ablation effect) and heat transmission, but also by gravity through examining the sizes of the welding spots on the four contact welding surfaces. The maximum bonding strength of the lower interface (56.2 MPa) in the optical-contact regime is more than double that (27.6 MPa) in the non-optical-contact regime.

  16. On the Generalized Correlation Equation of Welding Current for the Tig Welding Machine Used in Nuclear Fuel Fabrication

    International Nuclear Information System (INIS)

    Umar, Efrizon

    1995-01-01

    In nuclear fuel fabrication, welding plays a very important role to join the end cap to the tube. In order to determine the welding current in TIG welding process for various materials, weld geometries and welding rates, the correlation between the welding current and the other parameters are needed. This paper presents the correlation of those parameters mentioned above. The proposed correlation was tested and produced satisfactory results. (author). 8 refs., 2 tabs., 2 figs

  17. Method for strength calculating of structural elements of mobile machines for flash butt welding of rails

    Directory of Open Access Journals (Sweden)

    Andriy Valeriy Moltasov

    2017-12-01

    Full Text Available Purpose. The subject of this study is the strength of the loaded units of mobile machines for flash butt welding by refining high-strength rails. The theme of the work is related to the development of a technique for strength calculating of the insulation of the central axis of these machines. The aim of the paper is to establish the mathematical dependence of the pressure on the insulation on the magnitude of deflections of the central axis under the action of the upset force. Design/methodology/approach. Using the Mohr’s method, the displacements of the investigated sections of the central axis under the action of the upset force and the equivalent load distributed along the length of the insulation were calculated. The magnitude of the load distributed along the length of the insulation equivalent to the draft force was determined from the condition that the displacements of the same cross sections are equal under the action of this load and under the action of the upset force. Results. An analytical expression for establishing the relationship between the pressure acting on the insulation and the magnitude of the upset force and the geometric dimensions of the structural elements of the machine was obtained. Based on the condition of the strength of the insulation for crushing, an analytical expression for establishing the relationship between the length of insulation and the size of the upset force, the geometric dimensions of the structural elements of the machine, and the physical and mechanical properties of the insulation material was obtained. Originality/cost. The proposed methodology was tested in the calculation and design of the K1045 mobile rail welding machine, 4 of which is currently successfully used in the USA for welding rails in hard-to-reach places.

  18. Joining of Dissimilar alloy Sheets (Al 6063&AISI 304 during Resistance Spot Welding Process: A Feasibility Study for Automotive industry

    Directory of Open Access Journals (Sweden)

    Reddy Sreenivasulu

    2014-12-01

    Full Text Available Present design trends in automotive manufacture have shifted emphasis to alternative lightweight materials in order to achieve higher fuel efficiency and to bring down vehicle emission. Although some other joining techniques are more and more being used, spot welding still remains the primary joining method in automobile manufacturing so far. Spot welds for automotive applications should have a sufficiently large diameter, so that nugget pullout mode is the dominant failure mode. Interfacial mode is unacceptable due to its low load carrying and energy absorption capability. Strength tests with different static loading were performed in, to reveal the failure mechanisms for the lap-shear geometry and the cross-tension geometry. Based on the literature survey performed, venture into this work was amply motivated by the fact that a little research work has been conducted to joining of dissimilar materials like non ferrous to ferrous. Most of the research works concentrated on joining of different materials like steel to steel or aluminium alloy to aluminium alloy by resistance spot welding. In this work, an experimental study on the resistance spot weldability of aluminium alloy (Al 6063 and austenitic stainless steel (AISI304 sheets, which are lap joined by using a pedestal type resistance spot welding machine. Welding was conducted using a 45-deg truncated cone copper electrode with 10-mm face diameter. The weld nugget diameter, force estimation under lap shear test and T – peel test were investigated using digital type tensometer attached with capacitive displacement transducer (Mikrotech, Bangalore, Model: METM2000ER1. The results shows that joining of Al 6063 and AISI 304 thin sheets by RSW method are feasible for automotive structural joints where the loads are below 1000N act on them, it is observed that by increasing the spots per unit length, then the joint with standing strength to oppose failure is also increased linearly incase of

  19. Structure of Ti-6Al-4V nanostructured titanium alloy joint obtained by resistance spot welding

    Energy Technology Data Exchange (ETDEWEB)

    Klimenov, V. A., E-mail: klimenov@tpu.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation); Kurgan, K. A., E-mail: kirill-k2.777@mail.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); Chumaevskii, A. V., E-mail: tch7av@gmail.com [Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences, 2/4 Akademicheskii pr., Tomsk, 634021 (Russian Federation); Klopotov, A. A., E-mail: klopotovaa@tsuab.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634050 (Russian Federation); Gnyusov, S. F., E-mail: gnusov@rambler.ru [National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation)

    2016-01-15

    The structure of weld joints of the titanium alloy Ti-6Al-4V in the initial ultrafine-grained state, obtained by resistance spot welding, is studied using the optical and scanning electron microscopy method and the X-ray structure analysis. The carried out studies show the relationship of the metal structure in the weld zone with main joint zones. The structure in the core zone and the heat affected zone is represented by finely dispersed grains of needle-shaped martensite, differently oriented in these zones. The change in the microhardness in the longitudinal section of the weld joint clearly correlates with structural changes during welding.

  20. The lack of penetration effect on fatigue crack propagation resistance of atmospheric corrosion resistant steel welded joints

    International Nuclear Information System (INIS)

    Martins, Geraldo de Paula; Cimini Junior, Carlos Alberto; Godefroid, Leonardo Barbosa

    2005-01-01

    The welding process introduces defects on the welded joints, as lack of fusion and penetration, porosity, between others. These defects can compromise the structures or components, relative to the crack propagation. This engagement can be studied by fatigue crack propagation tests. The efficiency of the structure, when submitted to a cyclic loading can be evaluated by these tests. The aim of this work is to study the behavior of welded joints containing defects as lack of penetration at the root or between welding passes relative to crack propagation resistance properties, and to compare these properties with the properties of the welded joints without defects. This study was accomplished from fatigue crack propagation test results, in specimens containing lack of penetration between welding passes. With the obtained results, the Paris equation coefficients and exponents that relate the crack propagation rate with the stress intensity cyclic factor for welded joints with and without defects were obtained. (author)

  1. Effect of welding processes on corrosion resistance of UNS S31803 duplex stainless steel

    International Nuclear Information System (INIS)

    Chiu, Liu Ho; Hsieh, Wen Chin

    2003-01-01

    An attractive combination of corrosion resistance and mechanical properties in the temperature range -50 to 250 .deg. C is offered by duplex stainless steel. However, undesirable secondary precipitation phase such as σ, γ 2 and Cr 2 N may taken place at the cooling stage from the welding processes. Therefore, this paper describes the influence of different welding procedures such as manual metal arc welding (MMA), tungsten inert gas welding (TIG) and vacuum brazing on corrosion resistance of the welded joint for UNS S31803 duplex stainless steel. Microstructure and chemical compositions of the welded joint were examined. The weight loss of specimens immersed in 6% FeCl 3 solution at 47.5 .deg. C for 24-hours was determined and used to evaluate the pitting resistance of duplex stainless steel and their welds. The region of heat-affected zone of specimen obtained by the MMA is much wider than that resulted from TIG, therefore, the weight loss of welds by MMA was larger than that of weld by TIG. The weight loss of brazed specimens cooled from slow cooling rate was larger than those of specimens cooled from high cooling rate, because the precipitation of σ phase. Beside that, the weight loss of brazed specimen is greater than those of the welded specimens. The galvanic corrosion was observed in brazed duplex stainless steel joints in the chloride solution

  2. Effect of prior machining deformation on the development of tensile residual stresses in weld-fabricated nuclear components

    International Nuclear Information System (INIS)

    Prevey, P.S.; Mason, P.W.; Hornbach, D.J.; Molkenthin, J.P.

    1996-01-01

    Austenitic alloy weldments in nuclear systems may be subject to stress-corrosion cracking (SCC) failure if the sum of residual and applied stresses exceeds a critical threshold. Residual stresses developed by prior machining and welding may either accelerate or retard SCC, depending on their magnitude and sign. A combined x-ray diffraction and mechanical procedure was used to determine the axial and hoop residual stress and yield strength distributions into the inside-diameter surface of a simulated Alloy 600 penetration J-welded into a reactor pressure vessel. The degree of cold working and the resulting yield strength increase caused by prior machining and weld shrinkage were calculated from the line-broadening distributions. Tensile residual stresses on the order of +700 MPa were observed in both the axial and the hoop directions at the inside-diameter surface in a narrow region adjacent to the weld heat-affected zone. Stresses exceeding the bulk yield strength were found to develop due to the combined effects of cold working of the surface layers during initial machining and subsequent weld shrinkage. The residual stress and cold work distributions produced by prior machining were found to influence strongly the final residual stress state developed after welding

  3. Fundamental studies on electron-beam welding of heat-resistant superalloys for nuclear plants: Report 4. Mechanical properties of welded joints

    International Nuclear Information System (INIS)

    Susei, S.; Shimizu, S.; Aota, T.

    1982-04-01

    In this report, electron-beam (EB) welded joints and TIG welded joints of various superalloys to be used for nuclear plants, such as Hastelloy-type, Inconel-type and Incoloy-type, are systematically evaluated in terms of tensile properties, low-cycle fatigue properties at elevated temperatures, creep and creep-rupture properties. It was fully confirmed as conclusion that the EB welded joints are superior to the TIG welded ones in mechanical properties, especially at high temperature. In the evaluation of creep properties, ductility is one of the most important criteria to represent the resistance against fracture due to creep deformation, and this criterion is very useful in evaluating the properties of welded joints. Therefore, the more comparable to the base metal the electron beam welded joint becomes in terms of ductility, the more resistant is it against fracture. From this point of view, the electron beam welded joint is considerably superior to the TIG welded joint [fr

  4. Fatique Resistant, Energy Efficient Welding Program, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Egland, Keith; Ludewig, Howard

    2006-05-25

    The program scope was to affect the heat input and the resultant weld bead geometry by synchronizing robotic weave cycles with desired pulsed waveform shapes to develop process parameters relationships and optimized pulsed gas metal arc welding processes for welding fatique-critical structures of steel, high strength steel, and aluminum. Quality would be addressed by developing intelligent methods of weld measurement that accurately predict weld bead geometry from process information. This program was severely underfunded, and eventually terminated. The scope was redirected to investigate tandem narrow groove welding of steel butt joints during the one year of partial funding. A torch was designed and configured to perform a design of experiments of steel butt weld joints that validated the feasability of the process. An initial cost model estimated a 60% cost savings over conventional groove welding by eliminating the joint preparation and reducing the weld volume needed.

  5. Resistance spot welding of AISI 430 ferritic stainless steel: Phase transformations and mechanical properties

    International Nuclear Information System (INIS)

    Alizadeh-Sh, M.; Marashi, S.P.H.; Pouranvari, M.

    2014-01-01

    Highlights: • Phase transformations during RSW of AISI430 are detailed. • Grain growth, martensite formation and carbide precipitation are dominant phase transformations. • Failure mode of AISI430 resistance spot welded joints are analyzed. • Larger FZ size provided improved load bearing capacity and energy absorption capability. - Abstract: The paper aims at investigating the process–microstructure–performance relationship in resistance spot welding of AISI 430 ferritic stainless steel. The phase transformations which occur during weld thermal cycle were analyzed in details, based on the physical metallurgy of welding of the ferritic stainless steels. It was found that the microstructure of the fusion zone and the heat affected zone is influenced by different phenomena including grain growth, martensite formation and carbide precipitation. The effects of welding cycle on the mechanical properties of the spot welds in terms of peak load, energy absorption and failure mode are discussed

  6. Development of resistance welding process. 6. Evaluation test of welding properties of martensitic ODS steel)

    International Nuclear Information System (INIS)

    Kono, Shusaku; Seki, Masayuki; Ishibashi, Fujio

    2003-05-01

    The welding condition and the heat-treatment condition were optimized to evaluate welding properties of the martensitic ODS steel cladding tube. The test pieces for evaluation of strength properties of the welded zone were produced by the optimized welding condition. In order to evaluate the strength of the welded zone, the internal creep rapture test, the single axis creep rapture test, the burst test and the tensile test were conducted. Following results were obtained in these tests. (1) Weld ability: An excellent welding characteristic was observed. The micro cracks, etc. were not served at the joint starting point. The joint starting points were connected uniformly with errors less than 0.05 mm. It is considered that an excellent welding characteristic was result of homogeneous micro structure of cladding material. (2) End plug material: In case of the material of end plug was martensitic ODS steel as same as that of cladding tube, the micro structure and the precipitation state carbide near the welded zone were found to be almost same as that of cladding tube. (3) Optimization of heat-treatment condition: The heat treatments of normalizing (1050degC) and tempering (780degC) were performed after welding and the micro structure near the welded zone was the isometric structure with low dislocation density, the precipitation state of carbide was uniform as same as that of cladding tube. These heat treatments can relax the residual stress accumulated when welding; it is considered that these heat treatments after welding are indispensable. (4) Strength of welded zone: The strength of the welded zone was found to be equal to that of cladding tube in all the strength tests. Therefore, it is concluded that the welding technology for the martensitic ODS steel is completed. (author)

  7. A comparative study of the microstructure and mechanical properties of HTLA steel welds obtained by the tungsten arc welding and resistance spot welding

    Energy Technology Data Exchange (ETDEWEB)

    Ghazanfari, H., E-mail: ghazanfari@aut.ac.ir [AmirKabir University of Technology, Department of Mining and Metallurgy, 424 Hafez Ave, Tehran (Iran, Islamic Republic of); Naderi, M., E-mail: mnaderi@aut.ac.ir [AmirKabir University of Technology, Department of Mining and Metallurgy, 424 Hafez Ave, Tehran (Iran, Islamic Republic of); Iranmanesh, M., E-mail: imehdi@aut.ac.ir [AmirKabir University of Technology, Department of Maritime Engineering, 424 Hafez Ave, Tehran (Iran, Islamic Republic of); Seydi, M., E-mail: afsan_sy@yahoo.com [Zarin Joosh Aria Co., Tehran (Iran, Islamic Republic of); Poshteban, A., E-mail: ali_poshtiban@yahoo.com [Hamyar Sanat Eghbal Co., Tehran (Iran, Islamic Republic of)

    2012-02-01

    Highlights: Black-Right-Pointing-Pointer Hardness mapping is a novel method to identify different phases. Black-Right-Pointing-Pointer Surface hardness mapping, tabulates the hardness of a large area of weld. Black-Right-Pointing-Pointer Hardness maps can be used to depict the strength map through the specimen. Black-Right-Pointing-Pointer Hardness mapping is an easy way to identify the phase fractions within the specimen. - Abstract: Hardness tests are routinely employed as simple and efficient methods to investigate the microstructure and mechanical properties of steels. Each microstructural phase in steel has its own hardness level. Therefore, using surface hardness mapping data over a large area of weld zone would be a reasonable method to identify the present phases in steel. The microstructure distribution and mechanical properties variation through welded structures is inhomogeneous and not suitable for certain applications. So, studying the microstructure of weld zone has a significant importance. 4130 steel is classified in HTLA steels and it is widely used in marine industry due to its superior hardenability, good corrosion resistance and high strength. Gas tungsten arc and resistance spot welding are the most usable processes in joining of 4130 sheets. In this work a series of welds have been fabricated in 4130 steel tube by gas tungsten arc and resistance spot welding. The tube was subjected to quench-tempered heat treatment. Slices from the welds before and after heat treatment were polished and etched and the macrostructure and microstructure were observed. Hardness maps were then determined over the large area of weld zone, including the heat affected zone and base plate. Results show good relations between the various microstructures, strength and hardness values. It is also proved that this method is precise and applicable to estimate phase fraction of each phase in various regions of weld. In the current study some equations were proposed to

  8. A comparative study of the microstructure and mechanical properties of HTLA steel welds obtained by the tungsten arc welding and resistance spot welding

    International Nuclear Information System (INIS)

    Ghazanfari, H.; Naderi, M.; Iranmanesh, M.; Seydi, M.; Poshteban, A.

    2012-01-01

    Highlights: ► Hardness mapping is a novel method to identify different phases. ► Surface hardness mapping, tabulates the hardness of a large area of weld. ► Hardness maps can be used to depict the strength map through the specimen. ► Hardness mapping is an easy way to identify the phase fractions within the specimen. - Abstract: Hardness tests are routinely employed as simple and efficient methods to investigate the microstructure and mechanical properties of steels. Each microstructural phase in steel has its own hardness level. Therefore, using surface hardness mapping data over a large area of weld zone would be a reasonable method to identify the present phases in steel. The microstructure distribution and mechanical properties variation through welded structures is inhomogeneous and not suitable for certain applications. So, studying the microstructure of weld zone has a significant importance. 4130 steel is classified in HTLA steels and it is widely used in marine industry due to its superior hardenability, good corrosion resistance and high strength. Gas tungsten arc and resistance spot welding are the most usable processes in joining of 4130 sheets. In this work a series of welds have been fabricated in 4130 steel tube by gas tungsten arc and resistance spot welding. The tube was subjected to quench-tempered heat treatment. Slices from the welds before and after heat treatment were polished and etched and the macrostructure and microstructure were observed. Hardness maps were then determined over the large area of weld zone, including the heat affected zone and base plate. Results show good relations between the various microstructures, strength and hardness values. It is also proved that this method is precise and applicable to estimate phase fraction of each phase in various regions of weld. In the current study some equations were proposed to calculate the ultimate tensile stress and yield stress from the weld. The calculated data were compared

  9. Experimental investigation and characterization of micro resistance welding with an electro-thermal actuator

    International Nuclear Information System (INIS)

    Chang, Chun-Wei; Yeh, Cheng-Chi; Hsu Wensyang

    2009-01-01

    Resistance welding is a common scheme of assembly on the macro scale by pressing together two workpieces with current passing through them to generate joule heating at the contact region due to high contact resistance. However, micro assembly by resistance welding is seldom reported. Here, resistance welding with an electro-thermal microactuator to assemble micro Ni structures is experimentally investigated and characterized. The bent-beam electro-thermal microactuator is designed to provide the necessary displacements and pressing forces. The two-mask metal-based surface micromachining process is adopted to fabricate the micro Ni structures. The calibrated initial contact resistance is shown to decrease with increasing contact pressure. Furthermore, stronger welding strength is achieved at a smaller initial contact resistance, which indicates that a larger clamping force would enhance the welding strength as large as 3.09 MPa (74.4 µN) at a contact resistance of 2.7 Ω here. The input welding energy is also found to be a critical factor. In our tests, when welding energy is below the threshold limit of 0.05 J, the welding trials all fail. For the energy between 0.05 J and 1 J, there is a transition from a lower yield of 33.3% to a higher yield of 58.3%. At high welding energy, between 1 and 10 J, 100% yield is achieved. With the demonstration and characterization of micro resistance welding by the electro-thermal microactuator, the scheme proposed here would be helpful in the automation of micro assembly

  10. Prediction of microsegregation and pitting corrosion resistance of austenitic stainless steel welds by modelling

    Energy Technology Data Exchange (ETDEWEB)

    Vilpas, M. [VTT Manufacturing Technology, Espoo (Finland). Materials and Structural Integrity

    1999-07-01

    The present study focuses on the ability of several computer models to accurately predict the solidification, microsegregation and pitting corrosion resistance of austenitic stainless steel weld metals. Emphasis was given to modelling the effect of welding speed on solute redistribution and ultimately to the prediction of weld pitting corrosion resistance. Calculations were experimentally verified by applying autogenous GTA- and laser processes over the welding speed range of 0.1 to 5 m/min for several austenitic stainless steel grades. Analytical and computer aided models were applied and linked together for modelling the solidification behaviour of welds. The combined use of macroscopic and microscopic modelling is a unique feature of this work. This procedure made it possible to demonstrate the effect of weld pool shape and the resulting solidification parameters on microsegregation and pitting corrosion resistance. Microscopic models were also used separately to study the role of welding speed and solidification mode in the development of microsegregation and pitting corrosion resistance. These investigations demonstrate that the macroscopic model can be implemented to predict solidification parameters that agree well with experimentally measured values. The linked macro-micro modelling was also able to accurately predict segregation profiles and CPT-temperatures obtained from experiments. The macro-micro simulations clearly showed the major roles of weld composition and welding speed in determining segregation and pitting corrosion resistance while the effect of weld shape variations remained negligible. The microscopic dendrite tip and interdendritic models were applied to welds with good agreement with measured segregation profiles. Simulations predicted that weld inhomogeneity can be substantially decreased with increasing welding speed resulting in a corresponding improvement in the weld pitting corrosion resistance. In the case of primary austenitic

  11. Anodising and corrosion resistance of AA 7050 friction stir welds

    International Nuclear Information System (INIS)

    Atz Dick, Pedro; Knörnschild, Gerhard H.; Dick, Luís F.P.

    2017-01-01

    Highlights: • Sulphuric Anodizing films of AA7050 friction stir welds are 25% thinner on the nugget zone. • Semicoherent MgZn_2 precipitates locally pin the formation of anodic oxide film. • Coarse Al_7Cu_2Fe precipitates anodize irregularly and produces locally thicker films. • Localized corrosion occurs preferentially on the nugget zone and is related to the thinner oxide film and irregular anodizing on stirring voids. - Abstract: The influence of friction stir welding on the sulphuric anodising and corrosion of AA7050 was studied in 0.1 M NaCl by the scanning vibrating electrode technique under simultaneous polarization. The oxide films obtained were characterized by scanning electron microscopy. The porous oxide films are up to 25% thicker on the thermomechanically and heat affected zones and 25% thinner on the nugget. This thinner defective oxide film explains the lower pitting resistance of the nugget zone. Individual pit current transients were indirectly determined from current maps. However, the calculated values are lower than expected, due to underestimation of electrolyte conductivity near pits.

  12. Solid-state resistance upset welding: A process with unique advantages for advanced materials

    International Nuclear Information System (INIS)

    Kanne, W.R. Jr.

    1993-01-01

    Solid-state resistance upset welding is suitable for joining many alloys that are difficult to weld using fusion processes. Since no melting takes place, the weld metal retains many of the characteristics of the base metal. Resulting welds have a hot worked structure, and thereby have higher strength than fusion welds in the same mate. Since the material being joined is not melted, compositional gradients are not introduced, second phase materials are minimally disrupted, and minor alloying elements, do not affect weldability. Solid-state upset welding has been adapted for fabrication of structures considered very large compared to typical resistance welding applications. The process has been used for closure of capsules, small vessels, and large containers. Welding emphasis has been on 304L stainless steel, the material for current applications. Other materials have, however, received enough attention to have demonstrated capability for joining alloys that are not readily weldable using fusion welding methods. A variety of other stainless steels (including A-286), superalloys (including TD nickel), refractory metals (including tungsten), and aluminum alloys (including 2024) have been successfully upset welded

  13. Grey relational and neural network approach for multi-objective optimization in small scale resistance spot welding of titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Xiaodong; Wang, Yuanxun; Zhao, Dawei [Huazhong University of Science and Technology, Wuhan (China)

    2016-06-15

    The prediction and optimization of weld quality characteristics in small scale resistance spot welding of TC2 titanium alloy were investigated. Grey relational analysis, neural network and genetic algorithm were applied separately. Quality characteristics were selected as nugget diameter, failure load, failure displacement and failure energy. Welding parameters to be optimized were set as electrode force, welding current and welding time. Grey relational analysis was conducted for a rough estimation of the optimum welding parameters. Results showed that welding current played a key role in weld quality improvement. Different back propagation neural network architectures were then arranged to predict multiple quality characteristics. Interaction effects of welding parameters were analyzed with the proposed neural network. Failure load was found more sensitive to the change of welding parameters than nugget diameter. Optimum welding parameters were determined by genetic algorithm. The predicted responses showed good agreement with confirmation experiments.

  14. Feasibility demonstration of using wire electrical-discharge machining, abrasive flow honing, and laser spot welding to manufacture high-precision triangular-pitch Zircaloy-4 fuel-rod-support grids

    International Nuclear Information System (INIS)

    Horwood, W.A.

    1982-05-01

    Results are reported supporting the feasibility of manufacturing high precision machined triangular pitch Zircaloy-4 fuel rod support grids for application in water cooled nuclear power reactors. The manufacturing processes investigated included wire electrical discharge machining of the fuel rod and guide tube cells in Zircaloy plate stock to provide the grid body, multistep pickling of the machined grid to provide smooth and corrosion resistant surfaces, and laser welding of thin Zircaloy cover plates to both sides of the grid body to capture separate AM-350 stainless steel insert springs in the grid body. Results indicated that dimensional accuracy better than +- 0.001 and +- 0.002 inch could be obtained on cell shape and position respectively after wire EDM and surface pickling. Results on strength, corrosion resistance, and internal quality of laser spot welds are provided

  15. A study of weld quality in ultrasonic spot welding of similar and dissimilar metals

    International Nuclear Information System (INIS)

    Al-Sarraf, Z; Lucas, M

    2012-01-01

    Several difficulties are faced in joining thinner sheets of similar and dissimilar materials from fusion welding processes such as resistance welding and laser welding. Ultrasonic metal welding overcomes many of these difficulties by using high frequency vibration and applied pressure to create a solid-state weld. Ultrasonic metal welding is an effective technique in joining small components, such as in wire bonding, but is also capable of joining thicker sheet, depending on the control of welding conditions. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal welding device. The ultrasonic welding horn is modelled using finite element analysis and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. Control of the vibration amplitude profile through the weld cycle is used to enhance weld strength and quality, providing an opportunity to reduce part marking. Optical microscopic examination and scanning electron microscopy (SEM) were employed to investigate the weld quality. The results show how the weld quality is particularly sensitive to the combination of clamping force and vibration amplitude of the welding tip.

  16. Electrical resistance determination of actual contact area of cold welded metal joints

    Science.gov (United States)

    Hordon, M. J.

    1970-01-01

    Method measures the area of the bonded zone of a compression weld by observing the electrical resistance of the weld zone while the load changes from full compression until the joint ruptures under tension. The ratio of bonding force to maximum tensile load varies considerably.

  17. Modeling and control of a DC upset resistance butt welding process

    NARCIS (Netherlands)

    Naus, G.J.L.; Meulenberg, R.; Molengraft, van de M.J.G.

    2007-01-01

    This paper presents the analysis and synthesis of modeling and control of the DC upset resistance butt welding process used in rim production lines. A new control strategy is developed, enabling active control of the welding seam temperature and the upset size. As a result, set-up times and energy

  18. Influence of nitrogen in the shielding gas on corrosion resistance of duplex stainless steel welds

    Science.gov (United States)

    Bhatt, R. B.; Kamat, H. S.; Ghosal, S. K.; de, P. K.

    1999-10-01

    The influence of nitrogen in shielding gas on the corrosion resistance of welds of a duplex stainless steel (grade U-50), obtained by gas tungsten arc (GTA) with filler wire, autogenous GTA (bead-on-plate), electron beam welding (EBW), and microplasma techniques, has been evaluated in chloride solutions at 30 °C. Pitting attack has been observed in GTA, electron beam welding, and microplasma welds when welding has been carried out using pure argon as the shielding gas. Gas tungsten arc welding with 5 to 10% nitrogen and 90 to 95% argon, as the shielding gas, has been found to result in an improved pitting corrosion resistance of the weldments of this steel. However, the resistance to pitting of autogenous welds (bead-on-plate) obtained in pure argon as the shielding gas has been observed to remain unaffected. Microscopic examination, electron probe microanalysis (EPMA), and x-ray diffraction studies have revealed that the presence of nitrogen in the shielding gas in the GTA welds not only modifies the microstructure and the austenite to ferrite ratio but also results in a nearly uniform distribution of the various alloying elements, for example, chromium, nickel, and molybdenum among the constitutent phases, which are responsible for improved resistance to pitting corrosion.

  19. Construction and final assembly of an automatic arc welding machine; Construccion y puesta a punto de una maquina automatica para soldadura remota por arco bajo atmosfera inerte

    Energy Technology Data Exchange (ETDEWEB)

    Herrero Alvarez, J; Diaz Diaz, J; Diaz Diaz, J L

    1972-07-01

    It has been constructed a remote are welding machine, wholly transistorized, to be used in a Hot Cell of 1.000 Cu. In this work are presented the different parts of the equipment and its electronic description. Finally, some works of final preparation are shown such as ending of irradiation capsules, thermocouples welding, stainless steel cover welding. For these types of welding are quoted its relative programs. (Author)

  20. Specification for corrosion-resisting chromium and chromium-nickel steel bare and composite metal cored and stranded arc welding electrodes and welding rods

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    This specification prescribes requirements for corrosion or heat resisting chromium and chromium-nickel steel electrodes and welding rods. These electrodes and welding rods are normally used for arc welding and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

  1. Development of stress corrosion cracking resistant welds of 321 stainless steel by simple surface engineering

    Science.gov (United States)

    Mankari, Kamal; Acharyya, Swati Ghosh

    2017-12-01

    We hereby report a simple surface engineering technique to make AISI grade 321 stainless steel (SS) welds resistant to stress corrosion cracking (SCC) in chloride environment. Heat exchanger tubes of AISI 321 SS, welded either by (a) laser beam welding (LBW) or by (b) metal inert gas welding (MIG) were used for the study. The welds had high magnitude of tensile residual stresses and had undergone SCC in chloride environment while in service. The welds were characterized using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Subsequently, the welded surfaces were subjected to buffing operation followed by determination of residual stress distribution and surface roughness by XRD and surface profilometer measurements respectively. The susceptibility of the welds to SCC was tested in buffed and un-buffed condition as per ASTM G-36 in boiling MgCl2 for 5 h and 10 h, followed by microstructural characterization by using optical microscope and FESEM. The results showed that the buffed surfaces (both welds and base material) were resistant to SCC even after 10 h of exposure to boiling MgCl2 whereas the un-buffed surfaces underwent severe SCC for the same exposure time. Buffing imparted high magnitude of compressive stresses on the surface of stainless steel together with reduction in its surface roughness and reduction in plastic strain on the surface which made the welded surface, resistant to chloride assisted SCC. Buffing being a very simple, portable and economic technique can be easily adapted by the designers as the last step of component fabrication to make 321 stainless steel welds resistant to chloride assisted SCC.

  2. Spatially resolved ultrasonic attenuation in resistance spot welds: implications for nondestructive testing.

    Science.gov (United States)

    Mozurkewich, George; Ghaffari, Bita; Potter, Timothy J

    2008-09-01

    Spatial variation of ultrasonic attenuation and velocity has been measured in plane parallel specimens extracted from resistance spot welds. In a strong weld, attenuation is larger in the nugget than in the parent material, and the region of increased attenuation is surrounded by a ring of decreased attenuation. In the center of a stick weld, attenuation is even larger than in a strong weld, and the low-attenuation ring is absent. These spatial variations are interpreted in terms of differences in grain size and martensite formation. Measured frequency dependences indicate the presence of an additional attenuation mechanism besides grain scattering. The observed attenuations do not vary as commonly presumed with weld quality, suggesting that the common practice of using ultrasonic attenuation to indicate weld quality is not a reliable methodology.

  3. Specification for corrosion-resisting chromium and chromium-nickel steel welding rods and bare electrodes - approved 1969

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    This specification covers corrosion-resisting chromium and chromium-nickel steel welding rods for use with the atomic hydrogen and gas-tungsten-arc welding processes and bare electrodes for use with the submerged arc and gas metal-arc welding processes. These welding rods and electrodes include those alloy steels designated as corrosion- or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4% and nickel does not exceed 50%

  4. Resistance to corrosion fatigue fracture in heat resistant steels and their welded joints

    International Nuclear Information System (INIS)

    Timofeev, B.T.; Fedorova, V.A.; Zvezdin, Yu.I.; Vajner, L.A.; Filatov, V.M.

    1987-01-01

    Experimental data on cyclic crack resistance of heat-resistant steels and their welded joints employed for production of the reactor bodies are for the first time generalized and systematized. The formula is suggested accounting for surface and inner defects to calculate the fatigue crack growth in the process of operation. This formula for surface defects regards also the effect of the corrosion factor. Mechanisms of the reactor water effect on the fatigue crack growth rate are considered as well as a combined effect of radiation and corrosive medium on this characteristic

  5. Failure mode transition in AHSS resistance spot welds. Part I. Controlling factors

    International Nuclear Information System (INIS)

    Pouranvari, M.; Marashi, S.P.H.

    2011-01-01

    Highlights: → Interfacial to pullout failure mode transition for AHSS RSWs is studied. → An analytical mode is proposed to predict failure mode of AHSS RSWs. → Hardness characteristics of RSWs plays key role in the failure mode transition. - Abstract: Failure mode of resistance spot welds is a qualitative indicator of weld performance. Two major types of spot weld failure are pull-out and interfacial fracture. Interfacial failure, which typically results in reduced energy absorption capability, is considered unsatisfactory and industry standards are often designed to avoid this occurrence. Advanced High Strength Steel (AHSS) spot welds exhibit high tendency to fail in interfacial failure mode. Sizing of spot welds based on the conventional recommendation of 4t 0.5 (t is sheet thickness) does not guarantee the pullout failure mode in many cases of AHSS spot welds. Therefore, a new weld quality criterion should be found for AHSS resistance spot welds to guarantee pull-out failure. The aim of this paper is to investigate and analyze the transition between interfacial and pull-out failure modes in AHSS resistance spot welds during the tensile-shear test by the use of analytical approach. In this work, in the light of failure mechanism, a simple analytical model is presented for estimating the critical fusion zone size to prevent interfacial fracture. According to this model, the hardness ratio of fusion zone to pull-out failure location and the volume fraction of voids in fusion zone are the key metallurgical factors governing type of failure mode of AHSS spot welds during the tensile-shear test. Low hardness ratio and high susceptibility to form shrinkage voids in the case of AHSS spot welds appear to be the two primary causes for their high tendency to fail in interfacial mode.

  6. Optimization of resistance spot welding on the assembly of refractory alloy 50Mo-50Re thin sheet

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jianhui [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States); Jiang, Xiuping [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States); Zeng, Qiang [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States); Zhai, Tongguang [Department of Chemical and Materials Engineering, University of Kentucky, 177 Anderson Hall, Lexington, KY 40506 (United States)]. E-mail: tzhai0@engr.uky.edu; Leonhardt, Todd [Rhenium Alloys Inc., Elyria, OH 44036 (United States); Farrell, John [Semicon Associates, 695 Laco Drive, Lexington, KY 40510 (United States); Umstead, Williams [Semicon Associates, 695 Laco Drive, Lexington, KY 40510 (United States); Effgen, Michael P. [Semicon Associates, 695 Laco Drive, Lexington, KY 40510 (United States)

    2007-07-01

    Resistance spot welding (RSW) was employed to pre-join refractory alloy 50Mo-50Re (wt%) sheet with a 0.127 mm gage. Five important welding parameters (hold time, electrode, ramp time, weld current and electrode force) were adjusted in an attempt to optimize the welding quality. It was found that increasing the hold time from 50 ms to 999 ms improved the weld strength. Use of rod-shaped electrodes produced symmetric nugget and enhanced the weld strength. Use of a ramp time of 8 ms minimized electrode sticking and molten metal expulsion. The weld strength continuously increased with increasing the weld current up to 1100 A, but the probabilities of occurrence of electrode sticking and molten metal expulsion were also increased. Electrode force was increased from 4.44 N to 17.8 N, in order to reduce the inconsistency of the welding quality. Welding defects including porosities, columnar grains and composition segregation were also studied.

  7. Analysis and Modelling of Electrode Wear in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Madsen, Anders; Pedersen, Kim; Friis, Kasper Storgaard

    2010-01-01

    A model describing electrode wear as a function of weld number, initial tip diameter, truncated cone angle, welding current and electrode force is proposed. Excellent agreement between the model and experimental results is achieved, showing that the model can describe the change in electrode tip...... diameter with increasing weld number at different weld settings. Furthermore a method for measuring the worn tip diameter in a fast and robust manner is developed. The method relies on a well-known technique for capturing the electrode tip area by the use of carbon imprints and a new developed image...... a central cavity is formed and one where smaller pits are formed randomly across the electrode face. The influence of these two types of surface pits on the nugget size are investigated using the FE code SORPAS, revealing ring welds and undersized weld nuggets....

  8. Electron-beam welding of 21-6-9 (Cr--Ni--Mn) stainless steel: effect of machine parameters on weldability

    International Nuclear Information System (INIS)

    Casey, H.

    1975-04-01

    The high-manganese, nitrogen-strengthened 21-6-9 (Cr--Ni--Mn) austenitic stainless steel has a weldability rating similar to that of more common austenitic stainless steels in terms of cracking, porosity, etc. However, weld pool disruption problems may occur with this alloy that can be related to instability within the molten weld pool. Selection of machine parameters is critical to achieving weld pool quiescence as this report confirms from recent tests. Test samples came from heats of air-melted, vacuum-arc remelted, and electroslag remelted material. Low- and high-voltage machine parameters are discussed, and effects of parameter variation on weld pool behavior are given. Data relate weld pool behavior to weld fusion-zone geometry. Various weld parameters are recommended for the 21-6-9 alloy, regardless of its source or chemistry. (auth)

  9. The Influence of Welding Parameters on the Nugget Formation of Resistance Spot Welding of Inconel 625 Sheets

    Science.gov (United States)

    Rezaei Ashtiani, Hamid Reza; Zarandooz, Roozbeh

    2015-09-01

    A 2D axisymmetric electro-thermo-mechanical finite element (FE) model is developed to investigate the effect of current intensity, welding time, and electrode tip diameter on temperature distributions and nugget size in resistance spot welding (RSW) process of Inconel 625 superalloy sheets using ABAQUS commercial software package. The coupled electro-thermal analysis and uncoupled thermal-mechanical analysis are used for modeling process. In order to improve accuracy of simulation, material properties including physical, thermal, and mechanical properties have been considered to be temperature dependent. The thickness and diameter of computed weld nuggets are compared with experimental results and good agreement is observed. So, FE model developed in this paper provides prediction of quality and shape of the weld nuggets and temperature distributions with variation of each process parameter, suitably. Utilizing this FE model assists in adjusting RSW parameters, so that expensive experimental process can be avoided. The results show that increasing welding time and current intensity lead to an increase in the nugget size and electrode indentation, whereas increasing electrode tip diameter decreases nugget size and electrode indentation.

  10. Welding-induced local maximum residual stress in heat affected zone of low-carbon austenitic stainless steel with machined surface layer and its influential factors

    International Nuclear Information System (INIS)

    Okano, Shigetaka; Ihara, Ryohei; Kanamaru, Daisuke; Mochizuki, Masahito

    2015-01-01

    In this study, the effects of work-hardening and pre-existing stress in the machined surface layer of low-carbon austenitic stainless steel on the welding-induced residual stress were experimentally investigated through the use of weld specimens with three different surface layers; as-cutout, mechanically-polished and electrolytically-polished. The high tensile and compressive stresses exist in the work-hardened surface layer of the as-cutout and mechanically-polished specimens, respectively. Meanwhile, no stress and work-hardened surface layer exist in the electrolytically-polished specimen. TIG bead-on-plate welding under the same welding heat input conditions was performed to introduce the residual stress into these specimens. Using these welded specimens, the distributions of welding-induced residual stress were measured by the X-ray diffraction method. Similarly, the distributions of hardness in welds were estimated by the Vickers hardness test. And then, these distributions were compared with one another. Based on the results, the residual stress in the weld metal (WM) is completely unaffected by the machined surface layer because the work-hardened surface layer disappears through the processes of melting and solidification during welding. The local maximum longitudinal tensile residual stress in the heat affected zone (HAZ) depends on the work-hardening but not on the existing stress, regardless of whether tensile or compressive, in the machined surface layer before welding. At the base metal far from WM and HAZ, the residual stress is formed by the addition of the welding-induced residual stress to the pre-existing stress in the machined surface layer before welding. The features of the welding-induced residual stress in low-carbon austenitic stainless steel with the machined surface layer and their influential factors were thus clarified. (author)

  11. The Microstructure and Pitting Resistance of Weld Joints of 2205 Duplex Stainless Steel

    Science.gov (United States)

    Wu, Mingfang; Liu, Fei; Pu, Juan; Anderson, Neil E.; Li, Leijun; Liu, Dashuang

    2017-11-01

    2205 duplex stainless steel (DSS) was welded by submerged arc welding. The effects of both heat input and groove type on the ferrite/austenite ratio and elemental diffusion of weld joints were investigated. The relationships among welding joint preparation, ferrite/austenite ratio, elemental diffusion, and pitting corrosion resistance of weld joints were analyzed. When the Ni content of the weld wire deposit was at minimum 2-4% higher than that of 2205 DSS base metal, the desired ratio of ferrite/austenite and elemental partitioning between the austenite and ferrite phases were obtained. While the pitting sensitivity of weld metal was higher than that of base metal, the self-healing capability of the passive film of weld metal was better than that of the base metal when a single V-type groove was used. Furthermore, the heat input should be carefully controlled since pitting corrosion occurred readily in the coarse-grained heat-affected zone near the fusion line of welded joints.

  12. Welding hazards

    International Nuclear Information System (INIS)

    Khan, M.A.

    1992-01-01

    Welding technology is advancing rapidly in the developed countries and has converted into a science. Welding involving the use of electricity include resistance welding. Welding shops are opened in residential area, which was causing safety hazards, particularly the teenagers and children who eagerly see the welding arc with their naked eyes. There are radiation hazards from ultra violet rays which irritate the skin, eye irritation. Welding arc light of such intensity could damage the eyes. (Orig./A.B.)

  13. Bearing Capacity of Resistance Spot Welding Under Conditions of Europe, Indonesia

    Directory of Open Access Journals (Sweden)

    Miroslav Müller

    2015-01-01

    Full Text Available A common attribute of production companies is a requirement for a bond creation. A resistance spot welding is a prospective method of bonding. An effect determination of environmental influences on mechanical properties of resistance spot welded bonds is necessary owing to export activities of particular companies. The operating conditions and degradation processes influence were examined in Central Europe, southeast Indonesia and laboratory during 2, 4 and 6 months. From the results the simulation was worked out serving for the prediction of the welded bond bearing capacity for longer time interval. The simulation was verified by the parametric testing during 80 months (Central Europe. The experimental determination of the climatic and geographic different environment influence on the bearing capacity of the resistance spot welded bonds was the aim of the laboratory testing. Considering the globalized society and the export possibilities the knowledge of the experimental study will be used for further testing.

  14. Corrosion resistance of the welded AISI 316L after various surface treatments

    Directory of Open Access Journals (Sweden)

    Tatiana Liptáková

    2014-01-01

    Full Text Available The main aim of this work is to monitor the surface treatment impact on the corrosion resistance of the welded stainless steel AISI 316L to local corrosion forms. The excellent corrosion resistance of austenitic stainless steel is caused by the existence of stable, thin and well adhering passive layer which quality is strongly influenced by welding. Therefore surface treatment of stainless steel is very important with regard to its local corrosion susceptibility Surfaces of welded stainless steel were treated by various mechanical methods (grinding, garnet blasting. Surface properties were studied by SEM, corrosion resistance was evaluated after exposition tests in chlorides environment using weight and metalographic analysis. The experimental outcomes confirmed that the mechanical finishing has a significant effect on the corrosion behavior of welded stainless steel AISI 316L.

  15. Machine learning: novel bioinformatics approaches for combating antimicrobial resistance.

    Science.gov (United States)

    Macesic, Nenad; Polubriaginof, Fernanda; Tatonetti, Nicholas P

    2017-12-01

    Antimicrobial resistance (AMR) is a threat to global health and new approaches to combating AMR are needed. Use of machine learning in addressing AMR is in its infancy but has made promising steps. We reviewed the current literature on the use of machine learning for studying bacterial AMR. The advent of large-scale data sets provided by next-generation sequencing and electronic health records make applying machine learning to the study and treatment of AMR possible. To date, it has been used for antimicrobial susceptibility genotype/phenotype prediction, development of AMR clinical decision rules, novel antimicrobial agent discovery and antimicrobial therapy optimization. Application of machine learning to studying AMR is feasible but remains limited. Implementation of machine learning in clinical settings faces barriers to uptake with concerns regarding model interpretability and data quality.Future applications of machine learning to AMR are likely to be laboratory-based, such as antimicrobial susceptibility phenotype prediction.

  16. Assessment of Stress Corrosion Cracking Resistance of Activated Tungsten Inert Gas-Welded Duplex Stainless Steel Joints

    Science.gov (United States)

    Alwin, B.; Lakshminarayanan, A. K.; Vasudevan, M.; Vasantharaja, P.

    2017-12-01

    The stress corrosion cracking behavior of duplex stainless steel (DSS) weld joint largely depends on the ferrite-austenite phase microstructure balance. This phase balance is decided by the welding process used, heat input, welding conditions and the weld metal chemistry. In this investigation, the influence of activated tungsten inert gas (ATIG) and tungsten inert gas (TIG) welding processes on the stress corrosion cracking (SCC) resistance of DSS joints was evaluated and compared. Boiling magnesium chloride (45 wt.%) environment maintained at 155 °C was used. The microstructure and ferrite content of different weld zones are correlated with the outcome of sustained load, SCC test. Irrespective of the welding processes used, SCC resistance of weld joints was inferior to that of the base metal. However, ATIG weld joint exhibited superior resistance to SCC than the TIG weld joint. The crack initiation and final failure were in the weld metal for the ATIG weld joint; they were in the heat-affected zone for the TIG weld joint.

  17. Development of resistance welding process. 4. Preparation of pressuring enclosed creep test specimen of 7A material

    International Nuclear Information System (INIS)

    Endo, Hideo; Seki, Masayuki; Ishibashi, Fujio; Hirako, Kazuhito; Tsukada, Tatsuya

    2001-02-01

    Mechanical strength in the position welded by resistance welding system was examined in 1999. The test specimens were destroyed in the welding position in a shorter time than expected in the creep test. Therefore, test specimens were prepared to evaluate the cause of destruction. Inner-pressure enclosed creep test specimens were prepared by resistance welding method. Cladding material with low deviation of thickness and high re-crystallization rate was used. Heat treatment after resistance welding was performed to remove the influence of residual stress and the precipitation of carbides. (1) Before preparation of specimens, the welding condition was fixed. Three test specimens were prepared. Two specimens without heat treatment were transported to MMS in Oarai Engineering Center on Aug. 4, 2000. One specimen with heat treatment was transported to MMS after evaluating the residual stress to get optimum heat treatment condition. (2) Specimens were prepared with welding end plugs to both ends of ferritic ODS cladding. Enclosing sides were welded with highly strong Ferritic/Martensitic steel end plugs. The other sides were welded with ferritic ODS end plugs. (3) Some kinds of electrical wave data were obtained during performing welding. Welding position was evaluated with supersonic detector after performing welding. (4) Mechanical strength of welding position in high temperature 800degC was confirmed to be equal to or larger than that of cladding material. The highly qualified specimens in the present were successfully prepared. (author)

  18. Weld metal resistant to neutron-bombardment embrittlement

    International Nuclear Information System (INIS)

    Biemiller, E.C.

    1980-01-01

    The object of the invention is the provision of a broad range of weldments for reactor pressure vessels that exhibit resistance to neutron-induced changes sufficient to prevent the weldments from being limiting factors in reactor operation. The weld materials of the present invention are defined by as deposited weight percentages in the following ranges: carbon 0.00-0.l5, manganese 1.00 - 2.20, phosphorus 0.000 - 0.015, sulfur 0.00 - 0.02, silicon 0.00 - 0.40, nickel 0.00 - 1.20, chromium 0.00 - 2.50, molybdenum 0.30 - 1.20, copper 0.00 - 0.10, vanadium 0.00 - 0.15, balance essentially iron. A further constraint is that, in its deposited state, A/B <0.4, where A is the sum of the weight percents of nickel and silicon in the metal and B is the sum of the weight percents of manganese, chromium, and molybdenum. (LL)

  19. Real-Time Measurement of Machine Efficiency during Inertia Friction Welding.

    Energy Technology Data Exchange (ETDEWEB)

    Tung, Daniel Joseph [The Ohio State Univ., Columbus, OH (United States); Mahaffey, David [Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States); Senkov, Oleg [Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States); Semiatin, Sheldon [Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States); Zhang, Wei [The Ohio State Univ., Columbus, OH (United States)

    2017-12-01

    Process efficiency is a crucial parameter for inertia friction welding (IFW) that is largely unknown at the present time. A new method has been developed to determine the transient profile of the IFW process efficiency by comparing the workpiece torque used to heat and deform the joint region to the total torque. Particularly, the former is measured by a torque load cell attached to the non-rotating workpiece while the latter is calculated from the deceleration rate of flywheel rotation. The experimentally-measured process efficiency for IFW of AISI 1018 steel rods is validated independently by the upset length estimated from an analytical equation of heat balance and the flash profile calculated from a finite element based thermal stress model. The transient behaviors of torque and efficiency during IFW are discussed based on the energy loss to machine bearings and the bond formation at the joint interface.

  20. Determination of ductile tearing resistance J-R curves in welded joints; Determination de courbes de resistance a la dechirure ductile dans les joints soudes

    Energy Technology Data Exchange (ETDEWEB)

    Gilles, Ph.; Ould, P. [AREVA NP, Tour AREVA, 92086 Paris La Defense (France); Marie, St. [CEA Saclay, DM2S, 91191 Gif sur Yvette Cedex (France)

    2010-05-15

    The ductile tearing resistance of steels is generally characterized in terms of resistance curves giving the increase of a resistance parameter such as the crack driving force J or a crack opening displacement as a function of the crack extension {Delta}a. Welded joints are often the weakest part of structures because of greater risk of defects, heterogeneity of the microstructure of the weld, strain concentration along mismatched interfaces. This paper recalls the transferability issues common to all integrity assessments based on tearing resistance curves and points out the difficulties of characterization specific to welds. Several recommendations are proposed for the experimental determination of tearing resistance of welded joints. (authors)

  1. Fracture toughness and crack growth resistance of pressure vessel plate and weld metal steels

    International Nuclear Information System (INIS)

    Moskovic, R.

