Physical simulation method for the investigation of weld seam formation during the extrusion of aluminum alloys

NARCIS (Netherlands)

Fang, G; Zhou, J.

2017-01-01

Extrusion through the porthole die is a predominant forming process used in the production of hollow aluminum alloy profiles across the aluminum extrusion industry. Longitudinal weld seams formed during the process may negatively influence the quality of extruded profiles. It is therefore of

Study on Mg/Al Weld Seam Based on Zn–Mg–Al Ternary Alloy

Directory of Open Access Journals (Sweden)

Liming Liu

2014-02-01

Full Text Available Based on the idea of alloying welding seams, a series of Zn–xAl filler metals was calculated and designed for joining Mg/Al dissimilar metals by gas tungsten arc (GTA welding. An infrared thermography system was used to measure the temperature of the welding pool during the welding process to investigate the solidification process. It was found that the mechanical properties of the welded joints were improved with the increasing of the Al content in the Zn–xAl filler metals, and when Zn–30Al was used as the filler metal, the ultimate tensile strength could reach a maximum of 120 MPa. The reason for the average tensile strength of the joint increasing was that the weak zone of the joint using Zn–30Al filler metal was generated primarily by α-Al instead of MgZn2. When Zn–40Al was used as the filler metal, a new transition zone, about 20 μm-wide, appeared in the edge of the fusion zone near the Mg base metal. Due to the transition zones consisting of MgZn2- and Al-based solid solution, the mechanical property of the joints was deteriorated.

Sensor integration for robotic laser welding processes

NARCIS (Netherlands)

Iakovou, D.; Aarts, Ronald G.K.M.; Meijer, J.; Ostendorf, A; Hoult, A.; Lu, Y.

2005-01-01

The use of robotic laser welding is increasing among industrial applications, because of its ability to weld objects in three dimensions. Robotic laser welding involves three sub-processes: seam detection and tracking, welding process control, and weld seam inspection. Usually, for each sub-process,

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.

Reactor cooling water expansion joint bellows: The role of the seam weld in fatigue crack development

International Nuclear Information System (INIS)

West, S.L.; Nelson, D.Z.; Louthan, M.R. Jr.

1992-01-01

The secondary cooling water system pressure boundary of Savannah River Site reactors includes expansion joints utilizing a thin-wall bellows. While successfully used for over thirty years, an occasional replacement has been required because of the development of small, circumferential fatigue cracks in a bellows convolute. One such crack was recently shown to have initiated from a weld heat-affected zone liquation microcrack. The crack, initially open to the outer surface of the rolled and seam welded cylindrical bellows section, was closed when cold forming of the convolutes placed the outer surface in residual compression. However, the bellows was placed in tension when installed, and the tensile stresses reopened the microcrack. This five to eight grain diameter microcrack was extended by ductile fatigue processes. Initial extension was by relatively rapid propagation through the large-grained weld metal, followed by slower extension through the fine-grained base metal. A significant through-wall crack was not developed until the crack extended into the base metal on both sides of the weld. Leakage of cooling water was subsequently detected and the bellows removed and a replacement installed

Possibility of designing television control system for welded joint formation on electron beam welding

International Nuclear Information System (INIS)

Lifshits, M.L.; Lobanova, N.G.

1987-01-01

Regression equations (models), connecting seam characteristics: width and depth with the welding bath leading front in joint gap and seam width respectively - are obtained at electron beam welding of circular articles with guaranteed clearance with application of television control system. Dispersion analysis showed the models adequancy to the process in the range, where they were identified

Microstructure evolution of Al/Mg butt joints welded by gas tungsten arc with Zn filler metal

International Nuclear Information System (INIS)

Liu Fei; Zhang Zhaodong; Liu Liming

2012-01-01

Based on the idea of alloying welding seam, Gas tungsten arc welding method with pure Zn filler metal was chosen to join Mg alloy and Al alloy. The microstructures, phases, element distribution and fracture morphology of welding seams were examined. The results indicate that there was a transitional zone in the width of 80–100 μm between the Mg alloy substrate and fusion zone. The fusion zone was mainly composed of MgZn 2 , Zn-based solid solution and Al-based solid solution. The welding seam presented distinct morphology in different location owning to the quite high cooling rate of the molten pool. The addition of Zn metal could prevent the formation of Mg–Al intermetallics and form the alloyed welding seam during welding. Therefore, the tensile strengths of joints have been significantly improved compared with those of gas tungsten arc welded joints without Zn metal added. Highlights: ► Mg alloy AZ31B and Al alloy 6061 are welded successfully. ► Zinc wire is employed as a filler metal to form the alloyed welding seam. ► An alloyed welding seam is benefit for improving of the joint tensile strength.