    1988-01-01

    Compact tension specimens were used to measure the initiation fracture toughness and crack growth resistance of pressure vessel steel plates and submerged arc weld metal. Plate test specimens were manufactured from four different casts of steel comprising: aluminium killed C-Mn-Mo-Cu and C-Mn steel and two silicon killed C-Mn steels. Unionmelt No. 2 weld metal test specimens were extracted from welds of double V butt geometry having either the C-Mn-Mo-Cu steel (three weld joints) or one particular silicon killed C-Mn steel (two weld joints) as parent plate. A multiple specimen test technique was used to obtain crack growth data which were analysed by simple linear regression to determine the crack growth resistance lines and to derive the initiation fracture toughness values for each test temperature. These regression lines were highly scattered with respect to temperature and it was very difficult to determine precisely the temperature dependence of the initiation fracture toughness and crack growth resistance. The data were re-analysed, using a multiple linear regression method, to obtain a relationship between the materials' crack growth resistance and toughness, and the principal independent variables (temperature, crack growth, weld joint code and strain ageing). (author)

  2. Joining of fuel pin end plugs. Pulsed magnetic welding (PMW), pressurized resistance welding (PRW) and their inspection

    International Nuclear Information System (INIS)

    Kamimura, Katsuichiro; Seki, Masayuki

    1996-01-01

    In Power Reactor and Nuclear Fuel Development Corporation, in order to attain the high burnup of FBR fuel, the development of new cladding tube materials mainly aiming at the improvement of swelling resistance has been advanced. Oxide dispersion-strengthened ferritic steel has excellent swelling characteristics and high temperature creep strength, but the strength of its welded parts lowers remarkably. As the result of the investigation of solid phase joining, the conclusion that PMW and PRW are promising was obtained. So far, the manufacture of a welder was started first, the welding test was advanced, and the ultrasonic flaw detection technology of high accuracy was developed for the inspection of welding defects. The features, the principle of welding, the welders and the examples of application of the PMW and the PRW are reported. The features of the ultrasonic inspection apparatus are explained. The inspection apparatus comprises 5 pulse motors for driving probes and one pulse motor for turning a sample. The example of flaw detection test results is shown. (K.I.)

  3. Comparison of Metallurgical and Ultrasonic Inspections of Galvanized Steel Resistance Spot Welds

    International Nuclear Information System (INIS)

    Potter, Timothy J.; Ghaffari, Bita; Mozurkewich, George; Reverdy, Frederic; Hopkins, Deborah

    2006-01-01

    Metallurgical examination of galvanized steel resistance spot welds was used to gauge the capabilities of two ultrasonic, non-destructive, scanning techniques. One method utilized the amplitude of the echo from the weld faying surface, while the other used the spectral content of the echo train to map the fused area. The specimens were subsequently sectioned and etched, to distinguish the fused, zinc-brazed, and non-fused areas. The spectral maps better matched the metallurgical maps, while the interface-amplitude method consistently overestimated the weld size

  4. Fatigue strength of welds and welded materials of high-temperature steels resistant to pressurized hydrogen of the type 2.25% Cr/1% Mo

    International Nuclear Information System (INIS)

    Burlat, J.; Cheviet, A.; Million, A.

    1986-01-01

    The aim of the study is to examine systematically the creep strength of welded joints (base material, heat influence zone and welded seam) and of pure welding materials of the type 2 1/4-3% Cr/1% Mo. According to the AD standard rules, the rule which stipulates that the creep strength of welded seams under full stress be calculated with the strength characteristic value reduced by 20% applies to all heat-resistant steels, if no rupture stress values for the welded joints are available. Manufacturers of steel and weld fillers together with the Union of Technical Control Associations (VdTUeV) have prepared a test programme according to which on the one hand welded joints are tested at right angles to their seams, and on the other pure welding material is tested with respect to its creep strength. The development of the testes and their results have been described. The first results are available as VdTUeV material performance sheets, for 2 materials, and as provisional VdTUeV specification sheets, for 3 weld fillers. With the tested materials, it becomes practically feasible to reduce the creep strength of longitudinally welded pressure-bearing components by about 20% of wall thickness. (orig.) [de

  5. Voltage balancing in modular energy storage of power supply for micro resistance welding

    Directory of Open Access Journals (Sweden)

    Kozhushko Yu. V.

    2017-10-01

    Full Text Available Micro resistance welding is one of the most effective ways to obtain permanent joints of metal parts. The quality of welded joints strongly depends on the characteristics of the power supply of welding equipment. The power supplies for micro resistance welding based on Energy Storage topology have a softer impact on the network than the ones based on Direct Energy topology. The use of supercapacitors for Energy Storage type power supplies makes it possible to reduce the dimensions of welding equipment and to improve its technical parameters. However, the feature of the supercapacitors is low value of the nominal voltage, which usually does not exceed 3 V. To provide higher voltage, the modules of supercapacitors connected in series are designed. In order to extend the life time of such modules, a voltage balancing system is required. A circuit for balancing the voltage of a modular supercapacitor energy storage of a power supply for micro resistance welding is proposed. The fragments of calculation of control units of a supercapacitor module cell are given. The simulation of the balancing circuit operation is carried out and time charts of the supercapacitor charge process are obtained. The operability and effectiveness of the proposed solution is confirmed. The advantage of the proposed circuit is the possibility of obtaining the high efficiency because of returning the excessive energy of the module cell back into the power supply.

  6. Elemental segregation during resistance spot welding of boron containing advanced high strength steels

    NARCIS (Netherlands)

    Amirthalingam, M.; Van der Aa, E.M.; Kwakernaak, C.; Hermans, M.J.M.; Richardson, I.M.

    2015-01-01

    The partitioning behaviour of carbon, phosphorous and boron during the solidification of a resistance spot weld pool was studied using experimental simulations and a phase field model. Steels with varying carbon, phosphorous and boron contents were designed and subjected to a range of resistant spot

  7. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes normally are used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium-nickel steels in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

  8. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes are normally used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0% and nickel does not exceed 50.0%

  9. Specification for corrosion-resisting chromium and chromium-nickel steel covered welding electrodes

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This specification prescribes requirements for covered corrosion-resisting chromium and chromium-nickel steel electrodes. These electrodes are normally used for shielded metal arc welding, and include those alloy steels designated as corrosion or heat-resisting chromium and chromium-nickel steels, in which chromium exceeds 4.0 percent and nickel does not exceed 50.0 percent

  10. Effect of composition on corrosion resistance of high-alloy austenitic stainless steel weld metals

    International Nuclear Information System (INIS)

    Marshall, P.I.; Gooch, T.G.

    1993-01-01

    The corrosion resistance of stainless steel weld metal in the ranges of 17 to 28% chromium (Cr), 6 to 60% nickel (Ni), 0 to 9% molybdenum (Mo), and 0.0 to 0.37% nitrogen (N) was examined. Critical pitting temperatures were determined in ferric chloride (FeCl 3 ). Passive film breakdown potentials were assessed from potentiodynamic scans in 3% sodium chloride (NaCl) at 50 C. Potentiodynamic and potentiostatic tests were carried out in 30% sulfuric acid (H 2 SO 4 ) ar 25 C, which was representative of chloride-free acid media of low redox potential. Metallographic examination and microanalysis were conducted on the test welds. Because of segregation of alloying elements, weld metal pitting resistance always was lower than that of matching composition base steel. The difference increased with higher Cr, Mo, and N contents. Segregation also reduced resistance to general corrosion in H 2 SO 4 , but the effect relative to the base steel was less marked than with chloride pitting. Segregation of Cr, Mo, and N in fully austenitic deposits decreased as the Ni' eq- Cr' eq ratio increased. Over the compositional range studied, weld metal pitting resistance was dependent mainly on Mo content and segregation. N had less effect than in wrought alloys. Both Mo and N enhanced weld metal corrosion resistance in H 2 SO 4

  11. Microstructure and mechanical properties of weld-bonded and resistance spot welded magnesium-to-steel dissimilar joints

    International Nuclear Information System (INIS)

    Xu, W.; Chen, D.L.; Liu, L.; Mori, H.; Zhou, Y.

    2012-01-01

    Highlights: ► Adhesive reduces shrinkage porosity and stress concentration around the weld nugget. ► Adhesive promotes the formation of intermetallic compounds during weld bonding. ► In Mg/steel joints fusion zone appears only at the Mg side with dendritic structures. ► Weld-bonded Mg/steel joints are considerably stronger than RSW Mg/steel joints. ► Fatigue strength is three-fold higher for weld-bonded joints than for RSW joints. - Abstract: The aim of this study was to evaluate microstructures, tensile and fatigue properties of weld-bonded (WB) magnesium-to-magnesium (Mg/Mg) similar joints and magnesium-to-steel (Mg/steel) dissimilar joints, in comparison with resistance spot welded (RSW) Mg/steel dissimilar joints. In the WB Mg/Mg joints, equiaxed dendritic and divorced eutectic structures formed in the fusion zone (FZ). In the dissimilar joints of RSW and WB Mg/steel, FZ appeared only at Mg side with equiaxed and columnar dendrites. At steel side no microstructure changed in the WB Mg/steel joints, while the microstructure in the RSW Mg/steel joints consisted of lath martensite, bainite, pearlite and retained austenite leading to an increased microhardness. The relatively low cooling rate suppressed the formation of shrinkage porosity but promoted the formation of MgZn 2 and Mg 7 Zn 3 in the WB Mg/steel joints. The added adhesive layer diminished stress concentration around the weld nugget. Both WB Mg/Mg and Mg/steel joints were significantly stronger than RSW Mg/steel joints in terms of the maximum tensile shear load and energy absorption, which also increased with increasing strain rate. Fatigue strength was three-fold higher for WB Mg/Mg and Mg/steel joints than for RSW Mg/steel joints. Fatigue failure in the RSW Mg/steel joints occurred from the heat-affected zone near the notch root at lower load levels, and in the mode of interfacial fracture at higher load levels, while it occurred in the Mg base metal at a maximum cyclic load up to ∼10 kN in

  12. Influence of electrical resistivity and machining parameters on electrical discharge machining performance of engineering ceramics.

    Science.gov (United States)

    Ji, Renjie; Liu, Yonghong; Diao, Ruiqiang; Xu, Chenchen; Li, Xiaopeng; Cai, Baoping; Zhang, Yanzhen

    2014-01-01

    Engineering ceramics have been widely used in modern industry for their excellent physical and mechanical properties, and they are difficult to machine owing to their high hardness and brittleness. Electrical discharge machining (EDM) is the appropriate process for machining engineering ceramics provided they are electrically conducting. However, the electrical resistivity of the popular engineering ceramics is higher, and there has been no research on the relationship between the EDM parameters and the electrical resistivity of the engineering ceramics. This paper investigates the effects of the electrical resistivity and EDM parameters such as tool polarity, pulse interval, and electrode material, on the ZnO/Al2O3 ceramic's EDM performance, in terms of the material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR). The results show that the electrical resistivity and the EDM parameters have the great influence on the EDM performance. The ZnO/Al2O3 ceramic with the electrical resistivity up to 3410 Ω·cm can be effectively machined by EDM with the copper electrode, the negative tool polarity, and the shorter pulse interval. Under most machining conditions, the MRR increases, and the SR decreases with the decrease of electrical resistivity. Moreover, the tool polarity, and pulse interval affect the EWR, respectively, and the electrical resistivity and electrode material have a combined effect on the EWR. Furthermore, the EDM performance of ZnO/Al2O3 ceramic with the electrical resistivity higher than 687 Ω·cm is obviously different from that with the electrical resistivity lower than 687 Ω·cm, when the electrode material changes. The microstructure character analysis of the machined ZnO/Al2O3 ceramic surface shows that the ZnO/Al2O3 ceramic is removed by melting, evaporation and thermal spalling, and the material from the working fluid and the graphite electrode can transfer to the workpiece surface during electrical discharge

  13. Welding.

    Science.gov (United States)

    Cowan, Earl; And Others

    The curriculum guide for welding instruction contains 16 units presented in six sections. Each unit is divided into the following areas, each of which is color coded: terminal objectives, specific objectives, suggested activities, and instructional materials; information sheet; transparency masters; assignment sheet; test; and test answers. The…

  14. Mechanism of selective corrosion in electrical resistance seam welded carbon steel pipe

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Fajardo, Pedro; Godinez Salcedo, Jesus; Gonzalez Velasquez, Jorge L. [Instituto Politecnico Nacional, Mexico D.F., (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas. Dept. de Ingenieria Metalurgica

    2009-07-01

    In this investigation the studies of the mechanism of selective corrosion in electrical resistance welded (ERW) carbon steel pipe was started. Metallographic characterizations and evaluations for inclusions were performed. The susceptibility of ERW pipe to selective corrosion in sea water (NACE 1D182, with O{sub 2} or CO{sub 2} + H{sub 2}S) was studied by the stepped potential Potentiostatic electrochemical test method in samples of 1 cm{sup 3} (ASTM G5) internal surface of the pipe (metal base-weld). The tests were looking for means for predicting the susceptibility of ERW pipe to selective corrosion, prior to placing the pipeline in service. Manganese sulfide inclusions are observed deformed by the welding process and they are close to the weld centerline. A slight decarburization at the weld line is observed, and a distinct out bent fiber pattern remains despite the post-weld seam annealing. The microstructure of the weld region consists of primarily polygonal ferrite grains mixed with small islands of pearlite. It is possible to observe the differences of sizes of grain of the present phases in the different zones. Finally, scanning electron microscopic observation revealed that the corrosion initiates with the dissolution of MnS inclusions and with small crack between the base metal and ZAC. (author)

  15. A knowledge-based diagnosis system for welding machine problem solving

    International Nuclear Information System (INIS)

    Bonnieres, P. de; Boutes, J.L.; Calas, M.A.; Para, S.

    1986-06-01

    This paper presents a knowledge-based diagnosis system which can be a valuable aid in resolving malfunctions and failures encountered using the automatic hot-wire TIG weld cladding process. This knowledge-based system is currently under evaluation by welding operators at the Framatome heavy fabricating facility. Extension to other welding processes is being considered

  16. Microstructure of bonding interface for resistance welding of Zr-based metallic glass sheets

    International Nuclear Information System (INIS)

    Kuroda, Toshio; Ikeuchi, Kenji; Shimada, Masahiro; Kobayashi, Akira; Kimura, Hisamichi; Inoue, Akihisa

    2009-01-01

    Resistance welding of Zr 55 Cu 30 Al 10 Ni 5 metallic glass sheets was investigated at 723 K in a supercooled liquid region. The welding time was changed from 5 s to 20 s at 723 K. The joint interface of the metallic glass was no defect and no crack. X-ray diffraction technique of the bonding interface of specimens was performed. The specimens showed halo patterns showing existence of only glassy phase, when the welding time was 5 s and 10 s. X-ray diffraction patterns of specimen bonded for 20 s showed crystalline peaks with halo patterns for the welding for 20 s. The crystalline phase at the bonding interface was small. Transmission electron micrograph at the bonding interface showed nanostructures of NiZr 2 and Al 5 Ni 3 Zr 2 . (author)

  17. Electrochemical heterogeneity and corrosion resistance of a welded titanium-zirconium joint

    International Nuclear Information System (INIS)

    Polyakov, S.G.; Goncharov, A.B.; Onoprienko, L.M.; Smiyan, O.D.

    1992-01-01

    The electrochemical behavior and corrosion resistance of various welded joints of zirconium alloy N-2.5 with commercial titanium VT1 made by the argon-arc method are studied. Electrochemical heterogeneity is studied by measuring the distribution of potentials over the surface, galvanic currents, and recording of polarization curves for different zones of a welded joint in 5% sulfuric acid solution at 340 K. It is established that electrochemical heterogeneity of the zones of an N-2.5 + VT1 welded joint leads to acceleration of the cathodic process in a welded joint and the anodic process along the fusion line from the titanium direction where the greatest hydrogenation of the metal and corrosion damage is correspondingly observed

  18. Embedded Artificial Neuval Network-Based Real-Time Half-Wave Dynamic Resistance Estimation during the A.C. Resistance Spot Welding Process

    Directory of Open Access Journals (Sweden)

    Liang Gong

    2013-01-01

    Full Text Available Online monitoring of the instantaneous resistance variation during the A.C. resistance spot welding is of paramount importance for the weld quality control. On the basis of the welding transformer circuit model, a new method is proposed to measure the transformer primary-side signal for estimating the secondary-side resistance in each 1/4 cycle. The tailored computing system ensures that the measuring method possesses a real-time computational capacity with satisfying accuracy. Since the dynamic resistance cannot be represented via an explicit function with respect to measurable parameters from the primary side of the welding transformer, an offline trained embedded artificial neural network (ANN successfully realizes the real-time implicit function calculation or estimation. A DSP-based resistance spot welding monitoring system is developed to perform ANN computation. Experimental results indicate that the proposed method is applicable for measuring the dynamic resistance in single-phase, half-wave controlled rectifier circuits.

  19. Drag resistance measurements for newly applied antifouling coatings and welding seams on ship hull surface

    DEFF Research Database (Denmark)

    Wang, Xueting; Olsen, S. M.; Andres, E.

    Drag resistances of newly applied antifouling coatings and welding seams on ship hull surface have been investigated using a pilot-scale rotary setup. Both conventional biocide-based antifouling (AF) coatings and silicone-based fouling release (FR) coatings have been studied and compared in their......Drag resistances of newly applied antifouling coatings and welding seams on ship hull surface have been investigated using a pilot-scale rotary setup. Both conventional biocide-based antifouling (AF) coatings and silicone-based fouling release (FR) coatings have been studied and compared...

  20. Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

    Science.gov (United States)

    Zhang, Zhiqiang; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; Zhao, Lei; Zhang, Jianli

    2017-02-01

    The influences of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel joints welded by gas tungsten arc welding (GTAW) and flux-cored arc welding (FCAW) with different shielding gas compositions were studied by optical microscopy, electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, and potentiostatic and potentiodynamic polarization methods The adding 2% N2 in shielding gas facilitated primary austenite formation in GTAW weld metal (WM) and suppressed Cr2N precipitation in GTAW weld root. In the HAZ, the banded microstructure disappeared while the coarse ferrite grains maintained same orientation as the banded ferrite in the BM. In the WM, the ferrite had one single orientation throughout a grain, whereas several families of austenite appeared. The austenite both in BM and WM enriched in Ni and nitro`gen, while Cr and Mo were concentrated in the ferrite and thus no element showed clear dendritic distribution in the WM (ER2209 and E2209T1). In addition, the secondary austenite had higher Ni content but lower Cr and Mo content than the primary austenite. The N2-supplemented shielding gas promoted nitrogen solid-solution in the primary and secondary austenite. Furthermore, the secondary austenite had relatively lower pitting resistance equivalent number (PREN) than the ferrite and primary austenite, thereby resulting in its preferential corrosion. The Cr2N precipitation led to relatively poor resistance to pitting corrosion in three HAZs and pure Ar shielding GTAW weld root. The N2-supplemented shielding gas improved pitting corrosion resistance of GTAW joint by increasing PREN of secondary austenite and suppressing Cr2N precipitation. In addition, the FCAW WM had much poorer resistance to pitting corrosion than the GTAW WM due to many O-Ti-Si-Mn inclusions. In the BM, since the austenite with lower PREN compared

  1. Precision machining, sheet-metal work and welding at the heart of CERN

    CERN Multimedia

    2001-01-01

    From the writing of specifications and the production of high-tech components, to technology transfer and call-out work on-site, the MF group in EST Division offers CERN users a wide variety of services. Its full range of activities is presented in a new brochure. In addition to its many physicists and engineers, CERN also has teams of mechanics, welders and sheet-metalworkers whose expertise is a precious asset for the Organization. Within the MF Group (Manufacturing Facilities, EST Division) these teams perform precision machining, sheet-metal work and welding. As an example, the Group has been responsible for producing radiofrequency accelerating cells to a precision of the order of 1/100th mm and with a surface roughness of only 0.1 micron. The Group's workshops also manufactured the stainless steel vacuum chamber for the brand new n-TOF experiment (Bulletin n°47/2000), a 200-m long cylindrical chamber with a diameter of just 800 millimetres! The MF Group is assisted in its task of providing me...

  2. Laser and Pressure Resistance Weld of Thin-Wall Cladding for LWR Accident-Tolerant Fuels

    Science.gov (United States)

    Gan, J.; Jerred, N.; Perez, E.; Haggard, D. C.

    2018-02-01

    FeCrAl alloy with typical composition of approximately Fe-15Cr-5Al is considered a primary candidate cladding material for light water reactor accident-tolerant fuel because of its superior resistance to oxidation in high-temperature steam compared with Zircaloy cladding. Thin-walled FeCrAl cladding at 350 μm wall thickness is required, and techniques for joining endplug to cladding need to be developed. Fusion-based laser weld and solid-state joining with pressure resistance weld were investigated in this study. The results of microstructural characterization, mechanical property evaluation by tensile testing, and hydraulic pressure burst testing of the welds for the cladding-endplug specimen are discussed.

  3. Resistance welding of ODS cladding fuel a nuclear reactor of the fourth generation

    International Nuclear Information System (INIS)

    Corpace, F.

    2011-01-01

    ODS steels (Oxide Dispersion Strengthened) are candidate materials for fuel cladding in Sodium Fast Reactors (SFR), one of the studied concepts for the fourth generation of nuclear power plants. These materials possess good mechanical properties at high temperatures due to a dispersion of nano-meter-sized oxides into the matrix. Previous studies have shown that melting can induce a decrease in mechanical properties at high temperatures due to modifications of the nano-meter-sized oxide dispersion. Therefore the fusion welding techniques are not recommended and the solid state bonding has to be evaluated. This study is focused on resistance upset welding. Welding experiments and numerical simulations of the process are coupled in this thesis. All laboratory tests (experimental and numerical) are built using the experimental design method to evaluate the effects of the process parameters on the welding and on the weld. A 20Cr ODS steel is used for the experimental protocol. The first part is dedicated to the study of the influence of the process parameters on the welding process. The numerical simulations show that the welding steps can be divided in three stages. First, the contact temperature between the faying surfaces increases. The process is then driven in the second stage by the pieces geometry and especially the current constriction due to the thinness of the clad compared to the massive plug. Therefore, the heat generation is mainly located in the clad part out of the electrode leading to its collapse which is the third stage of the welding step. The evaluation of the process parameters influence on the physical phenomena (thermal, mechanical...) occurring during the welding step, allows adjusting them in order to influence thermal and mechanical solicitations undergone by the pieces during the welding process. The second part consists in studying the influence of physical phenomena on the welds. In the process parameter range, some welds exhibit compactness

  4. Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiqiang; Jing, Hongyang [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Xu, Lianyong, E-mail: xulianyong@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Han, Yongdian; Zhao, Lei [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Zhang, Jianli [Welding laboratory, Offshore Oil Engineering (Qing Dao) Company, Qing Dao 266520 (China)

    2017-02-01

    Highlights: • N{sub 2}-supplemented shielding gas promoted nitrogen solid-solution in the austenite. • Secondary austenite had higher Ni but lower Cr and Mo than primary austenite. • Pitting corrosion preferentially occurred at secondary austenite and Cr{sub 2}N. • Adding N{sub 2} in shielding gas improved pitting corrosion resistance of GTAW joint. • E2209T{sub 1} weld metal had very poor pitting corrosion resistance due to inclusions. - Abstract: The influences of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel joints welded by gas tungsten arc welding (GTAW) and flux-cored arc welding (FCAW) with different shielding gas compositions were studied by optical microscopy, electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, and potentiostatic and potentiodynamic polarization methods The adding 2% N{sub 2} in shielding gas facilitated primary austenite formation in GTAW weld metal (WM) and suppressed Cr{sub 2}N precipitation in GTAW weld root. In the HAZ, the banded microstructure disappeared while the coarse ferrite grains maintained same orientation as the banded ferrite in the BM. In the WM, the ferrite had one single orientation throughout a grain, whereas several families of austenite appeared. The austenite both in BM and WM enriched in Ni and nitrogen, while Cr and Mo were concentrated in the ferrite and thus no element showed clear dendritic distribution in the WM (ER2209 and E2209T{sub 1}). In addition, the secondary austenite had higher Ni content but lower Cr and Mo content than the primary austenite. The N{sub 2}-supplemented shielding gas promoted nitrogen solid-solution in the primary and secondary austenite. Furthermore, the secondary austenite had relatively lower pitting resistance equivalent number (PREN) than the ferrite and primary austenite, thereby resulting in its preferential

  5. Effect of electromagnetic interaction during fusion welding of AISI 2205 duplex stainless steel on the corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    García-Rentería, M.A., E-mail: marcogarciarenteria@uadec.edu.mx [Faculty of Metallurgy, Autonomous University of Coahuila, Carretera 57 Km. 5, CP 25720, Monclova, Coahuila (Mexico); López-Morelos, V.H., E-mail: vhlopez@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); González-Sánchez, J., E-mail: jagonzal@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); García-Hernández, R., E-mail: rgarcia@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); Dzib-Pérez, L., E-mail: franciscocl7@yahoo.com.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); Curiel-López, F.F., E-mail: franciscocl7@yahoo.com.mx [Faculty of Metallurgy, Autonomous University of Coahuila, Carretera 57 Km. 5, CP 25720, Monclova, Coahuila (Mexico)

    2017-02-28

    Highlights: • Application of EMILI during welding 2205 Duplex stainless steel hindered the coarsening of δ grains in HTHAZ and promoted regeneration of γ. • Welds made with simultaneous EMILI presented TPI values at the HTHAZ similar to those for BM. • Welds made under 3, 12 and 15 mT presented a mass loss by anodic polarisation similar to that observed for the as-received BM. • This behaviour is due to changes in the dynamics of microstructural evolution during welding with EMILI. - Abstract: The effect of electromagnetic interaction of low intensity (EMILI) applied during fusion welding of AISI 2205 duplex stainless steel on the resistance to localised corrosion in natural seawater was investigated. The heat affected zone (HAZ) of samples welded under EMILI showed a higher temperature for pitting initiation and lower dissolution under anodic polarisation in chloride containing solutions than samples welded without EMILI. The EMILI assisted welding process developed in the present work enhanced the resistance to localised corrosion due to a modification on the microstructural evolution in the HAZ and the fusion zone during the thermal cycle involved in fusion welding. The application of EMILI reduced the size of the HAZ, limited coarsening of the ferrite grains and promoted regeneration of austenite in this zone, inducing a homogeneous passive condition of the surface. EMILI can be applied during fusion welding of structural or functional components of diverse size manufactured with duplex stainless steel designed to withstand aggressive environments such as natural seawater or marine atmospheres.

  6. Machinability of magnesium and aluminium alloys. Part I: cutting resistance

    International Nuclear Information System (INIS)

    Balout, B.; Songmene, V.; Masounave, J.

    2002-01-01

    Aluminium (2.7 g/cm 3 ) and magnesium (1.7 g/cm 3 ) are two competing light metals with similar mechanical properties and excellent possibilities for recycling. The forming of magnesium is often seen as an impediment to its use. New forming techniques using magnesium shavings are being developed, particularly in Japan. The machining of magnesium alloys by removal of metal raises safety concerns (risk of fire), which limits many potential applications of magnesium. The purpose of this work is to clarify and compare the machining properties of these two types of metal and better understand the mechanisms that may explain the differences in behaviour. Such a comparison could eventually provide an estimate of the cost of producing shavings for the manufacture of aluminium and magnesium parts through forging and extrusion, which would limit environmental pollution. Based on an analysis of cutting resistance during machining, it was demonstrated that magnesium alloys are easier to machine than similar aluminium alloys. Magnesium shavings are shorter than those of 6061-T6, but are especially more regular than those of A356, and their size is independent of cutting speed. It was also demonstrated that the fragility of materials can be characterized based on the results of cutting resistance produced during drilling

  7. Studies on the Corrosion Resistance of Laser-Welded Inconel 600 and Inconel 625 Nickel-Based Superalloys

    Directory of Open Access Journals (Sweden)

    Łyczkowska K.

    2017-06-01

    Full Text Available The paper presents the results of the electrochemical corrosion tests of Inconel 600 and Inconel 625 laser-welded superalloys. The studies were conducted in order to assess the resistance to general and pitting corrosion in 3.5% NaCl solution. It was found that Inconel 600 possesses good corrosion resistance, however Inconel 625 is characterized by a greater resistance to general and also to pitting corrosion of the weld as well as the base metal.

  8. Artificial neural networks for prediction of quality in resistance spot welding

    International Nuclear Information System (INIS)

    Martin, O.; Lopez, M.; Martin, F.

    2006-01-01

    An artificial neural network is proposed as a tool for predicting from three parameters (weld time, current intensity and electrode sort) if the quality of a resistance spot weld reaches a certain level or not. The quality id determined by cross tension testing. The fact of reaching this quality level or not is the desired output that goes with each input of the artificial neural network during its supervised learning. The available data set is made up of input/desired output pairs and is split randomly into a training subset (to update synaptic weight values) and a validation subset (to avoid overfitting phenomenon by means of cross validation). (Author) 44 refs

  9. Microstructure and Hardness Distribution of Resistance Welded Advanced High Strength Steels

    DEFF Research Database (Denmark)

    Pedersen, Kim Richardt; Harthøj, Anders; Friis, Kasper Leth

    2008-01-01

    In this work a low carbon steel and two high strength steels (DP600 and TRIP700) have been resistance lap welded and the hardness profiles were measured by micro hardness indentation of cross sections of the joint. The resulting microstructure of the weld zone of the DP-DP and TRIP-TRIP joints were...... found to consist of a martensitic structure with a significant increase in hardness. Joints of dissimilar materials mixed completely in the melted region forming a new alloy with a hardness profile lying in between the hardness measured in joints of the similar materials. Furthermore the joints were...

  10. Comparative Analysis of Welded and Adhesive Joints Strength Made of Acid-Resistant Stainless Steel Sheets

    Directory of Open Access Journals (Sweden)

    Izabela Miturska

    2017-12-01

    Full Text Available The article presents the selected results of strength tests on the effectiveness of bonding high-alloy steel 1.4310. Sheet steel is one of the materials that are difficult to activate energy. Effective joining of it is difficult, requires selection of the appropriate bonding technology. The paper focuses on the comparative tests the shear strength of one-single lap welded and bonded joints. The welding process was performed 3 groups of samples TIG welding and argon, where the variable value of the welding process was current: 60A, 70A, 80A. The adhesion process was performed in 6 groups of samples which differed in the method of surface preparation and the type of the adhesive. Adhesive joints were made by using adhesive of epoxy resin and a hardener: Epidian 61/TFF at a mass ratio of 100:22 and Epidian 61/IDA at a mass ratio of 100:40. As a way of surface preparation applied 3 different, but simplified and environmentally friendly methods of surface preparation: degreasing with using cleaner Loctite 7061, abrasive machining with P320 and degreasing and grinding with abrasive T800 and degreasing were used. Make joints and curing the adhesive joints were carried out at ambient temperature. Analyzed the joints were tested destructive - which set out the shear strength, in accordance with DIN EN 1465 on the testing machine Zwick / Roell Z150. Based on the results of research it was found that better results were obtained for the maximum welded joints, but this result was similar to the maximum value of the strength of the adhesive bond.

  11. Development of Magnetorheological Resistive Exercise Device for Rowing Machine

    Directory of Open Access Journals (Sweden)

    Vytautas Grigas

    2016-01-01

    Full Text Available Training equipment used by professional sportsmen has a great impact on their sport performance. Most universal exercisers may help only to improve the general physical condition due to the specific kinematics and peculiar resistance generated by their loading units. Training of effective techniques and learning of psychomotor skills are possible only when exercisers conform to the movements and resistance typical for particular sports kinematically and dynamically. Methodology of developing a magnetorheological resistive exercise device for generating the desired law of passive resistance force and its application in a lever-type rowing machine are described in the paper. The structural parameters of a controllable hydraulic cylinder type device were found by means of the computational fluid dynamics simulation performed by ANSYS CFX software. Parameters describing the magnetorheological fluid as non-Newtonian were determined by combining numerical and experimental research of the resistance force generated by the original magnetorheological damper. A structural scheme of the device control system was developed and the variation of the strength of magnetic field that affects the magnetorheological fluid circulating in the device was determined, ensuring a variation of the resistance force on the oar handle adequate for the resistance that occurs during a real boat rowing stroke.

  12. Effect of residual stress and hardening on grain boundary sliding in welds of low-carbon stainless steels with surface machining

    International Nuclear Information System (INIS)

    Mori, Hiroaki; Mochizuki, Masahito; Nishimoto, Kazutoshi; Katsuyama, Jinya

    2007-01-01

    To clarify the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in welds of low-carbon austenitic stainless steels with surface machining, residual stress and hardness were evaluated by 3-dimentional thermo elastic-plastic analysis and grain boundary sliding behavior was examined using a constant strain rate tensile test. It was revealed that grain boundary sliding occurred in the material at 561K by the tensile test with the numerically simulated tensile residual stress due to welding and surface machining. In addition, it was clarified that the grain boundary energy is raised by the grain boundary sliding. On the basis of these results, it was concluded that the cause of IGSCC in the welds of low-carbon austenitic stainless steel with surface hardening is the increase in grain boundary energy due to grain boundary sliding accelerated by residual stress of multi pass welding and surface hardening. (author)

  13. Effect of residual stress and hardening on grain boundary sliding in welds of low-carbon stainless steels with surface machining

    International Nuclear Information System (INIS)

    Mori, Hiroaki; Mochizuki, Masahito; Nishimoto, Kazutoshi; Katsuyama, Jinya

    2008-01-01

    To clarify the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in welds of low-carbon austenitic stainless steels with surface machining, residual stress and hardness were evaluated by 3-dimentional thermo elastic-plastic analysis and grain boundary sliding behavior was examined using a constant strain rate tensile test. It was revealed that grain boundary sliding occurred in the material at 561K by the tensile test with the numerically simulated tensile residual stress due to multi-pass welding and surface machining. In addition, it was clarified that the grain boundary energy is raised by the grain boundary sliding. On the basis of these results, it was concluded that the cause of IGSCC in the welds of low-carbon austenitic stainless steel with surface hardening is the increase in grain boundary energy due to grain boundary sliding induced by residual stress of multi pass welding and surface hardening. (author)

  14. Resistance to wear and microstructure of martensitic welds deposits for recharge

    International Nuclear Information System (INIS)

    Gualco, Agustin; Svoboda, Hernan G; Surian, Estela S; Vedia, Luis A

    2006-01-01

    This work studied the welding metal for a martensitic steel (alloyed to Cr, Mn, Mo, V and W), deposited with a tubular metal-cored wire with gaseous protection of 82%Ar-18%Co 2 on a low carbon steel using the semi-automatic welding process. Transverse pieces were cut from the welded coupon for microstructural characterization, measurement of hardness profiles, determination of the chemical composition and wear trials. The microstructural characterization was done using optic and scanning electronic microscopes, X-rays diffraction and energy-dispersive X-ray spectroscopy and Vicker microhardness (1 kg.) was measured. The wear trials (metal-metal) were performed in an Amsler machine under pure flow conditions. Different loads were used and the reference material was a SAE 1020 steel. The temperatures for each case were measured and the weight loss curves were defined as a function of the distance run and of the load. After testing the wear surfaces and the debris were measured. The microstructure of the welded deposit mostly consists of martensite and some retained austenite, with a pattern of dendritic segregation, and a hardness on the surface of 612 HVI. A lineal variation between the weight loss and the load applied was obtained as a response to the wear. The following phenomena were observed: abrasion, plastic deformation, oxidation and adhesion to the wear surfaces, as well as a tempering effect in the condition of the biggest load. The wear mechanisms acting on both surfaces were identified (CW)

  15. Effects of surface coating on weld growth of resistance spot-welded hot-stamped boron steels

    International Nuclear Information System (INIS)

    Ji, Chang Wook; Lee, Hyun Ju; Kim, Yang Do; Jo, Il Guk; Choi, Il Dong; Park, Yeong Do

    2014-01-01

    Aluminum-silicon-based and zinc-based metallic coatings have been widely used for hot-stamped boron steel in automotive applications. In this study, resistance spot weldability was explored by investigating the effects of the properties of metallic coating layers on heat development and nugget growth during resistance spot welding. In the case of the aluminum-silicon-coated hot-stamped boron steel, the intermetallic coating transformed into a liquid film that covered the faying interface. A wide, weldable current range was obtained with slow heat development because of low contact resistance and large current passage. In the case of the zinc-coated hot-stamped boron steel, a buildup of liquid and vapor formation under large vapor pressure was observed at the faying interface because of the high contact resistance and low vaporization temperature of the intermetallic layers. With rapid heat development, the current passage was narrow because of the limited continuous layer at the faying interface. A more significant change in nugget growth was observed in the zinc coated hot-stamped boron steel than in the aluminum-silicon-coated hot-stamped boron steel.

  16. Development and control towards a parallel water hydraulic weld/cut robot for machining processes in ITER vacuum vessel

    International Nuclear Information System (INIS)

    Wu Huapeng; Handroos, Heikki; Pessi, Pekka; Kilkki, Juha; Jones, Lawrence

    2005-01-01

    This paper presents a special robot, able to carry out welding and machining processes from inside the ITER vacuum vessel (VV), consisting of a five degree-of-freedom parallel mechanism, mounted on a carriage driven by two electric motors on a rack. The kinematic design of the robot has been optimised for ITER access and a hydraulically actuated pre-prototype built. A hybrid controller is designed for the robot, including position, speed and pressure feedback loops to achieve high accuracy and high dynamic performances. Finally, the experimental tests are given and discussed

  17. Novel Robot Solutions for Carrying out Field Joint Welding and Machining in the Assembly of the Vacuum Vessel of ITER

    International Nuclear Information System (INIS)

    Pessi, P.

    2009-01-01

    It is necessary to use highly specialized robots in ITER (International Thermonuclear Experimental Reactor) both in the manufacturing and maintenance of the reactor due to a demanding environment. The sectors of the ITER vacuum vessel (VV) require more stringent tolerances than normally expected for the size of the structure involved. VV consists of nine sectors that are to be welded together. The vacuum vessel has a toroidal chamber structure. The task of the designed robot is to carry the welding apparatus along a path with a stringent tolerance during the assembly operation. In addition to the initial vacuum vessel assembly, after a limited running period, sectors need to be replaced for repair. Mechanisms with closed-loop kinematic chains are used in the design of robots in this work. One version is a purely parallel manipulator and another is a hybrid manipulator where the parallel and serial structures are combined. Traditional industrial robots that generally have the links actuated in series are inherently not very rigid and have poor dynamic performance in high speed and high dynamic loading conditions. Compared with open chain manipulators, parallel manipulators have high stiffness, high accuracy and a high force/torque capacity in a reduced workspace. Parallel manipulators have a mechanical architecture where all of the links are connected to the base and to the end-effector of the robot. The purpose of this thesis is to develop special parallel robots for the assembly, machining and repairing of the VV of the ITER. The process of the assembly and machining of the vacuum vessel needs a special robot. By studying the structure of the vacuum vessel, two novel parallel robots were designed and built; they have six and ten degrees of freedom driven by hydraulic cylinders and electrical servo motors. Kinematic models for the proposed robots were defined and two prototypes built. Experiments for machine cutting and laser welding with the 6-DOF robot were

  18. Novel Robot Solutions for Carrying out Field Joint Welding and Machining in the Assembly of the Vacuum Vessel of ITER

    Energy Technology Data Exchange (ETDEWEB)

    Pessi, P.

    2009-07-01

    It is necessary to use highly specialized robots in ITER (International Thermonuclear Experimental Reactor) both in the manufacturing and maintenance of the reactor due to a demanding environment. The sectors of the ITER vacuum vessel (VV) require more stringent tolerances than normally expected for the size of the structure involved. VV consists of nine sectors that are to be welded together. The vacuum vessel has a toroidal chamber structure. The task of the designed robot is to carry the welding apparatus along a path with a stringent tolerance during the assembly operation. In addition to the initial vacuum vessel assembly, after a limited running period, sectors need to be replaced for repair. Mechanisms with closed-loop kinematic chains are used in the design of robots in this work. One version is a purely parallel manipulator and another is a hybrid manipulator where the parallel and serial structures are combined. Traditional industrial robots that generally have the links actuated in series are inherently not very rigid and have poor dynamic performance in high speed and high dynamic loading conditions. Compared with open chain manipulators, parallel manipulators have high stiffness, high accuracy and a high force/torque capacity in a reduced workspace. Parallel manipulators have a mechanical architecture where all of the links are connected to the base and to the end-effector of the robot. The purpose of this thesis is to develop special parallel robots for the assembly, machining and repairing of the VV of the ITER. The process of the assembly and machining of the vacuum vessel needs a special robot. By studying the structure of the vacuum vessel, two novel parallel robots were designed and built; they have six and ten degrees of freedom driven by hydraulic cylinders and electrical servo motors. Kinematic models for the proposed robots were defined and two prototypes built. Experiments for machine cutting and laser welding with the 6-DOF robot were

  19. Laser, tungsten inert gas, and metal active gas welding of DP780 steel: Comparison of hardness, tensile properties and fatigue resistance

    International Nuclear Information System (INIS)

    Lee, Jeong Hun; Park, Sung Hyuk; Kwon, Hyuk Sun; Kim, Gyo Sung; Lee, Chong Soo

    2014-01-01

    Highlights: • We report the mechanical properties of DP780 steel welded by three methods. • The size of the welded zone increases with heat input (MAG > TIG > laser). • The hardness of the welded zone increases with cooling rate (laser > TIG > MAG). • Tensile and fatigue properties are strongly dependent on welding method. • Crack initiation sites depend on the microstructural features of the welded zone. - Abstract: The microstructural characteristics, tensile properties and low-cycle fatigue properties of a dual-phase steel (DP780) were investigated following its joining by three methods: laser welding, tungsten inert gas (TIG) welding, and metal active gas (MAG) welding. Through this, it was found that the size of the welded zone increases with greater heat input (MAG > TIG > laser), whereas the hardness of the weld metal (WM) and heat-affected zone (HAZ) increases with cooling rate (laser > TIG > MAG). Consequently, laser- and TIG-welded steels exhibit higher yield strength than the base metal due to a substantially harder WM. In contrast, the strength of MAG-welded steel is reduced by a broad and soft WM and HAZ. The fatigue life of laser-and TIG-welded steel was similar, with both being greater than that of MAG-welded steel; however, the fatigue resistance of all welds was inferior to that of the non-welded base metal. Finally, crack initiation sites were found to differ depending on the microstructural characteristics of the welded zone, as well as the tensile and cyclic loading

  20. Electrochemical machining of burn-resistant Ti40 alloy

    Directory of Open Access Journals (Sweden)

    Xu Zhengyang

    2015-08-01

    Full Text Available This study investigates the feasibility of using electrochemical machining (ECM to produce critical aeroengine components from a new burn-resistant titanium alloy (Ti40, thereby reducing costs and improving efficiency relative to conventional mechanical machining. Through this, it is found that an aqueous mix of sodium chloride and potassium bromide provides the optimal electrolyte and that the surface quality of the Ti40 workpiece is improved by using a pulsed current of 1 kHz rather than a direct current. Furthermore, the quality of cavities produced by ECM and the overall material removal rate are determined to be dependent on a combination of operating voltage, electrolyte inlet pressure, cathode feeding rate and electrolyte concentration. By optimizing these parameters, a surface roughness of 0.371 μm has been achieved in conjunction with a specific removal rate of more than 3.1 mm3/A·min.

  1. Characterization of the corrosion resistance of biologically active solutions: The effects of anodizing and welding

    Science.gov (United States)

    Walsh, Daniel W.

    1991-01-01

    An understanding of fabrication processes, metallurgy, electrochemistry, and microbiology is crucial to the resolution of microbiologically influenced corrosion (MIC) problems. The object of this effort was to use AC impedance spectroscopy to characterize the corrosion resistance of Type II anodized aluminum alloy 2219-T87 in sterile and biologically active media and to examine the corrosion resistance of 316L, alloy 2219-T87, and titanium alloy 6-4 in the welded and unwelded conditions. The latter materials were immersed in sterile and biologically active media and corrosion currents were measured using the polarization resistance (DC) technique.

  2. The role of nitrogen in improving pitting corrosion resistance of high-alloy austenitic and duplex stainless steel welds

    International Nuclear Information System (INIS)

    Vilpas, M.; Haenninen, H.

    1999-01-01

    The effects of nitrogen alloyed shielding gas on weld nitrogen content and pitting corrosion resistance of super austenitic (6%Mo) and super duplex stainless steels have been studied with special emphasis on microsegregation behaviour of Cr, Mo and N. The measurements performed with the 6%Mo steel indicate that all these elements segregate interdendritically in the fully austenitic weld metal. With nitrogen addition to the shielding gas the enrichment of nitrogen to the interdendritic regions is more pronounced than to the dendrite cores due to which the pitting corrosion resistance of the dendrite cores increases only marginally. In the super duplex steel welds nitrogen enriches in austenite increasing its pitting corrosion resistance more effectively. In these welds the pitting corrosion resistance of the ferrite phase remains lower. (orig.)

  3. Modeling of electric and heat processes in spot resistance welding of cross-wire steel bars

    Science.gov (United States)

    Iatcheva, Ilona; Darzhanova, Denitsa; Manilova, Marina

    2018-03-01

    The aim of this work is the modeling of coupled electric and heat processes in a system for spot resistance welding of cross-wire reinforced steel bars. The real system geometry, dependences of material properties on the temperature, and changes of contact resistance and released power during the welding process have been taken into account in the study. The 3D analysis of the coupled AC electric and transient thermal field distributions is carried out using the finite element method. The novel feature is that the processes are modeled for several successive time stages, corresponding to the change of contact area, related contact resistance, and reduction of the released power, occurring simultaneously with the creation of contact between the workpieces. The values of contact resistance and power changes have been determined on the basis of preliminary experimental and theoretical investigations. The obtained results present the electric and temperature field distributions in the system. Special attention has been paid to the temperature evolution at specified observation points and lines in the contact area. The obtained information could be useful for clarification of the complicated nature of interrelated electric, thermal, mechanical, and physicochemical welding processes. Adequate modeling is also an opportunity for proper control and improvement of the system.

  4. Crack Resistance of Welded Joints of Pipe Steels of Strength Class K60 of Different Alloying Systems

    Science.gov (United States)

    Tabatchikova, T. I.; Tereshchenko, N. A.; Yakovleva, I. L.; Makovetskii, A. N.; Shander, S. V.

    2018-03-01

    The crack resistance of welded joints of pipe steels of strength class K60 and different alloying systems is studied. The parameter of the crack tip opening displacement (CTOD) is shown to be dependent on the size of the austenite grains and on the morphology of bainite in the superheated region of the heat-affected zone of the weld. The crack resistance is shown to be controllable due to optimization of the alloying system.

  5. Influence of structure on static cracking resistance and fracture of welded joints of pipe steels of strength class K60

    Science.gov (United States)

    Tereshchenko, N. A.; Tabatchikova, T. I.; Yakovleva, I. L.; Makovetskii, A. N.; Shander, S. V.

    2017-07-01

    The static cracking resistance of a number of welded joints made from pipe steels of K60 strength class has been determined. It has been established that the deformation parameter CTOD varies significantly at identical parameters of weldability of steels. The character of fracture has been investigated and the zone of local brittleness of welded joints has been studied. It has been shown that the ability of a metal to resist cracking is determined by the austenite grain size and by the bainite morphology in the region of overheating in the heat-affected zone of a welded joint.

  6. Corrosion Resistance Evaluation of Welded AISI 316 Stainless Steel by Electrochemical Method

    International Nuclear Information System (INIS)

    Baik, Shin Young; Kim, Kwan Hyu

    1990-01-01

    Electrochemical potentiokinetic polarization technique is known as quantitative, non-destructive and a rapid method for detecting sensitization and is essentially suitable for use in industrial fields and as laboratory research tools. In this study, electrochemical method was tested as a convenient means of the corrosion resistance evaluation for AISI 316L and 316 stainless steel(SS) and their welded sections. The sections were welded by TIG, MIG, CO 2 and ARC in 0.5N HCl as well as 1N H 2 SO 4 electrolyte with or without 0.01N KSCN. The results confirmed that electrochemical method could be used conveniently for corrosion resistance evaluation except reactivation aspect

  7. Microstructural and mechanical behavior of friction welds in a high creep resistance magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, G.A.; Olea, C.A.W.; dos Santos, J.F.; Kainer, K.U. [GKSS-Forschungszentrum Geesthacht GmbH, Institute for Materials Research, D-21502 Geesthacht (Germany)

    2007-09-15

    Friction weldability of Mg based alloys has been worldwide discussed. Within this context the aim of this study was to investigate rotational friction welding of an Aluminum-Rare Earth based high creep resistance Mg alloy AE42HP from the viewpoint of thermo cycle-microstructure-performance relationships to evaluate the potential use of FW in joining modern Mg-alloys. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  8. Analysis of fatigue resistance of continuous and non-continuous welded rectangular frame intersections by finite element method

    International Nuclear Information System (INIS)

    McCoy, M. L.; Moradi, R.; Lankarani, H. M.

    2011-01-01

    Agricultural and construction equipment are commonly implemented with rectangular tubing in their structural frame designs. A typical joining method to fabricate these frames is by welding and the use of ancillary structural plating at the connections. This aids two continuous members to pass through an intersection point of the frame with some degree of connectivity, but the connections are highly unbalanced as the tubing centroids exhibit asymmetry. Due to the practice of welded continuous member frame intersections in current agricultural equipment designs, a conviction may exist that welded continuous member frames are superior in structural strength over that of structural frame intersections implementing welded non-continuous members where the tubing centroids lie within two planes of symmetry, a connection design that would likely fabricating a more fatigue resistant structural frame. Three types of welded continuous tubing frame intersections currently observed in the designs of agricultural equipment were compared to two non-continuous frame intersection designs. Each design was subjected to the same loading condition and then examined for stress levels using the Finite Element Method to predict fatigue life. Results demonstrated that a lighter weight, non-continuous member frame intersection design was two magnitudes superior in fatigue resistance than some current implemented frame designs when using Stress-Life fatigue prediction methods and empirical fatigue strengths for fillet welds. Stress-Life predictions were also made using theoretical fatigue strength calculations for the fatigue strength at the welds for comparison to the empirical derived weld fatigue strength

  9. Effect of rotation speed and welding speed on Friction Stir Welding of AA1100 Aluminium alloy

    Science.gov (United States)

    Raja, P.; Bojanampati, S.; Karthikeyan, R.; Ganithi, R.

    2018-04-01

    Aluminum AA1100 is the most widely used grade of Aluminium due to its excellent corrosion resistance, high ductility and reflective finish, the selected material was welded with Friction Stir Welding (FSW) process on a CNC machine, using a combination of different tool rotation speed (1500 rpm, 2500 rpm, 3500 rpm) and welding speed (10 mm/min, 30 mm/min, 50 mm/min) as welding parameters. The effect of FSW using this welding parameter was studied by measuring the ultimate tensile strength of the welded joints. A high-speed steel tool was prepared for welding the Aluminium AA1100 alloy having an 8mm shoulder diameter and pin dimension of 4mm diameter and 2.8 mm length. The welded joints were tested using the universal testing machine. It was found that Ultimate Tensile Strength of FSW specimen was highest with a value of 98.08 MPa when the weld was performed at rotation speed of 1500 RPM and welding speed of 50 mm/min.

  10. A study on corrosion resistance of dissimilar welds between Monel 400 and 316L austenitic stainless steel

    Science.gov (United States)

    Mani, Cherish; Karthikeyan, R.; Vincent, S.

    2018-04-01

    An attempt has been made to study the corrosion resistance of bi-metal weld joints of Monel 400 tube to stainless steel 316 tube by GTAW process. The present research paper contributes to the ongoing research work on the use of Monel400 and 316L austenitic stainless steel in industrial environments. Potentiodynamic method is used to investigate the corrosion behavior of Monel 400 and 316L austenitic stainless steel welded joints. The analysis has been performed on the base metal, heat affected zone and weld zone after post weld heat treatment. Optical microscopy was also performed to correlate the results. The heat affected zone of Monel 400 alloy seems to have the lowest corrosion resistance whereas 316L stainless steel base metal has the highest corrosion resistance.

  11. Microstructure and Tensile-Shear Properties of Resistance Spot-Welded Medium Mn Steel

    Directory of Open Access Journals (Sweden)

    Qiang Jia

    2018-01-01

    Full Text Available The medium Mn steels are gaining increasing attention due to their excellent combination of mechanical properties and material cost. A cold-rolled 0.1C5Mn medium Mn steel with a ferrite matrix plus metastable austenite duplex microstructure was resistance spot-welded with various welding currents and times. The nugget size rose with the increase of heat input, but when the welding current exceeded the critical value, the tensile-shear load increased slowly and became unstable due to metal expulsion. The fusion zone exhibited a lath martensite microstructure, and the heat-affected zone was composed of a ferrite/martensite matrix with retained austenite. The volume fraction of retained austenite decreased gradually from the base metal to the fusion zone, while the microhardness presented a reverse varying trend. Interfacial failure occurred along the interface of the steel sheets with lower loading capacity. Sufficient heat input along with serious expulsion brought about high stress concentration around the weld nugget, and the joint failed in partial interfacial mode. Pull-out failure was absent in this study.

  12. Microstructure Evolution and Selective Corrosion Resistance in Underwater Multi-pass 2101 Duplex Stainless Steel Welding Joints

    Science.gov (United States)

    Hu, Yu; Shi, Yonghua; Shen, Xiaoqin; Wang, Zhongmin

    2018-05-01

    A recently developed promising material, 2101 lean duplex stainless steel, represents an alternative to 304 austenite stainless steel. In this work, multi-pass 2101 weld joints were fabricated using the flux-cored arc welding method in a hyperbaric chamber. The pressure varied from 0 to 0.75 MPa. The evolution of the welding process and microstructure was investigated. γ 2 formation in the reheated zones of the WM and HAZ was not uniform. The closer the reheated zone is to the subsequent heat source, the greater the γ 2 formation in the reheated zone. Sufficient primary austenite transformation inhibited Cr2N precipitation and the subsequent intragranular γ 2 formation in the reheated weld passes of the 0.45 MPa weld metal. The localized corrosion resistance of each zone of the 0.45 MPa DSS joint was measured using non-destructive double-loop electrochemical potentiokinetic reactivation tests. The localized corrosion was induced by γ 2 and Cr2N. The root region of the 0.45 MPa weld metal underwent two subsequent welding thermal cycles, which induced increased γ 2 formation and lower resistance to corrosion because of the decreased pitting resistance value of γ 2. The correlation between microstructure evolution and the distribution of selective corrosion was determined.

  13. Inline-process and quality control of spotwelds of car bodies - ultrasonic sensors integrated in resistance welding electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, G.; Rieger, D.; Koehler, C. [Vogt Werkstoffpruefsysteme, Burgwedel (Germany)

    2006-07-01

    The self-developed inline ultrasonic testing system SPOTline is used for inspection and process control of resistant spot weldings. SPOTline provides with directly into the welding tong integrated ultrasonic sensors a 100% inspection during the welding process. The through transmission and pulse echo signals will be collected, stored and evaluated by means of fuzzy-logic and neuronal network technic. The results will be transmitted online from the spotline-client in the sql-data-base of the server for processing. World-wide SPOTline is the only ultrasonic inspection system, which is working under real production conditions in a network of welding robots. Test with 2 and 3 plates, high strength steels and all coatings demonstrate the accurately identification of discrepant welds. (orig.)

  14. Metallurgical Effects of Shunting Current on Resistance Spot-Welded Joints of AA2219 Sheets

    Science.gov (United States)

    Jafari Vardanjani, M.; Araee, A.; Senkara, J.; Jakubowski, J.; Godek, J.

    2016-08-01

    Shunting effect is the loss of electrical current via the secondary circuit provided due to the existence of previous nugget in a series of welding spots. This phenomenon influences on metallurgical aspects of resistance spot-welded (RSW) joints in terms of quality and performance. In this paper RSW joints of AA2219 sheets with 1 mm thickness are investigated metallurgically for shunted and single spots. An electro-thermal finite element analysis is performed on the RSW process of shunted spot and temperature distribution and variation are obtained. These predictions are then compared with experimental micrographs. Three values of 5 mm, 20 mm, and infinite (i.e., single spot) are assumed for welding distance. Numerical and experimental results are matching each other in terms of nugget and HAZ geometry as increasing distance raised nugget size and symmetry of HAZ. In addition, important effect of shunting current on nugget thickness, microstructure, and Copper segregation on HAZ grain boundaries were discovered. A quantitative analysis is also performed about the influence of welding distance on important properties including ratio of nugget thickness and diameter ( r t), ratio of HAZ area on shunted and free side of nugget ( r HA), and ratio of equivalent segregated and total amount of Copper, measured in sample ( r Cu) on HAZ. Increasing distance from 5 mm to infinite, indicated a gain of 111.04, -45.55, and -75.15% in r t, r HA, and r Cu, respectively, while obtained ratios for 20 mm welding distance was suitable compared to single spot.

  15. Welding problems in nuclear power engineering

    International Nuclear Information System (INIS)

    Zubchenko, A.S.

    1986-01-01

    The problems of welding industry in nuclear power plant engineering, mainly related to the improvement of molten bath protection, are considered. Development of new materials for welding electrodes, for cladding and welding fluxes, is pointed out. Production of the following equipment is brought to a commercial level: welding heads and welding machines for branch pipe welding, anticorrosion cladding, zonal thermal treatment, electron beam welding facilities for the welding and maintenance of turbineblades, equipment for nondestructive testing of welded joints

  16. Expanding Options. A Model to Attract Secondary Students into Nontraditional Vocational Programs. For Emphasis in: Building Trades, Electronics, Health Services, Machine Shop, Welding.

    Science.gov (United States)

    Good, James D.; DeVore, Mary Ann

    This model has been designed for use by Missouri secondary schools in attracting females and males into nontraditional occupational programs. The research-based strategies are intended for implementation in the following areas: attracting females into building trades, electronics, machine shop, and welding; and males into secondary health…

  17. Fatigue limits of titanium-bar joints made with the laser and the electric resistance welding techniques: microstructural characterization and hardness properties.

    Science.gov (United States)

    Degidi, Marco; Nardi, Diego; Morri, Alessandro; Sighinolfi, Gianluca; Tebbel, Florian; Marchetti, Claudio

    2017-09-01

    Fatigue behavior of the titanium bars is of utmost importance for the safe and reliable operation of dental implants and prosthetic constructions based on these implants. To date, however, only few data are available on the fatigue strength of dental prostheses made with electric resistance welding and laser welding techniques. This in-vitro study highlighted that although the joints made with the laser welding approach are credited of a superior tensile strength, joints made with electric resistance welding exhibited double the minimum fatigue strength with respect to the joints made with laser welding (120 vs 60 N).

  18. Development of fatigue resistance evaluation method for socket-weld-jointed pipes

    International Nuclear Information System (INIS)

    Noguchi, Shinji; Shibayama, Motoaki; Iwata, Masazumi; Matsuura, Masayuki

    2003-01-01

    Vent line, drain line and sampling line in nuclear power station have many socket welded-joints made of austenitic stainless steel. Their slenderness and stagnation yield some potential of vibration-induced cracking and stress corrosion cracking. For the joints under vibration, the authors firstly elucidated their welding-defect-related fatigue strength by using fracture mechanics. It could define the allowable sets of stress amplitude and defect size. Secondly, authors developed an ultra-sonic detecting apparatus by using a focus-type probe and its programmed crawl on socket part. The authors finally measured the stress amplitude and frequency by sticking strain gage on suspected joints, then evaluated the fatigue resistance of the joints. For more efficient procedure, the method of stress amplitude analysis through vibration measurement is being developed. (author)

  19. Wrought stainless steel butt-welding fittings: including reference to other corrosion resistant materials - approved 1971

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    ANSI B16.9 is the American Standard for steel butt-welding fittings and although not so stated, it is implied that its scope deals primarily with the schedules of wall thicknesses which are common to carbon steel and the grades of alloy steel piping that are selected for pressure and temperature considerations. The purpose of this standard is to provide industry with a set of dimensional standards for butt-welding fittings that can be used with these light wall pipes of corrosion resisting materials. The center-to-end dimensions of all fittings are identical with those in ANSI B16.9 which give to industry the advantage of uniform design room practice and a maximum utilization of existing die equipment. The only departure from this is in the lap-joint stub end where for purposes of economy the face-to-end of the product has been reduced for use with thin wall piping

  20. Heat-affected zone liquation crack on resistance spot welded TWIP steels

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Dulal Chandra [Department of Advanced Materials Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of); Chang, InSung [Automotive Production Development Division, Hyundai Motor Company (Korea, Republic of); Park, Yeong-Do, E-mail: ypark@deu.ac.kr [Department of Advanced Materials Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of)

    2014-07-01

    In this study, the heat affected zone (HAZ) liquation crack and segregation behavior of the resistance spot welded twinning induced plasticity (TWIP) steel have been reported. Cracks appeared in the post-welded joints that originated at the partially melted zone (PMZ) and propagated from the PMZ through the heat affected zone (HAZ) to the base metal (BM). The crack length and crack opening widths were observed increasing with heat input; and the welding current was identified to be the most influencing parameter for crack formation. Cracks appeared at the PMZ when nugget diameter reached at 4.50 mm or above; and the liquation cracks were found to occur along two sides of the notch tip in the sheet direction rather than in the electrode direction. Cracks were backfilled with the liquid films which has lamellar structure and supposed to be the eutectic constituent. Co-segregation of alloy elements such as, C and Mn were detected on the liquid films by electron-probe microanalysis (EPMA) line scanning and element map which suggests that the liquid film was enrich of Mn and C. The eutectic constituent was identified by analyzing the calculated phase diagram along with thermal temperature history of finite element simulation. Preliminary experimental results showed that cracks have less/no significant effect on the static cross-tensile strength (CTS) and the tensile-shear strength (TSS). In addition, possible ways to avoid cracking were discussed. - Highlights: • The HAZ liquation crack during resistance spot welding of TWIP steel was examined. • Cracks were completely backfilled and healed with divorced eutectic secondary phase. • Co-segregation of C and Mn was detected in the cracked zone. • Heat input was the most influencing factor to initiate liquation crack. • Cracks have less/no significant effect on static tensile properties.

  1. Heat-affected zone liquation crack on resistance spot welded TWIP steels

    International Nuclear Information System (INIS)

    Saha, Dulal Chandra; Chang, InSung; Park, Yeong-Do

    2014-01-01

    In this study, the heat affected zone (HAZ) liquation crack and segregation behavior of the resistance spot welded twinning induced plasticity (TWIP) steel have been reported. Cracks appeared in the post-welded joints that originated at the partially melted zone (PMZ) and propagated from the PMZ through the heat affected zone (HAZ) to the base metal (BM). The crack length and crack opening widths were observed increasing with heat input; and the welding current was identified to be the most influencing parameter for crack formation. Cracks appeared at the PMZ when nugget diameter reached at 4.50 mm or above; and the liquation cracks were found to occur along two sides of the notch tip in the sheet direction rather than in the electrode direction. Cracks were backfilled with the liquid films which has lamellar structure and supposed to be the eutectic constituent. Co-segregation of alloy elements such as, C and Mn were detected on the liquid films by electron-probe microanalysis (EPMA) line scanning and element map which suggests that the liquid film was enrich of Mn and C. The eutectic constituent was identified by analyzing the calculated phase diagram along with thermal temperature history of finite element simulation. Preliminary experimental results showed that cracks have less/no significant effect on the static cross-tensile strength (CTS) and the tensile-shear strength (TSS). In addition, possible ways to avoid cracking were discussed. - Highlights: • The HAZ liquation crack during resistance spot welding of TWIP steel was examined. • Cracks were completely backfilled and healed with divorced eutectic secondary phase. • Co-segregation of C and Mn was detected in the cracked zone. • Heat input was the most influencing factor to initiate liquation crack. • Cracks have less/no significant effect on static tensile properties

  2. Microstructure and failure behavior of dissimilar resistance spot welds between low carbon galvanized and austenitic stainless steels

    International Nuclear Information System (INIS)

    Marashi, P.; Pouranvari, M.; Amirabdollahian, S.; Abedi, A.; Goodarzi, M.

    2008-01-01

    Resistance spot welding was used to join austenitic stainless steel and galvanized low carbon steel. The relationship between failure mode and weld fusion zone characteristics (size and microstructure) was studied. It was found that spot weld strength in the pullout failure mode is controlled by the strength and fusion zone size of the galvanized steel side. The hardness of the fusion zone which is governed by the dilution between two base metals, and fusion zone size of galvanized carbon steel side are dominant factors in determining the failure mode

  3. Effects of Ultrasonic Nanocrystal Surface Modification on the Residual Stress, Microstructure, and Corrosion Resistance of 304 Stainless Steel Welds

    Science.gov (United States)

    Ye, Chang; Telang, Abhishek; Gill, Amrinder; Wen, Xingshuo; Mannava, Seetha R.; Qian, Dong; Vasudevan, Vijay K.

    2018-03-01

    In this study, ultrasonic nanocrystal surface modification (UNSM) of 304 stainless steel welds was carried out. UNSM effectively eliminates the tensile stress generated during welding and imparts beneficial compressive residual stresses. In addition, UNSM can effectively refine the grains and increase hardness in the near-surface region. Corrosion tests in boiling MgCl2 solution demonstrate that UNSM can significantly improve the corrosion resistance due to the compressive residual stresses and changes in the near-surface microstructure.

  4. Effect of shroud material on the spherical aberration in electromagnetic focusing lens used in electron beam welding machines

    International Nuclear Information System (INIS)

    Saha, Srijit Kumar; Gupta, Sachin; Kandaswamy, E.

    2015-01-01

    Beam Power density on the target (typically 10"5 -10"6 W/cm"2 ) plays a major role in attaining good weld quality in electron beam welding. Spherical aberration in the electromagnetic focusing lenses places a limitation in attaining the required power density on the target. Conventionally, iron or low carbon steel core are being used as a shroud material in the electromagnetic lenses. The practical difficulty faced in the long term performance of these lenses has initiated a systematic study for various shroud materials and the effect on spherical aberration limited spot size. The particle trajectories were simulated with different magnetic materials, using commercial software. The spherical aberration was found to be the lowest in the air core lens. The possibility of using an aircore electromagnetic focusing lens in electron beam machines is discussed in this paper. The beam power density is limited by various factors such as spherical aberration, space charge aberrations, gun alignment and power source parameters. (author)

  5. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Energy Technology Data Exchange (ETDEWEB)

    García-Rentería, M.A., E-mail: crazyfim@gmail.com [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); López-Morelos, V.H., E-mail: vhlopez@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); García-Hernández, R., E-mail: rgarcia@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); Dzib-Pérez, L., E-mail: luirdzib@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); García-Ochoa, E.M., E-mail: emgarcia@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); González-Sánchez, J., E-mail: jagonzal@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico)

    2014-12-01

    Highlights: • Electromagnetic interaction in welding improved localised corrosion resistance. • Electromagnetic interaction in welding enhanced γ/δ phase balance of DuplexSS. • Welding under Electromagnetic interaction repress formation and growth of detrimental phases. • Welds made with gas protection (2% O{sub 2} + 98% Ar) have better microstructural evolution during welding. - Abstract: The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O{sub 2} (M1) and 97% Ar + 3% N{sub 2} (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  6. Laser welding engineering

    International Nuclear Information System (INIS)

    Bhieh, N. M.; El Eesawi, M. E.; Hashkel, A. E.

    2007-01-01

    Laser welding was in its early life used mainly for unusual applications where no other welding process would be suitable that was twenty five years ago. Today, laser welding is a fully developed part of the metal working industry, routinely producing welds for common items such as cigarette lighters, which springs, motor/transformer lamination, hermetic seals, battery and pacemaker cans and hybrid circuit packages. Yet very few manufacturing engineering have seriously considers employing lasers in their own operations. Why? There are many reasons, but a main one must be not acquainted with the operation and capabilities of a laser system. Other reasons, such as a relatively high initial cost and a concern about using lasers in the manufacturing environment, also are frequently cited, and the complexity of the component and flexibility of the light delivery system. Laser welding could be used in place of many different standard processes, such as resistance (spot or seam), submerged arc, RF induction, high-frequency resistance, ultrasonic and electronic and electron-beam. while each of these techniques has established an independent function in the manufacturing world, the flexible laser welding approach will operate efficiently and economically in many different applications. Its flexibility will even permit the welding system to be used for other machining function, such as drilling, scribing, sealing and serializing. In this article, we will look at how laser welding works and what benefits it can offer to manufacturing engineers. Some industry observers state that there are already 2,000 laser machine tools being used for cutting, welding and drilling and that the number could reach 30,000 over the next 15 years as manufacturing engineers become more aware of the capabilities of lasers [1). While most laser applications are dedicated to one product or process that involves high-volume, long-run manufacturing, the flexibility of a laser to supply energy to hard

  7. Influence of the post-weld surface treatment on the corrosion resistance of the duplex stainless steel 1.4062

    Science.gov (United States)

    Rosemann, P.; Müller, C.; Baumann, O.; Modersohn, W.; Halle, T.

    2017-03-01

    The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polished or blasting depending on the application and the requested corrosion resistance. Blasted surfaces are often used in industrial practice due to the easier and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the different performed corrosion tests (potential measurement, KorroPad-test and pitting potential) on welding seams with different surface treatments.

  8. Corrosion resistance and microstructure of alloy 625 weld overlay on ASTM A516 grade 70

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Mohammad J. [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Petroleum Engineering Dept.; Ketabchi, Mostafa [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Mining and Metallurgical Engineering Dept.

    2016-02-01

    Nickel-based alloys are a crucial class of materials because of their excellent corrosion resistance. In the present study, single layer and two layers alloy 625 weld overlays were deposited by GTAW process on A516 grade 70 carbon steel. The dilution in terms of Fe, Ni, Mo and Nb content was calculated in 30 points of weld overlay. Microstructure observations showed that alloy 625 had austenitic structure with two types of Laves and NbC secondary phases. The uniform and pitting corrosion resistance of alloy 625 weld overlay as casted and as forged were evaluated in accordance with ASTM G48-2011 standard at different temperatures to determine the weight loss and critical pitting temperature. For achieving a better comparison, samples from alloy 625 as casted and as forged were tested under the same conditions. The results point out that single layer alloy 625 weld overlay is not suitable for chloride containing environments, two layers alloy 625 weld overlay and alloy 625 as casted have acceptable corrosion resistance and almost the same critical pitting temperature. Alloy 625 as forged has the best corrosion resistance and the highest critical pitting temperature among all test specimens. Also, the corrosion behavior was evaluated in accordance with ASTM G28 standard. The corrosion rate of single layer weld overlay was unacceptable. The average corrosion rate of two layers weld overlay and in casted condition were 35.82 and 33.01 mpy, respectively. [German] Nickellegierungen sind aufgrund ihres exzellenten Korrosionswiderstandes eine bedeutende Werkstoffklasse. In der diesem Beitrag zugrunde liegenden Studie wurden mittels WIG-Schweissens ein- und zweilagige Schweissplattierungen auf den Kohlenstoffstahl A516 (Grade 70) aufgebracht. Die Vermischung in Form des Fe-, Ni-, Mo- und Nb-Gehaltes wurde an 30 Punkten der Schweissplattierungen berechnet. Die mikrostrukturellen Untersuchungen ergaben, dass die Legierung 625 eine austenitische Struktur mit zwei Arten von

  9. A precision analogue integrator system for heavy current measurement in MFDC resistance spot welding

    International Nuclear Information System (INIS)

    Xia, Yu-Jun; Zhang, Zhong-Dian; Xia, Zhen-Xin; Zhu, Shi-Liang; Zhang, Rui

    2016-01-01

    In order to control and monitor the quality of middle frequency direct current (MFDC) resistance spot welding (RSW), precision measurement of the welding current up to 100 kA is required, for which Rogowski coils are the only viable current transducers at present. Thus, a highly accurate analogue integrator is the key to restoring the converted signals collected from the Rogowski coils. Previous studies emphasised that the integration drift is a major factor that influences the performance of analogue integrators, but capacitive leakage error also has a significant impact on the result, especially in long-time pulse integration. In this article, new methods of measuring and compensating capacitive leakage error are proposed to fabricate a precision analogue integrator system for MFDC RSW. A voltage holding test is carried out to measure the integration error caused by capacitive leakage, and an original integrator with a feedback adder is designed to compensate capacitive leakage error in real time. The experimental results and statistical analysis show that the new analogue integrator system could constrain both drift and capacitive leakage error, of which the effect is robust to different voltage levels of output signals. The total integration error is limited within  ±0.09 mV s −1 0.005% s −1 or full scale at a 95% confidence level, which makes it possible to achieve the precision measurement of the welding current of MFDC RSW with Rogowski coils of 0.1% accuracy class. (paper)

  10. Friction stir welded AM50 and AZ31 Mg alloys: Microstructural evolution and improved corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Templeman, Yael [Department of Materials Engineering, Ben Gurion University of the Negev, PO Box 653, Beer Sheva 84105 (Israel); Ben Hamu, Guy [Department of Mechanical Engineering, Sami Shamoon College of Engineering, Ashdod 77245 (Israel); Meshi, Louisa, E-mail: Louisa@bgu.ac.il [Department of Materials Engineering, Ben Gurion University of the Negev, PO Box 653, Beer Sheva 84105 (Israel)

    2017-04-15

    One of the major drawbacks of Mg alloys is poor weldability, caused by porosity formation during conventional fusion welding processes. Friction Stir Welding (FSW) is promising technique in this context since it is a solid state technique. Contradicting results were published in the literature regarding the FSWed Mg alloys joint's properties. Current research was performed in order to investigate the microstructure and corrosion properties of FSWed Mg alloys, studying representatives of two commercial families: wrought AZ31-H24 and die cast AM50. It was found that in both alloys recrystallization occurred during the FSW. In AM50 the mechanism of the recrystallization was continuous, manifested by dislocation rearrangement into sub grain boundaries. In AZ31 discontinuous recrystallization had occurred through grain boundaries migration - twins rotated with respect to the matrix, turning into low angle grain boundaries. Corrosion resistance has improved during the FSW in both alloys to different extents. In the AM50 alloy, the nugget exhibited significantly higher surface potential than the base metal mainly due to the higher Al concentration in the matrix of the nugget, resulting from the dissolution of Al-enrichment and β-Mg{sub 17}Al{sub 12} phase. In the AZ31 alloy, no change in Al concentration had occurred, and the surface potential measured in the nugget was only slightly higher than in the base metal. These results underline the appropriateness of the FSW for Mg alloys since during the conventional welding deterioration of the corrosion resistance occurs. - Highlights: • Following FSW, AZ31-H24 experienced discontinuous recrystallization. • In AZ31 grain boundaries migration occurred, thus twins rotated. • In die cast AM50 continuous recrystallization occurred during the FSW. • In AM50 - dislocations rearranged into sub grain boundaries. • Corrosion resistance has improved during the FSW in both alloys to different extent.

  11. Friction stir welded AM50 and AZ31 Mg alloys: Microstructural evolution and improved corrosion resistance

    International Nuclear Information System (INIS)

    Templeman, Yael; Ben Hamu, Guy; Meshi, Louisa

    2017-01-01

    One of the major drawbacks of Mg alloys is poor weldability, caused by porosity formation during conventional fusion welding processes. Friction Stir Welding (FSW) is promising technique in this context since it is a solid state technique. Contradicting results were published in the literature regarding the FSWed Mg alloys joint's properties. Current research was performed in order to investigate the microstructure and corrosion properties of FSWed Mg alloys, studying representatives of two commercial families: wrought AZ31-H24 and die cast AM50. It was found that in both alloys recrystallization occurred during the FSW. In AM50 the mechanism of the recrystallization was continuous, manifested by dislocation rearrangement into sub grain boundaries. In AZ31 discontinuous recrystallization had occurred through grain boundaries migration - twins rotated with respect to the matrix, turning into low angle grain boundaries. Corrosion resistance has improved during the FSW in both alloys to different extents. In the AM50 alloy, the nugget exhibited significantly higher surface potential than the base metal mainly due to the higher Al concentration in the matrix of the nugget, resulting from the dissolution of Al-enrichment and β-Mg 17 Al 12 phase. In the AZ31 alloy, no change in Al concentration had occurred, and the surface potential measured in the nugget was only slightly higher than in the base metal. These results underline the appropriateness of the FSW for Mg alloys since during the conventional welding deterioration of the corrosion resistance occurs. - Highlights: • Following FSW, AZ31-H24 experienced discontinuous recrystallization. • In AZ31 grain boundaries migration occurred, thus twins rotated. • In die cast AM50 continuous recrystallization occurred during the FSW. • In AM50 - dislocations rearranged into sub grain boundaries. • Corrosion resistance has improved during the FSW in both alloys to different extent.

  12. Corrosion resistance of a laser spot-welded joint of NiTi wire in simulated human body fluids.

    Science.gov (United States)

    Yan, Xiao-Jun; Yang, Da-Zhi

    2006-04-01

    The purpose of this study was to investigate corrosion resistance of a laser spot-welded joint of NiTi alloy wires using potentiodynamic tests in Hank's solution at different PH values and the PH 7.4 NaCl solution for different Cl- concentrations. Scanning electron microscope observations were carried out before and after potentiodynamic tests. The composition of a laser spot-welded joint and base metal were characterized by using an electron probe microanalyzer. The results of potentiodynamic tests showed that corrosion resistance of a laser spot-welded joint of NiTi alloy wire was better than that of base metal, which exhibited a little higher breakdown potential and passive range, and a little lower passive current density. Corrosion resistances of a laser spot-welded joint and base metal decreased with increasing of the Cl- concentration and PH value. The improvement of corrosion resistance of the laser spot-welded joint was due to the decrease of the surface defects and the increase of the Ti/Ni ratio. (c) 2005 Wiley Periodicals, Inc.

  13. Correlation between corrosion resistance properties and thermal cycles experienced by gas tungsten arc welding and laser beam welding Alloy 690 butt weldments

    International Nuclear Information System (INIS)

    Lee, H T; Wu, J L

    2009-01-01

    This study investigates the correlation between the thermal cycles experienced by Alloy 690 weldments fabricated using gas tungsten arc welding (GTAW) and laser beam welding (LBW) processes, and their corresponding corrosion resistance properties. The corrosion resistance of the weldments is evaluated using a U-bend stress corrosion test in which the specimens are immersed in a boiling, acid solution for 240 h. The experimental results reveal that the LBW inputs significantly less heat to the weldment than the GTAW, and therefore yields a far faster cooling rate. Moreover, the corrosion tests show that in the GTAW specimen, intergranular corrosion (IGC) occurs in both the fusion zone (FZ) and the heat affected zone (HAZ). By contrast, the LBW specimen shows no obvious signs of IGC.

  14. Effect of electromagnetic interaction during fusion welding of AISI 2205 duplex stainless steel on the corrosion resistance

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; González-Sánchez, J.; García-Hernández, R.; Dzib-Pérez, L.; Curiel-López, F. F.

    2017-02-01

    The effect of electromagnetic interaction of low intensity (EMILI) applied during fusion welding of AISI 2205 duplex stainless steel on the resistance to localised corrosion in natural seawater was investigated. The heat affected zone (HAZ) of samples welded under EMILI showed a higher temperature for pitting initiation and lower dissolution under anodic polarisation in chloride containing solutions than samples welded without EMILI. The EMILI assisted welding process developed in the present work enhanced the resistance to localised corrosion due to a modification on the microstructural evolution in the HAZ and the fusion zone during the thermal cycle involved in fusion welding. The application of EMILI reduced the size of the HAZ, limited coarsening of the ferrite grains and promoted regeneration of austenite in this zone, inducing a homogeneous passive condition of the surface. EMILI can be applied during fusion welding of structural or functional components of diverse size manufactured with duplex stainless steel designed to withstand aggressive environments such as natural seawater or marine atmospheres.

  15. Enhancement of mechanical properties and corrosion resistance of friction stir welded joint of AA2014 using water cooling

    Energy Technology Data Exchange (ETDEWEB)

    Sinhmar, S., E-mail: sinhmarsunil88@gmail.com; Dwivedi, D.K.

    2017-01-27

    An investigation on the microstructure, mechanical properties, and corrosion behavior of friction stir welded joint of AA2014 in natural cooled (NC) and water cooled (WC) conditions have been reported. Optical microscopy, field emission scanning electron microscopy (FESEM) with Energy dispersive X-ray spectroscopy (EDS), Vicker's microhardness, tensile testing, X-ray diffraction (XRD), and electrochemical potentiodynamic polarization corrosion test (Tafel curve) were carried out to characterize the friction stir weld joints in both the cooling conditions. Water cooling resulted in higher strength and microhardness of friction stir weld joint compared to the natural cooling. The width of heat affected zone was reduced by the use of water cooling during friction stir welding (FSW) and minimum hardness zone was shifted towards weld center. The corrosion test was performed in 3.5% NaCl solution. Corrosion resistance of water cooled joint was found higher than natural cooled FSW joint. The precipitation behavior of weld nugget and heat affected zone impacts the corrosion resistance of FSW joint of AA 2014. Hardness, tensile, and corrosion properties of FSW joints produced under NC and WC conditions have been discussed in the light of microstructure.

  16. Enhancement of mechanical properties and corrosion resistance of friction stir welded joint of AA2014 using water cooling

    International Nuclear Information System (INIS)

    Sinhmar, S.; Dwivedi, D.K.

    2017-01-01

    An investigation on the microstructure, mechanical properties, and corrosion behavior of friction stir welded joint of AA2014 in natural cooled (NC) and water cooled (WC) conditions have been reported. Optical microscopy, field emission scanning electron microscopy (FESEM) with Energy dispersive X-ray spectroscopy (EDS), Vicker's microhardness, tensile testing, X-ray diffraction (XRD), and electrochemical potentiodynamic polarization corrosion test (Tafel curve) were carried out to characterize the friction stir weld joints in both the cooling conditions. Water cooling resulted in higher strength and microhardness of friction stir weld joint compared to the natural cooling. The width of heat affected zone was reduced by the use of water cooling during friction stir welding (FSW) and minimum hardness zone was shifted towards weld center. The corrosion test was performed in 3.5% NaCl solution. Corrosion resistance of water cooled joint was found higher than natural cooled FSW joint. The precipitation behavior of weld nugget and heat affected zone impacts the corrosion resistance of FSW joint of AA 2014. Hardness, tensile, and corrosion properties of FSW joints produced under NC and WC conditions have been discussed in the light of microstructure.

  17. 3D modelling of plug failure in resistance spot welded shear-lab specimens (DP600-steel)

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    2008-01-01

    are based on uni-axial tensile testing of the basis material, while the modelled tensile response of the shear-lab specimens is compared to experimental results for the case of a ductile failure near the heat affected zone (HAZ). A parametric study for a range of weld diameters is carried out, which makes......Ductile plug failure of resistance spot welded shear-lab specimens is studied by full 3D finite element analysis, using an elastic-viscoplastic constitutive relation that accounts for nucleation and growth of microvoids to coalescence (The Gurson model). Tensile properties and damage parameters...... it possible to numerically relate the weld diameter to the tensile shear force (TSF) and the associated displacement, u (TSF) , respectively. Main focus in the paper is on modelling the localization of plastic flow and the corresponding damage development in the vicinity of the spot weld, near the HAZ...

  18. Welding and corrosion resistance of the new nitrogen alloyed steel X2 CrNiMnMoN241764

    International Nuclear Information System (INIS)

    Arit, N.; Henser, H.; GroB, V.

    1994-01-01

    Remanit 4565 S is a new developed nitrogen alloyed austenitic stainless steel. Characteristic features are: improved strength and toughness, delayed precipitation of carbides and intermetallic phases, improved corrosion resistance. Welding fabrication is possible without the risk of pore formation. TIG-welded joints are as resistant as the base metal, using filler metal SG-NiCr 20 Mo 15 (Thermanit Nimo C) respectively SG-NiCr 28 Mo(Thermanit 30/40 E) according to the area of application. (Author) 8 refs

  19. Corrosion Resistance and Mechanical Properties of TIG and A-TIG Welded Joints of Lean Duplex Stainless Steel S82441 / 1.4662

    Directory of Open Access Journals (Sweden)

    Brytan Z.

    2016-06-01

    Full Text Available This paper presents results of pitting corrosion resistance of TIG (autogenous and with filler metal and A-TIG welded lean duplex stainless steel S82441/1.4662 evaluated according to ASTM G48 method, where autogenous TIG welding process was applied using different amounts of heat input and shielding gases like pure Ar and Ar+N2 and Ar+He mixtures. The results of pitting corrosion resistance of the welded joints of lean duplex stainless steel S82441 were studied in as weld conditions and after different mechanical surface finish treatments. The results of the critical pitting temperature (CPT determined according to ASTM G48 at temperatures of 15, 25 and 35°C were presented. Three different surface treatment after welding were applied: etching, milling, brushing + etching. The influence of post weld surface treatment was studied in respect to the pitting corrosion resistance, basing on CPT temperature.

  20. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; García-Hernández, R.; Dzib-Pérez, L.; García-Ochoa, E. M.; González-Sánchez, J.

    2014-12-01

    The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  1. CrN-based wear resistant hard coatings for machining and forming tools

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S; Cooke, K E; Teer, D G [Teer Coatings Ltd, West Stone House, Berry Hill Industrial Estate, Droitwich, Worcestershire WR9 9AS (United Kingdom); Li, X [School of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom); McIntosh, F [Rolls-Royce plc, Inchinnan, Renfrewshire PA4 9AF, Scotland (United Kingdom)

    2009-05-21

    Highly wear resistant multicomponent or multilayer hard coatings, based on CrN but incorporating other metals, have been developed using closed field unbalanced magnetron sputter ion plating technology. They are exploited in coated machining and forming tools cutting and forming of a wide range of materials in various application environments. These coatings are characterized by desirable properties including good adhesion, high hardness, high toughness, high wear resistance, high thermal stability and high machining capability for steel. The coatings appear to show almost universal working characteristics under operating conditions of low and high temperature, low and high machining speed, machining of ordinary materials and difficult to machine materials, and machining under lubricated and under minimum lubricant quantity or even dry conditions. These coatings can be used for cutting and for forming tools, for conventional (macro-) machining tools as well as for micromachining tools, either as a single coating or in combination with an advanced, self-lubricating topcoat.

  2. Proton-irradiation technology for high-frequency high-current silicon welding diode manufacturing

    International Nuclear Information System (INIS)

    Lagov, P B; Drenin, A S; Zinoviev, M A

    2017-01-01

    Different proton irradiation regimes were tested to provide more than 20 kHz-frequency, soft reverse recovery “snap-less” behavior, low forward voltage drop and leakage current for 50 mm diameter 7 kA/400 V welding diode Al/Si/Mo structure. Silicon diode with such parameters is very suitable for high frequency resistance welding machines of new generation for robotic welding. (paper)

  3. Proton-irradiation technology for high-frequency high-current silicon welding diode manufacturing

    Science.gov (United States)

    Lagov, P. B.; Drenin, A. S.; Zinoviev, M. A.

    2017-05-01

    Different proton irradiation regimes were tested to provide more than 20 kHz-frequency, soft reverse recovery “snap-less” behavior, low forward voltage drop and leakage current for 50 mm diameter 7 kA/400 V welding diode Al/Si/Mo structure. Silicon diode with such parameters is very suitable for high frequency resistance welding machines of new generation for robotic welding.

  4. Structure evolution of multilayer materials of heat-resistant intermetallic compounds under the influence of temperature in the process of diffusion welding under pressure and their mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Korzhov, Valeriy P.; Karpov, Michael I.; Prokhorov, Dmitriy V. [Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka (Russian Federation)

    2013-07-01

    Multilayer materials of high-resistant intermetallic compounds of some transition metals with aluminum and silicon were obtained by diffusion welding of packages, collected from a large number of the respective foils, such as niobium and aluminum. Materials of intermetallics with silicon were obtained by the welding of packages built from metal foils with Si-coating. The change in the structure according to the temperature of the welding was studied, and the high-temperature bending strength was determined. Key words: multilayer composite, high-resistant material, intermetallic compound, diffusion welding, package rolling, layered structure, bending strength.

  5. A high molybdenum stainless steel and its resistance to chloride environments in the welded condition

    International Nuclear Information System (INIS)

    Coppolecchia, V.D.; Jasner, M.; Rockel, M.B.

    1988-01-01

    Highly alloyed stainless steels, such as 1925 hMo UNS N08925 with 6 percent molybdenum, are finding widespread use in high chloride cooling water and process environments. This alloy has good general corrosion resistance to a variety of chloride environments but it's main attraction is excellent resistance to all forms of localized corrosion. In aggressive chloride environments weldments are generally the area of concern with regard to localized corrosion. Temperature-time-sensitization diagrams are presented that demonstrate the resistance of 1925 hMo weldments to intergranular attack. Immersion tests in 10% ferric chloride substantiate that autogenous tube welds, also have excellent pitting resistance. Various filler metals are compared both electrochemically and in immersion tests. These comparisons reveal that an overalloyed filler metal is required to achieve pitting and crevice corrosion resistance equal or better than that of the base metal. Alloy 625 (UNS NO6625) has been selected. Constant extension rate tests in boiling 62% calcium chloride reveal that 1925 hMo weldments are immune to stress corrosion cracking in this environment which virtually guarantees absence of SCC in seawater regardless of temperature as well as in most commercial chemical environments

  6. Deformation behavior of laser welds in high temperature oxidation resistant Fe–Cr–Al alloys for fuel cladding applications

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G., E-mail: fieldkg@ornl.gov; Gussev, Maxim N., E-mail: gussevmn@ornl.gov; Yamamoto, Yukinori, E-mail: yamamotoy@ornl.gov; Snead, Lance L., E-mail: sneadll@ornl.gov

    2014-11-15

    Ferritic-structured Fe–Cr–Al alloys are being developed and show promise as oxidation resistant accident tolerant light water reactor fuel cladding. This study focuses on investigating the weldability and post-weld mechanical behavior of three model alloys in a range of Fe–(13–17.5)Cr–(3–4.4)Al (wt.%) with a minor addition of yttrium using modern laser-welding techniques. A detailed study on the mechanical performance of bead-on-plate welds using sub-sized, flat dog-bone tensile specimens and digital image correlation (DIC) has been carried out to determine the performance of welds as a function of alloy composition. Results indicated a reduction in the yield strength within the fusion zone compared to the base metal. Yield strength reduction was found to be primarily constrained to the fusion zone due to grain coarsening with a less severe reduction in the heat affected zone. For all proposed alloys, laser welding resulted in a defect free weld devoid of cracking or inclusions.

  7. Deformation behavior of laser welds in high temperature oxidation resistant Fe-Cr-Al alloys for fuel cladding applications

    Science.gov (United States)

    Field, Kevin G.; Gussev, Maxim N.; Yamamoto, Yukinori; Snead, Lance L.

    2014-11-01

    Ferritic-structured Fe-Cr-Al alloys are being developed and show promise as oxidation resistant accident tolerant light water reactor fuel cladding. This study focuses on investigating the weldability and post-weld mechanical behavior of three model alloys in a range of Fe-(13-17.5)Cr-(3-4.4)Al (wt.%) with a minor addition of yttrium using modern laser-welding techniques. A detailed study on the mechanical performance of bead-on-plate welds using sub-sized, flat dog-bone tensile specimens and digital image correlation (DIC) has been carried out to determine the performance of welds as a function of alloy composition. Results indicated a reduction in the yield strength within the fusion zone compared to the base metal. Yield strength reduction was found to be primarily constrained to the fusion zone due to grain coarsening with a less severe reduction in the heat affected zone. For all proposed alloys, laser welding resulted in a defect free weld devoid of cracking or inclusions.

  8. Fundamental studies on electron beam welding on heat-resistant superalloys for nuclear plants, 2

    International Nuclear Information System (INIS)

    Arata, Yoshiaki; Terai, Kiyohide; Nagai, Hiroyoshi; Shimizu, Shigeki; Aota, Toshiichi.

    1978-01-01

    In this report, the correlation was discussed between the susceptibility to weld cracking in electron beam welding of heat-resistant superalloys for nuclear plants and its characteristics of hot ductility. Trans-Varestraint and Varestraint tests. Obtained conclusions may be summarized as follows, using technical symbols which are given meanings in this report. 1) Such criteria obtained in the hot ductility test are herein employed to evaluate the susceptibility to microcracking as sub(ND) T sub(H), sub(ND) T sub(C), ΔT sub(H.C) (= sub(ND) T sub(H) - sub(ND) T sub(C)) and sub(B) T sub(R) (= T sub(L) - sub(ND) T sub(C)). Both with the decrease of sub(ND) T sub(H) and sub(ND) T sub(C) and with the increase of ΔT sub(H.C) and sub(B) T sub(R), superalloys are considered to become more susceptible to microcracking. Of these criteria, ΔT sub(H.C.) and sub(B) T sub(R) correlate best with q sub(CR) which is one of the effective criteria to evaluate the susceptibility to microcracking in the electron beam welding. 2) It is recognized that ΔT sub(H.C) and sub(B) T sub(R) in hot ductility test correlate well with sub(TV) T sub(R.5%) in Trans-Varestraint test and sub(V) C sub(m.1%) in the Varestraint test. 3) sub(TV) T sub(R.5%) in the Trans-Varestraint test and sub(V) C sub(m.1%) in the Varestraint test are respectively effective to evaluate the susceptibility to microcracking. Moreover, these criteria clearly correlate with q sub(CR). (auth.)

  9. Grinding Parts For Automatic Welding

    Science.gov (United States)

    Burley, Richard K.; Hoult, William S.

    1989-01-01

    Rollers guide grinding tool along prospective welding path. Skatelike fixture holds rotary grinder or file for machining large-diameter rings or ring segments in preparation for welding. Operator grasps handles to push rolling fixture along part. Rollers maintain precise dimensional relationship so grinding wheel cuts precise depth. Fixture-mounted grinder machines surface to quality sufficient for automatic welding; manual welding with attendant variations and distortion not necessary. Developed to enable automatic welding of parts, manual welding of which resulted in weld bead permeated with microscopic fissures.

  10. Relationship between Microstructure and Ductility Dip Cracking resistance of Alloy 600/690 weld metals

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Jae Yong; Lee, Chang Hee [Hanyang University, Seoul (Korea, Republic of); Kim, Min Chul; Lee, Ho Jin; Kim, Keoung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Kwang Soo; Shim, Deog Nam [Doosan HEAVY Industries and Construction, Seoul (Korea, Republic of)

    2009-10-15

    Ni-Cr-Fe alloys are used extensively in nuclear power systems for their resistance to general corrosion, localized corrosion, and environmentally assisted cracking. However, concerns with stress corrosion cracking of moderate chromium (14.22 wt-%) alloys such as Alloy 600 and its filler metals(FMs) (E-182 and EN82) have driven the application of higher chromium (28.30 wt-%) alloys like Alloy 690. While Alloy 690 and its FMs show outstanding resistance to environmentally assisted cracking in most water-reactor environments, these alloys are prone to welding defects, most notably to ductility dip cracking(DDC). The DDC occurs at temperatures between 0.5 and 0.8 of their melting temperature. This ductility drop may result in intergranular elevated temperature cracking often referred to as DDC. The DDC may occur during the high temperature processing of these alloys or during welding if the imposed strain exhausts the available ductility within this temperature range. Several alloy systems including Ni-base alloys, Ni.Cu alloys, Cu alloys, stainless steels and steels, have been reported to be susceptible to DDC. A complete understanding of the DDC mechanism does not exist, which makes DDC control in actual production conditions a very difficult task. In this study, the DDC resistance was evaluated with different FMs which have different chemical composition. The microstructural features of FMs such as precipitation behavior and grain boundaries morphology were observed, and it were correlated with the DDC susceptibility. The hot ductility test and strainto- fracture test was used to evaluate the DDC susceptibility at high temperature.

  11. Relationship between Microstructure and Ductility Dip Cracking resistance of Alloy 600/690 weld metals

    International Nuclear Information System (INIS)

    Ryu, Jae Yong; Lee, Chang Hee; Kim, Min Chul; Lee, Ho Jin; Kim, Keoung Ho; Park, Kwang Soo; Shim, Deog Nam

    2009-01-01

    Ni-Cr-Fe alloys are used extensively in nuclear power systems for their resistance to general corrosion, localized corrosion, and environmentally assisted cracking. However, concerns with stress corrosion cracking of moderate chromium (14.22 wt-%) alloys such as Alloy 600 and its filler metals(FMs) (E-182 and EN82) have driven the application of higher chromium (28.30 wt-%) alloys like Alloy 690. While Alloy 690 and its FMs show outstanding resistance to environmentally assisted cracking in most water-reactor environments, these alloys are prone to welding defects, most notably to ductility dip cracking(DDC). The DDC occurs at temperatures between 0.5 and 0.8 of their melting temperature. This ductility drop may result in intergranular elevated temperature cracking often referred to as DDC. The DDC may occur during the high temperature processing of these alloys or during welding if the imposed strain exhausts the available ductility within this temperature range. Several alloy systems including Ni-base alloys, Ni.Cu alloys, Cu alloys, stainless steels and steels, have been reported to be susceptible to DDC. A complete understanding of the DDC mechanism does not exist, which makes DDC control in actual production conditions a very difficult task. In this study, the DDC resistance was evaluated with different FMs which have different chemical composition. The microstructural features of FMs such as precipitation behavior and grain boundaries morphology were observed, and it were correlated with the DDC susceptibility. The hot ductility test and strainto- fracture test was used to evaluate the DDC susceptibility at high temperature

  12. Resistance Upset Welding of ODS Steel Fuel Claddings—Evaluation of a Process Parameter Range Based on Metallurgical Observations

    Directory of Open Access Journals (Sweden)

    Fabien Corpace

    2017-08-01

    Full Text Available Resistance upset welding is successfully applied to Oxide Dispersion Strengthened (ODS steel fuel cladding. Due to the strong correlation between the mechanical properties and the microstructure of the ODS steel, this study focuses on the consequences of the welding process on the metallurgical state of the PM2000 ODS steel. A range of process parameters is identified to achieve operative welding. Characterizations of the microstructure are correlated to measurements recorded during the welding process. The thinness of the clad is responsible for a thermal unbalance, leading to a higher temperature reached. Its deformation is important and may lead to a lack of joining between the faying surfaces located on the outer part of the join which can be avoided by increasing the dissipated energy or by limiting the clad stick-out. The deformation and the temperature reached trigger a recrystallization phenomenon in the welded area, usually combined with a modification of the yttrium dispersion, i.e., oxide dispersion, which can damage the long-life resistance of the fuel cladding. The process parameters are optimized to limit the deformation of the clad, preventing the compactness defect and the modification of the nanoscale oxide dispersion.

  13. Increasing the brittle fracture resistance in manual arc welding and heat treatment of type 12KhM steels

    International Nuclear Information System (INIS)

    Tikhonov, V.P.; Bychenkova, G.A.; Gordeev, Y.V.; Ilyuhov, C.V.

    1984-01-01

    The extensive application of heat-resisting steels is delayed by their poor weldability. Optimum technology has been developed for manual arc welding and heat treatment of structures of type 12KhM steels resulting in high cracking resistance. Trials were conducted to evaluate the efficiency of removing the structural stresses in tempering the structures. On the basis of the experimental results, it may be assumed that the toughness properties of the welded joints produced by manual arc welding can be improved by optimizing the alloying system of the weld metal, with the parent metal treated in the optimum heat treatment conditions. The aim of subsequent investigations was to assess the properties of the weld metal made with vanadium-free electrodes. It was found that the impact toughness increased two to three times; the mean hardness and the maximum hardness were both less than 220. The reduction in hardness and increase of the toughness properties of the metal are caused by the lower degree of hardening of the bulk of the grain and, consequently, by the lower concentration of plastic strain at the grain boundaries

  14. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2011-01-01

    Offers an introduction to the range of available welding technologies. This title includes chapters on individual techniques that cover principles, equipment, consumables and key quality issues. It includes material on such topics as the basics of electricity in welding, arc physics, and distortion, and the weldability of particular metals.$bThe first edition of Welding processes handbook established itself as a standard introduction and guide to the main welding technologies and their applications. This new edition has been substantially revised and extended to reflect the latest developments. After an initial introduction, the book first reviews gas welding before discussing the fundamentals of arc welding, including arc physics and power sources. It then discusses the range of arc welding techniques including TIG, plasma, MIG/MAG, MMA and submerged arc welding. Further chapters cover a range of other important welding technologies such as resistance and laser welding, as well as the use of welding techniqu...