Weld analysis and control system

Science.gov (United States)

Kennedy, Larry Z. (Inventor); Rodgers, Michael H. (Inventor); Powell, Bradley W. (Inventor); Burroughs, Ivan A. (Inventor); Goode, K. Wayne (Inventor)

1994-01-01

The invention is a Weld Analysis and Control System developed for active weld system control through real time weld data acquisition. Closed-loop control is based on analysis of weld system parameters and weld geometry. The system is adapted for use with automated welding apparatus having a weld controller which is capable of active electronic control of all aspects of a welding operation. Enhanced graphics and data displays are provided for post-weld analysis. The system provides parameter acquisition, including seam location which is acquired for active torch cross-seam positioning. Torch stand-off is also monitored for control. Weld bead and parent surface geometrical parameters are acquired as an indication of weld quality. These parameters include mismatch, peaking, undercut, underfill, crown height, weld width, puddle diameter, and other measurable information about the weld puddle regions, such as puddle symmetry, etc. These parameters provide a basis for active control as well as post-weld quality analysis and verification. Weld system parameters, such as voltage, current and wire feed rate, are also monitored and archived for correlation with quality parameters.

Q-switch Nd:YAG laser welding of AISI 304 stainless steel foils

Energy Technology Data Exchange (ETDEWEB)

P' ng, Danny [Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States); Molian, Pal [Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011-2161 (United States)], E-mail: molian@iastate.edu

2008-07-15

Conventional fusion welding of stainless steel foils (<100 {mu}m thickness) used in computer disk, precision machinery and medical device applications suffer from excessive distortion, formation of discontinuities (pore, void and hot crack), uncontrolled melting (melt-drop through) and poor aesthetics. In this work, a 15 ns pulsed, 400 mJ Nd:YAG laser beam was utilized to overcome these barriers in seam welding of 60 {mu}m thin foil of AISI 304 stainless steel. Transmission electron microscopy was used to characterize the microstructures while hardness and tensile-shear tests were used to evaluate the strengths. Surface roughness was measured using a DekTak profilometer while porosity content was estimated using the light microscope. Results were compared against the data obtained from resistance seam welding. Laser welding, compared to resistance seam welding, required nearly three times less heat input and produced welds having 50% narrower seam, 15% less porosity, 25% stronger and improved surface aesthetics. In addition, there was no evidence of {delta}-ferrite in laser welds, supporting the absence of hot cracking unlike resistance welding.

Integrated sensors for robotic laser welding

NARCIS (Netherlands)

Iakovou, D.; Aarts, Ronald G.K.M.; Meijer, J.; Beyer, E.; Dausinger, F; Ostendorf, A; Otto, A.

2005-01-01

A welding head is under development with integrated sensory systems for robotic laser welding applications. Robotic laser welding requires sensory systems that are capable to accurately guide the welding head over a seam in three-dimensional space and provide information about the welding process as

Unraveling the Processing Parameters in Friction Stir Welding

Science.gov (United States)

Schneider, Judy; Nunes, Arthur C., Jr.

2005-01-01

In friction stir welding (FSW), a rotating threaded pin tool is translated along a weld seam, literally stirring the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path or paths is required. In this study, various markers are used to trace the flow paths of the metal. X-ray radiographs record the segmentation and position of the wire. Several variations in the trajectories can be differentiated within the weld zone.