  15. Characterization of Contact and Bulk Thermal Resistance of Laminations for Electric Machines

    Energy Technology Data Exchange (ETDEWEB)

    Cousineau, J. Emily [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bennion, Kevin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); DeVoto, Doug [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mihalic, Mark [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-06-30

    The ability to remove heat from an electric machine depends on the passive stack thermal resistances within the machine and the convective cooling performance of the selected cooling technology. This report focuses on the passive thermal design, specifically properties of the stator and rotor lamination stacks. Orthotropic thermal conductivity, specific heat, and density are reported. Four materials commonly used in electric machines were tested, including M19 (29 and 26 gauge), HF10, and Arnon 7 materials.

  16. An assessment of microstructure, mechanical properties and corrosion resistance of dissimilar welds between Inconel 718 and 310S austenitic stainless steel

    International Nuclear Information System (INIS)

    Mortezaie, A.; Shamanian, M.

    2014-01-01

    In the present study, dissimilar welding between Inconel 718 nickel-base superalloy and 310S austenitic stainless steel using gas tungsten arc welding process was performed to determine the relationship between the microstructure of the welds and the resultant mechanical and corrosion properties. For this purpose, three filler metals including Inconel 625, Inconel 82 and 310 stainless steel were used. Microstructural observations showed that weld microstructures for all filler metals were fully austenitic. In tension tests, welds produced by Inconel 625 and 310 filler metals displayed the highest and the lowest ultimate tensile strength, respectively. The results of Charpy impact tests indicated that the maximum fracture energy was related to Inconel 82 weld metal. According to the potentiodynamic polarization test results, Inconel 82 exhibited the highest corrosion resistance among all tested filler metals. Finally, it was concluded that for the dissimilar welding between Inconel 718 and 310S, Inconel 82 filler metal offers the optimum properties at room temperature. - Highlights: • Three filler metals including Inconel 625, Inconel 82 and 310 SS were used. • A columnar to equiaxed dendritic structure was seen for IN-625 weld metal. • A granular austenitic microstructure obtained for Inconel 82 weld metal. • Microstructure of 310 weld metal includes solidification cracks along SSGB. • IN-82 weld metal showed the highest corrosion potential

  17. Effectiveness of Hamstring Knee Rehabilitation Exercise Performed in Training Machine vs. Elastic Resistance Electromyography Evaluation Study

    DEFF Research Database (Denmark)

    Jakobsen, M. D.; Sundstrup, E.; Andersen, C. H.

    2014-01-01

    Objective The aim of this study was to evaluate muscle activity during hamstring rehabilitation exercises performed in training machine compared with elastic resistance. Design Six women and 13 men aged 28-67 yrs participated in a crossover study. Electromyographic (EMG) activity was recorded...... inclinometers. Results Training machines and elastic resistance showed similar high levels of muscle activity (biceps femoris and semitendinosus peak normalized EMG >80%). EMG during the concentric phase was higher than during the eccentric phase regardless of exercise and muscle. However, compared with machine.......001) during hamstring curl performed with elastic resistance (7.58 +/- 0.08) compared with hamstring curl performed in a machine (5.92 +/- 0.03). Conclusions Hamstring rehabilitation exercise performed with elastic resistance induces similar peak hamstring muscle activity but slightly lower EMG values at more...

  18. Safety of stationary grinding machines - impact resistance of work zone enclosures.

    Science.gov (United States)

    Mewes, Detlef; Adler, Christian

    2017-09-01

    Guards on machine tools are intended to protect persons from being injured by parts ejected with high kinetic energy from the work zone of the machine. Stationary grinding machines are a typical example. Generally such machines are provided with abrasive product guards closely enveloping the grinding wheel. However, many machining tasks do not allow the use of abrasive product guards. In such cases, the work zone enclosure has to be dimensioned so that, in case of failure, grinding wheel fragments remain inside the machine's working zone. To obtain data for the dimensioning of work zone enclosures on stationary grinding machines, which must be operated without an abrasive product guard, burst tests were conducted with vitrified grinding wheels. The studies show that, contrary to widely held opinion, narrower grinding wheels can be more critical concerning the impact resistance than wider wheels although their fragment energy is smaller.

  19. Radiation Tolerance of Controlled Fusion Welds in High Temperature Oxidation Resistant FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    High temperature oxidation resistant iron-chromium-aluminum (FeCrAl) alloys are candidate alloys for nuclear applications due to their exceptional performance during off-normal conditions such as a loss-of-coolant accident (LOCA) compared to currently deployed zirconium-based claddings [1]. A series of studies have been completed to determine the weldability of the FeCrAl alloy class and investigate the weldment performance in the as-received (non-irradiated) state [2,3]. These initial studies have shown the general effects of composition and microstructure on the weldability of FeCrAl alloys. Given this, limited details on the radiation tolerance of FeCrAl alloys and their weldments exist. Here, the highest priority candidate FeCrAl alloys and their weldments have been investigated after irradiation to enable a better understanding of FeCrAl alloy weldment performance within a high-intensity neutron field. The alloys examined include C35M (Fe-13%Cr-5% Al) and variants with aluminum (+2%) or titanium carbide (+1%) additions. Two different sub-sized tensile geometries, SS-J type and SS-2E (or SS-mini), were neutron irradiated in the High Flux Isotope Reactor to 1.8-1.9 displacements per atom (dpa) in the temperature range of 195°C to 559°C. Post irradiation examination of the candidate alloys was completed and included uniaxial tensile tests coupled with digital image correlation (DIC), scanning electron microscopy-electron back scattered diffraction analysis (SEM-EBSD), and SEM-based fractography. In addition to weldment testing, non-welded parent material was examined as a direct comparison between welded and non-welded specimen performance. Both welded and non-welded specimens showed a high degree of radiation-induced hardening near irradiation temperatures of 200°C, moderate radiation-induced hardening near temperatures of 360°C, and almost no radiation-induced hardening at elevated temperatures near 550°C. Additionally, low-temperature irradiations showed

  20. Researches concerning the ultasonic energy influence on the resistence to the abrasive wear of loaded welded parts

    Directory of Open Access Journals (Sweden)

    Gh. Amza

    2013-01-01

    Full Text Available The researches presented in the paper refer to the effect of ultrasounds propagation in the liquid metal bath on the process of transferring the additive material through the electric arch and on the crystallization process, and all these effects are analyzed for loaded welded parts solicited at the abrasive wear. All these influences are conferred to these two basic phenomena due to the ultrasounds propagation in liquid environments, namely, ultra-acoustic cavitation and acceleration of the diffusion process. The results concerns the resistance to the wear obtained for the loaded parts through manual welding with electric arch and classically covered electrode and ultrasonically activated.

  1. Fundamental studies of electron beam welding of heat-resistant superalloys for nuclear plants, 5

    International Nuclear Information System (INIS)

    Arata, Yoshiaki; Terai, Kiyohide; Nagai, Hiroyoshi; Shimizu, Shigeki; Aota, Toshiichi.

    1978-01-01

    In this paper, the mechanical properties of base metal, its electron beam and TIG weld joint of superalloys for nuclear plants were made clear and compared with each other. As a result, it has been clarified that electron beam weld joint is superior to TIG weld joint and nearly comparable to base metal. (author)

  2. Influence of surface pretreatment in resistance spot welding of aluminum AA1050

    DEFF Research Database (Denmark)

    Al Naimi, Ihsan K.; Al Saadi, Moneer H.; Daws, Kasim M.

    2015-01-01

    quality. An experimental study of the influence of pretreatment on weld quality in RSW of AA1050 sheets with three thicknesses, comparing welding of as-received sheet with pretreated sheet by either pickling in NaOH or glass-blasting were investigated. Different weld settings were applied with low...

  3. Corrosion resistance of welded joints in 08Kh22N6T and 08Kh21N6M2T steels made with new electrodes

    International Nuclear Information System (INIS)

    Sidorkina, Y.S.; Leibzon, V.M.; Mankevich, T.V.; Sidlin, E.A.; Zheltova, G.A.

    1986-01-01

    This paper examines the corrosion resistance of 08Kh22N6T and 08Kh21N6M2T steels which would make it possible to ensure equal properties of all the zones of the welded joints. The investigations were carried out on the welded joints in the steels produced with new OZL-40 and OZL-41 electrodes and with standard TsL-11 and EA-400/10u electrodes. The chemical compositions of the steels and deposited metal are presented. The tests of the intercrystalline corrosion resistances of the welded joints in the steels in the as-welded condition and after heat treatment showed that the weld metal is not attacked by intercrystalline corrosion. The tests also showed that the welded joints in 08Kh22N6T steel made with the OZL-40 and TsL-11 electrodes are resistant to corrosion in 55% phosphoric acid at 90 C in 1% sulfuric acid, and in 25% formic acid at 80 C. The investigated steels made with the OZL-40 and OZL-41 electrode respectively show that the welded joints are resistant to intercrystalline and general corrosion, have high mechanical and processing properties and the electrodes, and can be used for welding equipment designed for service in alkaline, neutral, and slightly acid media

  4. Pitting Corrosion of the Resistance Welding Joints of Stainless Steel Ventilation Grille Operated in Swimming Pool Environment

    Directory of Open Access Journals (Sweden)

    Mirosław Szala

    2018-01-01

    Full Text Available This work focuses on the pitting corrosion of ventilation grilles operated in swimming pool environments. The ventilation grille was made by resistance welding of stainless steel rods. Based on the macroscopic and microscopic examinations, the mechanism of the pitting corrosion was confirmed. Chemical composition microanalysis of sediments as well as base metal using scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS method was carried out. The weldments did not meet the operating conditions of the swimming pool environment. The wear due to the pitting corrosion was identified in heat affected zones of stainless steel weldment and was more severe than the corrosion of base metal. The low quality finish of the joints and influence of the welding process on the weld metal microstructure lead to accelerated deposition of corrosion effecting elements such as chlorine.

  5. Effect of post weld heat treatments on the resistance to the hydrogen embrittlement of soft martensitic stainless steel

    International Nuclear Information System (INIS)

    Hazarabedian, Alfredo; Ovejero Garcia, Jose; Bilmes, P.; Llorente, C.

    2003-01-01

    The effect of external hydrogen on the tensile properties of an all weld sample of a soft martensitic stainless steel was studied. The material was tested in the as weld condition and after tempered conditions modifying the austenite content, and changing the quantity, type and distribution of precipitates. Hydrogen was introduced by cathodic charge or by immersion in an acid brine saturated whit 1 atm hydrogen sulphide, during the mechanical test. The as weld condition showed a good resistance in the hydrogen sulphide, were the tempered samples were embrittled. Under cathodic charge, all samples were susceptible to hydrogen damage. The embritting mechanisms were the same in both environments. When the austenite content, was below 10% the crack path is on the primary austenite grain boundary. At higher austenite content, the crack is transgranular. (author)

  6. Low-temperature cyclic cracking resistance of Fe-Cr-Ni and Fe-Cr-Mn steels welded joints

    International Nuclear Information System (INIS)

    Ostash, O.P.; Zhmur-Klimenko, V.T.; Yarema, S.Ya.; Yushchenko, K.A.; Strok, L.P.; Belotserkovets, V.I.

    1983-01-01

    Results of further investigations into regularities of development of low-temperature fatigue fracture of welded oints in 07Kh13G20AN4 steel are presented, they are compared with analogous data traditional cryogenic 0Kh18N10T and 03Kh13AG19 steels. Welded joints have been prepared by means of automatic V-like level arc Welding of plates; 0Kh18N10T and 07Kh13G20AN4 steels have been welded by means of sv-04Kh19N9 wire, 03Kh13AG19 steel-by means of sv-07Kh13AG19 wire. Tests at almost zero (asymmetry coefficient R=0.05) cycle of extension at 15-20 Hz frequency have been conducted on 5 mm thick disk samples at 20 deg C and - 160 deg C according to the given methods. It is shown that by cyclic crack resistance of welded joint zones of 0Kh18N10T steel and chromium-manganese steels at normal temperature the 07Kh13G20AN4 steel exceeds 0Kh18N10T steel, at low temperature it yields to 0Kh18N10T only by fracture toughness of heat affected zones HAZ and weld metal (ne). 07Kh13G20AN4 steel and its welded joints as most hardened and cheap may be a good substituent for 0Kh18N10T steel. Optimization of WM alloying for increase of its cyclic fracture toughness at cryogenic temperatures is necessary

  7. Technical Support of Performance Improvement for Resistance Welding Using Zr-4 Endcap and Endplate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soo Sung

    2008-10-15

    The proper welding process for Zircaloy-4 endplate of PHWR and DUPIC fuel bundle assembly is considered important in respect to the soundness of weldment and the improvement of the performance of nuclear fuel bundle during the operation in reactor. The Zircaloy-4 endplate of PHWR and DUPIC fuel bundles are welded by the projection joint type, connecting the endcaps of fuel elements. Therefore, the purpose of this projection joint is to improve the welding quality of torque strength and welding deformation and to apply the commercial productions for the endplate welding of PHWR and DUPIC nuclear fuel bundle assembly.

  8. Weld repair of helium degraded reactor vessel material

    International Nuclear Information System (INIS)

    Kanne, W.R. Jr.; Lohmeier, D.A.; Louthan, M.R. Jr.; Rankin, D.T.; Franco-Ferreira, E.A.; Bruck, G.J.; Madeyski, A.; Shogan, R.P.; Lessmann, G.G.

    1990-01-01

    Welding methods for modification or repair of irradiated nuclear reactor vessels are being evaluated at the Savannah River Site. A low-penetration weld overlay technique has been developed to minimize the adverse effects of irradiation induced helium on the weldability of metals and alloys. This technique was successfully applied to Type 304 stainless steel test plates that contained 3 to 220 appm helium from tritium decay. Conventional welding practices caused significant cracking and degradation in the test plates. Optical microscopy of weld surfaces and cross sections showed that large surface toe cracks formed around conventional welds in the test plates but did not form around overlay welds. Scattered incipient underbead cracks (grain boundary separations) were associated with both conventional and overlay test welds. Tensile and bend tests were used to assess the effect of base metal helium content on the mechanical integrity of the low-penetration overlay welds. The axis of tensile specimens was perpendicular to the weld-base metal interface. Tensile specimens were machined after studs were resistance welded to overlay surfaces

  9. Mechanical and Acoustic Characteristics of the Weld and the Base Metal Machine Part of Career Transport

    Science.gov (United States)

    Smirnov, Alexander N.; Knjaz'kov, Victor L.; Levashova, Elena E.; Ababkov, Nikolay V.; Pimonov, Maksim V.

    2018-01-01

    Currently, many industries use foreign-made machinery. There is no opportunity to purchase quality original spare parts for which machinery. Therefore, enterprises operating this equipment are looking for producers of analogues of various parts and assemblies. Quite often, the metal of such analog components turns out to be substandard, which leads to their breakdown at a much earlier date and the enterprises incur material losses. Due to the fact that the complex of performance characteristics and the resource of products are laid at the stage of their production, it is extremely important to control the quality of the raw materials. The structure, mechanical, acoustic and magnetic characteristics of metal samples of such destroyed details of quarry transport as hydraulic cylinders and detail “axis” of an excavator are investigated. A significant spread of data on the chemical composition of metal, hardness and characteristics of non-destructive testing is established, which gives grounds to recommend to manufacturers and suppliers of parts is more responsible to approach the incoming quality control. The results of the investigation of metal samples by destructive and non-destructive methods of control are compared, which showed that the spectral-acoustic method of nondestructive testing can be used to control the quality of the responsible machine parts under conditions of import substitution.

  10. Variations the diameter tip of electrode on the resistance spot welding using electrode Cu on worksheet Fe

    Science.gov (United States)

    Baskoro, A. S.; Sugeng, S.; Sifa, Agus; Badruzzaman; Endramawan, Tito

    2018-04-01

    Resistance Spot Weld (RSW) is a welding technology which plays an important role that is often used in industry in large manufacturing industries, especially in the automotive sector, some of the parameters are affecting the welding process that give impact in the weld quality, diameter tip important impact on the resistance spot welding, This study can be categorized as experimental study by using Electrode material such as Cu and Fe Worksheet Materials, with a material thickness of 1 mm,0,8 mm, and 0,6 mm on each worksheet, and the large diameter of tip electrode (5√t) depend on the thickness of worksheet. Testing the material in the electrode and the worksheet by testing the composition and tensile test, and the hardness of the material used are to know the material used certainly. The result of the welding process was done by using the parameters voltage of 8KV, with a duty cycle of 50% using a variation of the time 8s-10s, and variations the electrode tip diameter that are affected by the thickness of the worksheet 5\\sqrt{t}, plate thickness used 1 mm, 0,8 mm and 0,6 mm, so that the electrodes was used to a thickness of 1 mm diameter tip electrode 5 mm, thickness 0,8 mm with an electrode tip diameter 4,5 mm and a thickness 0,6 mm with an electrode diameter of 4 mm, with current welding parameter 8kVA, and variations in holding time 10s, 9s and 8s 50% duty cycle, then testing welds with the standard shear test refers ASTM A370-2012 with more results to a thickness of 0,6 has the ability to withstand greater load on the holding time 8s and 9s, 10s, to a thickness 0,8 mm and 1 mm shear test results demonstrate the ability to withstand loads on the holding time of 10s and 9s have a greater ability than 8s on worksheet that has thickness 1 mm at a holding time of 10s, and then Maximum shear test averaging of 36,41 N at a worksheet with a thickness of 0,8 mm (diameter tip 4,5 mm) at a holding time of 8s and a mean minimum shear stress of 23,73 N at worksheet that

  11. Submerged Arc Stainless Steel Strip Cladding—Effect of Post-Weld Heat Treatment on Thermal Fatigue Resistance

    Science.gov (United States)

    Kuo, I. C.; Chou, C. P.; Tseng, C. F.; Lee, I. K.

    2009-03-01

    Two types of martensitic stainless steel strips, PFB-132 and PFB-131S, were deposited on SS41 carbon steel substrate by a three-pass submerged arc cladding process. The effects of post-weld heat treatment (PWHT) on thermal fatigue resistance and hardness were evaluated by thermal fatigue and hardness testing, respectively. The weld metal microstructure was investigated by utilizing optical microscopy, scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). Results showed that, by increasing the PWHT temperature, hardness decreased but there was a simultaneous improvement in weldment thermal fatigue resistance. During tempering, carbide, such as (Fe, Cr)23C6, precipitated in the weld metals and molybdenum appeared to promote (Fe, Cr, Mo)23C6 formation. The precipitates of (Fe, Cr, Mo)23C6 revealed a face-centered cubic (FCC) structure with fine grains distributed in the microstructure, thereby effectively increasing thermal fatigue resistance. However, by adding nickel, the AC1 temperature decreased, causing a negative effect on thermal fatigue resistance.

  12. Alloying system for cold-resisting high-tensile welds of maraging steels

    International Nuclear Information System (INIS)

    Yushchenko, K.A.; Pustovit, A.I.; Taver, E.I.; Piskarev, M.N.

    1978-01-01

    Studied was the effect of molybdenum (2.2-5%) and chromium (11.3-13.5%) on the structure and properties of welds in steel of the Cr-Ni-Mo-Co-Ti system at heat strengthened condition (hardening, cold treatment, ageing). The welds were made by argon-arc welding process involving a nonconsumable electrode without additives. The welds were tested at temperatures of 20 and -196 deg C. It is pointed out that the welds with a pure martensite structure at -196 deg C have a low ductility and impact strength. To obtain welds having a satisfactory value of impact strength more than 120 kGf/mm 2 at 20 deg C, it is necessary that the metal contains 20...60 % of residual austenite

  13. Finite Element and Experimental Study of Shunting in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Seyyedian Choobi, M.; Nielsen, C. V.; Bay, N.

    2015-01-01

    This research is focused on one of the problems frequently encountered in spot welding in industry. In many applications several spot welds are made close to each other. The spots made after the first spot may become smaller in size due to shunt effect. A numerical and experimental study has been...... conducted to investigate the effect of shunting on nugget size in spot welding of HSLA steel sheets. Different cases with different spacing between weld spots have been examined. The nugget sizes have been measured by metallographic examination and have been compared with 3D finite element simulations...

  14. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve...

  15. Creep properties and simulation of weld repaired low alloy heat resistant CrMo and Mo steels at 540 deg C. Sub project 1 - Ex-serviced parent metal and virgin weld metals

    Energy Technology Data Exchange (ETDEWEB)

    Rui Wu; Storesund, Jan; Borggreen, Kjeld; Weilin Zang

    2006-10-15

    Many existing power generating and process plants, where low alloy heat resistant CrMo(V) steels are extensively used for critical components, have exceeded their design lifetime of usually 100,000 hours. Assessment of residual lifetime and extension of economic life by weld repair have become increasingly important and attractive. This project aims at i) performing weld repair and determining the degree of mismatching, ii) evaluating the creep properties of weld repairs, iii) analysing creep behaviour of weld repair and providing necessary data for further reliable simulations of weld repair creep behaviour in long term service, and iv), simulating and assessing lifetime and creep damage evolution of weld repair. Weld repair using 10 CrMo 9 10, 13 CrMo 4 4 and 15 Mo 3 consumables has been carried out in a service-exposed 10 CrMo 9 10 pipe. Creep specimens have been extracted from the service-exposed 10 CrMo 9 10 parent metal (PM), from the virgin 10 CrMo 9 10 weld metal (WM), from the virgin 13 CrMo 4 4 WM as well as from the virgin 15 Mo 3 WM. Iso-thermal uniaxial creep tests have been performed at 540 deg C in air. Pre- and post-metallography are carried out on the selected samples. FEM simulations using obtained creep data are executed. Pre-test metallography shows normal and acceptable weld repairs at given welding conditions. Creep tests demonstrate that the virgin 10 CrMo 9 10, 13 CrMo 4 4 and 15 Mo 3 WMs have apparently longer creep lifetime than the service-exposed CrMo 9 10 PM at higher stresses than 110 MPa. Among the weld metals, the longest creep lifetime is found in 10 CrMo 9 10. Higher creep strength and lower creep strain rate in the weld metals indicate an overmatch weld. At 95 MPa, however, lifetime of 13 CrMo 4 4 WM is surprisingly short (factors which may shorten lifetime are discussed and one more test will start to verify creep strength at low stress) and tests are still running for other two weld metals. More results regarding low stress

  16. Welding facilities for NPP assembling

    International Nuclear Information System (INIS)

    Rojtenberg, S.S.

    1987-01-01

    Recommendations concerning the choice of equipment for welding in pre-assembling work shops, in the enlarging assembling shops and at the assembling site, are given. Advanced production automatic welders and semiautomatic machines, applied during the NPP equipment assembling as well as automatic machines specially produced for welding the main reactor components and pipelines are described. Automatic and semiautomatic machine and manual welding post supply sources are considered

  17. Friction welding of a nickel free high nitrogen steel: influence of forge force on microstructure, mechanical properties and pitting corrosion resistance

    Directory of Open Access Journals (Sweden)

    Mrityunjoy Hazra

    2014-01-01

    Full Text Available In the present work, nickel free high nitrogen austenitic stainless steel specimens were joined by continuous drive friction welding process by varying the amount of forge (upsetting force and keeping other friction welding parameters such as friction force, burn-off, upset time and speed of rotation as constant at appropriate levels. The joint characterization studies include microstructural examination and evaluation of mechanical (micro-hardness, impact toughness and tensile and pitting corrosion behaviour. The integrity of the joint, as determined by the optical microscopy was very high and no crack and area of incomplete bonding were observed. Welds exhibited poor Charpy impact toughness than the parent material. Toughness for friction weld specimens decreased with increase in forge force. The tensile properties of all the welds were almost the same (irrespective of the value of the applied forge force and inferior to those of the parent material. The joints failed in the weld region for all the weld specimens. Weldments exhibited lower pitting corrosion resistance than the parent material and the corrosion resistance of the weld specimens was found to decrease with increase in forge force.

  18. Characterization of microstructure, chemical composition, corrosion resistance and toughness of a multipass weld joint of superduplex stainless steel UNS S32750

    International Nuclear Information System (INIS)

    Tavares, S.S.M.; Pardal, J.M.; Lima, L.D.; Bastos, I.N.; Nascimento, A.M.; Souza, J.A. de

    2007-01-01

    The superduplex stainless steels have an austeno-ferritic microstructure with an average fraction of each phase of approximately 50%. This duplex microstructure improves simultaneously the mechanical properties and corrosion resistance. Welding of these steels is often a critical operation. In this paper we focus on characterization and analysis of a multipass weld joint of UNS S32750 steel prepared using welding conditions equal to industrial standards. The toughness and corrosion resistance properties of the base metal, root pass welded with gas tungsten arc welding, as well as the filler passes, welded with shielded metal arc welding, were evaluated. The microstructure and chemical composition of the selected areas were also determined and correlated to the corrosion and mechanical properties. The root pass was welded with low nickel filler metal and, as a consequence, presented low austenite content and significant precipitation. This precipitation is reflected in the corrosion and mechanical properties. The filler passes presented an adequate ferrite:austenite proportion but, due to their high oxygen content, the toughness was lower than that of the root pass. Corrosion properties were evaluated by cyclic polarization tests in 3.5% NaCl and H 2 SO 4 media

  19. Structure and Corrosion Resistance of Welded Joints of Alloy 1151 in Marine Atmosphere

    Science.gov (United States)

    Bakulo, A. V.; Yakushin, B. F.; Puchkov, Yu. A.

    2017-07-01

    The corrosion behavior of joints formed by TIG and IMIG welding from clad sheets of heat-hardenable aluminum alloy 1151 of the Al - Cu - Mg system is studied. The corrosion tests are performed in an aqueous solution of NaCl in a salt-spray chamber. The welded joints are subjected to a metallographic analysis.

  20. Cerium Addition Improved the Dry Sliding Wear Resistance of Surface Welding AZ91 Alloy

    Directory of Open Access Journals (Sweden)

    Qingqiang Chen

    2018-02-01

    Full Text Available In this study, the effects of cerium (Ce addition on the friction and wear properties of surface welding AZ91 magnesium alloys were evaluated by pin-on-disk dry sliding friction and wear tests at normal temperature. The results show that both the friction coefficient and wear rate of surfacing magnesium alloys decreased with the decrease in load and increase in sliding speed. The surfacing AZ91 alloy with 1.5% Ce had the lowest friction coefficient and wear rate. The alloy without Ce had the worst wear resistance, mainly because it contained a lot of irregularly shaped and coarse β-Mg17Al12 phases. During friction, the β phase readily caused stress concentration and thus formed cracks at the interface between β phase and α-Mg matrix. The addition of Ce reduced the size and amount of Mg17Al12, while generating Al4Ce phase with a higher thermal stability. The Al-Ce phase could hinder the grain-boundary sliding and migration and reduced the degree of plastic deformation of subsurface metal. Scanning electron microscopy observation showed that the surfacing AZ91 alloy with 1.5% Ce had a total of four types of wear mechanism: abrasion, oxidation, and severe plastic deformation were the primary mechanisms; delamination was the secondary mechanism.

  1. Effect of Microstructure on Stress Corrosion Cracking Behaviour of High Nitrogen Stainless Steel Gas Tungsten Arc Welds

    Science.gov (United States)

    Mohammed, Raffi; Srinivasa Rao, K.; Madhusudhan Reddy, G.

    2018-03-01

    Present work is aimed to improve stress corrosion cracking resistance of high nitrogen steel and its welds. An attempt to weld high nitrogen steel of 5 mm thick plate using gas tungsten arc welding (GTAW) with three high strength age hardenable fillers i.e., 11-10 PH filler, PH 13- 8Mo and maraging grade of MDN 250 filler is made. Welds were characterized by optical microscopy and scanning electron microscopy. Vickers hardness testing of the welds was carried out to study the mechanical behaviour of welds. Potentio-dynamic polarization studies were done to determine pitting corrosion resistance in aerated 3.5% NaCl solution. Stress corrosion cracking (SCC) testing was carried out using constant load type machine with applied stress of 50% yield strength and in 45% MgCl2 solution boiling at 155°C. The results of the present investigation established that improvement in resistance to stress corrosion cracking was observed for PH 13- 8Mo GTA welds when compared to 11-10 PH and MDN 250 GTA welds. However, All GTA welds failed in the weld interface region. This may be attributed to relatively lower pitting potential in weld interface which acts as active site and the initiation source of pitting.

  2. A comparative study of the SSC resistance of a novel welding process IEA with SAW and MIG

    International Nuclear Information System (INIS)

    Natividad, C.; Salazar, M.; Espinosa-Medina, M.A.; Perez, R.

    2007-01-01

    The Stress Sulphide Cracking resistance of X65 weldments produced by Indirect Electric Arc, Submerged Arc Welding (SAW) and Metal Inert Gas (MIG) processes were evaluated in a NACE solution saturated with H 2 S at 25 deg. C, 37 deg. C and 50 deg. C using Slow Strain Rate Tests (SSRT) and electrochemical measurements. Weldments produced by the Indirect Electric Arc presented the best Stress Sulphide Cracking resistance at 25 deg. C. This behavior is attributed to the microstructural modification of the weld bead from ferrite in a needlelike form to a fine grain microstructure, which was not observed at 37 deg. C and 50 deg. C. In addition, the hydrogen permeation flux increased with the temperature, this result is associated with the ferrite phase. The electrochemical results show a decrease of the trapping sites for the atomic hydrogen on this weldment. This behavior has not been observed for the other welding processes due to their microstructure (a typical columnar growth of coarse grain)

  3. Preparation and cold welding of silver nanowire based transparent electrodes with optical transmittances >90% and sheet resistances ohm/sq.

    Science.gov (United States)

    Xu, Feng; Xu, Wei; Mao, Bingxin; Shen, Wenfeng; Yu, Yan; Tan, Ruiqin; Song, Weijie

    2018-02-15

    In this article, silver nanowires (AgNWs) with aspect ratios of 1000 and lengths up to 200 μm are obtained by a modified polyol approach. These very long AgNWs are then utilized to prepare transparent electrodes (TEs) displaying a transmittance of 91.3% at a sheet resistance of 8.6 ohm/sq without any post-treatment. Furthermore, we also demonstrate a process for the cold welding of Ag NWs by simply dipping the AgNWs films into CTAB solutions, resulting in a further improvement for the optoelectronic performance. After the post-treatment, the AgNW-based TEs can achieve a transmittance of 93% at a sheet resistance of 9.5 ohm/sq. In addition, the electric behaviors of AgNW-based TEs are investigated. In the bulk-like regime, for the as-prepared AgNW-based TEs, the Figure of merit (FOM), DC to optical conductivity ratio reaches up to 566.8. After the cold welding process, the DC to optical conductivity ratio can reach even higher values (631.6). In the percolative regime, the as-prepared and welded AgNW-based TEs can achieve Π (FOM with percolative-like behavior) values of 166.8 and 242.1, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Recent Corrosion Research Trends in Weld Joints

    International Nuclear Information System (INIS)

    Kim, Hwan Tae; Kil, Sang Cheol; Hwang, Woon Suk

    2007-01-01

    The increasing interest in the corrosion properties of weld joints in the corrosive environment is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency welding process to produce welds. Welding plays an important role in the fabrication of chemical plants, nuclear power plant, ship construction, and this has led to an increasing attention to the corrosion resistant weld joints. This paper covers recent technical trends of welding technologies for corrosion resistance properties including the COMPENDEX DB analysis of welding materials, welding process, and welding fabrications

  5. Additional materials for welding of the EP99 heat resisting alloy with the EI868 alloy and 12Kh18N9T steel

    International Nuclear Information System (INIS)

    Sorokin, L.I.; Filippova, S.P.; Petrova, L.A.

    1978-01-01

    Presented are the results of the studies aimed at selecting an additive material for argon-arc welding process involving heat-resistant nickel EP99 alloy to be welded to the EI868 alloy and 12Kh18N9T steel. As the additive material use was made of wire made of nickel-chromium alloys and covered electrodes made of the EP367 alloy with additions of tungsten. It has been established that in order to improve the resistance of metal to hot-crack formation during argon arc welding of the EP99 alloy with the EI868 alloy, it is advisable to use an additive material of the EP533 alloy, and while welding the same alloy with the 12Kh18N9T steel, filler wire of the EP367 alloy is recommended

  6. Wear analysis and cyclic fatigue resistance of electro discharge machined NiTi rotary instruments

    Directory of Open Access Journals (Sweden)

    F. Iacono

    2016-06-01

    Conclusions: The typical irregular surface of HyFlex EDM remained unaffected after multiple uses, confirming a high wear resistance. The new manufacturing process of electrical discharge machining had a substantial impact on fatigue lifetime of EDM files when compared with HyFlex CM. Within limitations of the present in vitro results, EDM files appeared suitable in shaping severely curved canals.

  7. Swiss ball abdominal crunch with added elastic resistance is an effective alternative to training machines

    DEFF Research Database (Denmark)

    Sundstrup, Emil; Jakobsen, Markus D; Andersen, Christoffer H

    2012-01-01

    crunches in training machine (27±3.7 vs 65±3.8% nEMG respectively, Pinfluence the findings. CONCLUSION: Crunches on a Swiss ball with added elastic resistance induces high rectus abdominis activity accompanied by low hip flexor...

  8. Spot Welding Characterizations With Time Variable

    International Nuclear Information System (INIS)

    Abdul Hafid; Pinitoyo, A.; History; Paidjo, Andryansyah; Sagino, Sudarmin; Tamzil, M.

    2001-01-01

    For obtain spot welding used effective data, this research is made, so that time operational of machine increasing. Welding parameters are material classification, electrical current, and weld time. All of the factors are determined welding quality. If the plate more thick, the time must be longer when the current constant. Another factor as determined welding quality are surface condition of electrode, surface condition of weld material, and material classifications. In this research, the weld machine type IP32A2 VI (110 V), Rivoira trademark is characterized

  9. Low Speed Control for Automatic Welding

    Science.gov (United States)

    Iceland, W. E.

    1982-01-01

    Amplifier module allows rotating positioner of automatic welding machine to operate at speeds below normal range. Low speeds are precisely regulated by a servomechanism as are normal-range speeds. Addition of module to standard welding machine makes it unnecessary to purchase new equipment for low-speed welding.

  10. An experimental study on fracture toughness of resistance spot welded galvanized and ungalvanized DP 450 steel sheets used in automotive body

    Directory of Open Access Journals (Sweden)

    Sevim, Ibrahim

    2016-09-01

    Full Text Available The purpose of this study is to determine fracture toughness of Resistance Spot Welded (RSW Dual Phase (DP steels. RSW of galvanized and ungalvanized DP 450 steel sheets was carried out on spot welding machine. Fracture toughness of RSW joints of galvanized and ungalvanized DP 450 steel sheets was calculated from tensile-shear tests. New empirical equations were developed using Least Squares Method (LSM between energy release rate, fracture toughness and critical crack size depending on the relationship between hardness and fracture toughness values. Results indicated that fracture toughness of joints welded by using RSW increased exponentially while the hardness decreased. In addition, fracture toughness and energy release rate of RSW galvanized DP 450 steel sheets were lower compared to RSW ungalvanized DP 450 steel sheets which had approximately the same hardness.El objetivo de este estudio es determinar la tenacidad de fractura de los aceros dual (DP soldados por puntos de resistencia (RSW. En la máquina de soldadura por puntos se realizó la soldadura de láminas de acero DP 450 galvanizado y sin galvanizar. A partir de los ensayos de tracción-cizallamiento, se calculó la tenacidad a la fractura de las uniones del acero DP 450 galvanizado y sin galvanizar. Aplicando el método de mínimos cuadrados (LSM se desarrollaron nuevas ecuaciones empíricas entre el porcentaje de energía liberada, la tenacidad de fractura y el tamaño de grieta crítica en función de la relación entre los valores de tenacidad de fractura y de dureza. Los resultados indicaron que la tenacidad de fractura de las uniones soldadas por RSW aumentó exponencialmente, mientras que la dureza disminuyó. Además, el porcentaje de energía liberada de las láminas de acero DP 450 galvanizadas y soldadas fueron menores que en el caso de las láminas sin galvanizar a valores iguales de dureza.

  11. Error Analysis of 3D Metal Micromold Fabricated by Femtosecond Laser Cutting and Microelectric Resistance Slip Welding

    Directory of Open Access Journals (Sweden)

    Bin Xu

    2013-01-01

    Full Text Available We used micro-double-staged laminated object manufacturing process (micro-DLOM to fabricate 3D micromold. Moreover, the error of the micro-DLOM was also studied. Firstly, we got the principle error of the micro-DLOM. Based on the mathematical expression, it can be deduced that the smaller the opening angle α and the steel foil thickness h are, the smaller the principle error δ is. Secondly, we studied the error of femtosecond laser cutting. Through the experimental results, we know that the error of femtosecond laser cutting is 0.5 μm under 110 mW femtosecond laser power, 100 μm/s cutting speed, and 0.75 μm dimension compensation. Finally, we researched the error of microelectric resistance slip welding. Based on the research results, we can know that the minimum error of microcavity mold in the height direction is only 0.22 μm when welding voltage is 0.21 V and the number of slip welding discharge is 160.

  12. The interface microstructure, mechanical properties and corrosion resistance of dissimilar joints during multipass laser welding for nuclear power plants

    Science.gov (United States)

    Li, Gang; Lu, Xiaofeng; Zhu, Xiaolei; Huang, Jian; Liu, Luwei; Wu, Yixiong

    2018-05-01

    This study presents the interface microstructure, mechanical properties and corrosion resistance of dissimilar joints between Inconel 52M overlays and 316L stainless steel during multipass laser welding for nuclear power plants. The results indicate that the microstructure at the interface beside 316L stainless steel consists of cellular with the width of 30-40 μm, which also exhibits numerous Cr and Mo-rich precipitates like flocculent structure and in chains along grain boundaries as a mixed chemical solution for etching. Many dendritic structure with local melting characteristics and Nb-rich precipitates are exhibited at the interface beside Inconel 52M overlays. Such Nb-rich precipitates at the interface beside Inconel 52M overlays deteriorate the tensile strength and toughness of dissimilar joints at room temperature. The tensile strength of 316L stainless steel at 350 °C significantly decreases with the result that dissimilar joints are fractured in 316L stainless steel. The correlation between corrosion behavior and microstructure of weld metals is also discussed. The difference in high corrosion potential between Nb-rich precipitates and the matrix could result in establishing effective galvanic couples, and thus accelerating the corrosion of weld metals.

  13. Effects of microplasma arc AISI 316L welds on the corrosion behaviour of pipelines in LiBr cooling systems

    International Nuclear Information System (INIS)

    Sánchez-Tovar, R.; Montañés, M.T.; García-Antón, J.

    2013-01-01

    Highlights: •SECM tests reveal differences in electrochemical activity of base and welded alloys. •The highest electrochemical activity is obtained for the welded alloy. •Microplasma arc welding process hinders passivation in lithium bromide. •Microplasma arc welding increases corrosion rate and susceptibility to pitting. •The galvanic pair between base and welded alloys in LiBr is weak. -- Abstract: The effect of microplasma arc welding (MPAW) on the electrochemical and corrosion behaviour of AISI 316L stainless steel tubes has been studied. Scanning electrochemical measurements were performed in sodium chloride to evaluate the difference in the electrochemical activity of base (non-welded) and welded samples. Oxygen reduction rates increase in AISI 316L due to the heat treatment effect induced by welding, indicating a higher electrochemical activity in the welded samples. Additionally, the use of MPA weldments in lithium bromide (LiBr) absorption machines was also analysed at typical operating temperatures and Reynolds numbers. The welding process increases corrosion rates, hinders passivation and increases the susceptibility to pitting attack in LiBr. However, zero-resistance ammeter and localization index measurements show that the galvanic pair generated between the base and welded alloys is weak, both electrodes being in their passive state. Temperature greatly affects the corrosion process

  14. Evaluation of Microstructure, Mechanical Properties and Corrosion Resistance of Friction Stir-Welded Aluminum and Magnesium Dissimilar Alloys

    Science.gov (United States)

    Verma, Jagesvar; Taiwade, Ravindra V.; Sapate, Sanjay G.; Patil, Awanikumar P.; Dhoble, Ashwinkumar S.

    2017-10-01

    Microstructure, mechanical properties and corrosion resistance of dissimilar friction stir-welded aluminum and magnesium alloys were investigated by applying three different rotational speeds at two different travel speeds. Sound joints were obtained in all the conditions. The microstructure was examined by an optical and scanning electron microscope, whereas localized chemical information was studied by energy-dispersive spectroscopy. Stir zone microstructure showed mixed bands of Al and Mg with coarse and fine equiaxed grains. Grain size of stir zone reduced compared to base metals, indicated by dynamic recrystallization. More Al patches were observed in the stir zone as rotational speed increased. X-ray diffraction showed the presence of intermetallics in the stir zone. Higher tensile strength and hardness were obtained at a high rotational speed corresponding to low travel speed. Tensile fractured surface indicated brittle nature of joints. Dissimilar friction stir weld joints showed different behaviors in different corrosive environments, and better corrosion resistance was observed at a high rotational speed corresponding to low travel speed (FW3) in a sulfuric and chloride environments. Increasing travel speed did not significantly affect on microstructure, mechanical properties and corrosion resistance as much as the rotational speed.

  15. Hydrogen diffusion and effect on degradation in welded microstructures of creep-resistant low-alloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Rhode, Michael

    2016-04-04

    The main challenge for the future is to further increase the power plant thermal efficiency independent of the type of power plant concept, i.e. fossil-fired or nuclear power plant, where the material selection can directly affect reduction of CO{sub 2} emissions. In power plant design, welding is the most applied manufacturing technique in component construction. The necessary weld heat input causes metallurgical changes and phase transitions in the heat affected zone (HAZ) of the base materials and in the deposited weld metal. The weld joint can absorb hydrogen during welding or in later service - This absorption can cause degradation of mechanical properties of the materials, and in certain loading conditions, hydrogen-assisted cold cracks can occur. This cracking phenomenon can appear time delayed due to the temperature dependency of the hydrogen diffusion and the presence of a ''critical'' hydrogen concentration. Additionally, each specific weld microstructure shows a certain hydrogen diffusion and solubility that contribute to susceptibility of the cracking phenomenon. Therefore hydrogen cannot be neglected as possible failure effect, which was identified recently in the case of T24 creep-resistant tube-to-tube weld joints. It is necessary to identify and assess the hydrogen effect in weld joints of low-alloyed steel grades for to improve further early detection of possible failures. For each specific weld joint microstructure, it is necessary to separate the interdependencies between mechanical load and the hydrogen concentration. The diffusivity and solubility must be considered to identify hydrogen quantities in the material at any given time. In this case, the effects of mechanical loading were dealt with independently. For the characterization of the mechanical properties, hydrogen charged tensile specimens were investigated for the base materials and thermally simulated HAZ microstructures. The hydrogen diffusion was characterized

  16. Hydrogen diffusion and effect on degradation in welded microstructures of creep-resistant low-alloyed steels

    International Nuclear Information System (INIS)

    Rhode, Michael

    2016-01-01

    The main challenge for the future is to further increase the power plant thermal efficiency independent of the type of power plant concept, i.e. fossil-fired or nuclear power plant, where the material selection can directly affect reduction of CO 2 emissions. In power plant design, welding is the most applied manufacturing technique in component construction. The necessary weld heat input causes metallurgical changes and phase transitions in the heat affected zone (HAZ) of the base materials and in the deposited weld metal. The weld joint can absorb hydrogen during welding or in later service - This absorption can cause degradation of mechanical properties of the materials, and in certain loading conditions, hydrogen-assisted cold cracks can occur. This cracking phenomenon can appear time delayed due to the temperature dependency of the hydrogen diffusion and the presence of a ''critical'' hydrogen concentration. Additionally, each specific weld microstructure shows a certain hydrogen diffusion and solubility that contribute to susceptibility of the cracking phenomenon. Therefore hydrogen cannot be neglected as possible failure effect, which was identified recently in the case of T24 creep-resistant tube-to-tube weld joints. It is necessary to identify and assess the hydrogen effect in weld joints of low-alloyed steel grades for to improve further early detection of possible failures. For each specific weld joint microstructure, it is necessary to separate the interdependencies between mechanical load and the hydrogen concentration. The diffusivity and solubility must be considered to identify hydrogen quantities in the material at any given time. In this case, the effects of mechanical loading were dealt with independently. For the characterization of the mechanical properties, hydrogen charged tensile specimens were investigated for the base materials and thermally simulated HAZ microstructures. The hydrogen diffusion was characterized with

  17. Machinability of Stellite 6 hardfacing

    Directory of Open Access Journals (Sweden)

    Dudzinski D.

    2010-06-01

    Full Text Available This paper reports some experimental findings concerning the machinability at high cutting speed of nickel-base weld-deposited hardfacings for the manufacture of hot tooling. The forging work involves extreme impacts, forces, stresses and temperatures. Thus, mould dies must be extremely resistant. The aim of the project is to create a rapid prototyping process answering to forging conditions integrating a Stellite 6 hardfacing deposed PTA process. This study talks about the dry machining of the hardfacing, using a two tips machining tool and a high speed milling machine equipped by a power consumption recorder Wattpilote. The aim is to show the machinability of the hardfacing, measuring the power and the tip wear by optical microscope and white light interferometer, using different strategies and cutting conditions.

  18. Plug-welding of ODS cladding tube for BOR-60 irradiation. Welding condition setting. Device remodeling and welding

    International Nuclear Information System (INIS)

    Seki, Masayuki; Ishibashi, Fujio; Kono, Syusaku; Hirako, Kazuhito; Tsukada, Tatsuya

    2003-04-01

    Irradiation test in BOR-60 at RIAR to judge practical use prospect of ODS cladding tube at early stage is planned as Japan-Russia a joint research. RIAR does fuel design of fuel pin used for this joint research. JNC manufactures ODS cladding tube and bar materials (two steel kind of martensite and ferrite), upper endplug production. They are welded by pressurized resistance welding, and are inspected in JNC Tokai, transported to RIAR. And RIAR manufactures vibration packing fuel pin. On the upper endplug welding by pressurized resistance welding method, we worded on the problems such as decision of welding condition by changing the size and crystallization of cladding tube and the design of endplug, and the chucking device remodeling to correspond to the long scale cladding tube welding system (included handling) and of quality assurance method. Especially, use of long scale cladding tube caused problem that bending transformation occurred in cladding tube by welding pressure. However, we solved this problem by shortening the distance of cladding tube colette chuck and pressure receiving, and by putting the sleeve in an internal space of welding machine, losing the bending of cladding tube. Moreover, welding defects were occurred by the difference of an inside state, an inside defect and recrystallization of cladding tube. We solved the problem by inside grinding for the edge of tube, angle beam method by ultrasonic wave, and ultrasonic wave form confirmation. Manufacturing process with long scale cladding tube including heat-treatment to remove combustion return and remaining stress was established besides, Afterwards, welding of ODS cladding tube and upper endplug. As the quality assurance system, we constructed [Documented procedure (referred to JOYO)] based on [Document of the QA plan] by OEC. Welding and inspection were executed by the document procedure. It is thought that the quality assurance method become references for the irradiation test in JOYO in the

  19. Failure mechanism of resistance-spot-welded specimens impacted on base material by bullets

    Directory of Open Access Journals (Sweden)

    Chunlei Fan

    2018-01-01

    Full Text Available The tests of bullet impact on the base material (BM of a simple specimen with a single resistance-spot-welded (RSW nugget of TRIP800 steel are performed to investigate the response of the RSW specimen to the ballistic debris impact on the RSW specimen. A one-stage gas gun is used to fire the bullets while a laser velocity interferometer system for any reflector (VISAR is used to measure the velocity histories of the free surfaces of the RSW specimen. The recovered RSW specimens are examined with the three-dimensional super depth digital microscope (SDDM and the scanning electro microscope (SEM. For the tests of small multiple-bullet impact, it is revealed that the wave train of the VISAR measured results and the detachment of the base material interfaces in the recovered RSW specimens are directly related to the reflection and refraction of the curved stress waves incoming to the interfaces and the free surfaces in the RSW specimens. The detachment of BM interfaces can lead to the impact failure of the RSW joints for the larger multiple-bullet impact at higher velocity, the mechanism of which is different from the case for normal incidence (spalling. For the tests of single large bullet impact, it is brought to light experimentally that the plastic strain concentration at the “notch tip” spurs either the crack near the RSW joint or the split of the nugget. The numerical simulation shows up the process of splitting the nugget: a crack initiates at the “notch tip”, propagates across the nugget interface and splits the nugget into two parts. It is indicated that the interaction between the stress waves and many interfaces/free surfaces in the RSW specimen under ballistic impact causes variable local stress triaxialities and stress Lode angles, which affects the deformation and fracture mechanism of the RSW specimen including stretching and shearing failure. It is shown that the impact failure of the RSW joints is a mixture of brittle

  20. Failure mechanism of resistance-spot-welded specimens impacted on base material by bullets

    Science.gov (United States)

    Fan, Chunlei; Ma, Bohan; Chen, Danian; Wang, Huanran; Ma, Dongfang

    2018-01-01

    The tests of bullet impact on the base material (BM) of a simple specimen with a single resistance-spot-welded (RSW) nugget of TRIP800 steel are performed to investigate the response of the RSW specimen to the ballistic debris impact on the RSW specimen. A one-stage gas gun is used to fire the bullets while a laser velocity interferometer system for any reflector (VISAR) is used to measure the velocity histories of the free surfaces of the RSW specimen. The recovered RSW specimens are examined with the three-dimensional super depth digital microscope (SDDM) and the scanning electro microscope (SEM). For the tests of small multiple-bullet impact, it is revealed that the wave train of the VISAR measured results and the detachment of the base material interfaces in the recovered RSW specimens are directly related to the reflection and refraction of the curved stress waves incoming to the interfaces and the free surfaces in the RSW specimens. The detachment of BM interfaces can lead to the impact failure of the RSW joints for the larger multiple-bullet impact at higher velocity, the mechanism of which is different from the case for normal incidence (spalling). For the tests of single large bullet impact, it is brought to light experimentally that the plastic strain concentration at the "notch tip" spurs either the crack near the RSW joint or the split of the nugget. The numerical simulation shows up the process of splitting the nugget: a crack initiates at the "notch tip", propagates across the nugget interface and splits the nugget into two parts. It is indicated that the interaction between the stress waves and many interfaces/free surfaces in the RSW specimen under ballistic impact causes variable local stress triaxialities and stress Lode angles, which affects the deformation and fracture mechanism of the RSW specimen including stretching and shearing failure. It is shown that the impact failure of the RSW joints is a mixture of brittle fracture and ductile

  1. Quality status display for a vibration welding process

    Science.gov (United States)

    Spicer, John Patrick; Abell, Jeffrey A.; Wincek, Michael Anthony; Chakraborty, Debejyo; Bracey, Jennifer; Wang, Hui; Tavora, Peter W.; Davis, Jeffrey S.; Hutchinson, Daniel C.; Reardon, Ronald L.; Utz, Shawn

    2017-03-28

    A system includes a host machine and a status projector. The host machine is in electrical communication with a collection of sensors and with a welding controller that generates control signals for controlling the welding horn. The host machine is configured to execute a method to thereby process the sensory and control signals, as well as predict a quality status of a weld that is formed using the welding horn, including identifying any suspect welds. The host machine then activates the status projector to illuminate the suspect welds. This may occur directly on the welds using a laser projector, or on a surface of the work piece in proximity to the welds. The system and method may be used in the ultrasonic welding of battery tabs of a multi-cell battery pack in a particular embodiment. The welding horn and welding controller may also be part of the system.

  2. Optimization of the pulsed current gas tungsten arc welding (PCGTAW) parameters for corrosion resistance of super duplex stainless steel (UNS S32760) welds using the Taguchi method

    International Nuclear Information System (INIS)

    Yousefieh, M.; Shamanian, M.; Saatchi, A.

    2011-01-01

    Research highlights: → Among the four factors and three levels tested, it was concluded that the pulse current had the most significant effect on the pitting potential and the background current had the next most significant effect. The effects of pulse frequency and % on time are less important when compared to the other factors. → The percentage contributions of the pulse current, the background current, % on time, and pulse frequency to the corrosion resistance are 66.28%, 25.97%, 2.71% and 5.04%, respectively. → The optimum conditions within the selected parameter values were found as the second level of pulse current (120 A), second level of background current (60 A), third level of % on time (80%) and third level of pulse frequency (5 Hz). → The confirmation test was carried out at optimum working conditions. Pitting potential was increased to 1.06 V SCE by setting the control factors. Predicted (1.04 V SCE ) and observed (1.06 V SCE ) pitting potential values are close to each other, which are the highest values obtained in the present study. - Abstract: In the present work, a design of experiment (DOE) technique, the Taguchi method, has been used to optimize the pulsed current gas tungsten arc welding (PCGTAW) parameters for the corrosion resistance of super duplex stainless steel (UNS S32760) welds. A L 9 (3 4 ) orthogonal array (OA) of Taguchi design which involves nine experiments for four parameters (pulse current, background current, % on time, pulse frequency) with three levels was used. Corrosion resistance in 3.5%NaCl solution was evaluated by anodic polarization tests at room temperature. Analysis of variance (ANOVA) is performed on the measured data and S/N (signal to noise) ratios. The higher the better response category was selected to obtain optimum conditions. The optimum conditions providing the highest pitting potential were estimated. The optimum conditions were found as the second level of pulse current (120 A), second level of

  3. A control system for uniform bead in fillet arc welding on tack welds

    International Nuclear Information System (INIS)

    Kim, Jae Woong; Lee, Jun Young

    2008-01-01

    Positioning a workpiece accurately and preventing weld distortion, tack welding is often adopted before main welding in the construction of welded structures. However, this tack weld deteriorates the final weld bead profile, so that the grinding process is usually performed for a uniform weld bead profile. In this study, a control system for uniform weld bead is proposed for the fillet arc welding on tack welds. The system consists of GMA welding machine, torch manipulator, laser vision sensor for measuring the tack weld size and the database for optimal welding conditions. Experiments have been performed for constructing the database and for evaluating the control capability of the system. It has been shown that the system has the capability to smooth the bead at the high level of quality

  4. Fundamentals and advances in the development of remote welding fabrication systems

    Science.gov (United States)

    Agapakis, J. E.; Masubuchi, K.; Von Alt, C.

    1986-01-01

    Operational and man-machine issues for welding underwater, in outer space, and at other remote sites are investigated, and recent process developments are described. Probable remote welding missions are classified, and the essential characteristics of fundamental remote welding tasks are analyzed. Various possible operational modes for remote welding fabrication are identified, and appropriate roles for humans and machines are suggested. Human operator performance in remote welding fabrication tasks is discussed, and recent advances in the development of remote welding systems are described, including packaged welding systems, stud welding systems, remotely operated welding systems, and vision-aided remote robotic welding and autonomous welding systems.

  5. Application of local vacuum slide sealing electron beam welding procedure

    International Nuclear Information System (INIS)

    Sato, Shozo; Takano, Genta; Minami, Masaharu; Enami, Koji; Uchikawa, Takashi; Kuri, Shuhei

    1982-01-01

    Electron beam welding process is efficient and is superior in workmanship and its application to the welding of large plate structures is eagerly awaited. However, since electron beam welding is generally performed with the object of welding entirely put in a vacuum chamber, high welding cost becomes a problem. In response to this demand, two kinds of local vacuum slide sealing type electron beam welding machines have been developed. These welding machines are designed to perform welding with only the neighborhood of the weld line put in vacuum, one of which is for longitudinal joints and the other for circumferential joints. The welding machine for circumferential joints has been put to practical use for the welding of nucear fusion reactor vacuum vessels (outside diameter 3.5 m, inside diameter 1.7 m), showing that it is applicable to the welding of large structures. (author)

  6. Study of weld quality real-time monitoring system for auto-body assembly

    Science.gov (United States)

    Xu, Jun; Li, Yong-Bing; Chen, Guan-Long

    2005-12-01

    Resistance spot welding (RSW) is widely used for the auto-body assembly in automotive industry. But RSW suffers from a major problem of inconsistent quality from weld to weld. The major problem is the complexity of the basic process that may involve material coatings, electrode force, electrode wear, fit up, etc. Therefore weld quality assurance is still a big challenge and goal. Electrode displacement has proved to be a particularly useful signal which correlates well with weld quality. This paper introduces a novel auto-body spot weld quality monitoring system which uses electrode displacement as the quality parameter. This system chooses the latest laser displacement sensor with high resolution to measure the real-time electrode displacement. It solves the interference problem of sensor mounting by designing special fixture, and can be successfully applied on the portable welding machine. It is capable of evaluating weld quality and making diagnosis of process variations such as surface asperities, shunting, worn electrode and weld expansion with real-time electrode displacement. As proved by application in the workshop, the monitoring system has good stability and reliability, and is qualified for monitoring weld quality in process.

  7. Hybrid metallic nanocomposites for extra wear-resistant diamond machining tools

    DEFF Research Database (Denmark)

    Loginov, P.A.; Sidorenko, D.A.; Levashov, E.A.

    2018-01-01

    The applicability of metallic nanocomposites as binder for diamond machining tools is demonstrated. The various nanoreinforcements (carbon nanotubes, boron nitride hBN, nanoparticles of tungsten carbide/WC) and their combinations are embedded into metallic matrices and their mechanical properties...... are determined in experiments. The wear resistance of diamond tools with metallic binders modified by various nanoreinforcements was estimated. 3D hierarchical computational finite element model of the tool binder with hybrid nanoscale reinforcements is developed, and applied for the structure...

  8. Torque Measurement of Welding of Endplug-Endplate using Multi-pin Remote Welding System

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae-Seo; Kim, Soo-Sung; Park, Geun-Il; Lee, Jung-Won; Song, Kee-Chan [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2006-07-01

    As fuel bundles in PHWR irradiates, inner pressure in claddings of fuel rods increases owing to outer pressure and fission products of nuclear fissions. Because of leak possibility of welding between cladding and end plug, this welding part connects with safety of nuclear fuel rods. Because of importance of this welding part, weldability of end plug-cladding of nuclear fuel rods is continually researched. Welding method for research and commercialization is classified as melting, solid type welding or resistance welding. End plug cladding welding of nuclear fuel rods in PHWR takes advantage of resistance upset butt welding using multicycle mode. This method makes weld flash and shapes re-entrant corner owing to welding heat due to resistivity, contact resistance of cladding-end plug, and inelasticity deformation due to pressure. Welding part between cladding and end plug receives stresses and makes small cracks. In this study, remote welding system for multi-pin assembly was designed, fabricated and welding specimens of end plug-endplate were made using electrical resistance method. The torques of welding between end plug and endplate were measured. These results on welding current, pressure of main electrode and pressure of branch electrode were analyzed. Weldability between end plug and endplate was confirmed through metallographic examinations. In the future, optimal welding examinations due to welding current, welding pressure and welding time will be performed to improve weldability of end plug-endplate.

  9. Influence of Step Annealing Temperature on the Microstructure and Pitting Corrosion Resistance of SDSS UNS S32760 Welds

    Science.gov (United States)

    Yousefieh, M.; Shamanian, M.; Saatchi, A.

    2011-12-01

    In the present work, the influence of step annealing heat treatment on the microstructure and pitting corrosion resistance of super duplex stainless steel UNS S32760 welds have been investigated. The pitting corrosion resistance in chloride solution was evaluated by potentiostatic measurements. The results showed that step annealing treatments in the temperature ranging from 550 to 1000 °C resulted in a precipitation of sigma phase and Cr2N along the ferrite/austenite and ferrite/ferrite boundaries. At this temperature range, the metastable pits mainly nucleated around the precipitates formed in the grain boundary and ferrite phase. Above 1050 °C, the microstructure contains only austenite and ferrite phases. At this condition, the critical pitting temperature of samples successfully arrived to the highest value obtained in this study.

  10. Primary water stress corrosion cracking resistance of alloy 690 heat affected zones of butt welds

    International Nuclear Information System (INIS)

    Fournier, L.; Calonne, O.; Toloczko, M.B.; Bruemmer, S.M.; Massoud, J.P.; Lemaire, E.; Gerard, R.; Somville, F.; Richnau, A.; Lagerstrom, J.

    2015-01-01

    A wide V-groove butt weld was fabricated from Alloy 690 plates using Alloy 152 filler material, maximum allowable heat input, and very stiff strong-backs. Alloy 690 heat affected zones (HAZ) was characterized in terms of microstructure and plastic strains induced by weld shrinkage. Crack initiation tests were carried out in pure hydrogenated steam at 400 C. degrees for 4000 h. Crack growth rate tests were performed in simulated PWR primary water at a temperature of 360 C. degrees. A maximum plastic strain around 5% was measured in the vicinity of the fusion line, which decreased almost linearly with the distance from the fusion line. Crack initiation tests on Alloy 690 HAZ specimens as well as on 30% cold-rolled Alloy 690 specimens were performed in pure hydrogenated steam at 400 C. degrees (partial pressure of hydrogen = 0.7 bar) for a total of 4000 h using cylindrical notched tensile specimens, reverse U-bends and flat micro-tensile specimens. No crack initiation was detected. Stress corrosion propagation rates revealed extremely low SCC (Stress Corrosion Cracking) growth rates both in the base metal and in the HAZ region whose magnitudes are of no engineering significance. Overall, the results indicated limited plastic strain induced by weld shrinkage in butt weld HAZ, and to no particular susceptibility of primary water stress corrosion cracking. (authors)

  11. Real time computer controlled weld skate

    Science.gov (United States)

    Wall, W. A., Jr.

    1977-01-01

    A real time, adaptive control, automatic welding system was developed. This system utilizes the general case geometrical relationships between a weldment and a weld skate to precisely maintain constant weld speed and torch angle along a contoured workplace. The system is compatible with the gas tungsten arc weld process or can be adapted to other weld processes. Heli-arc cutting and machine tool routing operations are possible applications.

  12. Circumferential welding applied for inox steel super duplex UNS S32750 using the process MIG using CMT® control

    International Nuclear Information System (INIS)

    Invernizzi, Bruno Pizol

    2017-01-01

    This study carried out circumferential welding experiments in UNS S32750 Super Duplex Stainless Steel tubes using diameters of 19,05 mm and 48,20 mm. Welds were performed using various welding parameters on a MIG machine with Cold Metal Transfer® CMT control. The weld joints were evaluated by visual and dimensional inspection in addition to the Vickers microhardness and traction tests, as well as the microstructural analysis in conjunction with phase precipitation analysis, which was performed according to practice A of ASTM A923, and corrosion test in accordance with practice A of ASTM G48 in conjunction with ASTM A923. The results indicated that welds performed in pipes with a diameter of 19.05 mm showed a weld joint with unacceptable dimensions according to the standard, this condition being attributed the use of a high wire diameter for the welding conditions used. Welding performed for pipes with a diameter of 48.20 mm showed a lack of penetration under the conditions employed when welded by the conventional CMT® process. In the case of the use of CMT® combined with pulsed arc, under conditions that generated greater heat input during welding, this resulted in total penetration of the joint and adequate surface finish. The results indicated that welding using the CMT® process combined with pulsed arc, under the conditions (parameters) employed generated good surface finish, combined mechanical properties, meeting standards requirements, as well as a balanced microstructure and high resistance to corrosion. (author)

  13. Staphylococcus aureus Survives with a Minimal Peptidoglycan Synthesis Machine but Sacrifices Virulence and Antibiotic Resistance.

    Directory of Open Access Journals (Sweden)

    Patricia Reed

    2015-05-01

    Full Text Available Many important cellular processes are performed by molecular machines, composed of multiple proteins that physically interact to execute biological functions. An example is the bacterial peptidoglycan (PG synthesis machine, responsible for the synthesis of the main component of the cell wall and the target of many contemporary antibiotics. One approach for the identification of essential components of a cellular machine involves the determination of its minimal protein composition. Staphylococcus aureus is a Gram-positive pathogen, renowned for its resistance to many commonly used antibiotics and prevalence in hospitals. Its genome encodes a low number of proteins with PG synthesis activity (9 proteins, when compared to other model organisms, and is therefore a good model for the study of a minimal PG synthesis machine. We deleted seven of the nine genes encoding PG synthesis enzymes from the S. aureus genome without affecting normal growth or cell morphology, generating a strain capable of PG biosynthesis catalyzed only by two penicillin-binding proteins, PBP1 and the bi-functional PBP2. However, multiple PBPs are important in clinically relevant environments, as bacteria with a minimal PG synthesis machinery became highly susceptible to cell wall-targeting antibiotics, host lytic enzymes and displayed impaired virulence in a Drosophila infection model which is dependent on the presence of specific peptidoglycan receptor proteins, namely PGRP-SA. The fact that S. aureus can grow and divide with only two active PG synthesizing enzymes shows that most of these enzymes are redundant in vitro and identifies the minimal PG synthesis machinery of S. aureus. However a complex molecular machine is important in environments other than in vitro growth as the expendable PG synthesis enzymes play an important role in the pathogenicity and antibiotic resistance of S. aureus.

  14. Dictionary: Welding, cutting and allied processes. Pt. 2

    International Nuclear Information System (INIS)

    Kleiber, A.W.

    1987-01-01

    The dictionary contains approximately 40 000 entries covering all aspects of welding technology. It is based on the evaluation of numerous English, American and German sources. This comprehensive and up to date dictionary will be a reliable and helpful aid in evaluation and translating. The dictionary covers the following areas: Welding: gas welding, arc welding, gas shielded welding, resistance welding, welding of plastics, special welding processes; Cutting: flame cutting, arc cutting and special thermal cutting processes; Soldering: brazing and soldering; Other topics: thermal spraying, metal to metal adhesion, welding filler materials and other consumables, test methods, plant and equipment, accessories, automation, welding trade, general welding terminology. (orig./HP) [de

  15. Effects of Copper and Sulfur Additions on Corrosion Resistance and Machinability of Austenitic Stainless Steel

    International Nuclear Information System (INIS)

    Kim, Soon Tae; Park, Yong Soo; Kim, Hyung Joon

    1999-01-01

    Effects of Cu and S on corrosion resistance and machinability of austenitic stainless steel were investigated using immersion test, metallographic examination, Auger surface analysis and tool life test with single point turning tools. Corrosion resistance of the experimental Cu containing alloys in 18.4N H 2 SO 4 at 80 ∼ 120 .deg. C and 3N HCl at 40 .deg. C decreased as S content increased. However, one of the experimental alloys (Fe- 18%Cr- 21%Ni-3.2%Mo- 1.6%W- 0.2%N- 3.1%Cu- 0.091%S) showed general and pitting corrosion resistance equivalent to that of CW12MW in highly concentrated SO 4 2- environment. The alloy also showed pitting corrosion resistance superior to super stainless steel such as 654SMO in Cl - environment. The reasons why the increase in S content deteriorated the corrosion resistance were first, that the number and size of (Mn, Cr)S sulfides having corrosion resistance lower than that of matrix increased, leading to pitting corrosion and second, that rapid dissolution of the matrix around the pits was caused by adsorbed S. However, the alloy containing 3.1 %Cu and 0.091 % S maintained high general and pitting corrosion resistance due to heavily enriched noble Cu through selective dissolution of active Fe and Ni. The tool life for 3.1 % Cu + 0.091 % S added alloy was about four times that of 0.06%Cu + 0.005% S added alloy due to high shear strain rate generated by Cu addition giving easy cross slip of dislocation, lubrication of ductile (Mn, Cr)S sulfides adhering to tool crater surface and low cutting force resulting from thin continuous sulfides formed in chips during machining

  16. Prediction of the Chloride Resistance of Concrete Modified with High Calcium Fly Ash Using Machine Learning.

    Science.gov (United States)

    Marks, Michał; Glinicki, Michał A; Gibas, Karolina

    2015-12-11

    The aim of the study was to generate rules for the prediction of the chloride resistance of concrete modified with high calcium fly ash using machine learning methods. The rapid chloride permeability test, according to the Nordtest Method Build 492, was used for determining the chloride ions' penetration in concrete containing high calcium fly ash (HCFA) for partial replacement of Portland cement. The results of the performed tests were used as the training set to generate rules describing the relation between material composition and the chloride resistance. Multiple methods for rule generation were applied and compared. The rules generated by algorithm J48 from the Weka workbench provided the means for adequate classification of plain concretes and concretes modified with high calcium fly ash as materials of good, acceptable or unacceptable resistance to chloride penetration.

  17. Numerical and experimental analysis of resistance projection welding of square nuts to sheets

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Zhang, Wenqi; Martins, Paulo A.F.

    2014-01-01

    Projection welding of nuts to sheets is a widely utilized manufacturing process in the automotive industry. The process entails challenges due the necessity of joining different sheet thicknesses and nut sizes made from dissimilar materials, and due to the fact of experiencing large local deforma...... of the square nut to the sheet under different operating conditions. © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license...

  18. Optimization of the Closure-Weld Region of cylindrical Containers for Long-Term Corrosion Resistance

    International Nuclear Information System (INIS)

    Zekai Ceylan; Mohamed B. Trabia

    2001-01-01

    Welded cylindrical containers are susceptible to stress corrosion cracking (SCC) in the closure-weld area. An induction coil heating technique may be used to relieve the residual stresses in the closure-weld. This technique involves localized heating of the material by the surrounding coils. The material is then cooled to room temperature by quenching. A two-dimensional axisymmetric finite element model is developed to study the effects of induction coil heating and subsequent quenching. The finite element results are validated through an experimental test. The parameters of the design are tuned to maximize the compressive stress from the outer surface to a depth that is equal to the long-term general corrosion rate of Alloy 22 (Appendix A) multiplied by the desired container lifetime. The problem is subject to geometrical and stress constraints. Two different solution methods are implemented for this purpose. First, off-the-shelf optimization software is used to obtain an optimum solution. These results are not satisfactory because of the highly nonlinear nature of the problem. The paper proposes a novel alternative: the Successive Heuristic Quadratic Approximation (SHQA) technique. This algorithm combines successive quadratic approximation with an adaptive random search. Examples and discussion are included

  19. Finite Element Method Based Modeling of Resistance Spot-Welded Mild Steel

    Directory of Open Access Journals (Sweden)

    Miloud Zaoui

    Full Text Available Abstract This paper deals with Finite Element refined and simplified models of a mild steel spot-welded specimen, developed and validated based on quasi-static cross-tensile experimental tests. The first model was constructed with a fine discretization of the metal sheet and the spot weld was defined as a special geometric zone of the specimen. This model provided, in combination with experimental tests, the input data for the development of the second model, which was constructed with respect to the mesh size used in the complete car finite element model. This simplified model was developed with coarse shell elements and a spring-type beam element was used to model the spot weld behavior. The global accuracy of the two models was checked by comparing simulated and experimental load-displacement curves and by studying the specimen deformed shapes and the plastic deformation growth in the metal sheets. The obtained results show that both fine and coarse finite element models permit a good prediction of the experimental tests.

  20. Spot Welding of Honeycomb Structures

    Science.gov (United States)

    Cohal, V.

    2017-08-01

    Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

  1. Heat Transfer Modeling of an Annular On-Line Spray Water Cooling Process for Electric-Resistance-Welded Steel Pipe.

    Science.gov (United States)

    Chen, Zejun; Han, Huiquan; Ren, Wei; Huang, Guangjie

    2015-01-01

    On-line spray water cooling (OSWC) of electric-resistance-welded (ERW) steel pipes can replace the conventional off-line heat treatment process and become an important and critical procedure. The OSWC process improves production efficiency, decreases costs, and enhances the mechanical properties of ERW steel pipe, especially the impact properties of the weld joint. In this paper, an annular OSWC process is investigated based on an experimental simulation platform that can obtain precise real-time measurements of the temperature of the pipe, the water pressure and flux, etc. The effects of the modes of annular spray water cooling and related cooling parameters on the mechanical properties of the pipe are investigated. The temperature evolutions of the inner and outer walls of the pipe are measured during the spray water cooling process, and the uniformity of mechanical properties along the circumferential and longitudinal directions is investigated. A heat transfer coefficient model of spray water cooling is developed based on measured temperature data in conjunction with simulation using the finite element method. Industrial tests prove the validity of the heat transfer model of a steel pipe undergoing spray water cooling. The research results can provide a basis for the industrial application of the OSWC process in the production of ERW steel pipes.

  2. Heat Transfer Modeling of an Annular On-Line Spray Water Cooling Process for Electric-Resistance-Welded Steel Pipe

    Science.gov (United States)

    Chen, Zejun; Han, Huiquan; Ren, Wei; Huang, Guangjie

    2015-01-01

    On-line spray water cooling (OSWC) of electric-resistance-welded (ERW) steel pipes can replace the conventional off-line heat treatment process and become an important and critical procedure. The OSWC process improves production efficiency, decreases costs, and enhances the mechanical properties of ERW steel pipe, especially the impact properties of the weld joint. In this paper, an annular OSWC process is investigated based on an experimental simulation platform that can obtain precise real-time measurements of the temperature of the pipe, the water pressure and flux, etc. The effects of the modes of annular spray water cooling and related cooling parameters on the mechanical properties of the pipe are investigated. The temperature evolutions of the inner and outer walls of the pipe are measured during the spray water cooling process, and the uniformity of mechanical properties along the circumferential and longitudinal directions is investigated. A heat transfer coefficient model of spray water cooling is developed based on measured temperature data in conjunction with simulation using the finite element method. Industrial tests prove the validity of the heat transfer model of a steel pipe undergoing spray water cooling. The research results can provide a basis for the industrial application of the OSWC process in the production of ERW steel pipes. PMID:26201073

  3. Microstructure and mechanical properties of resistance spot welded dissimilar thickness DP780/DP600 dual-phase steel joints

    International Nuclear Information System (INIS)

    Zhang, Hongqiang; Wei, Ajuan; Qiu, Xiaoming; Chen, Jianhe

    2014-01-01

    Highlights: • We examine changes of microstructure of dissimilar thickness DP600/DP780 joints. • The hardness profile of RSW joints can be predicted by the equation. • Failure modes, peak load and energy describes the mechanical properties of joints. • The nugget diameter is the key factor of transition between the failure modes. - Abstract: In this study, resistance spot welding (RSW) experiments were performed in order to evaluate the microstructure and mechanical properties of single-lap joints between DP780 and DP600. The results show that the weld joints consist of three regions including base metal (BM), heat affected zone (HAZ) and fusion zone (FZ). The grain size and martensite volume fractions increase in the order of BM, HAZ and FZ. The hardness in the FZ is significantly higher than hardness of base metals. Tensile properties of the joints were described in terms of the failure modes and static load-carrying capabilities. Two distinct failure modes were observed during the tensile shear test of the joints: interfacial failure (IF) and pullout failure (PF). The FZ size plays a dominate role in failure modes of the joints

  4. Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

    Science.gov (United States)

    Looney, Alan

    1991-01-01

    Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

  5. Artificial neural networks for prediction of quality in resistance spot welding; Redes neuronales artificiales para la prediccion de la calidad en soldadura por resistencia por puntos

    Energy Technology Data Exchange (ETDEWEB)

    Martin, O.; Lopez, M.; Martin, F.

    2006-07-01

    An artificial neural network is proposed as a tool for predicting from three parameters (weld time, current intensity and electrode sort) if the quality of a resistance spot weld reaches a certain level or not. The quality is determined by cross tension testing. The fact of reaching this quality level or not is the desired output that goes with each input of the artificial neural network during its supervised learning. The available data set is made up of input/desired output pairs and is split randomly into a training subset (to update synaptic weight values) and a validation subset (to avoid overfitting phenomenon by means of cross validation). (Author) 44 refs.

  6. Machinability and scratch wear resistance of carbon-coated WC inserts

    Energy Technology Data Exchange (ETDEWEB)

    Pazhanivel, B., E-mail: palcecri@yahoo.co.in; Kumar, T. Prem; Sozhan, G.

    2015-03-15

    Highlights: • Cemented WC inserts were coated with carbon by CVD. • The deposits were either loosely held MWCNTs or adherent carbides. • Co-efficient of friction (ramp load; 1–13 N); 0.2 and 0.1 μ, respectively, for the uncoated and carbide-coated inserts. • The carbide-coated insert exhibited better machinability and surface finish than a commercial TiCN-coated insert. - Abstract: In this work, cemented tungsten carbide (WC) inserts were coated with nanocarbons/carbides by chemical vapor deposition (CVD) and their machinability and scratch wear resistance were investigated. The hardness and surface conditions of the WC substrate were studied before and after coating. The CVD-generated nanocarbons on the insert surfaces were examined by SEM, FE-SEM and TEM. The electron microscopic images revealed that the carbons generated were multi-walled carbon nanotubes (MWCNTs) or carbides depending on the experimental conditions. In both the cases, the cutting edges of the inserts had dense deposits. Scratch wear test with the coated inserts showed that the co-efficient of friction was 0.1 μ as against 0.2 μ for the uncoated inserts under a ramp load of 1–13 N. The machinability characteristics of commercially available TiCN-coated inserts and the carbon-coated WC inserts were compared by using a CNC machine and a Rapid I vision inspection system. It was found that the carbide-coated inserts exhibited machinability with better surface finish comparable to that of the TiCN-coated inserts while the MWCNT-coated inserts showed inferior adhesion properties.

  7. Comparative Studies on microstructure, mechanical and corrosion behaviour of DMR 249A Steel and its welds

    Science.gov (United States)

    Mohammed, Raffi; Dilkush; Madhusudhan Reddy, G.; Srinivasa Rao, K.

    2018-03-01

    DMR249A Medium strength (low carbon) Low-alloy steels are used as structural components in naval applications due to its low cost and high availability. An attempt has been made to weld the DMR 249A steel plates of 8mm thickness using shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW). Welds were characterized for metallography to carry out the microstructural changes, mechanical properties were evaluated using vickers hardness tester and universal testing machine. Potentio-dynamic polarization tests were carried out to determine the pitting corrosion behaviour. Constant load type Stress corrosion cracking (SCC) testing was done to observe the cracking tendency of the joints in a 3.5%NaCl solution. Results of the present study established that SMA welds resulted in formation of relatively higher amount of martensite in ferrite matrix when compared to gas tungsten arc welding (GTAW). It is attributed to faster cooling rates achieved due to high thermal efficiency. Improved mechanical properties were observed for the SMA welds and are due to higher amount of martensite. Pitting corrosion and stress corrosion cracking resistance of SMA welds were poor when compared to GTA welds.

  8. Self-protective powder wire for semiautomatic welding of corrosion resistant chromium-nickel type 18-10 steels

    International Nuclear Information System (INIS)

    Lipodaev, V.N.; Kakhovskij, N.I.; Fadeeva, G.V.

    1977-01-01

    Self-protecting NP-ANV1 powder wire has been developed for welding 18-10 type stainless steels. The use of the wire provides for the same running properties of the welds as the TsL-11 electrodes, the welding being 3-5 times more efficient

  9. Method for welding beryllium

    Science.gov (United States)

    Dixon, R.D.; Smith, F.M.; O`Leary, R.F.

    1997-04-01

    A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs.

  10. Method for welding beryllium

    International Nuclear Information System (INIS)

    Dixon, R.D.; Smith, F.M.; O'Leary, R.F.

    1997-01-01

    A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs

  11. Effect of flux powder SiO2 for the welding of 304-austenitic stainless ...

    African Journals Online (AJOL)

    optimal weld pool geometry in the tungsten inert gas (TIG) welding of ..... Flux assisted gas tungsten arc and laser welding of titanium with cryolite containing fluxes: arc spectroscopy and corrosion resistance studies, Welding Journal, Vol.

  12. The effect of Electro Discharge Machining (EDM) on the corrosion resistance of dental alloys.

    Science.gov (United States)

    Ntasi, Argyro; Mueller, Wolf Dieter; Eliades, George; Zinelis, Spiros

    2010-12-01

    The aim of the present study was to evaluate the effect of Electro Discharge Machining (EDM) on the corrosion resistance of two types of dental alloys used for fabrication of implant retained superstructures. Two groups of specimens were prepared from a Co-Cr (Okta-C) and a grade II cpTi (Biotan) alloys respectively. Half of the specimens were subjected to EDM with Cu electrodes and the rest were conventionally finished (CF). The corrosion resistance of the alloys was evaluated by anodic polarization in Ringer's solution. Morphological and elemental alterations before and after corrosion testing were studied by SEM/EDX. Six regions were analyzed on each surface before and after corrosion testing and the results were statistically analyzed by paired t-test (a=0.05). EDM demonstrated inferior corrosion resistance compared to CF surfaces, the latter being passive in a wider range of potential demonstrating higher polarization resistance and lower I(corr) values. Morphological alterations were found before and after corrosion testing for both materials tested after SEM analysis. EDX showed a significant decrease in Mo, Cr, Co, Cu (Co-Cr) and Ti, Cu (cpTi) after electrochemical testing plus an increase in C. According to the results of this study the EDM procedure decreases the corrosion resistance of both the alloys tested, increasing thus the risk of possible adverse biological reactions. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  13. Application of Hard Metal Weld Deposit in the Area of Mixing Organic Materials

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2014-01-01

    Full Text Available Any machine part is subject to degradation processes. Intensive wear occurs either when two bearing surfaces come into contact or when loose particles rub the function surface of a machine part. Soil processing machines are a good example. A similar process of abrasive wear occurs also in mixing machines or lines for material transport, such as worm-conveyors. The experiment part of this paper analyses hard metal weld deposit dedicated for renovation of abrasive stressed surfaces. In order to prolong the service life of a blade disc in a mixing machine Kreis-Biogas-Dissolver, the technology of hard surfacing by an electric arc was used. Tested hard metal electrodes were applied on a steel tape class 11 373. To eliminate mixing with the base material, weld beads were applied in two layers. Firstly, the weld bead was visually analyzed on a binocular microscope. Further, weld bead as well as the base material was analyzed from the metallographic point of view, whose aim was to identify the structure of weld metal and the origin of microcracks in weld bead. Moreover, there was also measured microhardness of weld metal. Abrasive resistance was tested according to the norm ČSN 01 5084, which is an abrasive cloth test. As in the mixing process also erosion wear occurs, there was also processed a test on a Bond device simulating stress of test samples by loose abrasive particles. The abrading agents were formed by broken stones of 8–16 mm in size. Based on the results of the individual tests, the recommendation of usage hard metal electrodes for prolonging service life of machine parts will be made.

  14. Welding Penetration Control of Fixed Pipe in TIG Welding Using Fuzzy Inference System

    Science.gov (United States)

    Baskoro, Ario Sunar; Kabutomori, Masashi; Suga, Yasuo

    This paper presents a study on welding penetration control of fixed pipe in Tungsten Inert Gas (TIG) welding using fuzzy inference system. The welding penetration control is essential to the production quality welds with a specified geometry. For pipe welding using constant arc current and welding speed, the bead width becomes wider as the circumferential welding of small diameter pipes progresses. Having welded pipe in fixed position, obviously, the excessive arc current yields burn through of metals; in contrary, insufficient arc current produces imperfect welding. In order to avoid these errors and to obtain the uniform weld bead over the entire circumference of the pipe, the welding conditions should be controlled as the welding proceeds. This research studies the intelligent welding process of aluminum alloy pipe 6063S-T5 in fixed position using the AC welding machine. The monitoring system used a charge-coupled device (CCD) camera to monitor backside image of molten pool. The captured image was processed to recognize the edge of molten pool by image processing algorithm. Simulation of welding control using fuzzy inference system was constructed to simulate the welding control process. The simulation result shows that fuzzy controller was suitable for controlling the welding speed and appropriate to be implemented into the welding system. A series of experiments was conducted to evaluate the performance of the fuzzy controller. The experimental results show the effectiveness of the control system that is confirmed by sound welds.

  15. Classification of Breast Cancer Resistant Protein (BCRP) Inhibitors and Non-Inhibitors Using Machine Learning Approaches.

    Science.gov (United States)

    Belekar, Vilas; Lingineni, Karthik; Garg, Prabha

    2015-01-01

    The breast cancer resistant protein (BCRP) is an important transporter and its inhibitors play an important role in cancer treatment by improving the oral bioavailability as well as blood brain barrier (BBB) permeability of anticancer drugs. In this work, a computational model was developed to predict the compounds as BCRP inhibitors or non-inhibitors. Various machine learning approaches like, support vector machine (SVM), k-nearest neighbor (k-NN) and artificial neural network (ANN) were used to develop the models. The Matthews correlation coefficients (MCC) of developed models using ANN, k-NN and SVM are 0.67, 0.71 and 0.77, and prediction accuracies are 85.2%, 88.3% and 90.8% respectively. The developed models were tested with a test set of 99 compounds and further validated with external set of 98 compounds. Distribution plot analysis and various machine learning models were also developed based on druglikeness descriptors. Applicability domain is used to check the prediction reliability of the new molecules.

  16. Automatic welding of stainless steel tubing

    Science.gov (United States)

    Clautice, W. E.

    1978-01-01

    The use of automatic welding for making girth welds in stainless steel tubing was investigated as well as the reduction in fabrication costs resulting from the elimination of radiographic inspection. Test methodology, materials, and techniques are discussed, and data sheets for individual tests are included. Process variables studied include welding amperes, revolutions per minute, and shielding gas flow. Strip chart recordings, as a definitive method of insuring weld quality, are studied. Test results, determined by both radiographic and visual inspection, are presented and indicate that once optimum welding procedures for specific sizes of tubing are established, and the welding machine operations are certified, then the automatic tube welding process produces good quality welds repeatedly, with a high degree of reliability. Revised specifications for welding tubing using the automatic process and weld visual inspection requirements at the Kennedy Space Center are enumerated.

  17. Performance of mesh seam welds in tailor welded blanks; Terado blank yo mash seam yosetsubu no tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Uchihara, M; Takahashi, M; Kurita, M; Hirose, Y; Fukui, K [Sumitomo Metal Industries, Ltd., Osaka (Japan)

    1997-10-01

    Formability, fatigue properties and corrosion behavior of mash seam welded steel sheets were investigated and the results were compared with laser weld. The stretch formability of mash seam weld and laser weld were same level. Mash seam weld however, showed slightly smaller formability in hole expansion test. The fatigue strength of mash seam welds was lower than that of laser welds in case of differential thickness joints. Corrosion was apt to initiate at weld in both mash seam and laser weld with E-coat. The corrosion resistance of welds was improved by using zinc coated steel. 3 refs., 14 figs., 2 tabs.

  18. Properties of thick welded joints on superheater collectors made from new generation high alloy martensitic creep-resisting steels for supercritical parameters

    Energy Technology Data Exchange (ETDEWEB)

    Dobrzanski, Janusz; Zielinski, Adam [Institute for Ferrous Metallurgy, Gliwice (Poland); Pasternak, Jerzy [Boiler Engineering Company RAFAKO S.A., Raciborz (Poland)

    2010-07-01

    The continuously developing power generation sector, including boilers with supercritical parameters, requires applications of new creep-resistant steel grades for construction of boilers steam superheater components. This paper presents selected information, experience within the field of research and implementation of a new group of creep-resistant as X10CrMoVNb9-1(P91), X10CrWMoVNb9-2(P92) and X12CrCoWVNb12-2-2(VM12) grades, containing 9-12%Cr. During welding and examination process the results of mechanical properties, requested level for base material and welded joints, as well as: tensile strength, impact strength and technological properties have been evaluated. Additional destructive examinations, with evaluation of structure stability, hardness distribution, for base material and welded joints after welding, heat treatment, again process have been determined. Recommendations due to the implementation influence of operating parameters of the main boiler components are part of this paper. (orig.)

  19. Advanced Control Methods for Optimization of Arc Welding

    DEFF Research Database (Denmark)

    Thomsen, J. S.

    Gas Metal Arc Welding (GMAW) is a proces used for joining pieces of metal. Probably, the GMAW process is the most successful and widely used welding method in the industry today. A key issue in welding is the quality of the welds produced. The quality of a weld is influenced by several factors...... in the overall welding process; one of these factors are the ability of the welding machine to control the process. The internal control algorithms in GMAW machines are the topic of this PhD project. Basically, the internal control includes an algorithm which is able to keep the electrode at a given distance...

  20. Machine Learning Leveraging Genomes from Metagenomes Identifies Influential Antibiotic Resistance Genes in the Infant Gut Microbiome

    Science.gov (United States)

    Olm, Matthew R.; Morowitz, Michael J.

    2018-01-01

    ABSTRACT Antibiotic resistance in pathogens is extensively studied, and yet little is known about how antibiotic resistance genes of typical gut bacteria influence microbiome dynamics. Here, we leveraged genomes from metagenomes to investigate how genes of the premature infant gut resistome correspond to the ability of bacteria to survive under certain environmental and clinical conditions. We found that formula feeding impacts the resistome. Random forest models corroborated by statistical tests revealed that the gut resistome of formula-fed infants is enriched in class D beta-lactamase genes. Interestingly, Clostridium difficile strains harboring this gene are at higher abundance in formula-fed infants than C. difficile strains lacking this gene. Organisms with genes for major facilitator superfamily drug efflux pumps have higher replication rates under all conditions, even in the absence of antibiotic therapy. Using a machine learning approach, we identified genes that are predictive of an organism’s direction of change in relative abundance after administration of vancomycin and cephalosporin antibiotics. The most accurate results were obtained by reducing annotated genomic data to five principal components classified by boosted decision trees. Among the genes involved in predicting whether an organism increased in relative abundance after treatment are those that encode subclass B2 beta-lactamases and transcriptional regulators of vancomycin resistance. This demonstrates that machine learning applied to genome-resolved metagenomics data can identify key genes for survival after antibiotics treatment and predict how organisms in the gut microbiome will respond to antibiotic administration. IMPORTANCE The process of reconstructing genomes from environmental sequence data (genome-resolved metagenomics) allows unique insight into microbial systems. We apply this technique to investigate how the antibiotic resistance genes of bacteria affect their ability to

  1. Effect of pulsed current welding on fatigue behaviour of high strength aluminium alloy joints

    International Nuclear Information System (INIS)

    Balasubramanian, V.; Ravisankar, V.; Madhusudhan Reddy, G.

    2008-01-01

    High strength aluminium alloys (Al-Zn-Mg-Cu alloys) have gathered wide acceptance in the fabrication of light weight structures requiring high strength-to weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding processes of high strength aluminium alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Rolled plates of 6 mm thickness have been used as the base material for preparing single pass welded joints. Single V butt joint configuration has been prepared for joining the plates. The filler metal used for joining the plates is AA 5356 (Al-5Mg (wt%)) grade aluminium alloy. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW) and (iv) pulsed current GMAW (PCGMAW) processes. Argon (99.99% pure) has been used as the shielding gas. Fatigue properties of the welded joints have been evaluated by conducting fatigue test using rotary bending fatigue testing machine. Current pulsing leads to relatively finer and more equi-axed grain structure in gas tungsten arc (GTA) and gas metal arc (GMA) welds. In contrast, conventional continuous current welding resulted in predominantly columnar grain structures. Grain refinement is accompanied by an increase in fatigue life and endurance limit

  2. Plasma spot welding of ferritic stainless steels

    International Nuclear Information System (INIS)

    Lesnjak, A.; Tusek, J.

    2002-01-01

    Plasma spot wedding of ferritic stainless steels studied. The study was focused on welding parameters, plasma and shieldings and the optimum welding equipment. Plasma-spot welded overlap joints on a 0.8 mm thick ferritic stainless steel sheet were subjected to a visual examination and mechanical testing in terms of tension-shear strength. Several macro specimens were prepared Plasma spot welding is suitable to use the same gas as shielding gas and as plasma gas , i. e. a 98% Ar/2% H 2 gas mixture. Tension-shear strength of plasma-spot welded joint was compared to that of resistance sport welded joints. It was found that the resistance welded joints withstand a somewhat stronger load than the plasma welded joints due to a large weld sport diameter of the former. Strength of both types of welded joints is approximately the same. (Author) 32 refs

  3. Multipass autogenous electron beam welding

    International Nuclear Information System (INIS)

    Murphy, J.L.; Mustaleski, T.M. Jr.; Watson, L.C.

    1986-01-01

    A multipass, autogenous welding procedure was developed for 7.6 mm (0.3 in.) wall thickness Type 304L stainless steel cylinders. The joint geometry has a 1.5 mm (0.06 in.) root-face width and a rectangular stepped groove that is 0.762 mm (0.03 in.) wide at the top of the root face and extends 1.5 mm in height, terminating into a groove width of 1.27 mm which extends to the outside of the 1.27 mm high weld-boss. One weld pass is made on the root, three passes on the 0.762 mm wide groove and three passes to complete the weld. Multipass, autogenous, electron beam welds maintain the characteristic high depth-to-width ratios and low heat input of single-pass, electron beam welds. The increased part distortion (which is still much less than from arc processes) in multipass weldments is corrected by a preweld machined compensation. Mechanical properties of multipass welds compare well with single-pass welds. The yield strength of welds in aluminum alloy 5083 is approximately the same for single-pass or multipass electron beam and gas, metal-arc welds. The incidence and size of porosity is less in multipass electron beam welding of aluminum as compared to gas, metal-arc welds. The multipass, autogenous, electron beam welding method has proven to be a reliable way to make some difficult welds in multilayer parts or in an instance where inside part temperature or weld underbead must be controlled and weld discontinuities must be minimized

  4. 29 CFR 1910.254 - Arc welding and cutting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Arc welding and cutting. 1910.254 Section 1910.254 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Welding, Cutting and Brazing § 1910.254 Arc welding and cutting. (a... following limits shall not be exceeded: (i) Alternating-current machines (A) Manual arc welding and cutting...

  5. Welding of large-size embelled fittings in NPP construction

    International Nuclear Information System (INIS)

    Semenov, N.A.; Savinov, O.A.

    1988-01-01

    Drawbacks of the accepted technology for peoducing embedded fittings are considered. Activities on modernization of the standard ADF-2001 automatic welding machine are described. Results of testing the samples of welded joints performed using the modernized automatic welding machine, and economic effect caused by its introduction at the balakovo NPP second unit construction are presented

  6. Mechanical behaviour of Astm A 297 grade Hp joints welded using different processes

    International Nuclear Information System (INIS)

    Emygdio, Paulo Roberto Oliveira; Zeemann, Annelise; Almeida, Luiz Henrique de

    1996-01-01

    The influence of different arc welding processes on mechanical behaviour was studied for cast heat resistant stainless steel welded joints, in the as welded conditions. ASTM A 297 grade HP with niobium and niobium/titanium additions were welded following three different welding procedures, using shielded metal arc welding gas tungsten arc welding and plasma arc welding, in six welded joints. The welded joint mechanical behaviour was evaluated by ambient temperature and 870 deg C tensile tests; and creep tests at 900 deg C and 50 MPa. Mechanical test results showed that the welding procedure qualification following welding codes is not suitable for high temperature service applications. (author)

  7. Aluminum 6060-T6 friction stir welded butt joints: fatigue resistance with different tools and feed rates

    International Nuclear Information System (INIS)

    Baragetti, S.; D'Urso, G.

    2014-01-01

    The fatigue behavior of AA6060-T6 friction stir welded butt joints was investigated. The joints were produced by using both a standard and a threaded tri-flute cylindrical-tool with flat shoulder. The friction stir welding process was carried out using different feed rates. Preliminary tensile tests, micrograph analyses and hardness profile measurements across the welds were carried out. Welded and unwelded fatigue samples were tested under axial loading (R = 0.1) with upper limits of 10 4 and 10 5 cycles, using threaded and unthreaded (standard) tools at different feed rates. The best tensile and fatigue performance was obtained using the standard tool at low feed rate.

  8. The Landauer resistance and band spectra for the counting quantum Turing machine

    International Nuclear Information System (INIS)

    Benioff, P.

    1996-01-01

    In other work, the generalized counting quantum Turing machine (GCQTM) was studied. For any N this machine enumerates the first 2 N integers in succession as binary strings. The generalization consists of associating a potential with read 1 steps only. The Landauer Resistance (LR) and band spectra were determined for the tight binding Hamiltonians associated with the GCQTM for energies below the potential height. Here these calculations are extended to energies both above and below the barrier height. For parameters and potentials in the electron region, the LR fluctuates rapidly between very high and very low values as a function of momentum. The rapidity and extent of the fluctuations increases rapidly with increasing N. For N = 18, the largest value considered, the LR shows good transmission probability as a function of momentum with numerous holes of very high LR values present. This is true for energies both above and below the potential height. It is suggested that the main features of the LR can be explained by coherent superposition of the component waves reflected from or transmitted through or across the 2 N-1 potentials present in the distribution. If this explanation is correct, it provides a dramatic illustration of the effects of quantum nonlocality

  9. An experimental and computational investigation of electrical resistivity imaging for prediction ahead of tunnel boring machines

    Science.gov (United States)

    Schaeffer, Kevin P.

    Tunnel boring machines (TBMs) are routinely used for the excavation of tunnels across a range of ground conditions, from hard rock to soft ground. In complex ground conditions and in urban environments, the TBM susceptible to damage due to uncertainty of what lies ahead of the tunnel face. The research presented here explores the application of electrical resistivity theory for use in the TBM tunneling environment to detect changing conditions ahead of the machine. Electrical resistivity offers a real-time and continuous imaging solution to increase the resolution of information along the tunnel alignment and may even unveil previously unknown geologic or man-made features ahead of the TBM. The studies presented herein, break down the tunneling environment and the electrical system to understand how its fundamental parameters can be isolated and tested, identifying how they influence the ability to predict changes ahead of the tunnel face. A proof-of-concept, scaled experimental model was constructed in order assess the ability of the model to predict a metal pipe (or rod) ahead of face as the TBM excavates through a saturated sand. The model shows that a prediction of up to three tunnel diameters could be achieved, but the unique presence of the pipe (or rod) could not be concluded with certainty. Full scale finite element models were developed in order evaluate the various influences on the ability to detect changing conditions ahead of the face. Results show that TBM/tunnel geometry, TBM type, and electrode geometry can drastically influence prediction ahead of the face by tens of meters. In certain conditions (i.e., small TBM diameter, low cover depth, large material contrasts), changes can be detected over 100 meters in front of the TBM. Various electrode arrays were considered and show that in order to better detect more finite differences (e.g., boulder, lens, pipe), the use of individual cutting tools as electrodes is highly advantageous to increase spatial

  10. The acute hormonal response to free weight and machine weight resistance exercise.

    Science.gov (United States)

    Shaner, Aaron A; Vingren, Jakob L; Hatfield, Disa L; Budnar, Ronald G; Duplanty, Anthony A; Hill, David W

    2014-04-01

    Resistance exercise can acutely increase the concentrations of circulating neuroendocrine factors, but the effect of mode on this response is not established. The purpose of this study was to examine the effect of resistance exercise selection on the acute hormonal response using similar lower-body multijoint movement free weight and machine weight exercises. Ten resistance trained men (25 ± 3 years, 179 ± 7 cm, 84.2 ± 10.5 kg) completed 6 sets of 10 repetitions of squat or leg press at the same relative intensity separated by 1 week. Blood samples were collected before (PRE), immediately after (IP), and 15 (P15) and 30 minutes (P30) after exercise, and analyzed for testosterone (T), growth hormone (GH), and cortisol (C) concentrations. Exercise increased (p ≤ 0.05) T and GH at IP, but the concentrations at IP were greater for the squat (T: 31.4 ± 10.3 nmol·L(-1); GH: 9.5 ± 7.3 μg·L(-1)) than for the leg press (T: 26.9 ± 7.8 nmol·L(-1); GH: 2.8 ± 3.2 μg·L(-1)). At P15 and P30, GH was greater for the squat (P15: 12.3 ± 8.9 μg·L(-1); P30: 12.0 ± 8.9 μg·L(-1)) than for the leg press (P15: 4.8 ± 3.4 μg·L(-1); P30: 5.4 ± 4.1 μg·L(-1)). C was increased after exercise and was greater for the squat than for the leg press. Although total work (external load and body mass moved) was greater for the squat than for the leg press, rating of perceived exertion did not differ between the modes. Free weight exercises seem to induce greater hormonal responses to resistance exercise than machine weight exercises using similar lower-body multijoint movements and primary movers.