Study on robot motion control for intelligent welding processes based on the laser tracking sensor

Science.gov (United States)

Zhang, Bin; Wang, Qian; Tang, Chen; Wang, Ju

2017-06-01

A robot motion control method is presented for intelligent welding processes of complex spatial free-form curve seams based on the laser tracking sensor. First, calculate the tip position of the welding torch according to the velocity of the torch and the seam trajectory detected by the sensor. Then, search the optimal pose of the torch under constraints using genetic algorithms. As a result, the intersection point of the weld seam and the laser plane of the sensor is within the detectable range of the sensor. Meanwhile, the angle between the axis of the welding torch and the tangent of the weld seam meets the requirements. The feasibility of the control method is proved by simulation.

Automatic weld torch guidance control system

Science.gov (United States)

Smaith, H. E.; Wall, W. A.; Burns, M. R., Jr.

1982-01-01

A highly reliable, fully digital, closed circuit television optical, type automatic weld seam tracking control system was developed. This automatic tracking equipment is used to reduce weld tooling costs and increase overall automatic welding reliability. The system utilizes a charge injection device digital camera which as 60,512 inidividual pixels as the light sensing elements. Through conventional scanning means, each pixel in the focal plane is sequentially scanned, the light level signal digitized, and an 8-bit word transmitted to scratch pad memory. From memory, the microprocessor performs an analysis of the digital signal and computes the tracking error. Lastly, the corrective signal is transmitted to a cross seam actuator digital drive motor controller to complete the closed loop, feedback, tracking system. This weld seam tracking control system is capable of a tracking accuracy of + or - 0.2 mm, or better. As configured, the system is applicable to square butt, V-groove, and lap joint weldments.

Constitutive model of friction stir weld with consideration of its inhomogeneous mechanical properties

Science.gov (United States)

Zhang, Ling; Min, Junying; Wang, Bin; Lin, Jianping; Li, Fangfang; Liu, Jing

2016-03-01

In practical engineering, finite element(FE) modeling for weld seam is commonly simplified by neglecting its inhomogeneous mechanical properties. This will cause a significant loss in accuracy of FE forming analysis, in particular, for friction stir welded(FSW) blanks due to the large width and good formability of its weld seam. The inhomogeneous mechanical properties across weld seam need to be well characterized for an accurate FE analysis. Based on a similar AA5182 FSW blank, the metallographic observation and micro-Vickers hardness analysis upon the weld cross-section are performed to identify the interfaces of different sub-zones, i.e., heat affected zone(HAZ), thermal-mechanically affected zone(TMAZ) and weld nugget(WN). Based on the rule of mixture and hardness distribution, a constitutive model is established for each sub-zone to characterize the inhomogeneous mechanical properties across the weld seam. Uniaxial tensile tests of the AA5182 FSW blank are performed with the aid of digital image correlation(DIC) techniques. Experimental local stress-strain curves are obtained for different weld sub-zones. The experimental results show good agreement with those derived from the constitutive models, which demonstrates the feasibility and accuracy of these models. The proposed research gives an accurate characterization of inhomogeneous mechanical properties across the weld seam produced by FSW, which provides solutions for improving the FE simulation accuracy of FSW sheet forming.

Laser welding closed-loop power control

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove

2003-01-01

A closed-loop control system is developed to maintain an even seam width on the root side of a laser weld by continually controlling the output laser power of a 1500 W CO2 laser.......A closed-loop control system is developed to maintain an even seam width on the root side of a laser weld by continually controlling the output laser power of a 1500 W CO2 laser....

Electron beam welding of high-purity copper accelerator cells

International Nuclear Information System (INIS)

Delis, K.; Haas, H.; Schlebusch, P.; Sigismund, E.

1986-01-01

The operating conditions of accelerator cells require high thermal conductivity, low gas release in the ultrahigh vacuum, low content of low-melting metals and an extremely good surface quality. In order to meet these requirements, high-purity copper (OFHC, Grade 1, according to ASTM B 170-82 and extra specifications) is used as structural material. The prefabricated components of the accelerator cells (noses, jackets, flanges) are joined by electron beam welding, the weld seam being assessed on the basis of the same criteria as the base material. The welding procedures required depend, first, on the material and, secondly, on the geometries involved. Therefore experimental welds were made first on standardized specimens in order to study the behaviour of the material during electron beam welding and the influence of parameter variations. The welded joints of the cell design were planned on the basis of these results. Seam configuration, welding procedures and the parameters were optimized on components of original geometry. The experiments have shown that high-quality joints of this grade of copper can be produced by the electron beam welding process, if careful planning and preparation of the seams and adequate containment of the welding pool are assured. (orig.)