  11. Experimental study on variations in Charpy impact energies of low carbon steel, depending on welding and specimen cutting method

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaorui; Kang, Hansaem; Lee, Young Seog [Chung-Ang University, Seoul (Korea, Republic of)

    2016-05-15

    This paper presents an experimental study that examines variations of Charpy impact energy of a welded steel plate, depending upon the welding method and the method for obtaining the Charpy specimens. Flux cored arc welding (FCAW) and Gas tungsten arc welding (GTAW) were employed to weld an SA516 Gr. 70 steel plate. The methods of wire cutting and water-jet cutting were adopted to take samples from the welded plate. The samples were machined according to the recommendations of ASTM SEC. II SA370, in order to fit the specimen dimension that the Charpy impact test requires. An X-ray diffraction (XRD) method was used to measure the as-weld residual stress and its redistribution after the samples were cut. The Charpy impact energy of specimens was considerably dependent on the cutting methods and locations in the welded plate where the specimens were taken. The specimens that were cut by water jet followed by FCAW have the greatest resistance-to-fracture (Charpy impact energy). Regardless of which welding method was used, redistributed transverse residual stress becomes compressive when the specimens are prepared using water-jet cutting. Meanwhile, redistributed transverse residual stress becomes tensile when the specimens are prepared using wire cutting.

  12. New generation of welded semiautomatic for production of structures out of steels and aluminium alloys

    International Nuclear Information System (INIS)

    Belousov, A.N.; Poloskov, S.I.; Efanov, V.A.; Sedov, Yu.S.; Bukhta, O.Ya.

    1988-01-01

    Analysis of the type of semiautomatic welding machines, produced in our country and abroad, is presented. New designs, realized in the 80th, are described. Design of KOMBI-500 and PRM-4M semiautomatic welding machines is described

  13. State of the art of the welding method for sealing spent nuclear fuel canister made of copper. Part 2 - EBW

    International Nuclear Information System (INIS)

    Salonen, T.

    2014-05-01

    This report consist the results of the development of the electron beam welding (EBW) method for sealing spent nuclear fuel (SNF) disposal canister. This report has been used as background material for selection of the sealing method for the SNF canister. Report contains the state of the art knowledge of the EBW method and research and development (R and D) results done by Posiva. Relevant R and D results of EB-welds done by SKB are also reviewed in this report. Requirements set for the welding and weld are present. These requirements are based on the long term safety and also some part of requirements are set by other processes like non-destructive testing (NDT) and manufacturing processes of components. Initial state of the weld is described in this report. Initial state has significant effect on the long term safety issues like corrosion resistance and creep ductility. Also short and long term mechanical properties as well as corrosion properties are described. Microstructure and residual stresses of the weld is represented in this report. Report consists also imperfections of the weld and statistical analysis of the evaluation of the probability of the largest defect size on the weld. Results of corrosion and creep tests of EB-welds are reviewed in this report. EBW process and machine are described. Preliminary designing of the EBW-machine has been done including component handling equipments. Preliminary welding procedure specification (pWPS) has drawn up and qualification of the personnel is described briefly. In-line process and quality control system including seam tracking system is implemented in modern EBW machine. Also NDT methods for inspection of the weld are described in this report. Concerning the results from the research and development work it can be concluded that EB welding method is suitable method for sealing SNF canister. Weld material fulfils requirements set by the long term safety. The welding system is robust and reliable and it is based

  14. Microstructure and mechanical properties of resistance-spot-welded joints for A5052 aluminum alloy and DP 600 steel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jianbin [College of Automotive Collaborative Innovation Center, Chongqing University, No. 174, Shazheng Street, Shapingba District, Chongqing 400044 (China); Yuan, Xinjian, E-mail: xinjianyuan@yahoo.com [College of Materials Science and Engineering, Chongqing University, No. 174, Shazheng Street, Shapingba District, Chongqing 400044 (China); Hu, Zhan; Sun, Changzheng; Zhang, Yanxin; Zhang, Yuxuan [College of Materials Science and Engineering, Chongqing University, No. 174, Shazheng Street, Shapingba District, Chongqing 400044 (China)

    2016-10-15

    The microstructure and mechanical properties of resistance-spot-welded A5052 aluminum alloy and DP 600 dual-phase steel joint were studied. The fusion zone (FZ) and heat-affected zone (HAZ) of DP 600 exhibited lath martensite and ferrite-martensite structures, respectively. The microstructure of FZ and HAZ in the A5052 side was composed of cellular crystals and the boundary region of FZ exhibited a columnar crystal morphology. A Fe{sub 2}Al{sub 5} intermetallic compound (IMC) layer with 3.3 μm thickness was found adjacent to the DP 600 side, whereas a needle-shaped Fe{sub 4}Al{sub 13} IMC layer with length of 0.67 μm to 15.8 μm was found adjacent to the aluminum alloy side. The maximum tensile shear load of the A5052/DP 600 joint was 5.5 KN, with a corresponding molten nugget diameter of 6.3 mm. The fracture morphology of the optimized A5052/DP 600 joint was mainly an elongated dimple fracture accompanied by cleavage fracture. - Highlights: •A5052 and DP 600 with large gaps in properties were investigated by RSW. •The microstructures of RSW joints in DP 600/A5052 were examined detailedly. •The micro/macro-characteristics and strength relations of joints were analyzed.

  15. Reactive resistance welding of Ti6Al4V alloy with the use of Ni(V)/Al multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Maj, Lukasz; Morgiel, Jerzy [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Krakow (Poland); Mars, Krzysztof; Godlewska, Elzbieta [Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Krakow (Poland)

    2017-02-15

    The freestanding Ni(V)/Al multilayer foil was applied as a filler material in order to join Ti6Al4V alloy with the use of reactive resistance welding (RRW) technique. Present investigations, performed with the use of transmission electron microscopy (TEM) method, allowed to show that an application of high current (I = 400 A for 2 min in vacuum conditions ∝10{sup -1} mbar) transformed the Ni(V)/Al multilayers into fine grain (<300 nm) NiAl phase. It also showed that the RRW process led to the formation of firm connection with nanoporosity limited only to the original contact plane between base material and the foil. Simultaneously, the formation of a narrow strip of crystallites of Ti{sub 3}Al intermetallic phase elongated along the joint line (average size of ∝200 nm) was observed. The base material was separated from the joint area by a layer of up to ∝2 μm thickness of nearly defect free α-Ti and β-Ti grains from a heat affected zone (HAZ). The performed experiment proved that Ni(V)/Al multilayer could serve as a filler material for joining of Ti6Al4V alloys even without additional solder layer. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Study on mechanism of intergranular stress corrosion cracking and analysis of residual stress and work hardening in welds of low-carbon austenitic stainless steel with hard surface machining

    International Nuclear Information System (INIS)

    Mori, Hiroaki; Mochizuki, Masahito; Nishimoto, Kazutoshi; Toyoda, Masao; Katsuyama, Jinya

    2007-01-01

    In order to make clear the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in the welds of Type 316L low-carbon austenitic stainless steel with surface hardening, the residual stress and hardness in the butt-joint of pipes as a typical example of the actual structure were estimated and the grain boundary sliding was analyzed from the viewpoint of micro-deformation. On the basis of these results, the mechanism of IGSCC was discussed by the integrated knowledge between metallurgy and mechanics. The relationship between plastic strain and hardness in hard-machined surface near welds was clarified from the experimented relationship and the analysis method by the thermal elastic-plastic analysis. The distributions of hardness and residual stress with the actual surface machining could be simulated. It was made clear that grain boundary sliding occurred in the steel at 561K by a constant strain rate tensile test. From the comparison of grain boundary sliding behavior between solution treated specimen and cold-rolled one, it was found that the grain boundary sliding in cold-rolled one occurs in smaller strain conditions than that in as received one, and the amount of grain boundary sliding in cold-rolled one increases remarkably with increases in rolling reduction. In addition, it was clarified that the grain boundary energy is raised by the grain boundary sliding. On the basis of these results, it was concluded that the cause of IGSCC in the welds of Type 316L low-carbon austenitic stainless steel with surface hardening is the increase in grain boundary energy due to grain boundary sliding induced by residual stress of multi pass welding and surface hardening. (author)

  17. Experimental and computer simulation results of the spot welding process using SORPAS software

    International Nuclear Information System (INIS)

    Al-Jader, M A; Cullen, J D; Athi, N; Al-Shamma'a, A I

    2009-01-01

    The highly competitive nature of the automotive industry drives demand for improvements and increased precision engineering in resistance spot welding. Currently there are about 4300 weld points on the average steel vehicle. Current industrial monitoring systems check the quality of the nugget after processing 15 cars, once every two weeks. The nuggets are examined off line using a destructive process, which takes approximately 10 days to complete causing a long delay in the production process. This paper presents a simulation of the spot welding growth curves, along with a comparison to growth curves performed on an industrial spot welding machine. The correlation of experimental results shows that SORPAS simulations can be used as an off line measurement to reduce factory energy usage. The first section in your paper

  18. Welding Curriculum.

    Science.gov (United States)

    Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

    This competency-based curriculum guide is a handbook for the development of welding trade programs. Based on a survey of Alaskan welding employers, it includes all competencies a student should acquire in such a welding program. The handbook stresses the importance of understanding the principles associated with the various elements of welding.…

  19. Heat-resisting alloys for hard surfacing and sealing pad welding

    Directory of Open Access Journals (Sweden)

    R.O. Wielgosz

    2010-07-01

    Full Text Available The paper deals with heat-resisting alloys used to harden surfaces of elements operating in increased temperatures. It also deals with alloysused to seal cooperating surfaces of elements operating in the conditions of increased temperatures and aggressive utilities. Application methods and properties of thus obtained layers have been presented and adhesion of layers with matrix material has been assessed.

  20. Evaluation of Fire Resistance for H-Section Columns Made of Rolled Steels for General Structures and for Welded Structures by Analytic Method

    International Nuclear Information System (INIS)

    Kwon, In-Kyu

    2014-01-01

    Fire resistance is an important factor in sustaining the structural stability of steel framed buildings on fire. However, evaluation of the fire resistance of steel columns has been conducted using rolled steels for general structures, SS 400. Recently, rolled steels for welded structures, such as SM 400 and SM 490, have been used frequently because they have better performance of welding than the SS 400. However, there has been doubt about how much fire resistance SM 400 and SM 490 have. To evaluate by calculation the fire resistance of an H-section column made of SS 400 its mechanical and thermal properties were derived and suggested respectively in the form of regressive equations and the analysis was done based on heat transfer and thermal stress analysis. In this study, the results of the evaluation of H-section columns made of SS 400 with loaded fire tests turned out to be conservative. As a result, a new guideline is required to get the exact fire resistance of another structural steel.

  1. Corrosion Behavior of Arc Weld and Friction Stir Weld in Al 6061-T6 Alloys

    International Nuclear Information System (INIS)

    Yoon, Byoung Hyun; Kim, Heung Ju; Chang, Woong Seong; Kweon, Young Gak

    2006-01-01

    For the evaluation of corrosion resistance of Al 6061-T6 Alloy, Tafel method and immersion test was performed with Friction Stir Weld(FSW) and Gas Metal Arc Weld(GMAW). The Tafel and immersion test results indicated that GMA weld was severely attacked compared with those of friction stir weld. It may be mainly due to the galvanic corrosion mechanism act on the GMA weld

  2. The effect of aging treatment on the high temperature fatigue strength and fatigue fracture behaviour of friction welded domestic heat resisting steels (SUH3-SUS303)

    International Nuclear Information System (INIS)

    Lee, K.Y.; Oh, S.K.; Kim, H.J.

    1981-01-01

    In this study the experiment was carried out as the high temperature rotary bending fatigue testing under the condition of 700 0 C high temperature to the friction welded domestic heat resisting steels, SUH3-SUS303, which were 10 hr., 100 hr. aging heat treated at 700 0 C after solution treatment 1 hr. at 1060 0 C for the purpose of observing the effects of the high temperature fatigue strength and fatigue fracture behaviours as well as with various mechanical properties of welded joints. The results obtained are summarized as follows: 1) Through mechanical tests and microstructural examinations, the determined optimum welding conditions, rotating speed 2420 rpm, heating pressure 8 kg/mm 2 , upsetting pressure 22 kg/mm 2 , the amount of total upset 7 mm (heating time 3 sec and upsetting time 2 sec) were satisfied. 2) The solution treated material SUH3, SUS303 and SUH3-SUS303, have the highest inclination gradiant on S-N curve due to the high temperature fatigue testing for long time at 700 0 C. 3) The optimum aging time of friction welded SUH3-SUS303, has been recognized near the 10 hr. at 700 0 C after the solution treatment of 1 hr. at 1060 0 C. 4) The high temperature fatigue limits of aging treated materials were compared with those of raw material according to the extender of aging time, on 10 hr. aging, fatigue limits were increased by SUH3 75.4%, SUS303 28.5%, friction welded joints SUH3-SUS303 44.2% and 100 hr. aging the rate were 64.9%, 30.4% and 36.6% respectively. 5) The fatigue fractures occurred at the side of the base metal SUS303 of the friction welded joints SUH3-SUS303 and it is difficult to find out fractures at the friction welding interfaces. 6) The cracking mode of SUS303, SUH3-SUS303 is intergranular in any case, but SUH3 is fractured by transgranular cracking. (author)

  3. Circumferential welding applied for inox steel super duplex UNS S32750 using the process MIG using CMT® control; Soldagem circunferencial do aço inoxidável super duplex UNS S32750 pelo processo MIG com controle CMT®

    Energy Technology Data Exchange (ETDEWEB)

    Invernizzi, Bruno Pizol

    2017-07-01

    This study carried out circumferential welding experiments in UNS S32750 Super Duplex Stainless Steel tubes using diameters of 19,05 mm and 48,20 mm. Welds were performed using various welding parameters on a MIG machine with Cold Metal Transfer® CMT control. The weld joints were evaluated by visual and dimensional inspection in addition to the Vickers microhardness and traction tests, as well as the microstructural analysis in conjunction with phase precipitation analysis, which was performed according to practice A of ASTM A923, and corrosion test in accordance with practice A of ASTM G48 in conjunction with ASTM A923. The results indicated that welds performed in pipes with a diameter of 19.05 mm showed a weld joint with unacceptable dimensions according to the standard, this condition being attributed the use of a high wire diameter for the welding conditions used. Welding performed for pipes with a diameter of 48.20 mm showed a lack of penetration under the conditions employed when welded by the conventional CMT® process. In the case of the use of CMT® combined with pulsed arc, under conditions that generated greater heat input during welding, this resulted in total penetration of the joint and adequate surface finish. The results indicated that welding using the CMT® process combined with pulsed arc, under the conditions (parameters) employed generated good surface finish, combined mechanical properties, meeting standards requirements, as well as a balanced microstructure and high resistance to corrosion. (author)

  4. Effect of groove design on mechanical and metallurgical properties of quenched and tempered low alloy abrasion resistant steel welded joints

    International Nuclear Information System (INIS)

    Sharma, Varun; Shahi, A.S.

    2014-01-01

    Highlights: • Effect of weld groove design on Q and T steel welded joints is investigated. • Groove design influences heat dissipation characteristics of welded joints. • Double-V groove joint possesses maximum yield strength and UTS. • C-groove joint possesses highest impact energy, both at room temperature and 0 °C. • A wide variation in microhardness exists across different zone of the weldments. - Abstract: Experimental investigations were carried out to study the influence of three different groove designs on mechanical and metallurgical properties of 15 mm thick Q and T (quenched and tempered) steel welded joints. Welding heat input variation corresponding to each joint configuration was kept to a minimal such that the objective of investigating, exclusively, the effect of varied weld volume on the mechanical and metallurgical performance of these joints could be accomplished. Mechanical performance of these joints was evaluated by subjecting them to transverse tensile testing, and Charpy V-notch impact testing of the weld zones at room temperature and 0 °C. The results of this study reveal that among all types of groove formations used for welding, double-V groove joint possessed maximum YS (yield strength) and UTS (ultimate tensile strength), besides maximum strength ratio (YS/UTS) that was followed by U-groove joint and C-groove joint, respectively. However, weld zone tested individually, for the cover as well as the root pass of the C-groove joint possessed highest CVN (Charpy V-notch) values, both at room temperature and 0 °C. Extensive microhardness studies of these weldments showed a wide variation in the microhardness values of the weld zone and the HAZ (heat affected zone). It was concluded that each groove formation/design exerted a significant influence on the heat dissipation characteristics of these joints, which is evident from different morphological features as revealed through optical microscopy. Scanning electron microscopic

  5. Effects of alloying element on weld characterization of laser-arc hybrid welding of pure copper

    Science.gov (United States)

    Hao, Kangda; Gong, Mengcheng; Xie, Yong; Gao, Ming; Zeng, Xiaoyan

    2018-06-01

    Effects of alloying elements of Si and Sn on weld characterizations of laser-arc hybrid welded pure copper (Cu) with thickness of 2 mm was studied in detail by using different wires. The weld microstructure was analyzed, and the mechanical properties (micro-hardness and tensile property), conductivity and corrosion resistance were tested. The results showed that the alloying elements benefit the growth of column grains within weld fusion zone (FZ), increase the ultimate tensile strength (UTS) of the FZ and weld corrosion resistance, and decrease weld conductivity. The mechanisms were discussed according to the results.

  6. Weldability of AISI 304 to copper by friction welding

    Energy Technology Data Exchange (ETDEWEB)

    Kirik, Ihsan [Batman Univ. (Turkey); Balalan, Zulkuf [Firat Univ., Elazig (Turkey)

    2013-06-01

    Friction welding is a solid-state welding method, which can join different materials smoothly and is excessively used in manufacturing industry. Friction welding method is commonly used in welding applications of especially cylindrical components, pipes and materials with different properties, for which other welding methods remain incapable. AISI 304 stainless steel and a copper alloy of 99.6 % purity were used in this study. This couple was welded in the friction welding machine. After the welding process, samples were analyzed macroscopically and microscopically, and their microhardness was measured. Tensile test was used to determine the bond strength of materials that were joined using the friction welding method. At the end of the study, it was observed that AISI 304 stainless steel and copper could be welded smoothly using the friction welding method and the bond strength is close to the tensile strength of copper. (orig.)

  7. Advanced Welding Concepts

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Four advanced welding techniques and their use in NASA are briefly reviewed in this poster presentation. The welding techniques reviewed are: Solid State Welding, Friction Stir Welding (FSW), Thermal Stir Welding (TSW) and Ultrasonic Stir Welding.

  8. The definition of insulin resistance using HOMA-IR for Americans of Mexican descent using machine learning.

    Science.gov (United States)

    Qu, Hui-Qi; Li, Quan; Rentfro, Anne R; Fisher-Hoch, Susan P; McCormick, Joseph B

    2011-01-01

    The lack of standardized reference range for the homeostasis model assessment-estimated insulin resistance (HOMA-IR) index has limited its clinical application. This study defines the reference range of HOMA-IR index in an adult Hispanic population based with machine learning methods. This study investigated a Hispanic population of 1854 adults, randomly selected on the basis of 2000 Census tract data in the city of Brownsville, Cameron County. Machine learning methods, support vector machine (SVM) and Bayesian Logistic Regression (BLR), were used to automatically identify measureable variables using standardized values that correlate with HOMA-IR; K-means clustering was then used to classify the individuals by insulin resistance. Our study showed that the best cutoff of HOMA-IR for identifying those with insulin resistance is 3.80. There are 39.1% individuals in this Hispanic population with HOMA-IR>3.80. Our results are dramatically different using the popular clinical cutoff of 2.60. The high sensitivity and specificity of HOMA-IR>3.80 for insulin resistance provide a critical fundamental for our further efforts to improve the public health of this Hispanic population.

  9. Welding of refractory alloys

    International Nuclear Information System (INIS)

    Lessmann, G.G.

    1984-01-01

    This review primarily summarizes welding evaluations supported by NASA-Lewis Research Center in the 1960s. A literature search run in preparation for this review indicates that more recent work is modest by comparison. Hence, this review restates these accomplishments briefly and addresses opportunities which have evolved in welding technology (such as lasers) in the intervening decade. Emphasis in this review is given to tantalum- and niobium-base alloys. Considerable work was also done to assure that a consistent comparison was made with tungsten. A wide variety of candidate alloys derived primarily from developments directed at aircraft propulsion applications were available. Early efforts by NASA were directed at screening studies to select promising structural alloys for the space power application. This objective required fine tuning of welding procedures, e.g., the demonstration of stringent standards for control of welding atmosphere to assure good corrosion resistance in liquid alkali metals. 16 figures, 6 tables

  10. Welding processes and ocular hazards and protection.

    Science.gov (United States)

    Pabley, A S; Keeney, A H

    1981-07-01

    There are approximately 60 different forms of welding, but only six of these are commonly used. Shielded metal-arc or stick welding, gas metal-arc welding, and oxyacetylene welding are the most frequently used. All produce ultraviolet, visible, and infrared radiation at damaging levels. Conventional glass welding shields contain ultraviolet, visible, and infrared absorbers. Infrared absorbers, however, cause heating and secondary re-radiation. New polycarbonate lenses offer greater impact resistance, and have less tendency to welding spatter. Early abrasion-resistant and reflective coatings on plastics were ineffective. Thin layers of gold with proprietary coatings provide cool reflection and surface resistance. Thermal monitoring of welding indicated that these new shields reduce temperature rises above the ambient by 150% to 175% compared to green glass filter plates without interfering with the welder's vision.

  11. Strength analysis of welded corners of PVC window profiles

    Science.gov (United States)

    Postawa, P.; Stachowiak, T.; Gnatowski, A.

    2017-08-01

    The article presents the results of researches which main purpose was to define the influence of welding parameters on strength of welded corners of PVC window profile. PVC profiles of a branded name GENEO® produced by Rehau Company were used for this research. The profiles were made by using a co-extrusion method. The surface of the profile was made of PVC mixture with no additives. Its main task was to get a smooth surface resistant to a smudge. The use of an unfilled polyester provides an aesthetic look and improves the resistance of extrudate to water getting into inner layers. The profile's inner layers have been filled up with glass fibre in order to improve its stiffness and mechanical properties. Window frames with cut corners used for this research, were produced on technological line of EUROCOLOR Company based in Pyskowice (Poland). The main goal of this analysis was to evaluate the influence of the main welding parameter (temperature upsetting) on hardness of welds we received in whole process. A universal testing machine was used for the research.

  12. Corrosion of carbon steel welds

    International Nuclear Information System (INIS)

    Daniel, B.

    1988-09-01

    This report assesses the factors which cause preferential attack to occur in carbon steel fusion welds. It was concluded that the main factors were: the inclusion content of the weld metal, the potential of the weld metal being less noble than that of the parent, and the presence of low-temperature transformation products in the heat-affected zone of the weld. These factors should be minimized or eliminated as appropriate so that the corrosion allowances determined for carbon steel waste drums is also adequate for the welds. An experimental/theoretical approach is recommended to evaluate the relative corrosion resistance of welds prepared from BS 4360 grade 43A steel to that of the parent material. (author)

  13. Welding, Bonding and Fastening, 1984

    Science.gov (United States)

    Buckley, J. D. (Editor); Stein, B. A. (Editor)

    1985-01-01

    A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Soceity, and Society of Manufacturing Engineers conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

  14. Welding Technician

    Science.gov (United States)

    Smith, Ken

    2009-01-01

    About 95% of all manufactured goods in this country are welded or joined in some way. These welded products range in nature from bicycle handlebars and skyscrapers to bridges and race cars. The author discusses what students need to know about careers for welding technicians--wages, responsibilities, skills needed, career advancement…

  15. GMR-based eddy current probe for weld seam inspection and its non-scanning detection study

    Science.gov (United States)

    Gao, Peng; Wang, Chao; Li, Yang; Wang, Libin; Cong, Zheng; Zhi, Ya

    2017-04-01

    Eddy current testing is one of the most important non-destructive testing methods for welding defects detection. This paper presents the use of a probe consisting of 4 giant magneto-resistive (GMR) sensors to detect weld defects. Information from four measuring points above and on both sides of the weld seam is collected at the same time. By setting the GMR sensors' sensing axes perpendicular to the direction of the excitation magnetic field, the information collected mainly reflects the change in the eddy current which is caused by defects. Digital demodulation technology is applied to extract the real part and imaginary part of the GMR sensors' output signals. The variables containing directional information of the magnetic field are introduced. Based on the data from the four GMR (4-GMR) sensors' output signals, four values, Ran, Mean, Var and k are selected as the feature quantities for defect recognition. Experiments are carried out on weld seams with and without defects, and the detection outputs are given in this paper. The 4-GMR probe is also employed to investigate non-scanning weld defect detection and the four feature quantities (Ran, Mean, Var and k) are studied to evaluate weld quality. The non-scanning weld defect detection is presented. A support vector machine is used to classify and discriminate welds with and without defects. Experiments carried out show that through the method in this paper, the recognition rate is 92% for welds without defects and 90% for welds with defects, with an overall recognition rate of 90.9%, indicating that this method could effectively detect weld defects.

  16. Analysed a defective of the machine for a cap-tube nuclear fuel element ME-27 from its electricity point of view

    International Nuclear Information System (INIS)

    Achmad Suntoro

    2009-01-01

    It has been analysed a defective of the machine for a cap-tube nuclear fuel element ME-27 from its electricity point of view. The machine uses magnetic force resistance welding technique. A short circuit was happened within the machine because the nut for tightening high voltage cable for welding transformer was broken so that the cable touched the machine body and produced the short circuit. This condition made both the primary circuit breaker in the building down and produced high voltage pulse induction to the electronic circuit within the machine so that one of its electronic components was defective. This case becomes warnings on how important of tightening a nut according to its strength specification (using wrench torque) and the necessity of voltage transient limitation circuit to be installed. Both of the warnings are necessary for any equipment consuming high electric current oriented such as the ME-27 machine. (author)

  17. Effect of the Cutting Tool Geometry on the Tool Wear Resistance When Machining Inconel 625

    Directory of Open Access Journals (Sweden)

    Tomáš Zlámal

    2017-12-01

    Full Text Available The paper deals with the design of a suitable cutting geometry of a tool for the machining of the Inconel 625 nickel alloy. This alloy is among the hard-to-machine refractory alloys that cause very rapid wear on cutting tools. Therefore, SNMG and RCMT indexable cutting insert were used to machine the alloy. The selected insert geometry should prevent notch wear and extend tool life. The alloy was machined under predetermined cutting conditions. The angle of the main edge and thus the size and nature of the wear changed with the depth of the material layer being cut. The criterion for determining a more suitable cutting geometry was the tool’s durability and the roughness of the machined surface.

  18. Effect of the Cutting Tool Geometry on the Tool Wear Resistance when Machining Inconel 625

    Directory of Open Access Journals (Sweden)

    Tomáš Zlámal

    2018-03-01

    Full Text Available The paper deals with the design of a suitable cutting geometry of a tool for the machining of the Inconel 625 nickel alloy. This alloy is among the hard-to-machine refractory alloys that cause very rapid wear on cutting tools. Therefore, SNMG and RCMT indexable cutting insert were used to machine the alloy. The selected insert geometry should prevent notch wear and extend tool life. The alloy was machined under predetermined cutting conditions. The angle of the main edge and thus the size and nature of the wear changed with the depth of the material layer being cut. The criterion for determining a more suitable cutting geometry was the tool’s durability and the roughness of the machined surface.

  19. Performance Improvement of Friction Stir Welds by Better Surface Finish

    Science.gov (United States)

    Russell, Sam; Nettles, Mindy

    2015-01-01

    The as-welded friction stir weld has a cross section that may act as a stress concentrator. The geometry associated with the stress concentration may reduce the weld strength and it makes the weld challenging to inspect with ultrasound. In some cases, the geometry leads to false positive nondestructive evaluation (NDE) indications and, in many cases, it requires manual blending to facilitate the inspection. This study will measure the stress concentration effect and develop an improved phased array ultrasound testing (PAUT) technique for friction stir welding. Post-welding, the friction stir weld (FSW) tool would be fitted with an end mill that would machine the weld smooth, trimmed shaved. This would eliminate the need for manual weld preparation for ultrasonic inspections. Manual surface preparation is a hand operation that varies widely depending on the person preparing the welds. Shaving is a process that can be automated and tightly controlled.

  20. Measurement of residual stresses in welded sample of dissimilar materials

    International Nuclear Information System (INIS)

    Mansur, Tanius Rodrigues; Gomes, Paulo de Tarso Vida; Scaldaferri, Denis Henrique Bianchi; Martins, Geraldo Antonio Scoralick; Atanazio Filho, Nelson do Nascimento

    2008-01-01

    The welding of dissimilar metals has several applications in the industry. Especially in the nuclear industry, this joint type, common between carbon steel and stainless steel, it is always reason of analysis and special cares tends in view the need to maintain the integrity of the equipment. Residual stresses are introduced in the material as a result of processes as welding, machining, sanding and polishing that can to produce deformation in the proximities of the surface of the material. Residual compressive stresses can be introduced in the material through the jetting process (bombardment of the surface for small glass spheres, dry sand or steel). That procedure allows a fine subsurface layer to suffer yielding, compressing the superficial layer and reducing the formation of areas of concentration of traction stresses, increasing the resistance of the material to the fatigue. The welding process introduces residual stresses due to the geometry resulting from the fusion of the material welded and of the heterogeneous cooling. Besides the microstructural alteration and chemical composition of the material in the affected area for the heat, introduced by the welding, it is also had the effect of the discontinuity of the passes and the formation of bubbles and emptiness that can contribute to the cracks nucleation, reducing the resistance to the fatigue. In the great majority of the times residual stresses are harmful and there are many documented cases which US these stresses went predominant factors for the failure for fatigue. A particularly dangerous aspect of the residual stresses is that their presence is not usually observed, what usually happens with an applied load to the structure. The knowledge of the surface residual stresses is important to predict the emergence of failure when the component or structure is requested. In nuclear power plants it is common to welding of piping of stainless steels with mouthpieces of carbon steel of pressure vases of

  1. Sustainability of Welding Process through Bobbin Friction Stir Welding

    Science.gov (United States)

    Sued, M. K.; Samsuri, S. S. M.; Kassim, M. K. A. M.; Nasir, S. N. N. M.

    2018-03-01

    Welding process is in high demand, which required a competitive technology to be adopted. This is important for sustaining the needs of the joining industries without ignoring the impact of the process to the environment. Friction stir welding (FSW) is stated to be benefitting the environment through low energy consumption, which cannot be achieved through traditional arc welding. However, this is not well documented, especially for bobbin friction stir welding (BFSW). Therefore, an investigation is conducted by measuring current consumption of the machine during the BFSW process. From the measurement, different phases of BFSW welding process and its electrical demand are presented. It is found that in general total energy in BFSW is about 130kW inclusive of all identified process phases. The phase that utilise for joint formation is in weld phase that used the highest total energy of 120kWs. The recorded total energy is still far below the traditional welding technology and the conventional friction stir welding (CFSW) energy demand. This indicates that BFSW technology with its vast benefit able to sustain the joining technology in near future.

  2. Forming Completely Penetrated Welded T-joints when Pulsed Arc Welding

    Science.gov (United States)

    Krampit, N. Yu; Krampit, M. A.; Sapozhkov, A. S.

    2016-04-01

    The paper is focused on revealing the influence of welding parameters on weld formation when pulsed arc welding. As an experimental sample a T-joint over 10 mm was selected. Welding was carried out in flat position, which required no edge preparation but provided mono-directional guaranteed root penetration. The following parameters of welding were subjected to investigation: gap in the joint, wire feed rate and incline angles of the torch along and across the weld axis. Technological recommendations have been made with respect to pulsed arc welding; the cost price of product manufacturing can be reduced on their basis due to reduction of labor input required by machining, lowering consumption of welding materials and electric power.

  3. Effect of weld metal properties on fatigue crack growth behaviour of gas tungsten arc welded AISI 409M grade ferritic stainless steel joints

    International Nuclear Information System (INIS)

    Shanmugam, K.; Lakshminarayanan, A.K.; Balasubramanian, V.

    2009-01-01

    The effect of filler metals such as austenitic stainless steel, ferritic stainless steel and duplex stainless steel on fatigue crack growth behaviour of the gas tungsten arc welded ferritic stainless steel joints was investigated. Rolled plates of 4 mm thickness were used as the base material for preparing single 'V' butt welded joints. Centre cracked tensile (CCT) specimens were prepared to evaluate fatigue crack growth behaviour. Servo hydraulic controlled fatigue testing machine was used to evaluate the fatigue crack growth behaviour of the welded joints. From this investigation, it was found that the joints fabricated by duplex stainless steel filler metal showed superior fatigue crack growth resistance compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Higher yield strength, hardness and relatively higher toughness may be the reasons for superior fatigue performance of the joints fabricated by duplex stainless steel filler metal.

  4. ITER lip seal welding and cutting developments

    International Nuclear Information System (INIS)

    Levesy, B.; Cordier, J.J.; Jokinen, T.; Kujanpää, V.; Karhu, M.; Le Barbier, R.; Määttä, T.; Martins, J.P.; Utin, Y.

    2015-01-01

    Highlights: • Different TIG and Laser welding techniques are tested. • Twin spot laser welding techniques is the best. • Limited heat input gives a stable weld pool in all positions. • Penetrations is achieved. • Lip seal welding and cutting with a robotic arm is successfully performed on a representative mock-up. - Abstract: The welded lip seals form part of the torus primary vacuum boundary in between the port plugs and the vacuum vessel, and are classified as Protection Important Component. In order to refurbish the port plugs or the in-vessel components, port plugs have to be removed from the machine. The lip seal design must enable up to ten opening of the vacuum vessel during the life time operation of the ITER machine. Therefore proven, remote reliable cutting and re-welding are essential, as these operations need to be performed in the port cells in a nuclear environment, where human presence will be restricted. Moreover, the combination of size of the components to be welded (∼10 m long vacuum compatible thin welds) and the congested environment close to the core of the machine constraint the type and size of tools to be used. This paper describes the lip seal cutting and welding development programme performed at the VTT Technical Research Centre, Finland. Potential cutting and welding techniques are analyzed and compared. The development of the cutting, TIG and laser welding techniques on samples are presented. Effects of lip seal misalignments and optimization of the 2 welding processes are discussed. Finally, the manufacturing and test of the two 1.2 m × 1 m representative mock-ups are presented. The set-up and use of a robotic arm for the mock-up cutting and welding operations are also described.

  5. ITER lip seal welding and cutting developments

    Energy Technology Data Exchange (ETDEWEB)

    Levesy, B.; Cordier, J.J.; Jokinen, T. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Kujanpää, V.; Karhu, M. [VTT Technical Research Centre of Finland (Finland); Le Barbier, R. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Määttä, T. [VTT Technical Research Centre of Finland (Finland); Martins, J.P.; Utin, Y. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2015-10-15

    Highlights: • Different TIG and Laser welding techniques are tested. • Twin spot laser welding techniques is the best. • Limited heat input gives a stable weld pool in all positions. • Penetrations is achieved. • Lip seal welding and cutting with a robotic arm is successfully performed on a representative mock-up. - Abstract: The welded lip seals form part of the torus primary vacuum boundary in between the port plugs and the vacuum vessel, and are classified as Protection Important Component. In order to refurbish the port plugs or the in-vessel components, port plugs have to be removed from the machine. The lip seal design must enable up to ten opening of the vacuum vessel during the life time operation of the ITER machine. Therefore proven, remote reliable cutting and re-welding are essential, as these operations need to be performed in the port cells in a nuclear environment, where human presence will be restricted. Moreover, the combination of size of the components to be welded (∼10 m long vacuum compatible thin welds) and the congested environment close to the core of the machine constraint the type and size of tools to be used. This paper describes the lip seal cutting and welding development programme performed at the VTT Technical Research Centre, Finland. Potential cutting and welding techniques are analyzed and compared. The development of the cutting, TIG and laser welding techniques on samples are presented. Effects of lip seal misalignments and optimization of the 2 welding processes are discussed. Finally, the manufacturing and test of the two 1.2 m × 1 m representative mock-ups are presented. The set-up and use of a robotic arm for the mock-up cutting and welding operations are also described.

  6. Some electron beam welding equipments for the nuclear industry

    International Nuclear Information System (INIS)

    Helm, H.; Rodier, R.; Sayegh, G.

    1978-01-01

    Results of various electron beam welding equipment developed for the nuclear industry obtained from a 100 kW electron beam machine to weld thick plates made of stainless steel and reactor steel, and from some equipment with local vacuum to weld pipes onto a pipe wall. (orig.) [de

  7. Evaluation of iron aluminide weld overlays for erosion - corrosion resistant boiler tube coatings in low NO{sub x} boilers

    Energy Technology Data Exchange (ETDEWEB)

    DuPont, J.N.; Banovic, S.W.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States)

    1996-08-01

    Low NOx burners are being installed in many fossil fired power plants in order to comply with new Clean Air Regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion is often enhanced and premature tube failures can occur. Failures due to oxidation and solid particle erosion are also a concern. A program was initiated in early 1996 to evaluate the use of iron aluminide weld overlays for erosion/corrosion protection of boiler tubes in Low NOx boilers. Composite iron/aluminum wires will be used with the Gas Metal Arc Welding (GMAW) process to prepare overlays on boiler tubes steels with aluminum contents from 8 to 16wt%. The weldability of the composite wires will be evaluated as a function of chemical composition and welding parameters. The effect of overlay composition on corrosion (oxidation and sulfidation) and solid particle erosion will also be evaluated. The laboratory studies will be complemented by field exposures of both iron aluminide weld overlays and co-extruded tubing under actual boiler conditions.

  8. Ultrasonic inspection of austenitic welds

    International Nuclear Information System (INIS)

    Baikie, B.L.; Wagg, A.R.; Whittle, M.J.; Yapp, D.

    1976-01-01

    Optical and X-ray metallography combined with ultrasonic testing by compression waves was used for inspection of stainless steel weld metal produced by three different welding techniques. X-ray diffraction showed that each weld possessed a characteristic fibre textured structure which was shown by optical microscopy to be parallel to columnar grain boundaries. Metallographic evidence suggested that the development of fibre texture is due to the mechanism of competitive growth. From observations made as a result of optical metallographic examination the orientation of the fibre axis could be predicted if the weld geometry and welding procedure were known. Ultrasonic velocity and attenuation measurements as a continuous function of grain orientation, made on cylinders machined from weld samples, showed that attenuation was strongly orientation dependent. It was concluded that the sensitivity of ultrasonic inspection to small defects is unlikely to be as high for austenitic welds as for ferritic even when transmission is improved by modifying the welding procedure to improve the ultrasonic transmission. (U.K.)

  9. Welding abilities of UFG metals

    Science.gov (United States)

    Morawiński, Łukasz; Chmielewski, Tomasz; Olejnik, Lech; Buffa, Gianluca; Campanella, Davide; Fratini, Livan

    2018-05-01

    Ultrafine Grained (UFG) metals are characterized by an average grain size of welded joints with similar properties to the base of UFG material are crucial for the production of finished engineering components. Conventional welding methods based on local melting of the joined edges cannot be used due to the UFG microstructure degradation caused by the heat occurrence in the heat affected zone. Therefore, the possibility of obtaining UFG materials joints with different shearing plane (SP) positions by means of friction welded processes, which do not exceed the melting temperature during the process, should be investigated. The article focuses on the Linear Friction Welding (LFW) method, which belongs to innovative welding processes based on mixing of the friction-heated material in the solid state. LFW is a welding process used to joint bulk components. In the process, the friction forces work due to the high frequency oscillation and the pressure between the specimens is converted in thermal energy. Character and range of recrystallization can be controlled by changing LFW parameters. Experimental study on the welded UFG 1070 aluminum alloy by means of FLW method, indicates the possibility of reducing the UFG structure degradation in the obtained joint. A laboratory designed LFW machine has been used to weld the specimens with different contact pressure and oscillation frequency.

  10. Influence of Welding Process and Post Weld Heat Treatment on Microstructure and Pitting Corrosion Behavior of Dissimilar Aluminium Alloy Welds

    Science.gov (United States)

    Venkata Ramana, V. S. N.; Mohammed, Raffi; Madhusudhan Reddy, G.; Srinivasa Rao, K.

    2018-03-01

    Welding of dissimilar Aluminum alloy welds is becoming important in aerospace, shipbuilding and defence applications. In the present work, an attempt has been made to weld dissimilar aluminium alloys using conventional gas tungsten arc welding (GTAW) and friction stir welding (FSW) processes. An attempt was also made to study the effect of post weld heat treatment (T4 condition) on microstructure and pitting corrosion behaviour of these welds. Results of the present investigation established the differences in microstructures of the base metals in T4 condition and in annealed conditions. It is evident that the thickness of the PMZ is relatively more on AA2014 side than that of AA6061 side. In FS welds, lamellar like shear bands are well noticed on the top of the stir zone. The concentration profile of dissimilar friction stir weld in T4 condition revealed that no diffusion has taken place at the interface. Poor Hardness is observed in all regions of FS welds compared to that of GTA welds. Pitting corrosion resistance of the dissimilar FS welds in all regions was improved by post weld heat treatment.

  11. Influence of weld structure on cross-weld creep behavior in P23 steel

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D.J.; Degnan, C.C. [E.ON Engineering (United Kingdom); Brett, S.J. [RWE npower (United Kingdom); Buchanan, L.W. [Doosan Babcock (United Kingdom)

    2010-07-01

    A thick section pipe weld in low alloy steel P23 has been characterised by cross-weld creep rupture testing at a range of stresses, together with all-weld-metal and parent material testing, under the auspices of the UK High Temperature Power Plant Forum. The results generally show that the weld metal can be weak when tested in the transverse (cross-weld) orientation, and can fail with limited overall ductility by cracking in the zone of refined weld metal beneath the fusion boundary of the superposed weld bead. However, one specimen showed a much superior performance, which could be understood in terms of its locally more creep resistant weld macrostructure. The implications for P23 performance and weld manufacture are discussed. (orig.)

  12. Electric machine

    Science.gov (United States)

    El-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Reddy, Patel Bhageerath [Madison, WI

    2012-07-17

    An interior permanent magnet electric machine is disclosed. The interior permanent magnet electric machine comprises a rotor comprising a plurality of radially placed magnets each having a proximal end and a distal end, wherein each magnet comprises a plurality of magnetic segments and at least one magnetic segment towards the distal end comprises a high resistivity magnetic material.

  13. Investigation of fracture in pressurized gas metal arc welded beryllium

    International Nuclear Information System (INIS)

    Heiple, C.R.; Merlini, R.J.; Adams, R.O.

    1976-01-01

    Premature failures during proof testing of pressurized-gas-metal-arc (PGMA) welded beryllium assemblies were investigated. The failures were almost entirely within the beryllium (a forming grade, similar to HP-10 or S-240), close to and parallel to the weld interface. The aluminum-silicon weld filler metal deposit was not centered in the weld groove in the failed assemblies, and failure occurred on the side of the weld opposite the bias in the weld deposit. Tensile tests of welded samples demonstrated that the failures were unrelated to residual machining damage from cutting the weld groove, and indicated small lack-of-fusion areas near the weld start to be the most likely origin of the failures. Acoustic emission was monitored during tensile tests of the welds. The majority of acoustic emission was probably from crack propagation through the weld filler metal. Tensile bars cut from the region of the weld start behaved differently; they failed at lower loads and exhibited an acoustic emission behavior believed to be from cracking in the weld metal-beryllium interface. Improvement in the quality of these and similar beryllium welds can therefore most likely be made by centering the weld deposit and reducing the size of the weld start defect. 21 fig

  14. Fracture toughness of partially welded joints of SUS316 stainless steel at 4 K by large bend tests

    International Nuclear Information System (INIS)

    Nishimura, A.; Tobler, R.L.; Tamura, H.; Imagawa, S.; Mito, T.; Yamamoto, J.; Motojima, O.; Takahashi, H.; Suzuki, S.

    1996-01-01

    Austenitic stainless steels in relatively thick sections are specified in support structure designs for huge superconducting magnets in fusion energy machines such as the Large Helical Device (LHD). In the LHD under construction at the National Institute for Fusion Science (NIFS) in Japan, partial welding of SUS 316 stainless steel is employed to fabricate the 100-mm thick coil can and coil support structures. Partial welding lowers the heat input and reduces residual deformation after welding. The main disadvantage is that a sizable crack-like defect remains embedded in the unwelded portion of the primary structural component. Here, SUS 316 stainless steel bars were partially welded and tested in 3-point bending to evaluate the effect of natural cracks on fusion zone toughness at 4 K. The specimens had a cross-section 87.5 mm x 175 mm and were fractured in liquid helium using a 10 MN cryogenic mechanical testing machine. In two tests, unstable fracture occurred at maximum load and at critical stress intensity factors K max = 227 and 228 MPa√m. Results indicate a high resistance to fracture initiation but no stable tearing. Therefore, no resistance to crack propagation may exist in a fusion zone at a weld root under cryogenic temperature

  15. Electricity of machine tool

    International Nuclear Information System (INIS)

    Gijeon media editorial department

    1977-10-01

    This book is divided into three parts. The first part deals with electricity machine, which can taints from generator to motor, motor a power source of machine tool, electricity machine for machine tool such as switch in main circuit, automatic machine, a knife switch and pushing button, snap switch, protection device, timer, solenoid, and rectifier. The second part handles wiring diagram. This concludes basic electricity circuit of machine tool, electricity wiring diagram in your machine like milling machine, planer and grinding machine. The third part introduces fault diagnosis of machine, which gives the practical solution according to fault diagnosis and the diagnostic method with voltage and resistance measurement by tester.

  16. Device for electron beam machining

    International Nuclear Information System (INIS)

    Panzer, S.; Ardenne, T. von; Liebergeld, H.

    1984-01-01

    The invention concerns a device for electron beam machining, in particular welding. It is aimed at continuous operation of the electron irradiation device. This is achieved by combining the electron gun with a beam guiding chamber, to which vacuum chambers are connected. The working parts to be welded can be arranged in the latter

  17. Intelligent sensing and control of gas metal arc welding

    International Nuclear Information System (INIS)

    Smartt, H.B.; Johnson, J.A.

    1993-01-01

    Intelligent sensing and control is a multidisciplinary approach that attempts to build adequate sensing capability, knowledge of process physics, control capability, and welding engineering into the welding system such that the welding machine is aware of the state of the weld and knows how to make a good weld. The sensing and control technology should reduce the burden on the welder and welding engineer while providing the great adaptability needed to accommodate the variability found in the production world. This approach, accomplished with application of AI techniques, breaks the tradition of separate development of procedure and control technology

  18. Use of narrow gap welding in nuclear power engineering and development of welding equipment at Vitkovice Iron Works (VZSKG), Ostrava

    International Nuclear Information System (INIS)

    Lehar, F.; Sevcik, P.

    1988-01-01

    Briefly discussed are problems related to automatic submerged arc welding into narrow gaps. The said method was tested for the first time at the Vitkovice Iron Works VZSKG for peripheral welds on pressurizers for WWER-440 reactors. The demands are summed up which are put on the welding workplace which must be met for the use of the said technology. The requirements mainly include the provision of the positioning of the welding nozzle towards the weld gap in order to maximally exclude the effect of the welder. An automatic device was designed and manufactured at the VZSKG plant for mounting the welding nozzle on the automatic welding machine manufactured by ESAB which operates on the principle of the flexible compression of the nozzle to the wall of the weld gap. In the bottom part the welding nozzle is provided with a pulley which rolls during welding thereby providing a constant distance to be maintained between the welding wire and the wall of the weld gap. The diameter of the pulley is ruled by the diameter of the welding wire. Provided the clamping part is appropriately adjusted the developed equipment may be used for any type of automatic welding machine with motor driven supports. (Z.M.). 8 figs., 5 tabs., 9 refs

  19. Defect Detectability Improvement for Conventional Friction Stir Welds

    Science.gov (United States)

    Hill, Chris

    2013-01-01

    This research was conducted to evaluate the effects of defect detectability via phased array ultrasound technology in conventional friction stir welds by comparing conventionally prepped post weld surfaces to a machined surface finish. A machined surface is hypothesized to improve defect detectability and increase material strength.

  20. Effect of vanadium of mechanical behavior, machinability and wear resistance of aluminium grain refined by Ti+B

    International Nuclear Information System (INIS)

    Zaid, A.I.O.; Hamid, A.A.A.

    1999-01-01

    It is well established that aluminum and its alloys are industrially grain refined by adding either Ti or Ti-B to improve their mechanical behavior and surface finish. In a previous paper, it was found that the grain refining efficiency of aluminum master alloys containing Ti or Ti+B was enhanced by addition of small amounts of other elements including vanadium. V. Therefore, it is anticipated that such an element will improve mechanical behavior, machinability and wear resistance of aluminum and its alloys. In this paper, the effect of vanadium addition, up to 0.3% on mechanical behavior is investigated. Machinability was assessed under different cutting conditions: speed, feed and depth of cut and finally the wear resistance was determined at different loads and speeds. The results indicated that improvement in hardness and mechanical strength were achieved by the addition of V that addition of more than 0.2%V resulted in little or no improvement. Similarly, addition of V resulted in improvement of surface quality under the different cutting conditions of speed, feed and depth of cut, and resistance to wear. However addition of more than 0.2% V resulted in increase of wear rate and change of wear mechanisms. (author)

  1. Soldadura (Welding). Spanish Translations for Welding.

    Science.gov (United States)

    Hohhertz, Durwin

    Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

  2. Upgraded HFIR Fuel Element Welding System

    International Nuclear Information System (INIS)

    Sease, John D.

    2010-01-01

    The welding of aluminum-clad fuel plates into aluminum alloy 6061 side plate tubing is a unique design feature of the High Flux Isotope Reactor (HFIR) fuel assemblies as 101 full-penetration circumferential gas metal arc welds (GMAW) are required in the fabrication of each assembly. In a HFIR fuel assembly, 540 aluminum-clad fuel plates are assembled into two nested annular fuel elements 610 mm (24-inches) long. The welding process for the HFIR fuel elements was developed in the early 1960 s and about 450 HFIR fuel assemblies have been successfully welded using the GMAW process qualified in the 1960 s. In recent years because of the degradation of the electronic and mechanical components in the old HFIR welding system, reportable defects in plate attachment or adapter welds have been present in almost all completed fuel assemblies. In October 2008, a contract was awarded to AMET, Inc., of Rexburg, Idaho, to replace the old welding equipment with standard commercially available welding components to the maximum extent possible while maintaining the qualified HFIR welding process. The upgraded HFIR welding system represents a major improvement in the welding system used in welding HFIR fuel elements for the previous 40 years. In this upgrade, the new inner GMAW torch is a significant advancement over the original inner GMAW torch previously used. The innovative breakthrough in the new inner welding torch design is the way the direction of the cast in the 0.762 mm (0.030-inch) diameter aluminum weld wire is changed so that the weld wire emerging from the contact tip is straight in the plane perpendicular to the welding direction without creating any significant drag resistance in the feeding of the weld wire.

  3. WELDING TORCH

    Science.gov (United States)

    Correy, T.B.

    1961-10-01

    A welding torch into which water and inert gas are piped separately for cooling and for providing a suitable gaseous atmosphere is described. A welding electrode is clamped in the torch by a removable collet sleeve and a removable collet head. Replacement of the sleeve and head with larger or smaller sleeve and head permits a larger or smaller welding electrode to be substituted on the torch. (AEC)

  4. Influence of stress relieve heat treatment on fatigue crack propagation in structural steel resistant to atmospheric corrosion welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Geraldo de Paula; Villela, Jefferson Jose; Rabello, Emerson Giovani [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mails: gpm@cdtn.br; jjv@cdtn.br; egr@cdtn.br; Cimini Junior, Carlos Alberto[Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Mecanica]. E-mail: cimini@demet.ufmg.br; Godefroid, Leonardo Barbosa [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Dept. de Metalurgia]. E-mails: leonardo@demet.em.ufop.br

    2007-07-01

    In this work, the influence of stress relieve heat treatment (SRHT) on the fatigue crack propagation in USI-SAC 50 structural welded joints at the heat affected zone (HAZ) region was studied. Hardness measurements before and after the SRHT were made and crack propagation tests in specimens as welded (AW) and in specimens that were submitted to SRHT, which were accomplished. A reduction in hardness at the regions of HAZ and melted zone (MZ) after the SRHT were observed. It were also verified that the crack propagation rates (da/dN) versus DK on the specimens AW presented regions of retardation on the crack propagation rate, and in the specimens that were submitted to SRHT the crack propagation rate were homogeneous. (author)

  5. Computational Model for Impact-Resisting Critical Thickness of High-Speed Machine Outer Protective Plate

    Science.gov (United States)

    Wu, Huaying; Wang, Li Zhong; Wang, Yantao; Yuan, Xiaolei

    2018-05-01

    The blade or surface grinding blade of the hypervelocity grinding wheel may be damaged due to too high rotation rate of the spindle of the machine and then fly out. Its speed as a projectile may severely endanger the field persons. Critical thickness model of the protective plate of the high-speed machine is studied in this paper. For easy analysis, the shapes of the possible impact objects flying from the high-speed machine are simplified as sharp-nose model, ball-nose model and flat-nose model. Whose front ending shape to represent point, line and surface contacting. Impact analysis based on J-C model is performed for the low-carbon steel plate with different thicknesses in this paper. One critical thickness computational model for the protective plate of high-speed machine is established according to the damage characteristics of the thin plate to get relation among plate thickness and mass, shape and size and impact speed of impact object. The air cannon is used for impact test. The model accuracy is validated. This model can guide identification of the thickness of single-layer outer protective plate of a high-speed machine.

  6. Fatigue Crack Growth Behavior of Gas Metal Arc Welded AISI 409 Grade Ferritic Stainless Steel Joints

    Science.gov (United States)

    Lakshminarayanan, A. K.; Shanmugam, K.; Balasubramanian, V.

    2009-10-01

    The effect of filler metals such as austenitic stainless steel, ferritic stainless steel, and duplex stainless steel on fatigue crack growth behavior of the gas metal arc welded ferritic stainless steel joints was investigated. Rolled plates of 4 mm thickness were used as the base material for preparing single ‘V’ butt welded joints. Center cracked tensile specimens were prepared to evaluate fatigue crack growth behavior. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN was used to evaluate the fatigue crack growth behavior of the welded joints. From this investigation, it was found that the joints fabricated by duplex stainless steel filler metal showed superior fatigue crack growth resistance compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Higher yield strength and relatively higher toughness may be the reasons for superior fatigue performance of the joints fabricated by duplex stainless steel filler metal.

  7. History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Larry Zirker; Nathan Jerred; Dr. Indrajit Charit; James Cole

    2012-03-01

    Research proposal 08-1079, 'A Comparative Study of Welded ODS Cladding Materials for AFCI/GNEP,' was funded in 2008 under an Advanced Fuel Cycle Initiative (AFCI) Research and Development Funding Opportunity, number DE-PS07-08ID14906. Th proposal sought to conduct research on joining oxide dispersion strengthen (ODS) tubing material to a solid end plug. This document summarizes the scientific and technical progress achieved during the project, which ran from 2008 to 2011.

  8. History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies

    International Nuclear Information System (INIS)

    Zirker, Larry; Jerred, Nathan; Charit, Indrajit; Cole, James

    2012-01-01

    Research proposal 08-1079, 'A Comparative Study of Welded ODS Cladding Materials for AFCI/GNEP,' was funded in 2008 under an Advanced Fuel Cycle Initiative (AFCI) Research and Development Funding Opportunity, number DE-PS07-08ID14906. Th proposal sought to conduct research on joining oxide dispersion strengthen (ODS) tubing material to a solid end plug. This document summarizes the scientific and technical progress achieved during the project, which ran from 2008 to 2011.

  9. Welding stresses

    International Nuclear Information System (INIS)

    Poirier, J.; Barbe, B.; Jolly, N.

    1976-01-01

    The aim is to show how internal stresses are generated and to fix the orders of magnitude. A realistic case, the vertical welding of thick plates free to move one against the other, is described and the deformations and stresses are analyzed. The mathematical model UEDA, which accounts for the elastic modulus, the yield strength and the expansion coefficient of the metal with temperature, is presented. The hypotheses and results given apply only to the instantaneous welding of a welded plate and to a plate welded by a moving electrode [fr

  10. Improvement of wear resistance of machine elements by plasma spraying followed by hardening in the chlorine-barium melt

    International Nuclear Information System (INIS)

    Fominykh, V.V.; Stepanov, V.V.

    1979-01-01

    Proposed is the mathematical model, allowing to choose the optimal regime of sprayed coating hardening in the BaCl 2 salt melt. The method of hardening of machine elements by spraying wear resistance coatings of the Ni-Cr-B-Si alloys is described. It is established that diffusion heating followed by coating melting in the BaCl 2 solution increases the adhesion of sprayed layer to substrate metal. The formation of intermediate intermetallic compounds of the Ni 3 Si and Ni 3 Fe types takes place as a result of diffusion of interacting material atoms and valence electron joining

  11. Evaluation of welds on a ferritic-austenitic stainless steel

    International Nuclear Information System (INIS)

    Pleva, J.; Johansson, B.

    1984-01-01

    Five different welding methods for the ferritic-austenitic steel 22Cr6Ni3MoN have been evaluated on mill welded heavy wall pipes. The corrosion resistance of the weld joints has been tested both in standard tests and in special environments, related to certain oil and gas wells. The tests were conclusive in that a welding procedure with the addition of sufficient amounts of filler metal should be employed. TIG welds without or with marginal filler addition showed poor resistance to pitting, and to boiling nitric acid. Contents of main alloying elements in ferrite and austenite phases have been measured and causes of corrosion attack in welds are discussed

  12. DEFORMATION INFLUENCE ON A LIFETIME OF WELDING ELECTRODE TIPS

    Directory of Open Access Journals (Sweden)

    Ján Viňáš

    2009-02-01

    Full Text Available The contribution deals with the influence of welding electrode tips deformation on their lifetime. The influence of material properties, production technology and the intensity of welding electrodes load on their lifetime are presented. The electrode tips of the most used type of CuCr1Zr alloy of three basic standard shapes before and after the process of welding are evaluated. The process of welding is realized with low, middle and maximum welding parameters on programmable pneumatic spot welding machine VTS BPK 20. The influence of welding parameters on chosen material characteristics of welding tips is observed. Through the use of upsetting test, dependency of forming strength and deformation of material on used technology of welding tip production is observed.

  13. 10,170 flawless welds

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    The welding of tubes containing the principal current-carrying busbars in the LHC magnets was one of the main activities of the SMACC project. After a year of preparation and another of intense activity in the tunnel, the last weld was completed on Wednesday 14 May. Over 10,170 welds have been inspected and not a single fault has been found.    The welder (above) creates the weld using an orbital welding machine (below) specifically designed for CERN. Each of the eight sectors of the LHC contains around 210 interconnects between the superconducting magnets. Consolidating these interconnections was the SMACC project’s primary objective. One of the last jobs before closing the interconnects is the welding of the M lines: each has a 104 mm diameter and a radial clearance of just 45 mm. In total: 10,170 welds carried out in a single year of activities. A true challenge, which was carried out by a team of 30 highly specialised welders, working under the supervision o...

  14. Fracture toughness of stainless steel welds

    International Nuclear Information System (INIS)

    Mills, W.J.

    1985-11-01

    The effects of temperature, composition and weld-process variations on the fracture toughness behavior for Types 308 and 16-8-2 stainless steel (SS) welds were examined using the multiple-specimen J/sub R/-curve procedure. Fracture characteristics were found to be dependent on temperature and weld process but not on filler material. Gas-tungsten-arc (GTA) welds exhibited the highest fracture toughness, a shielded metal-arc (SMA) weld exhibited an intermediate toughness and submerged-arc (SA) welds yielded the lowest toughness. Minimum-expected fracture properties were defined from lower-bound J/sub c/ and tearing modulus values generated here and in previous studies. Fractographic examination revealed that microvoid coalescence was the operative fracture mechanism for all welds. Second phase particles of manganese silicide were found to be detrimental to the ductile fracture behavior because they separated from the matrix during the initial stages of plastic straining. In SA welds, the high density of inclusions resulting from silicon pickup from the flux promoted premature dimple rupture. The weld produced by the SMA process contained substantially less manganese silicide, while GTA welds contained no silicide inclusions. Delta ferrite particles present in all welds were substantially more resistant to local failure than the silicide phase. In welds containing little or no manganese silicide, delta ferrite particles initiated microvoid coalescence but only after extensive plastic straining

  15. Development of remote laser welding technology

    International Nuclear Information System (INIS)

    Kim, Soo-Sung; Kim, Woong-Ki; Lee, Jung-Won; Yang, Myung-Seung; Park, Hyun-Soo

    1999-01-01

    Various welding processes are now available for end cap closure of nuclear fuel element such as TIG(Tungsten Inert Gas) welding, magnetic resistance welding and laser welding. Even though the resistance and TIG welding process are widely used for manufacturing of the commercial fuel elements, it can not be recommended for the remote seal welding of fuel element at PIE facility due to its complexity of the electrode alignment, difficulty in the replacement of parts in the remote manner and its large heat input for thin sheath. Therefore, Nd:YAG laser system using the optical fiber transmission was selected for Zircaloy-4 end cap welding. Remote laser welding apparatus is developed using a pulsed Nd:YAG laser of 500 watt average power with optical fiber transmission. The laser weldability is satisfactory in respect of the microstructures and mechanical properties comparing with the TIG and resistance welding. The optimum operation processes of laser welding and the optical fiber transmission system for hot cell operation in remote manner have been developed. (author)

  16. WELDING METHOD

    Science.gov (United States)

    Cornell, A.A.; Dunbar, J.V.; Ruffner, J.H.

    1959-09-29

    A semi-automatic method is described for the weld joining of pipes and fittings which utilizes the inert gasshielded consumable electrode electric arc welding technique, comprising laying down the root pass at a first peripheral velocity and thereafter laying down the filler passes over the root pass necessary to complete the weld by revolving the pipes and fittings at a second peripheral velocity different from the first peripheral velocity, maintaining the welding head in a fixed position as to the specific direction of revolution, while the longitudinal axis of the welding head is disposed angularly in the direction of revolution at amounts between twenty minutas and about four degrees from the first position.

  17. Novel Process Revolutionizes Welding Industry

    Science.gov (United States)

    2008-01-01

    Glenn Research Center, Delphi Corporation, and the Michigan Research Institute entered into a research project to study the use of Deformation Resistance Welding (DRW) in the construction and repair of stationary structures with multiple geometries and dissimilar materials, such as those NASA might use on the Moon or Mars. Traditional welding technologies are burdened by significant business and engineering challenges, including high costs of equipment and labor, heat-affected zones, limited automation, and inconsistent quality. DRW addresses each of those issues, while drastically reducing welding, manufacturing, and maintenance costs.

  18. Linear friction welding for constructing and repairing rail for high speed and intercity passenger service rail : final report.

    Science.gov (United States)

    2016-08-01

    This project developed a solid-state welding process based on linear friction welding (LFW) technology. While resistance flash welding or : thermite techniques are tried and true methods for joining rails and performing partial rail replacement repai...

  19. Prevalence of β-lactamase genes in domestic washing machines and dishwashers and the impact of laundering processes on antibiotic-resistant bacteria.

    Science.gov (United States)

    Rehberg, L; Frontzek, A; Melhus, Å; Bockmühl, D P

    2017-12-01

    To investigate the prevalence of β-lactamase genes in domestic washing machines and dishwashers, and the decontamination efficacy of laundering. For the first investigation, swab samples from washing machines (n = 29) and dishwashers (n = 24) were analysed by real-time quantitative PCR to detect genes encoding β-lactamases. To test the impact of laundering on resistant bacteria, cotton test swatches were artificially contaminated with susceptible and resistant strains of Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus within a second investigation. They were washed in a domestic washing machine with or without activated oxygen bleach (AOB)-containing detergent at 20-50°C. β-Lactamase genes (most commonly of the AmpC- and OXA-type) were detected in 79% of the washing machines and in 96% of the dishwashers and Pseudomonadaceae dominated the microbiota. The level of bacterial reduction after laundering was ≥80% for all Ps. aeruginosa and Kl. pneumoniae strains, while it was only 37-61% for the methicillin-resistant Staph. aureus outbreak strain. In general, the reduction was tendentially higher for susceptible bacteria than for the resistant outbreak strains, especially for Staph. aureus. β-Lactamase genes seem to be frequently present in domestic appliances and may pose a potential risk for cross-contamination and horizontal transfer of genes encoding resistance against clinically important β-lactams. In general, higher temperatures and the use of AOB can improve the reduction of antibiotic-resistant bacteria, including Staph. aureus which appears to be less susceptible to the decontamination effect of laundering. Data on the presence of antibiotic-resistant bacteria in the domestic environment are limited. This study suggests that β-lactamase genes in washing machines and dishwashers are frequent, and that antibiotic-resistant strains are generally more resistant to the used washing conditions. © 2017 The Society for

  20. Microstructure, mechanical and corrosion behavior of high strength AA7075 aluminium alloy friction stir welds – Effect of post weld heat treatment

    Directory of Open Access Journals (Sweden)

    P. Vijaya Kumar

    2015-12-01

    It was observed that the hardness and strength of weld were observed to be comparatively high in peak aged (T6 condition but the welds showed poor corrosion resistance. The resistance to pitting corrosion was improved and the mechanical properties were maintained by RRA treatment. The resistance to pitting corrosion was improved in RRA condition with the minimum loss of weld strength.

  1. Effect on spot welding variables on nugget size and bond strength of 304 austenitic stainless steel

    International Nuclear Information System (INIS)

    Charde, Nachimani

    2012-01-01

    Resistance spot welding (RSW) has revolutionized mechanical assembly in the automotive industry since its introduction in the early 1970s. Currently, one mechanical assembly in five is welded using spot welding technology, with welding of stainless steel sheet becoming increasingly common. Consequently, this research paper examines the spot welding of 2 mm thick 304 austenitic stainless steel sheet. The size of a spot weld nugget is primarily determined by the welding parameters: welding current, welding time, electrode force and electrode tip diameter However, other factors such as electrode deformation, corrosion, dissimilar materials and material properties also affect the nugget size and shape. This paper analyzes only the effects of current, weld time and force variations with unchanged electrode tip diameter. A pneumatically driven 75kVA spot welder was used to accomplish the welding process and the welded samples were subjected to tensile, hardness and metallurgical testing to characterize the size and shape of the weld nugget and the bond strength.

  2. Dictionary: Welding, cutting and allied processes. Pt. 2. German/English. Fachwoerterbuch: Schweissen, Schneiden und verwandte Verfahren. Bd. 2. Deutsch/Englisch

    Energy Technology Data Exchange (ETDEWEB)

    Kleiber, A W

    1987-01-01

    The dictionary contains approximately 40 000 entries covering all aspects of welding technology. It is based on the evaluation of numerous English, American and German sources. This comprehensive and up to date dictionary will be a reliable and helpful aid in evaluation and translating. The dictionary covers the following areas: Welding: gas welding, arc welding, gas shielded welding, resistance welding, welding of plastics, special welding processes; Cutting: flame cutting, arc cutting and special thermal cutting processes; Soldering: brazing and soldering; Other topics: thermal spraying, metal to metal adhesion, welding filler materials and other consumables, test methods, plant and equipment, accessories, automation, welding trade, general welding terminology.

  3. Feasibility study of inside automatic welding system of cooling pipe of divertors for FER

    International Nuclear Information System (INIS)

    Yoshizawa, S.; Adachi, J.; Morishita, H.; Kakudate, S.; Taguchi, H.; Tada, E.

    1995-01-01

    In order to replace divertors for FER, cooling pipes of divertors should be cut and welded since they are too long to be replaced with divertors via horizontal maintenance ports. An inside cutting and welding system is also required because of an accessibility to pipes. A combination of an inside disc-cutting machine and an inside TIG-welding machine has been proposed as a candidate of the systems. We have made tests to confirm possibility to weld pipes which were cut with the disc-cutting machine. Possibility of welding has been proven. The tests result is described in the paper. (orig.)

  4. Influence of the arc plasma parameters on the weld pool profile in TIG welding

    International Nuclear Information System (INIS)

    Toropchin, A; Frolov, V; Pipa, A V; Kozakov, R; Uhrlandt, D

    2014-01-01

    Magneto-hydrodynamic simulations of the arc and fluid simulations of the weld pool can be beneficial in the analysis and further development of arc welding processes and welding machines. However, the appropriate coupling of arc and weld pool simulations needs further improvement. The tungsten inert gas (TIG) welding process is investigated by simulations including the weld pool. Experiments with optical diagnostics are used for the validation. A coupled computational model of the arc and the weld pool is developed using the software ANSYS CFX. The weld pool model considers the forces acting on the motion of the melt inside and on the surface of the pool, such as Marangoni, drag, electromagnetic forces and buoyancy. The experimental work includes analysis of cross-sections of the workpieces, highspeed video images and spectroscopic measurements. Experiments and calculations have been performed for various currents, distances between electrode and workpiece and nozzle diameters. The studies show the significant impact of material properties like surface tension dependence on temperature as well as of the arc structure on the weld pool behaviour and finally the weld seam depth. The experimental weld pool profiles and plasma temperatures are in good agreement with computational results

  5. Influence of the arc plasma parameters on the weld pool profile in TIG welding

    Science.gov (United States)

    Toropchin, A.; Frolov, V.; Pipa, A. V.; Kozakov, R.; Uhrlandt, D.

    2014-11-01

    Magneto-hydrodynamic simulations of the arc and fluid simulations of the weld pool can be beneficial in the analysis and further development of arc welding processes and welding machines. However, the appropriate coupling of arc and weld pool simulations needs further improvement. The tungsten inert gas (TIG) welding process is investigated by simulations including the weld pool. Experiments with optical diagnostics are used for the validation. A coupled computational model of the arc and the weld pool is developed using the software ANSYS CFX. The weld pool model considers the forces acting on the motion of the melt inside and on the surface of the pool, such as Marangoni, drag, electromagnetic forces and buoyancy. The experimental work includes analysis of cross-sections of the workpieces, highspeed video images and spectroscopic measurements. Experiments and calculations have been performed for various currents, distances between electrode and workpiece and nozzle diameters. The studies show the significant impact of material properties like surface tension dependence on temperature as well as of the arc structure on the weld pool behaviour and finally the weld seam depth. The experimental weld pool profiles and plasma temperatures are in good agreement with computational results.

  6. Laser welding to expand the allowable gap in bore welding for ITER blanket hydraulic connection

    Energy Technology Data Exchange (ETDEWEB)

    Tanigawa, Hisashi, E-mail: tanigawa.hisashi@jaea.go.jp; Maruyama, Takahito; Noguchi, Yuto; Takeda, Nobukazu; Kakudate, Satoshi

    2015-10-15

    For application to bore welding of hydraulic connection in the ITER blanket module, laser welding presents the following benefits: low weld heat input is preferred for re-welding of the irradiated material. Its contactless process can intrinsically avoid a failure mode of the tool sticking on the weld. The exact requirements for pipe alignment were assessed in comparison with the assembly tolerance. The groove geometry was modified to expand the allowable initial gap. The groove was machined to be partially thick to obviate the filler wire. First, plates with partially thick grooves were welded to elucidate the preferred groove geometry and welding conditions. With the modified groove, the plates were welded for the initial gap of 1.0 mm. Then the groove geometry and welding conditions were adjusted based on results of pipe welding tests. By application of the additional 0.5-mm-thick and 2.5-mm-wide metal in the groove, pipes with an initial gap of 0.7 mm were welded successfully.

  7. Welding process

    International Nuclear Information System (INIS)

    Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

    2008-01-01

    For the final chapter of this book, there is basic introduction on welding process. The good radiography must know somehow on welding process so that they can know what kind of welding that must rejected or not. All of the exposure technique that mention in earlier chapter almost applicable in this field because welding process is critical problem if there is no inspection will be done. So, for this chapter, all the discontinuity that usually appeared will be discussed and there is another discontinuity maybe not to important and do not give big impact if found it, do not described here. On top of that, the decision to accept or reject based on code, standard and specification that agreed by both to make sure that decision that agreed is corrected and more meaningful.

  8. Effect of friction stir welding on microstructure, mechanical and wear properties of AA6061/ZrB2 in situ cast composites

    International Nuclear Information System (INIS)

    Dinaharan, I.; Murugan, N.

    2012-01-01

    Highlights: ► Application of FSW to join AA6061/ZrB 2 in situ composites. ► Homogenous distribution of ZrB 2 particles in the weld zone. ► Clusters in the parent composite are fragmented by the stirring action of the tool. ► Hardening of weld zone. ► FSW enhanced the wear resistance of the composite. - Abstract: Inadequate development of fabrication methods restricts the applications of new families of aluminum matrix composites (AMCs). Friction stir welding (FSW) is a potential candidate to join AMCs without any defects associated with conventional fusion welding processes. The primary objective of the present work is to apply FSW process to join AA6061/(0, 5 and 10 wt.%) ZrB 2 in situ cast composites and evaluate the joint properties. The composites were prepared by reacting inorganic salts K 2 ZrF 6 and KBF 4 with molten aluminum and joined using a FSW machine at a tool rotational speed of 1150 rpm, welding speed of 50 mm/min and axial force of 6 kN. The joints showed the presence of various zones such as weld zone (WZ), thermomechanically affected zone (TMAZ) and heat affected zone (HAZ). The weld zone was characterized with a homogenous distribution of ZrB 2 particles. The stirring action of the tool resulted in fragmentation of several clusters present in the parent composite. The weld zone exhibited higher hardness than that of the parent composite. The tensile strength of welded joints was comparable to that of parent composites. The wear resistance of the composites improved subsequent to FSW.

  9. Maintenance service for major component of PWR plant. Replacement of pressurizer safe end weld

    International Nuclear Information System (INIS)

    Miyoshi, Yoshiyuki; Kobayashi, Yuki; Yamamoto, Kazuhide; Ueda, Takeshi; Suda, Naoki; Shintani, Takashi

    2017-01-01

    In October 2016, MHI completed the replacement of safe end weld of pressurizer (Pz) of Ringhals unit 3, which was the first maintenance work for main component of pressurized water reactor (PWR) plant in Europe. For higher reliability and longer lifetime of PWR plant, MHI has conducted many kinds of maintenance works of main components of PWR plants in Japan against stress corrosion cracking due to aging degradation. Technical process for replacement of Pz safe end weld were established by MHI. MHI has experienced the work for 21 PWR units in Japan. That of Ringhals unit 3 was planned and conducted based on the experiences. In this work, Alloy 600 used for welds of nozzles of Pz was replaced with Alloy 690. Alloy 690 is more corrosive-resistant than Alloy 600. Specially designed equipment and technical process were developed and established by MHI to replace safe end weld of Pz and applied for the Ringhals unit 3 as a first application in Europe. The application had been performed in success and achieved the planned replacement work duration and total radiation dose by using sophisticated machining and welding equipment designed to meet the requirements to be small, lightweight and remote-controlled and operating by well skilled MHI personnel experienced in maintenance activities for major components of PWR plant in Japan. The success shows that the experience, activities and technology developed in Japan for main components of PWR plant shall be applicable to contribute reliable operations of nuclear power plants in Europe and other countries. (author)

  10. Syllabus in Trade Welding.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    The syllabus outlines material for a course two academic years in length (minimum two and one-half hours daily experience) leading to entry-level occupational ability in several welding trade areas. Fourteen units covering are welding, gas welding, oxyacetylene welding, cutting, nonfusion processes, inert gas shielded-arc welding, welding cast…

  11. Cold-pressure-welded joints in large multifilamentary Nb--Ti superconductors

    International Nuclear Information System (INIS)

    Cornish, D.N.; Deis, D.W.; Zbasnik, J.P.

    1977-01-01

    A number of mechanical and electrical measurements were made on joints in typical conductors for the proposed mirror fusion test facility (MFTF) and high field test facility (HFTF). For such measurements, a commercially available cold-pressure-welding machine was used. For joints in the MFTF conductor, which has a large proportion of superconductor, joint strength approached conductor strength. For the HFTF conductor, where the Cu-to-superconductor ratio is 4.33/1, the joint is stronger than the conductor. Electrically, the joints were not superconducting.. While the resistance is higher than might be achieved by other forms of joining, we feel that the cold-weld joint has the advantages of simplicity, speed, reliability, and reproducibility. This makes the method attractive for MFTF, where resistance losses will be small compared with the total 4 K refrigeration requirements

  12. Pulsed magnetic welding application of fast breeder austenitic pins plugging

    International Nuclear Information System (INIS)

    Gallizzi, H.; Colombe, G.

    1986-11-01

    For specific nuclear needs, we had to develop pulsed magnetic welding on high resistivity coefficient alloys as austenitic steels. The magnetic force produced by an explosive inductor is transmitted on weld pieces by the use of an aluminium driver. A theoretical work carried out permitted to compare pulsed magnetic welding with explosive welding. With specific recordings, it was possible to study electrical and magnetical behavior during the active welding phase. By means of these informations, we are able to specify and to realize, with the financial help of ANVAR organization, a low impedance high velocity generator permitting to weld with a non destructible inductor. 6 refs [fr

  13. Renovascular resistance of machine-perfused DCD kidneys is associated with primary nonfunction.

    NARCIS (Netherlands)

    Vries, E.E. de; Hoogland, E.R.; Winkens, B.; Snoeijs, M.G.; Heurn, L.W.E. van

    2011-01-01

    Donation after cardiac death (DCD) has shown to be a valuable extension of the donor pool despite a higher percentage of primary nonfunction (PNF). Limiting the incidence of PNF is of vital importance. Renovascular resistance is believed to predict graft outcome; however the literature is

  14. Effect Of Additive Solar Oil On High Temperature Corrosion Resistance Of Diesel Machines

    International Nuclear Information System (INIS)

    Dani, Mohammad; H, Bagyo; Minsyahril, B.

    2004-01-01

    It has been done the study of thermal gravimetric analyse (TGA) accompanied with magnetic suspension balance (MSB) on the diesel machine of sample A (HV = 256.78 kgf/mm 2 , ρ = 6.65-7.16 g/cm 3 ) and sample B (HV 166.67 kgf/mm 2 , ρ= 5.39-5.57 g/cm 3 ). The samples were oxidized at 900 o C for 24 hours in the variation of with and without additives (Diesel Booster + Amylum Nitrate; DBANI and Diesel Booster;DB) in solar oil of 1: 1500. The samples were, then, characterized by X-Ray Diffraction (crystal structures) and Scanning Electron Microscope (microstructures). The result shows that the Fe 2 O 3 layers spread out over the sample surfaces and the oxidant grain boundaries are very compacted

  15. The possibility of tribopair lifetime extending by welding of quenched and tempered stainless steel with quenched and tempered carbon steel

    Directory of Open Access Journals (Sweden)

    V. Marušić

    2015-04-01

    Full Text Available In the conditions of tribocorrosion wear, extending of parts lifetime could be achieved by using stainless steel,which is hardened to sufficiently high hardness. In the tribosystem bolt/ bushing shell/link plate of the bucket elevator transporter conveyor machine, the previously quenched and tempered martensitic stainless steel for bolts is hardened at ≈47 HRC and welded with the quenched and tempered high yield carbon steel for bolts. Additional material, based on Cr-Ni-Mo (18/8/6 is used. The microstructure and hardness of welded samples are tested. On the tensile tester, resistance of the welded joint is tested with a simulated experiment. Dimensional control of worn tribosystem elements was performed after six months of service.

  16. Study on laser beam welding technology for nuclear power plants

    International Nuclear Information System (INIS)

    Chida, Itaru; Shiihara, Katsunori; Fukuda, Takeshi; Kono, Wataru; Obata, Minoru; Morishima, Yasuo

    2012-01-01

    Laser beam welding is one of the jointing processes by irradiating laser beam on the material surface locally and widely used at various industrial fields. Toshiba has developed various laser-based maintenance and repair technologies and already applied them to several existing nuclear power plants. Laser cladding is a technique to weld the corrosion resistant metal onto a substrate surface by feeding filler wire to improve the corrosion resistance. Temper-bead welding is the heat input process to provide the desired microstructure properties of welded low alloy steels without post weld heat treatment, by inducing proper heat cycle during laser welding. Both laser welding technologies would be performed underwater by blowing the shielding gas for creating the local dry area. In this report, some evaluation results of material characteristics by temper-bead welding to target at Reactor Coolant System nozzle of PWR are presented. (author)

  17. Improved design bases of welded joints in seawater

    DEFF Research Database (Denmark)

    Ólafsson, Ólafur Magnús

    The presented work aims to investigate and establish a precise, thorough and detailed database from series of experimental testing of submerged arc welded, SAW, specimens of various thicknesses typically applied in offshore structures and foundations. Additionally, the testing was performed in two...... environment on fatigue resistance. Furthermore, novelty 25 mm thick steel laser-hybrid welded specimens in the as welded condition were subjected to experimental testing. A fatigue resistance S-Ncurve was established for the laser hybrid welded joints in addition to a more detailed analysis. The laser hybrid...... different environments, i.e. under in-air conditions and in a corrosion environment. Welded structures of all sizes and shapes exhibit fatigue failure primarily in the welded region, rather than in the base material, due to imperfections and flaws relating to the welding procedure. The welded region has...

  18. Design of cylindrical pipe automatic welding control system based on STM32

    Science.gov (United States)

    Chen, Shuaishuai; Shen, Weicong

    2018-04-01

    The development of modern economy makes the demand for pipeline construction and construction rapidly increasing, and the pipeline welding has become an important link in pipeline construction. At present, there are still a large number of using of manual welding methods at home and abroad, and field pipe welding especially lacks miniature and portable automatic welding equipment. An automated welding system consists of a control system, which consisting of a lower computer control panel and a host computer operating interface, as well as automatic welding machine mechanisms and welding power systems in coordination with the control system. In this paper, a new control system of automatic pipe welding based on the control panel of the lower computer and the interface of the host computer is proposed, which has many advantages over the traditional automatic welding machine.

  19. Sensor controlled robotic welding for nuclear power plant operations

    International Nuclear Information System (INIS)

    Chin, B.A.

    1989-01-01

    The objective of the proposed research is to apply real time monitoring, artificial intelligence and on-line correction to dynamically control the depth of weld penetration and weld integrity during the welding process. Welding is a major technique used in the fabrication, construction and maintenance of power generating and energy conversion systems. In the welding process, fluctuations in process variables lead to weld defects such as lack of penetration, cracks, porosity and undesirable metallurgical structures. This research will apply advanced infrared sensing techniques which have been successfully used in seam tracking to the equally complex problem of weld defect and weld puddle penetration control. Thermal temperature distributions of plates being welded will be dynamically measured during welding using infrared techniques. These temperature distributions will be used to interpret changes in the size and shape of the molten metal pool and the presence of conditions that may lead to defects in the solidified weld. The ultimate result of this research will be the development of machines which are capable of sensing and altering process variables to eliminate defective welds and increase the productivity of the welding process. Successful completion of this proposed research will lead to potential major improvements in the fabrication, construction and maintenance of advanced nuclear reactors and promote increased safety and reliability while decreasing construction costs. 47 refs., 50 figs

  20. Fully Automatic Spot Welding System for Application in Automotive Industry

    Directory of Open Access Journals (Sweden)

    Peter Puschner

    2015-12-01

    Full Text Available Abstract A Virtual Machine has led to a fully automatic spot welding system. All necessary parameters are created by measuring systems and algorithms running in the Virtual Machine. A hybrid operating circuit allows the Virtual Machine to read the exact process voltage between the tips of the electrodes every 50 µs. Actual welding voltage and current allow for the first time reading process impedance, electric power and total energy being transferred to the spot weld. Necessary energy input is calculated by a calorimetric model after measuring the total thickness of the materials to be welded as soon as the welding gun is positioned at the workpiece. A precision potentiometer implemented in the gun delivers the total material thickness within the 0.1 mm range during the pre-pressure phases. The internal databank of the Virtual Machine controls all essential parameters to guide the total welding process. Special generator characteristics of the welding power unit are created by the Virtual Machine just during the upslope and the welding phases. So the process will be initialized in differentiating the kind of material, mild steel or high strengthen steel. This will affect the kind of energy input and current decrease during the upslope and downslope phases.

  1. Experimental Characterization and Modeling of Thermal Contact Resistance of Electric Machine Stator-to-Cooling Jacket Interface Under Interference Fit Loading

    Energy Technology Data Exchange (ETDEWEB)

    Cousineau, Justine E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bennion, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Chieduko, Victor [UQM Technologies, Inc.; Lall, Rajiv [UQM Technologies, Inc.; Gilbert, Alan [UQM Technologies, Inc.

    2018-05-08

    Cooling of electric machines is a key to increasing power density and improving reliability. This paper focuses on the design of a machine using a cooling jacket wrapped around the stator. The thermal contact resistance (TCR) between the electric machine stator and cooling jacket is a significant factor in overall performance and is not well characterized. This interface is typically an interference fit subject to compressive pressure exceeding 5 MPa. An experimental investigation of this interface was carried out using a thermal transmittance setup using pressures between 5 and 10 MPa. The results were compared to currently available models for contact resistance, and one model was adapted for prediction of TCR in future motor designs.

  2. PRGPred: A platform for prediction of domains of resistance gene analogue (RGA in Arecaceae developed using machine learning algorithms

    Directory of Open Access Journals (Sweden)

    MATHODIYIL S. MANJULA

    2015-12-01

    Full Text Available Plant disease resistance genes (R-genes are responsible for initiation of defense mechanism against various phytopathogens. The majority of plant R-genes are members of very large multi-gene families, which encode structurally related proteins containing nucleotide binding site domains (NBS and C-terminal leucine rich repeats (LRR. Other classes possess' an extracellular LRR domain, a transmembrane domain and sometimes, an intracellular serine/threonine kinase domain. R-proteins work in pathogen perception and/or the activation of conserved defense signaling networks. In the present study, sequences representing resistance gene analogues (RGAs of coconut, arecanut, oil palm and date palm were collected from NCBI, sorted based on domains and assembled into a database. The sequences were analyzed in PRINTS database to find out the conserved domains and their motifs present in the RGAs. Based on these domains, we have also developed a tool to predict the domains of palm R-genes using various machine learning algorithms. The model files were selected based on the performance of the best classifier in training and testing. All these information is stored and made available in the online ‘PRGpred' database and prediction tool.

  3. corrosion and wear resistant ternary Cr-C-N coatings deposited by the ARC PVD process for machining tools and machining parts

    International Nuclear Information System (INIS)

    Knotek, O.; Lugscheider, E.; Zimmermann, H.; Bobzin, K.

    1997-01-01

    With the deposition of PVD hard coatings on the tools applied in machining operations it is possible to achieve significant improvements in the performance and quality of the machining processes. Depending on the machined material and the operating principle, e.g. turning, milling or drilling, not only different machining parameters but also different coating materials are necessary. In interrupted cut machining of tempered steel, for example, the life time of Ti-C-N coated inserts is several times greater than the Ti-C-N coated ones. This is a result of the favourable thermophysical and tribological properties of Ti-N-C. The potential for tool protection by CrN coatings is a result of the high ductility and low internal stress of this coating materials. CrN films can be deposited with greater film thickness, still maintaining very good adhesion. This paper presents the development of new arc PVD coatings in the system Cr-C-N. Owing to the carbon content in the coating an increased hardness and a better wear behavior in comparison to CrN was expected. The effects of various carbon carrier gases on the coating properties were examined. The coating properties were investigated by mechanical tests. X-ray diffraction, SEM analysis and corrosion tests. Some of the coatings were tested in machining tests. The results of these tests are presented in this paper. (author)

  4. A 1993 review of welding in Japan

    Science.gov (United States)

    1994-07-01

    This paper describes a prospect on Japanese welding technologies available in 1993. Amid the increasing research publications on non-ferrous metals as structural materials, publications are also increasing on steel materials as to their fracture and welding mechanics, and structural control. Studies are being made on ceramics with respect to its bonding, interface reaction mechanisms, and mechanical characteristics. The paper describes the progress and improvement in conventional technologies in welding and cutting processes. Especially active is the study on solid face welding such as pressure welding and diffusion. A considerable decrease is seen in reports on thermal spraying. The paper also introduces surface processing and hydrostatic pressure processing as new processing techniques. In the area of welding devices, practical use of arc welding robots has come to near a completion stage. Technological development and cost reduction are indispensable to transfer to visual sensing with a higher intelligence level. With respect to the performance of joints, a large number of research has been reported on welding deformation and residual stress. The paper also dwells on corrosion resistance and welding cracks. Quality assurance, inspection, and related standards are described. Details are given on application of welding to different industrial fields.

  5. Variation behavior of residual stress distribution by manufacturing processes in welded pipes of austenitic stainless steel

    International Nuclear Information System (INIS)

    Ihara, Ryohei; Hashimoto, Tadafumi; Mochizuki, Masahito

    2012-01-01

    Stress corrosion cracking (SCC) has been observed near heat affected zone (HAZ) of primary loop recirculation pipes made of low-carbon austenitic stainless steel type 316L in the nuclear power plants. For the non-sensitization material, residual stress is the important factor of SCC, and it is generated by machining and welding. In the actual plants, welding is conducted after machining as manufacturing processes of welded pipes. It could be considered that residual stress generated by machining is varied by welding as a posterior process. This paper presents residual stress variation due to manufacturing processes of pipes using X-ray diffraction method. Residual stress distribution due to welding after machining had a local maximum stress in HAZ. Moreover, this value was higher than residual stress generated by welding or machining. Vickers hardness also had a local maximum hardness in HAZ. In order to clarify hardness variation, crystal orientation analysis with EBSD method was performed. Recovery and recrystallization were occurred by welding heat near the weld metal. These lead hardness decrease. The local maximum region showed no microstructure evolution. In this region, machined layer was remained. Therefore, the local maximum hardness was generated at machined layer. The local maximum stress was caused by the superposition effect of residual stress distributions due to machining and welding. Moreover, these local maximum residual stress and hardness are exceeded critical value of SCC initiation. In order to clarify the effect of residual stress on SCC initiation, evaluation including manufacturing processes is important. (author)

  6. Evaluation of Machine Learning and Rules-Based Approaches for Predicting Antimicrobial Resistance Profiles in Gram-negative Bacilli from Whole Genome Sequence Data.

    Science.gov (United States)

    Pesesky, Mitchell W; Hussain, Tahir; Wallace, Meghan; Patel, Sanket; Andleeb, Saadia; Burnham, Carey-Ann D; Dantas, Gautam

    2016-01-01

    The time-to-result for culture-based microorganism recovery and phenotypic antimicrobial susceptibility testing necessitates initial use of empiric (frequently broad-spectrum) antimicrobial therapy. If the empiric therapy is not optimal, this can lead to adverse patient outcomes and contribute to increasing antibiotic resistance in pathogens. New, more rapid technologies are emerging to meet this need. Many of these are based on identifying resistance genes, rather than directly assaying resistance phenotypes, and thus require interpretation to translate the genotype into treatment recommendations. These interpretations, like other parts of clinical diagnostic workflows, are likely to be increasingly automated in the future. We set out to evaluate the two major approaches that could be amenable to automation pipelines: rules-based methods and machine learning methods. The rules-based algorithm makes predictions based upon current, curated knowledge of Enterobacteriaceae resistance genes. The machine-learning algorithm predicts resistance and susceptibility based on a model built from a training set of variably resistant isolates. As our test set, we used whole genome sequence data from 78 clinical Enterobacteriaceae isolates, previously identified to represent a variety of phenotypes, from fully-susceptible to pan-resistant strains for the antibiotics tested. We tested three antibiotic resistance determinant databases for their utility in identifying the complete resistome for each isolate. The predictions of the rules-based and machine learning algorithms for these isolates were compared to results of phenotype-based diagnostics. The rules based and machine-learning predictions achieved agreement with standard-of-care phenotypic diagnostics of 89.0 and 90.3%, respectively, across twelve antibiotic agents from six major antibiotic classes. Several sources of disagreement between the algorithms were identified. Novel variants of known resistance factors and

  7. Evaluation of Machine Learning and Rules-Based Approaches for Predicting Antimicrobial Resistance Profiles in Gram-negative Bacilli from Whole Genome Sequence Data

    Directory of Open Access Journals (Sweden)

    Mitchell Pesesky

    2016-11-01

    Full Text Available The time-to-result for culture-based microorganism recovery and phenotypic antimicrobial susceptibility testing necessitate initial use of empiric (frequently broad-spectrum antimicrobial therapy. If the empiric therapy is not optimal, this can lead to adverse patient outcomes and contribute to increasing antibiotic resistance in pathogens. New, more rapid technologies are emerging to meet this need. Many of these are based on identifying resistance genes, rather than directly assaying resistance phenotypes, and thus require interpretation to translate the genotype into treatment recommendations. These interpretations, like other parts of clinical diagnostic workflows, are likely to be increasingly automated in the future. We set out to evaluate the two major approaches that could be amenable to automation pipelines: rules-based methods and machine learning methods. The rules-based algorithm makes predictions based upon current, curated knowledge of Enterobacteriaceae resistance genes. The machine-learning algorithm predicts resistance and susceptibility based on a model built from a training set of variably resistant isolates. As our test set, we used whole genome sequence data from 78 clinical Enterobacteriaceae isolates, previously identified to represent a variety of phenotypes, from fully-susceptible to pan-resistant strains for the antibiotics tested. We tested three antibiotic resistance determinant databases for their utility in identifying the complete resistome for each isolate. The predictions of the rules-based and machine learning algorithms for these isolates were compared to results of phenotype-based diagnostics. The rules based and machine-learning predictions achieved agreement with standard-of-care phenotypic diagnostics of 89.0% and 90.3%, respectively, across twelve antibiotic agents from six major antibiotic classes. Several sources of disagreement between the algorithms were identified. Novel variants of known resistance

  8. Genomic signatures for paclitaxel and gemcitabine resistance in breast cancer derived by machine learning.

    Science.gov (United States)

    Dorman, Stephanie N; Baranova, Katherina; Knoll, Joan H M; Urquhart, Brad L; Mariani, Gabriella; Carcangiu, Maria Luisa; Rogan, Peter K

    2016-01-01

    Increasingly, the effectiveness of adjuvant chemotherapy agents for breast cancer has been related to changes in the genomic profile of tumors. We investigated correspondence between growth inhibitory concentrations of paclitaxel and gemcitabine (GI50) and gene copy number, mutation, and expression first in breast cancer cell lines and then in patients. Genes encoding direct targets of these drugs, metabolizing enzymes, transporters, and those previously associated with chemoresistance to paclitaxel (n = 31 genes) or gemcitabine (n = 18) were analyzed. A multi-factorial, principal component analysis (MFA) indicated expression was the strongest indicator of sensitivity for paclitaxel, and copy number and expression were informative for gemcitabine. The factors were combined using support vector machines (SVM). Expression of 15 genes (ABCC10, BCL2, BCL2L1, BIRC5, BMF, FGF2, FN1, MAP4, MAPT, NFKB2, SLCO1B3, TLR6, TMEM243, TWIST1, and CSAG2) predicted cell line sensitivity to paclitaxel with 82% accuracy. Copy number profiles of 3 genes (ABCC10, NT5C, TYMS) together with expression of 7 genes (ABCB1, ABCC10, CMPK1, DCTD, NME1, RRM1, RRM2B), predicted gemcitabine response with 85% accuracy. Expression and copy number studies of two independent sets of patients with known responses were then analyzed with these models. These included tumor blocks from 21 patients that were treated with both paclitaxel and gemcitabine, and 319 patients on paclitaxel and anthracycline therapy. A new paclitaxel SVM was derived from an 11-gene subset since data for 4 of the original genes was unavailable. The accuracy of this SVM was similar in cell lines and tumor blocks (70-71%). The gemcitabine SVM exhibited 62% prediction accuracy for the tumor blocks due to the presence of samples with poor nucleic acid integrity. Nevertheless, the paclitaxel SVM predicted sensitivity in 84% of patients with no or minimal residual disease. Copyright © 2015 Federation of European Biochemical Societies

  9. Refining Prediction in Treatment-Resistant Depression: Results of Machine Learning Analyses in the TRD III Sample.

    Science.gov (United States)

    Kautzky, Alexander; Dold, Markus; Bartova, Lucie; Spies, Marie; Vanicek, Thomas; Souery, Daniel; Montgomery, Stuart; Mendlewicz, Julien; Zohar, Joseph; Fabbri, Chiara; Serretti, Alessandro; Lanzenberger, Rupert; Kasper, Siegfried

    The study objective was to generate a prediction model for treatment-resistant depression (TRD) using machine learning featuring a large set of 47 clinical and sociodemographic predictors of treatment outcome. 552 Patients diagnosed with major depressive disorder (MDD) according to DSM-IV criteria were enrolled between 2011 and 2016. TRD was defined as failure to reach response to antidepressant treatment, characterized by a Montgomery-Asberg Depression Rating Scale (MADRS) score below 22 after at least 2 antidepressant trials of adequate length and dosage were administered. RandomForest (RF) was used for predicting treatment outcome phenotypes in a 10-fold cross-validation. The full model with 47 predictors yielded an accuracy of 75.0%. When the number of predictors was reduced to 15, accuracies between 67.6% and 71.0% were attained for different test sets. The most informative predictors of treatment outcome were baseline MADRS score for the current episode; impairment of family, social, and work life; the timespan between first and last depressive episode; severity; suicidal risk; age; body mass index; and the number of lifetime depressive episodes as well as lifetime duration of hospitalization. With the application of the machine learning algorithm RF, an efficient prediction model with an accuracy of 75.0% for forecasting treatment outcome could be generated, thus surpassing the predictive capabilities of clinical evaluation. We also supply a simplified algorithm of 15 easily collected clinical and sociodemographic predictors that can be obtained within approximately 10 minutes, which reached an accuracy of 70.6%. Thus, we are confident that our model will be validated within other samples to advance an accurate prediction model fit for clinical usage in TRD. © Copyright 2017 Physicians Postgraduate Press, Inc.

  10. The Corrosion Resistance of Composite Arch Wire Laser-Welded By NiTi Shape Memory Alloy and Stainless Steel Wires with Cu Interlayer in Artificial Saliva with Protein

    Science.gov (United States)

    Zhang, Chao; Sun, Xinhua; Hou, Xu; Li, Hongmei; Sun, Daqian

    2013-01-01

    In this paper, the corrosion resistance of laser-welded composite arch wire (CoAW) with Cu interlayer between NiTi shape memory alloy and stainless steel wire in artificial saliva with different concentrations of protein was studied. It was found that protein addition had a significant influence on the corrosion behavior of CoAW. Low concentration of protein caused the corrosion resistance of CoAW decrease in electrochemical corrosion and immersion corrosion tests. High concentration of protein could reduce this effect. PMID:23801895

  11. Today's status of application of high power electron beam welding to heavy electric machinery

    International Nuclear Information System (INIS)

    Kita, Hisanao; Okuni, Tetsuo; Sejima, Itsuhiko.

    1980-01-01

    The progress in high energy welding is remarkable in recent years, and electron beam welding is now widely used in heavy industries. However, there are number of problems to be solved in the application of high power electron beam welding to ultra thick steel plates (over 100 mm). The following matters are described: the economy of high power electron beam welding; the development of the welding machines; the problems in the actual application; the instances of the welding in a high-pressure spherical gas tank, non-magnetic steel structures and high-precision welded structures; weldor training; etc. For the future rise in the capacities of heavy electric machinery, the high efficiency by high power electron beam welding will be useful. The current status is its applications to the high-precision welding of large structures with 6 m diameter and the high-quality welding of heavy structures with 160 mm thickness. (J.P.N.)

  12. Effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded high strength aluminium alloy

    International Nuclear Information System (INIS)

    Balasubramanian, V.; Ravisankar, V.; Reddy, G. Madhusudhan

    2007-01-01

    This paper reveals the effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded AA7075 aluminium alloy. This alloy has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding processes of high strength aluminium alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW) and (iv) pulsed current GMAW (PCGMAW) processes. As welded joint strength is much lower than the base metal strength and hence, a simple aging treatment has been given to improve the tensile strength of the joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. In contrast, conventional continuous current welding resulted in predominantly columnar grain structures. Post weld aging treatment is accompanied by an increase in tensile strength and tensile ductility

  13. Welding template

    International Nuclear Information System (INIS)

    Ben Venue, R.J. of.

    1976-01-01

    A welding template is described which is used to weld strip material into a cellular grid structure for the accommodation of fuel elements in a nuclear reactor. On a base plate the template carries a multitude of cylindrical pins whose upper half is narrower than the bottom half and only one of which is attached to the base plate. The others are arrested in a hexagonal array by oblong webs clamped together by chuck jaws which can be secured by means of screws. The parts are ground very accurately. The template according to the invention is very easy to make. (UWI) [de

  14. Characteristics comparison of weld metal zones welded to cast and forged steels for piston crown material

    Science.gov (United States)

    Moon, Kyung-Man; Kim, Yun-Hae; Lee, Myeong-Hoon; Baek, Tae-Sil

    2015-03-01

    An optimum repair welding for the piston crown which is one of the engine parts exposed to the combustion chamber is considered to be very important to prolong the engine lifetime from an economical point of view. In this study, two types of filler metals such as 1.25Cr-0.5Mo, 0.5Mo were welded with SMAW method and the other two types of filler metals such as Inconel 625 and 718 were welded with GTAW method, respectively, and the used base metals were the cast and forged steels of the piston crown material. The weld metal zones welded with Inconel 625 and 718 filler metals exhibited higher corrosion resistance compared to 1.25Cr-0.5Mo and 0.5Mo filler metals. In particular, the weld metal zone welded with Inconel 718 and 0.5Mo, filler metals indicated the best and worst corrosion resistance, respectively. Consequently, it is suggested that the corrosion resistance of the weld metal zone surely depends on the chemical components of each filler metal and welding method irrespective of the types of piston crown material.

  15. The variable polarity plasma arc welding process: Characteristics and performance

    Science.gov (United States)

    Hung, R. J.; Zhu, G. J.

    1991-01-01

    Significant advantages of the Variable Polarity Plasma Arc (VPPA) Welding Process include faster welding, fewer repairs, less joint preparation, reduced weldment distortion, and absence of porosity. The power distribution was analyzed for an argon plasma gas flow constituting the fluid in the VPPA Welding Process. The major heat loss at the torch nozzle is convective heat transfer; in the space between the outlet of the nozzle and the workpiece; radiative heat transfer; and in the keyhole in the workpiece, convective heat transfer. The power absorbed at the workpiece produces the molten puddle that solidifies into the weld bead. Crown and root widths, and crown and root heights of the weld bead are predicted. The basis is provided for an algorithm for automatic control of VPPA welding machine parameters to obtain desired weld bead dimensions.

  16. Quality status display for a vibration welding process

    Science.gov (United States)

    Spicer, John Patrick; Abell, Jeffrey A.; Wincek, Michael Anthony; Chakraborty, Debejyo; Bracey, Jennifer; Wang, Hui; Tavora, Peter W.; Davis, Jeffrey S.; Hutchinson, Daniel C.; Reardon, Ronald L.; Utz, Shawn

    2017-11-28

    A method includes receiving, during a vibration welding process, a set of sensory signals from a collection of sensors positioned with respect to a work piece during formation of a weld on or within the work piece. The method also includes receiving control signals from a welding controller during the process, with the control signals causing the welding horn to vibrate at a calibrated frequency, and processing the received sensory and control signals using a host machine. Additionally, the method includes displaying a predicted weld quality status on a surface of the work piece using a status projector. The method may include identifying and display a quality status of a suspect weld. The laser projector may project a laser beam directly onto or immediately adjacent to the suspect welds, e.g., as a red, green, blue laser or a gas laser having a switched color filter.

  17. Micro-tensile strength of a welded turbine disc superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Oluwasegun, K.M.; Cooper, C.; Chiu, Y.L.; Jones, I.P. [School of Metallurgy and Materials, University of Birmingham, B15 2TT (United Kingdom); Li, H.Y., E-mail: h.y.li.1@bham.ac.uk [School of Metallurgy and Materials, University of Birmingham, B15 2TT (United Kingdom); Baxter, G. [Rolls-Royce plc., P.O. Box 31, Derby DE24 8BJ (United Kingdom)

    2014-02-24

    A micro-tensile testing system coupled with focussed ion beam (FIB) machining was used to characterise the micro-mechanical properties of the weld from a turbine disc alloy. The strength variations between the weld and the base alloy are rationalised via the microstructure obtained.

  18. Studies on Fusion Welding of High Nitrogen Stainless Steel: Microstructure, Mechanical and corrosion Behaviour

    Science.gov (United States)

    Mohammed, Raffi; Srinivasa Rao, K.; Madhusudhan Reddy, G.

    2018-03-01

    An attempt has been made in the present investigation to weld high nitrogen steel of 5mm thick plates using various process i.e., shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW) and autogenous electron beam welding (EBW) process. Present work is aimed at studying the microstructural changes and its effects on mechanical properties and corrosion resistance. Microstructure is characterized by optical, scanning electron microscopy and electron back scattered diffraction technique. Vickers hardness, tensile properties, impact toughness and face bend ductility testing of the welds was carried out. Pitting corrosion resistance of welds was determined using potentio-dynamic polarization testing in 3.5%NaCl solution. Results of the present investigation established that SMA welds made using Cr-Mn-N electrode were observed to have a austenite dendritic grain structure in the weld metal and is having poor mechanical properties but good corrosion resistance. GTA welds made using 18Ni (MDN 250) filler wire were observed to have a reverted austenite in martensite matrix of the weld metal and formation of unmixed zone at the fusion boundary which resulted in better mechanical properties and poor corrosion resistance. Fine grains and uniform distribution of delta ferrite in the austenite matrix and narrow width of weld zone are observed in autogeneous electron beam welds. A good combination of mechanical properties and corrosion resistance was achieved for electron beam welds of high nitrogen steel when compared to SMA and GTA welds.

  19. Applicability evaluation of eddy current testing for underwater laser beam welding

    International Nuclear Information System (INIS)

    Kobayashi, Noriyasu; Kasuya, Takashi; Ueno, Souichi; Ochiai, Makoto; Yuguchi, Yasuhiro

    2010-01-01

    We clarified a defect detecting capability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding. An underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in groove and welding surface grinding as a post treatment. Therefore groove and grinded welding surface inspections are required underwater. We curried out defect detection tests using three kinds of specimens simulated a groove, reactor vessel nozzle dissimilar metal welding materials and a laser beam welding material with a cross coil ECT probe. From experimental results, we confirmed that it is possible to detect 0.3 mm or more depth electro-discharge machining slits on machining surfaces in all specimens and an ECT has possibility as a surface inspection technique for underwater laser beam welding. (author)

  20. Long-time rupture strength and creep behaviour of welded joints on heat-resistant CrMoV steels with 1 and 12% chrome

    International Nuclear Information System (INIS)

    Maier, G.; Maile, K.; Theofel, H.

    1985-01-01

    Power plant components in the creep range are damaged frequently in the weld joint zones. The investigation concentrated therefore on the reliability of the information supplied by tests on small- and large-size samples. Creep rupture tests of dissimilar welded joints (1% with 12% chrome) with variations of heat input and weld metal have been conducted. At creep rupture times of about 10 4 h all joints failed in the outside heat affected zone of the weaker base metal. Large-size samples, proved in comparison at same stresses, showed distinctly longer times to rupture. (orig.) [de

  1. Twin-Wire Pulsed Tandem Gas Metal Arc Welding of API X80 Steel Linepipe

    Directory of Open Access Journals (Sweden)

    Wenhao Wu

    2018-01-01

    Full Text Available Twin-Wire Pulsed Tandem Gas Metal Arc Welding process with high welding production efficiency was used to join the girth weld seam of API X80 steel linepipe of 18.4 mm wall thickness and 1422 mm diameter. The macrostructure, microstructure, hardness, and electrochemical corrosion behavior of welded joints were studied. Effects of temperature and Cl− concentration on the corrosion behavior of base metal and weld metal were investigated. Results show that the welded joint has good morphology, mechanical properties, and corrosion resistance. The corrosion resistance of both the base metal and the weld metal decreases with increasing temperature or Cl− concentration. In the solution with high Cl− concentration, the base metal and weld metal are more susceptible to pitting. The corrosion resistance of the weld metal is slightly lower than that of the base metal.

  2. Numerical modelling of steel arc welding

    International Nuclear Information System (INIS)

    Hamide, M.

    2008-07-01

    Welding is a highly used assembly technique. Welding simulation software would give access to residual stresses and information about the weld's microstructure, in order to evaluate the mechanical resistance of a weld. It would also permit to evaluate the process feasibility when complex geometrical components are to be made, and to optimize the welding sequences in order to minimize defects. This work deals with the numerical modelling of arc welding process of steels. After describing the industrial context and the state of art, the models implemented in TransWeld (software developed at CEMEF) are presented. The set of macroscopic equations is followed by a discussion on their numerical implementation. Then, the theory of re-meshing and our adaptive anisotropic re-meshing strategy are explained. Two welding metal addition techniques are investigated and are compared in terms of the joint size and transient temperature and stresses. The accuracy of the finite element model is evaluated based on experimental results and the results of the analytical solution. Comparative analysis between experimental and numerical results allows the assessment of the ability of the numerical code to predict the thermomechanical and metallurgical response of the welded structure. The models limitations and the phenomena identified during this study are finally discussed and permit to define interesting orientations for future developments. (author)

  3. Protection of welded joints against corrosion degradation

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2013-01-01

    Full Text Available Welded joints form an integral part of steel constructions. Welded joints are undetachable joints, which are however subjects of corrosion processes. The internal energy increases during the fusion welding especially in the heat affected places around the welded joint, which become initiating spot of corrosion degradation.The aim of the experiment is to put a welded joint produced by the MAG method to a test of corrosion degradation under the conditions of the norm ČSN ISO 9227 (salt-spray test. Organic and inorganic anticorrosion protections were applied on welded beads. First of all, there were prepared welded beads using the method MAG; secondly, metallographical analyses of welded metal, heat affected places and base material were processed. Further, microhardness as well as analysis of chemical composition using the EDS microscope were analysed. Based on a current trend in anticorrosion protections, there were chosen three types of protective coatings. First protective system was a double-layer synthetic system, where the base layer is formed by paint Pragroprimer S2000 and the upper layer by finishing paint Industrol S 2013. Second protective system is a duplex system formed by a combination of a base zinc coating with Zinorex paint. The last protective system was formed by zinc dipping only. Corrosion resistance of the individual tested samples was evaluated based on degradation of protective coating. The corrosion origin as well as the corrosion process were observed, the main criteria was the observation of welded bead.

  4. Laser penetration spike welding: a welding tool enabling novel process and design opportunities

    Science.gov (United States)

    Dijken, Durandus K.; Hoving, Willem; De Hosson, J. Th. M.

    2002-06-01

    A novel method for laser welding for sheet metal. is presented. This laser spike welding method is capable of bridging large gaps between sheet metal plates. Novel constructions can be designed and manufactured. Examples are light weight metal epoxy multi-layers and constructions having additional strength with respect to rigidity and impact resistance. Its capability to bridge large gaps allows higher dimensional tolerances in production. The required laser systems are commercially available and are easily implemented in existing production lines. The lasers are highly reliable, the resulting spike welds are quickly realized and the cost price per weld is very low.

  5. Repair welding of cracked steam turbine blades

    International Nuclear Information System (INIS)

    Bhaduri, A.K.; Gill, T.P.S.; Albert, S.K.; Shanmugam, K.; Iyer, D.R.

    1999-01-01

    The procedure for repair welding of cracked steam turbine blades made of martensitic stainless steels has been developed using the gas tungsten arc welding process. Weld repair procedures were developed using both ER316L austenitic stainless steel filler wire and ER410 martensitic stainless steel filler wire. The repair welding procedure with austenitic filler wire was developed to avoid preheating of the blade as also hydrogen induced cold cracking, and involved evaluation of three different austenitic filler wires, viz. ER309L, ER316L and ERNiCr-3. The overall development of the repair welding procedure included selection of welding consumables (for austenitic filler metal), optimisation of post weld heat treatment parameters, selection of suitable method for local pre-heating and post-weld heat treatment (PWHT) of the blades, determination of mechanical properties of weldments in as-welded and PWHT conditions, and microstructural examination. After various trials using different procedures, the procedure of local PWHT using electrical resistance heating on the top surface of the weldment and monitoring the temperature by placing a thermocouple at the bottom of the weld, was found to give the most satisfactory results. A similar procedure was used for preheating while using ER410 filler metal. Mechanical testing of weldments before and after PWHT involved tensile tests at room temperature, face and root bend tests, and microhardness measurements across the fusion line and heat affected zone. During procedure qualification, mock-ups and actual repair welding, dye penetrant testing was used at different stages and where ever possible radiography was carried out. These procedures were developed for repair welding of cracked blades in the low-pressure (LP) steam turbines of Indian nuclear power plants. The procedure with ER316 L filler wire has so far been applied for repair welding of 2 cracked blades (made of AISI 410 SS) of LP steam turbines, while the procedure

  6. Friction stir welding of 6061 aluminium alloy

    International Nuclear Information System (INIS)

    Abdel Rahman, M.A.M.S.

    2009-01-01

    6061 AA (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio and good corrosion resistance such as marine frames, pipelines, storage tanks, and aircraft components [1]. It is also used for the manufacturing of fuel elements in the nuclear research reactors. Compared to many of the fusion welding processes that are routinely used for joining structural alloys, friction stir welding (FSW) is a solid state joining process in which the material that is being welded is not melted and recast [2]. The welding parameters such as tool rotational speed, welding traverse speed, and tool profile play a major role in deciding the weld quality. Several FSW tools (differ from each other in pin angle, shoulder diameter, and shoulder concavity) have been used to fabricate a number of joints in order to obtain a tool with which a sound weld can be produced. It was found that the FSW tool with tapered cone pin, concave shoulder, and shoulder diameter equal to four times the welded plate thickness is suitable to produce a sound weld. The effect of the traverse speed on the global and local tensile properties of friction stir welded joints has been investigated in the 6061-T6 AA. The global tensile properties of the FSW joints were improved with increasing the traverse speed at constant rotation rate. It is found that the global tensile strength of the FSW joint is limited by the local tensile strength of the nearest region to the weld center at which the cross section is composed mainly of the HAZ. The effect of the initial butt surface on the formation of the zigzag line on the tensile properties of the welds was examined by using three types of welding samples differ in the preparation of the initial butt surface. The first type of samples welded without removing the oxide layer from the initial butt surface (uncleaned butt surfaces joint). In the second type of samples the oxide layer was removed from

  7. Sub-arc narrow gap welding of Atucha 2 RPV closure head

    International Nuclear Information System (INIS)

    Hantsch, H.; Million, K.; Zimmermann, H.

    1982-01-01

    Narrow gap technology was used for reasons of design and fabrication when welding the closure-head dome to its flange. Preliminary tests had yielded the necessary improvements of the well-proven sub-arc practice. New facilities had to be developed for welding proper and for the accompanying machining work (finishing in the narrow gap). Special measures were adopted for monitoring the welding process and for recording the welding parameters. The new method was tried out on several large test coupons before welding of the final product was started. No difficulties were encountered during the welding job. Fabrication of the closure head is shown in a short film sequence. (orig.)

  8. WELDABILITY, WELDING METALLURGY, WELDING CHEMISTRY

    OpenAIRE

    Sarjito Jokosisworo

    2012-01-01

    Sambungan las merupakan bagian penting dari stuktur/bangunan yang dilas, dan kunci dari logam induk yang baik adalah kemampuan las (weld ability). Kemampuan las yang baik dan kemudahan dalam fabrikasi dari suatu logam merupakan pertimbangan dalam memilih suatu logam untuk konstruksi.

  9. Low-cycle fatigue and cyclic deformation behavior of Type 16-8-2 weld metal at elevated temperature

    International Nuclear Information System (INIS)

    Raske, D.T.

    1977-01-01

    The low-cycle fatigue behavior of Type 16-8-2 stainless steel ASA weld metal at 593 0 C was investigated, and the results are compared with existing data for Type 316 stainless steel base metal. Tests were conducted under axial strain control and at a constant axial strain rate of 4 x 10 -3 s -1 for continuous cyclic loadings as well as hold times at peak tensile strain. Uniform-gauge specimens were machined longitudinally from the surface and root areas of 25.4-mm-thick welded plate and tested in the as-welded condition. Results indicate that the low-cycle fatigue resistance of this weld metal is somewhat better than that of the base metal for continuous-cycling conditions and significantly better for tension hold-time tests. This is attributed to the fine duplex delta ferrite-austenite microstructure in the weld metal. The initial monotonic tensile properties and the cyclic stress-strain behavior of this material were also determined. Because the cyclic changes in mechanical properties are strain-history dependent, a unique cyclic stress-strain curve does not exist for this material

  10. The National Shipbuilding Research Program: Evaluation of the Cincinnati Milacron T-3 Robot for Shipbuilding Welding

    Science.gov (United States)

    1984-01-01

    acknowledgement is extended to the members of Welding Panel SP-7 of the SNAME Ship Production Committee, who served as technical advisors in the preparation...Binzel Robo 450. . . . . . 4.4.4.1.3 Hobart WCG 600 . . . . . . 4.4.4.2 Maintenance and Service . . . . . . . 4.4.4.3 Recommendation...Machine Specialties D & F - Welding . . . Torch Binzel Robo 450 - Welding Torch. Hobart WCG - 600 - Welding Torch. Binzel Nozzle Cleaner

  11. Ground Reaction Force and Mechanical Differences Between the Interim Resistive Exercise Device (iRED) and Smith Machine While Performing a Squat

    Science.gov (United States)

    Amonette, William E.; Bentley, Jason R.; Lee, Stuart M. C.; Loehr, James A.; Schneider, Suzanne

    2004-01-01

    Musculoskeletal unloading in microgravity has been shown to induce losses in bone mineral density, muscle cross-sectional area, and muscle strength. Currently, an Interim Resistive Exercise Device (iRED) is being flown on board the ISS to help counteract these losses. Free weight training has shown successful positive musculoskeletal adaptations. In biomechanical research, ground reaction forces (GRF) trajectories are used to define differences between exercise devices. The purpose of this evaluation is to quantify the differences in GRF between the iRED and free weight exercise performed on a Smith machine during a squat. Due to the differences in resistance properties, inertial loading and load application to the body between the two devices, we hypothesize that subjects using iRED will produce GRF that are significantly different from the Smith machine. There will be differences in bar/harness range of motion and the time when peak GRF occurred in the ROMbar. Three male subjects performed three sets of ten squats on the iRED and on the Smith Machine on two separate days at a 2-second cadence. Statistically significant differences were found between the two devices in all measured GRF variables. Average Fz and Fx during the Smith machine squat were significantly higher than iRED. Average Fy (16.82 plus or minus.23; p less than .043) was significantly lower during the Smith machine squat. The mean descent/ascent ratio of the magnitude of the resultant force vector of all three axes for the Smith machine and iRED was 0.95 and 0.72, respectively. Also, the point at which maximum Fz occurred in the range of motion (Dzpeak) was at different locations with the two devices.

  12. Laser beam welding and friction stir welding of 6013-T6 aluminium alloy sheet

    International Nuclear Information System (INIS)

    Braun, R.; Dalle Donne, C.; Staniek, G.

    2000-01-01

    Butt welds of 1.6 mm thick 6013-T6 sheet were produced using laser beam welding and friction stir welding processes. Employing the former joining technique, filler powders of the alloys Al-5%Mg and Al-12%Si were used. Microstructure, hardness profiles, tensile properties and the corrosion behaviour of the welds in the as-welded condition were investigated. The hardness in the weld zone was lower compared to that of the base material in the peak-aged temper. Hardness minima were measured in the fusion zone and in the thermomechanically affected zone for laser beam welded and friction stir welded joints, respectively. Metallographic and fractographic examinations revealed pores in the fusion zone of the laser beam welds. Porosity was higher in welds made using the filler alloy Al-5%Mg than using the filler metal Al-12%Si. Transmission electron microscopy indicated that the β '' (Mg 2 Si) hardening precipitates were dissolved in the weld zone due to the heat input of the joining processes. Joint efficiencies achieved for laser beam welds depended upon the filler powders, being about 60 and 80% using the alloys Al-5%Mg and Al-12%Si, respectively. Strength of the friction stir weld approached over 80% of the ultimate tensile strength of the 6013-T6 base material. Fracture occurred in the region of hardness minima unless defects in the weld zone led to premature failure. The heat input during welding did not cause a degradation of the corrosion behaviour of the welds, as found in continuous immersion tests in an aqueous chloride-peroxide solution. In contrast to the 6013-T6 parent material, the weld zone was not sensitive to intergranular corrosion. Alternate immersion tests in 3.5% NaCl solution indicated high stress corrosion cracking resistance of the joints. For laser beam welded sheet, the weld zone of alternately immersed specimens suffered severe degradation by pitting and intergranular corrosion, which may be associated with galvanic coupling of filler metal and

  13. Pulsed infrared thermography for assessment of ultrasonic welds

    Science.gov (United States)

    McGovern, Megan E.; Rinker, Teresa J.; Sekol, Ryan C.

    2018-03-01

    Battery packs are a critical component in electric vehicles. During pack assembly, the battery cell tab and busbar are ultrasonically welded. The properties of the welds ultimately affect battery pack durability. Quality inspection of these welds is important to ensure durable battery packs. Pack failure is detrimental economically and could also pose a safety hazard, such as thermal runaway. Ultrasonic welds are commonly checked by measuring electrical resistance or auditing using destructive mechanical testing. Resistance measurements are quick, but sensitive to set-up changes. Destructive testing cannot represent the entire weld set. It is possible for a weak weld to satisfy the electrical requirement check, because only sufficient contact between the tabs and busbar is required to yield a low resistance measurement. Laboratory techniques are often not suitable for inline inspection, as they may be time-consuming, use couplant, or are only suitable for coupons. The complex surface geometry also poses difficulties for conventional nondestructive techniques. A method for inspection of ultrasonic welds is proposed using pulsed infrared thermography to identify discrepant welds in a manufacturing environment. Thermal measurements of welds were compared to electrical and mechanical measurements. The heat source distribution was calculated to obtain thermal images with high temporal and spatial resolution. All discrepant welds were readily identifiable using two thermographic techniques: pixel counting and the gradient image. A positive relationship between pixel count and mechanical strength was observed. The results demonstrate the potential of pulsed thermography for inline inspection, which can complement, or even replace, conventional electrical resistance measurements.

  14. Analysis of weld-cracking and improvement of the weld-repair process of superplastic forming tools

    International Nuclear Information System (INIS)

    Duchosal, A.; Deschaux-Beaume, F.; Lours, P.; Haro, S.; Fras, G.

    2013-01-01

    Highlights: ► Characterisation of the microstructure of a heat-resistant austenitic cast steel. ► Failure analysis using in situ tensile tests and isothermal fatigue tests. ► Analyses of weld cracking mechanism during shielded metal arc welding process. ► Improvement of weld-repair method by re-melting of the base material surface with GTAW process. - Abstract: Superplastic forming (SPF) dies are generally made of using heat resistant cast steels, which are very sensitive to weld cracking. In order to improve the weld-repair process of such dies to prevent weld-cracking, the microstructure and the mechanical behaviour of a typical heat-resistant cast steel was first studied, using isothermal low-cycle fatigue tests and in situ tensile tests. The welding behaviour of such steel was also investigated, using a shielded metal arc welding (SMAW) process and welding conditions similar to those employed for weld repair industrial dies. The comparison of the aspect of weld-cracking with the fracture mechanisms observed at room temperature or during isothermal low-cycle fatigue tests suggests a similar brittle failure mechanism, due to the presence of large interdendritic carbides in the cast steel. The melting of the cast steel surface using a gas tungsten arc welding (GTAW) process allowed to refine the primary carbides, and then to reduce the weld-cracking sensitivity. The refining method with GTAW before welding has been successfully tested to weld-repair a sample representative of SPF dies, and is recommended for subsequent repairs of such dies

  15. Real weld geometry determining mechanical properties of high power laser welded medium plates

    Science.gov (United States)

    Liu, Sang; Mi, Gaoyang; Yan, Fei; Wang, Chunming; Li, Peigen

    2018-06-01

    Weld width is commonly used as one of main factors to assess joint performances in laser welding. However, it changes significantly through the thickness direction in conditions of medium or thick plates. In this study, high-power autogenous laser welding was conducted on 7 mm thickness 201 stainless steel to elucidate the factor of whole weld transverse shape critically affecting the mechanical properties with the aim of predicting the performance visually through the weld appearance. The results show that single variation of welding parameters could result in great changes of weld pool figures and subsequently weld transverse shapes. All the obtained welds are composed of austenite containing small amount of cellular dendritic δ-Ferrite. The 0.2% proof stresses of Nail- and Peanut-shaped joint reach 458 MPa and 454 MPa, 88.2% and 87.5% of the base material respectively, while that of Wedge-shaped joint only comes to 371 MPa, 71.5% of the base material. The deterioration effect is believed to be caused by the axial grain zone in the weld center. The fatigue strength of joint P is a bit lower than N, but much better than W. Significant deformation incompatibility through the whole thickness and microstructure resistance to crack initiation should be responsible for the poor performance of W-shaped joints.

  16. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    Directory of Open Access Journals (Sweden)

    Koray Yurtisik

    2013-09-01

    Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

  17. Microstructure and Mechanical Properties of an Ultrasonic Spot Welded Aluminum Alloy: The Effect of Welding Energy

    Directory of Open Access Journals (Sweden)

    He Peng

    2017-04-01

    Full Text Available The aim of this study is to evaluate the microstructures, tensile lap shear strength, and fatigue resistance of 6022-T43 aluminum alloy joints welded via a solid-state welding technique–ultrasonic spot welding (USW–at different energy levels. An ultra-fine necklace-like equiaxed grain structure is observed along the weld line due to the occurrence of dynamic crystallization, with smaller grain sizes at lower levels of welding energy. The tensile lap shear strength, failure energy, and critical stress intensity of the welded joints first increase, reach their maximum values, and then decrease with increasing welding energy. The tensile lap shear failure mode changes from interfacial fracture at lower energy levels, to nugget pull-out at intermediate optimal energy levels, and to transverse through-thickness (TTT crack growth at higher energy levels. The fatigue life is longer for the joints welded at an energy of 1400 J than 2000 J at higher cyclic loading levels. The fatigue failure mode changes from nugget pull-out to TTT crack growth with decreasing cyclic loading for the joints welded at 1400 J, while TTT crack growth mode remains at all cyclic loading levels for the joints welded at 2000 J. Fatigue crack basically initiates from the nugget edge, and propagates with “river-flow” patterns and characteristic fatigue striations.

  18. Feasibility study of pipe welding using a homopolar generator. Final report

    International Nuclear Information System (INIS)

    Keith, R.E.; Weldon, W.F.; Rylander, H.G.; Woodson, H.H.

    1979-12-01

    The technical feasibility was studied of making girth welds of the upset butt resistance type in type 304 stainless steel boiling water reactor pipe using a homopolar generator as the power supply and a preliminary study of the process economics as compared with the present arc welding practice was made. The design and construction of a welding fixture and its use in conjunction with a 5 megajoule homopolar generator to accomplish successful welds having a nominal 28.4 cm 2 (4.4 in. 2 ) area in less than 1 second are discussed. The nature of the homopolar pulse resistance welding (HPRW) process is such that the time to accomplish the weld is independent of the size of the weld. Welds were produced having 100 percent joint efficiency as measured by the tensile test. It proved possible to obtain smooth inner diameter weld contours, but the joint design that resulted in the best contour also resulted in harmless oxide particles in the weld interface. A slight modification to the joint design was shown to eliminate the oxide particles, but resulted in a somewhat less desirable inner contour. Because of the relatively short heating cycle of HPR welding, the heat-affected zone of the weld is in the 400 to 800 C sensitization region for a substantially shorter time than in multipass arc welding. ASTM A262 Procedure A tests did not show any sensitization in HPR welds. HPR welding promises substantial savings in variable costs (labor, overhead, and materials) compared to arc welding

  19. Study on Temperature and Synthetic Compensation of Piezo-Resistive Differential Pressure Sensors by Coupled Simulated Annealing and Simplex Optimized Kernel Extreme Learning Machine.

    Science.gov (United States)

    Li, Ji; Hu, Guoqing; Zhou, Yonghong; Zou, Chong; Peng, Wei; Alam Sm, Jahangir

    2017-04-19

    As a high performance-cost ratio solution for differential pressure measurement, piezo-resistive differential pressure sensors are widely used in engineering processes. However, their performance is severely affected by the environmental temperature and the static pressure applied to them. In order to modify the non-linear measuring characteristics of the piezo-resistive differential pressure sensor, compensation actions should synthetically consider these two aspects. Advantages such as nonlinear approximation capability, highly desirable generalization ability and computational efficiency make the kernel extreme learning machine (KELM) a practical approach for this critical task. Since the KELM model is intrinsically sensitive to the regularization parameter and the kernel parameter, a searching scheme combining the coupled simulated annealing (CSA) algorithm and the Nelder-Mead simplex algorithm is adopted to find an optimal KLEM parameter set. A calibration experiment at different working pressure levels was conducted within the temperature range to assess the proposed method. In comparison with other compensation models such as the back-propagation neural network (BP), radius basis neural network (RBF), particle swarm optimization optimized support vector machine (PSO-SVM), particle swarm optimization optimized least squares support vector machine (PSO-LSSVM) and extreme learning machine (ELM), the compensation results show that the presented compensation algorithm exhibits a more satisfactory performance with respect to temperature compensation and synthetic compensation problems.

  20. Creep properties and simulation of weld repaired low alloy heat resistant CrMo and Mo steels at 540 deg C. Sub-project 2 - Ex-serviced 2.25Cr1M0 weld metal and cross weld repairs

    Energy Technology Data Exchange (ETDEWEB)

    Rui Wu; Storesund, Jan; Borggreen, Kjeld; Feilitzen, Carl von

    2007-12-15

    Weld repair has been carried out in an ex-serviced 10 CrMo 9 10 pipe by using 10 CrMo 9 10, 13 CrMo 4 4 and 15 Mo 3 consumables. Application of current welding procedure and consumables results in an over matched weld repair. This is verified by both creep tests and the creep simulations at even lower stresses than tested. Creep specimens have been extracted from ex-serviced 10 CrMo 9 10 parent metal (PM) and weld metal (WM), from virgin 10 CrMo 9 10 WM, from virgin 13 CrMo 4 4 WM, and from virgin 15 Mo 3 WM. In addition, cross weld specimens including weld metal, heat affected zone (HAZ) and parent metal have been taken from the ex-serviced 10 CrMo 9 10 weld joint, and from three weld repairs. In total, there are nine test series. The sequence of creep lifetime at 540 deg C at given stresses is; virgin 10 CrMo 9 10 weld metal > virgin 15 Mo 3 weld metal approx virgin 13 CrMo 4 4 weld metal approx ex-serviced 10 CrMo 9 10 weld metal >> ex-serviced 10 CrMo 9 10 parent metal > ex-serviced 10 CrMo 9 10 cross weld approx 10 CrMo 9 10 cross weld repair approx 13 CrMo 4 4 cross weld repair approx and 15 Mo 3 cross weld repair. All the series show good creep ductility. The ex-serviced 10 CrMo 9 10 parent metal shows a creep lifetime about one order of magnitude shorter than that for both the virgin parent metal and the ex-serviced 10 CrMo 9 10 weld metal, independent of stresses. Differences in creep lifetime among the ex-serviced 10 CrMo 9 10 cross weld and other cross weld repairs are negligible, simply because rupture always occurred in the ex-serviced 10 CrMo 9 10 parent metal, approximately 10 mm from HAZ, for all the cross welds. Necking is frequently observed in the ex-serviced 10 CrMo 9 10 parent metal at the opposite side of the fracture. Creep damage to a large and a small extend is found adjacent to the fracture and at the necking area, respectively. Other parts of the weld joint like weld metal and HAZ are damage-free, independent of stress, weld metal and

  1. Effect of post-weld aging treatment on mechanical properties of Tungsten Inert Gas welded low thickness 7075 aluminium alloy joints

    International Nuclear Information System (INIS)

    Temmar, M.; Hadji, M.; Sahraoui, T.

    2011-01-01

    Highlights: → The effects of post-weld aging treatment on the properties of joints is studied. → The post-weld aging treatment increases the tensile strength of TIG welded joints. → The strengthening is due to a balance of dissolution, reversion and precipitation. → Simple post-weld aging at 140 o C enhances the properties of the welded joints. -- Abstract: This paper reports the influence of post-weld aging treatment on the microstructure, tensile strength, hardness and Charpy impact energy of weld joints low thickness 7075 T6 aluminium alloy welded by Tungsten Inert Gas (TIG). Hot cracking occurs in aluminium welds when high levels of thermal stress and solidification shrinkage are present while the weld is undergoing various degrees of solidification. Weld fusion zones typically exhibit microstructure modifications because of the thermal conditions during weld metal solidification. This often results in low weld mechanical properties and low resistance to hot cracking. It has been observed that the mechanical properties are very sensitive to microstructure of weld metal. Simple post-weld aging treatment at 140 o C applied to the joints is found to be beneficial to enhance the mechanical properties of the welded joints. Correlations between microstructures and mechanical properties were discussed.

  2. WELDING PROCESS

    Science.gov (United States)

    Zambrow, J.; Hausner, H.

    1957-09-24

    A method of joining metal parts for the preparation of relatively long, thin fuel element cores of uranium or alloys thereof for nuclear reactors is described. The process includes the steps of cleaning the surfaces to be jointed, placing the sunfaces together, and providing between and in contact with them, a layer of a compound in finely divided form that is decomposable to metal by heat. The fuel element members are then heated at the contact zone and maintained under pressure during the heating to decompose the compound to metal and sinter the members and reduced metal together producing a weld. The preferred class of decomposable compounds are the metal hydrides such as uranium hydride, which release hydrogen thus providing a reducing atmosphere in the vicinity of the welding operation.

  3. Evaluation of endcap welds in thin walled fuel elements of pressurised heavy water reactor by ultrasonic testing

    International Nuclear Information System (INIS)

    Subramanian, C.V.; Thavasimuthu, M.; Kalyansundaram, P.; Bhattacharya, D.K.; Raj, Baldev

    1992-01-01

    In the pressurised heavy water reactor systems of India, the fuel is encapsulated in thin-walled tubes (0.342 mm) closed with endcaps by resistance welding. The integrity of these fuel elements should be such that no fission gas leakage takes place during reactor operation. The quality control of the endcap welds needed to satisfy this requirement includes helium leak test and destructive metallographic test (on sample basis). This paper discusses the feasibility study that has been carried out in the author's laboratory to develop an immersion ultrasonic test method for evaluating the integrity of the endcap weld region. Through holes of various sizes (0.15mm, 0.2mm, 0.4mm diameter and 0.185mm and 0.342mm deep) were machined by spark erosion machining at the weld joints to simulate defects of various sizes. Line focussed probe of 10 MHz frequency was used for the testing. It was possible to detect clearly all the machined holes. Based on the above standardised procedure, further testing was done on endcap welds which were rejected during fabrication on account of showing leak rate of 3 x 10 -6 std. c.c/sec. or more during helium leak test. Though it was possible to get echoes from the natural defects in the rejected tubes with echo amplitude of 70%, the signal was accompanied by the geometrical reflection (noise) giving an amplitude of 20% from the weld region, giving rise to the problem of resolving the defect indication from the geometric indications. Therefore, signal analysis approach was adopted. The signal obtained from the weld zone were subjected to various analysis procedures like a) autopower spectrum, b) total energy content and c) demodulated auto correlation function. It was possible by all the three methods to differentiate the defect signal from those due to weld geometry or due to noise. Subsequently, metallography was carried out to characterise the type of defects observed during the ultrasonic testing. (author). 4 figs

  4. Electron Beam Welding of Gear Wheels by Splitted Beam

    Directory of Open Access Journals (Sweden)

    Dřímal Daniel

    2014-06-01

    Full Text Available This contribution deals with the issue of electron beam welding of high-accurate gear wheels composed of a spur gearing and fluted shaft joined with a face weld for automotive industry. Both parts made of the high-strength low-alloy steel are welded in the condition after final machining and heat treatment, performed by case hardening, whereas it is required that the run-out in the critical point of weldment after welding, i. e. after the final operation, would be 0.04 mm max..

  5. Evaluation of residual stress on pipe welded joints using laser interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ho Seob; Na, Man Gyun; Kim, Koung Suk [Chosun University, Gwangju (Korea, Republic of)

    2014-02-15

    Residual stresses that occur during the welding process, are the main cause of failure and defects in welded structures. This paper, presents the use of an electronic processing laser speckle interferometer to measure the residual stress of a welded pipe for a nuclear power plant. A tensile testing machine was used to evaluate a welded pipe that failed in compression. The inform plane deformation and modulus of elasticity of the base metal and welds were measured using an interferometer. Varying the load on the welded pipe had a larger effect on the deformation of the base metal the other properties of the base metal and welds. The elastic moduli of the base metal and weld of the welded pipe were 202.46 and 212.14 GPa, respectively, the residual stress was measured to be 6.29 MPa.

  6. Automatic monitoring of the alignment and wear of vibration welding equipment

    Science.gov (United States)

    Spicer, John Patrick; Cai, Wayne W.; Chakraborty, Debejyo; Mink, Keith

    2017-05-23

    A vibration welding system includes vibration welding equipment having a welding horn and anvil, a host machine, a check station, and a welding robot. At least one displacement sensor is positioned with respect to one of the welding equipment and the check station. The robot moves the horn and anvil via an arm to the check station, when a threshold condition is met, i.e., a predetermined amount of time has elapsed or a predetermined number of welds have been completed. The robot moves the horn and anvil to the check station, activates the at least one displacement sensor, at the check station, and determines a status condition of the welding equipment by processing the received signals. The status condition may be one of the alignment of the vibration welding equipment and the wear or degradation of the vibration welding equipment.

  7. Automatization of welding for nuclear power equipments and facilities

    International Nuclear Information System (INIS)

    Tamai, Yasumasa; Matsumoto, Teruo; Koyama, Takaichi

    1980-01-01

    For the requirement of high reliability in the construction of nuclear power plants and the reduction of radiation exposure in the modefying works of existing plants, the automation and remote operation of welding have increased their necessity. In this paper, the present state of the automation of welding for making machines, equipments and pipings for nuclear power plants in Hitachi Ltd. is described, and the aim of developing the automation, the features of the equipments and the state of application to actual plants are introduced, centering around the automation of welding for large structures such as reactor containment vessels and the remote type automatic welding system for pipings. By these automations, the large outcomes were obtained in the improvement of welding quality required for the machines and equipments for atomic energy. Moreover, the conspicuous results were also obtained in case of the peculiar works to nuclear power plants, in which the reduction of the radiation exposure related to human bodies and the welding of high quality are demanded. The present state of the automation of welding for nuclear installations in Hitachi Ltd., the development of automatic welding equipments and the present state of application to actual plants, and the development and application of the automatic pipe working machine for reducing radiation exposure are explained. (Kako, I.)

  8. Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z.; Dong, P.; Liu, S.; Babu, S.; Olson, G.; DebRoy, T.

    2005-04-15

    The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high strength steels. In order to achieve high fatigue strength in a welded-joint it is necessary to manage the weld bead shape for lower stress concentration, produce preferable residual stress distribution, and obtain the desired microstructure for improved material toughness and strength. This is a systems challenge that requires the optimization of the welding process, the welding consumable, the base material, as well as the structure design. The concept of virtual welded-joint design has been proposed and established in this project. The goal of virtual welded-joint design is to develop a thorough procedure to predict the relationship of welding process, microstructure, property, residual stress, and the ultimate weld fatigue strength by a systematic modeling approach. The systematic approach combines five sub-models: weld thermal-fluid model, weld microstructure model, weld material property model, weld residual stress model, and weld fatigue model. The systematic approach is thus based on interdisciplinary applied sciences including heat transfer, computational fluid dynamics, materials science, engineering mechanics, and material fracture mechanics. The sub-models are based on existing models with further development. The results from modeling have been validated with critical experiments. The systematic modeling approach has been used to design high fatigue resistant welds considering the combined effects of weld bead geometry, residual stress, microstructure, and material property. In particular, a special welding wire has been developed in this project to introduce

  9. Discontinuity Detection in the Shield Metal Arc Welding Process.

    Science.gov (United States)

    Cocota, José Alberto Naves; Garcia, Gabriel Carvalho; da Costa, Adilson Rodrigues; de Lima, Milton Sérgio Fernandes; Rocha, Filipe Augusto Santos; Freitas, Gustavo Medeiros

    2017-05-10

    This work proposes a new methodology for the detection of discontinuities in the weld bead applied in Shielded Metal Arc Welding (SMAW) processes. The detection system is based on two sensors-a microphone and piezoelectric-that acquire acoustic emissions generated during the welding. The feature vectors extracted from the sensor dataset are used to construct classifier models. The approaches based on Artificial Neural Network (ANN) and Support Vector Machine (SVM) classifiers are able to identify with a high accuracy the three proposed weld bead classes: desirable weld bead, shrinkage cavity and burn through discontinuities. Experimental results illustrate the system's high accuracy, greater than 90% for each class. A novel Hierarchical Support Vector Machine (HSVM) structure is proposed to make feasible the use of this system in industrial environments. This approach presented 96.6% overall accuracy. Given the simplicity of the equipment involved, this system can be applied in the metal transformation industries.

  10. Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.

    2008-01-01

    Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

  11. The Effect of Welding Current and Composition of Stainless steel on the Panetration in GTAW

    Directory of Open Access Journals (Sweden)

    Ramazan Yılmaz

    2012-06-01

    Full Text Available In this study, welding was performed on the plates of two different types of AISI 316 and AISI 316Ti austenitic stainless steels by GTAW (Gas Tungsten Arc Welding without using welding consumable in flat position. Automatic GTAW welding machine was used to control and obtain the exact values. The effects of welding currents used in welding process and the compositions of the stainless steels materials on the penetration were investigated. Weld bead size and shape such as bead width and dept were important considerations for penetration. Welding process was performed using various welding current values. The study showed that both welding parameters and composition of the stainless steels has influence on the penetration and It is increased with increasing of welding current. Besides, P/W rate of the weldments were influenced by the current and hardness values of the weld metal decrease with increasing welding current. The microstructure of the weld metal was also changed by variation of welding current.

  12. FFTF report: FFTF piping installation and welding techniques

    International Nuclear Information System (INIS)

    Gilles, J.

    1975-01-01

    The main sodium piping with a diameter of 16'' or 28 '' is being installed at the FFTF construction site starting in December 1974. The supplier and authority demarcations are: Combustion Engineering supplies the reactor vessel, guard vessel and adjoining pipes and uses the machine welding equipment ''Dimetrics''; for the piping system of the primary and secondary loops the pipes manufactured by Rollmet at HUICO, Pasco, were delivered and prefabricated there, as far as compatible with the installation. ''Astroarc'' welding machines are used by Bechtel for the piping prefabrication in the weld laboratory as well as on site at the construction site. Technical welding problems occurring during the course of the installation at the construction site and several during this time are described. At present 6 weld seams in the reactor and 14 weld seams in the secondary loop are accepted. The requirement exists to carry out as many welds as possible automatically, in order to produce sodium pipe welds of high technical quality and which are reproducible. The welding equipment is described

  13. Definition of Beam Diameter for Electron Beam Welding

    Energy Technology Data Exchange (ETDEWEB)

    Burgardt, Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pierce, Stanley W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dvornak, Matthew John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-11

    It is useful to characterize the dimensions of the electron beam during process development for electron beam welding applications. Analysis of the behavior of electron beam welds is simplest when a single number can be assigned to the beam properties that describes the size of the beam spot; this value we generically call the “beam diameter”. This approach has worked well for most applications and electron beam welding machines with the weld dimensions (width and depth) correlating well with the beam diameter. However, in recent weld development for a refractory alloy, Ta-10W, welded with a low voltage electron beam machine (LVEB), it was found that the weld dimensions (weld penetration and weld width) did not correlate well with the beam diameter and especially with the experimentally determined sharp focus point. These data suggest that the presently used definition of beam diameter may not be optimal for all applications. The possible reasons for this discrepancy and a suggested possible alternative diameter definition is the subject of this paper.

  14. Optimization of the A-TIG welding for stainless steels

    Science.gov (United States)

    Jurica, M.; Kožuh, Z.; Garašić, I.; Bušić, M.

    2018-03-01

    The paper presents the influence of the activation flux and shielding gas on tungsten inert gas (A-TIG) welding of the stainless steel. In introduction part, duplex stainless steel was analysed. The A-TIG process was explained and the possibility of welding stainless steels using the A-TIG process to maximize productivity and the cost-effectiveness of welded structures was presented. In the experimental part duplex, 7 mm thick stainless steel has been welded in butt joint. The influence of activation flux chemical composition upon the weld penetration has been investigated prior the welding. The welding process was performed by a robot with TIG equipment. With selected A-TIG welding technology preparation of plates and consumption of filler material (containing Cr, Ni and Mn) have been avoided. Specimens sectioned from the produced welds have been subjected to tensile strength test, macrostructure analysis and corrosion resistance analysis. The results have confirmed that this type of stainless steel can be welded without edge preparation and addition of filler material containing critical raw materials as Cr, Ni and Mn when the following welding parameters are set: current 200 A, welding speed 9,1 cm/min, heat input 1,2 kJ/mm and specific activation flux is used.

  15. Progress in welding studies for Canadian nuclear fuel waste disposal containers

    International Nuclear Information System (INIS)

    Maak, P.Y.Y.

    1985-11-01

    This report describes the progress in the development of closure-welding technology for Canadian nuclear fuel waste disposal containers. Titanium, copper and Inconel 625 are being investigated as candidate materials for fabrication of these containers. Gas-tungsten-arc welding, gas metal-arc-welding, resistance-heated diffusion bonding and electron beam welding have been evaluated as candidate closure welding processes. Characteristic weldment properties, relative merits of welding techniques, suitable weld joint configurations and fit-up tolerances, and welding parameter control ranges have been identified for various container designs. Furthermore, the automation requirements for candidate welding processes have been assessed. Progress in the development of a computer-controlled remote gas-shielded arc welding system is described

  16. Physicochemical and toxicological characteristics of welding fume derived particles generated from real time welding processes.

    Science.gov (United States)

    Chang, Cali; Demokritou, Philip; Shafer, Martin; Christiani, David

    2013-01-01

    Welding fume particles have been well studied in the past; however, most studies have examined welding fumes generated from machine models rather than actual exposures. Furthermore, the link between physicochemical and toxicological properties of welding fume particles has not been well understood. This study aims to investigate the physicochemical properties of particles derived during real time welding processes generated during actual welding processes and to assess the particle size specific toxicological properties. A compact cascade impactor (Harvard CCI) was stationed within the welding booth to sample particles by size. Size fractionated particles were extracted and used for both off-line physicochemical analysis and in vitro cellular toxicological characterization. Each size fraction was analyzed for ions, elemental compositions, and mass concentration. Furthermore, real time optical particle monitors (DustTrak™, TSI Inc., Shoreview, Minn.) were used in the same welding booth to collect real time PM2.5 particle number concentration data. The sampled particles were extracted from the polyurethane foam (PUF) impaction substrates using a previously developed and validated protocol, and used in a cellular assay to assess oxidative stress. By mass, welding aerosols were found to be in coarse (PM 2.5–10), and fine (PM 0.1–2.5) size ranges. Most of the water soluble (WS) metals presented higher concentrations in the coarse size range with some exceptions such as sodium, which presented elevated concentration in the PM 0.1 size range. In vitro data showed size specific dependency, with the fine and ultrafine size ranges having the highest reactive oxygen species (ROS) activity. Additionally, this study suggests a possible correlation between welders' experience, the welding procedure and equipment used and particles generated from welding fumes. Mass concentrations and total metal and water soluble metal concentrations of welding fume particles may be

  17. Micro Structure and Hardness Analysis of Brass Metal Welded

    Science.gov (United States)

    Lukman Faris, N.; Muljadi; Djuhana

    2018-01-01

    Brass metals are widely used for plumbing fittings. High tensile brasses are more highly alloyed and find uses in marine engineering. The welding of brass metal has been done by using electrical weld machine (SMAW). The microstructure of brass metal welded was observed by optical microscope. The result can see that the microstructure has been changed due to heat from welding. The microstructure of original brass metal is seen a fine laminar stucture, but the microstructure at HAZ appears bigger grains and some area at HAZ is seen coarser microstructure. The microstructure at weld zone can be seen that it was found some of agglomeration of materials from reaction between brass metal and electrode coating wire. According the hardness measurement, it is found highest hardness value about 301.92 HV at weld zone, and hardness value at base metal is 177.84 HV

  18. Friction stir welding process to repair voids in aluminum alloys

    Science.gov (United States)

    Rosen, Charles D. (Inventor); Litwinski, Edward (Inventor); Valdez, Juan M. (Inventor)

    1999-01-01

    The present invention provides an in-process method to repair voids in an aluminum alloy, particularly a friction stir weld in an aluminum alloy. For repairing a circular void or an in-process exit hole in a weld, the method includes the steps of fabricating filler material of the same composition or compatible with the parent material into a plug form to be fitted into the void, positioning the plug in the void, and friction stir welding over and through the plug. For repairing a longitudinal void (30), the method includes machining the void area to provide a trough (34) that subsumes the void, fabricating filler metal into a strip form (36) to be fitted into the trough, positioning the strip in the trough, and rewelding the void area by traversing a friction stir welding tool longitudinally through the strip. The method is also applicable for repairing welds made by a fusing welding process or voids in aluminum alloy workpieces themselves.

  19. Introduction to Welding.

    Science.gov (United States)

    Fortney, Clarence; Gregory, Mike

    This curriculum guide provides six units of instruction on basic welding. Addressed in the individual units of instruction are the following topics: employment opportunities for welders, welding safety and first aid, welding tools and equipment, basic metals and metallurgy, basic math and measuring, and procedures for applying for a welding job.…

  20. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