Plasma Arc Augmented CO2 laser welding

DEFF Research Database (Denmark)

Bagger, Claus; Andersen, Mikkel; Frederiksen, Niels

2001-01-01

In order to reduce the hardness of laser beam welded 2.13 mm medium strength steel CMn 250, a plasma arc has been used simultaneously with a 2.6 kW CO2 laser source. In a number of systematic laboratory tests, the plasma arc current, plasma gas flow and distance to the laser source were varied...... with all laser parameters fixed. The welds were quality assessed and hardness measured transversely to the welding direction in the top, middle and root of the seam. In the seams welded by laser alone, hardness values between 275 and 304 HV1 were measured, about the double of the base material, 150 HV1...

The narrow-gap TIG welding concerns the electric power plants manufacturers

International Nuclear Information System (INIS)

Anon.

2009-01-01

Polysoude, France, played host to an expert forum on narrow gap welding from 5-7 November 2008. The successful event welcomed around one hundred experts.The power plant construction sector is currently booming worldwide. For plant construction this means using more pressure-resistant, thick-walled pipes made from high temperature steels. The key quality features of this new steel grade are the values for high creep rupture strength that also apply without restriction as the benchmark for every weld seam on these pipes. In particular, the forum on narrow gap welding addressed this area of automated welding technology. During the forum, Mr Hans-Peter Mariner (Polysoude's CEO), has offered an in-depth insight into the latest developments in narrow gap welding. This presentation highlighted that with wall thicknesses of over 60 mm, welding time is shortened by a factor of five to ten in comparison to conventional TIG processes with a traditional V seam. The welding characteristics of the parent material are the decisive factor in the application of the narrow gap process. Technical advances in equipment technology such as automatic centring, HF-free ignition, seam preparation and optimised gas protection further increase the application limits. The geometry and gap width of the weld groove are based on the mechanical properties of the materials being joined, with the shrinkage characteristics of the seam being particularly important. Another key part of the programme was a presentation on the three different narrow gap-welding techniques. The first involves a single pass weld per layer and torch or work-piece revolution. The second is dual pass welding next to one another, when the seam preparation or positioning exceed the required narrow tolerances of a few tenths of a millimetre for one stringer bead per layer. TIG narrow gap welding with a shuttle-motion electrode is ideal with very large wall thicknesses of 150-200 mm. This is particularly the case if the

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

A Brief Introduction to the Theory of 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 is already an important welding process for the aerospace industry, where welds of optimal quality are demanded. The structure of welds determines weld properties. The structure of friction stir welds is determined by the flow field in the weld metal in the vicinity of the weld tool. A simple kinematic model of the FSW flow field developed at Marshall Space Flight Center, which enables the basic features of FSW microstructure to be understood and related to weld process parameters and tool design, is explained.

Effects of Fusion Tack Welds on Self-Reacting Friction Stir Welds

Science.gov (United States)

Nunes, A. C., Jr.; Pendleton, M. L.; Brooke, S. A.; Russell, C. K.

2012-01-01

In order to know whether fusion tack welds would affect the strength of self-reacting friction stir seam welds in 2195-T87 aluminum alloy, the fracture stresses of 144 tensile test coupons cut from 24 welded panels containing segments of friction stir welds were measured. Each of the panels was welded under unique processing conditions. A measure of the effect of the tack welds for each panel was devised. An analysis of the measures of the tack weld effect supported the hypothesis that fusion tack welds do not affect the strength of self-reacting friction stir welds to a 5% level of confidence.

Welding induced residual stress evaluation using laser-generated Rayleigh waves

Science.gov (United States)

Ye, Chong; Zhou, Yuanlai; Reddy, Vishnu V. B.; Mebane, Aaron; Ume, I. Charles

2018-04-01

Welding induced residual stress could affect the dimensional stability, fatigue life, and chemical resistance of the weld joints. Ultrasonic method serves as an important non-destructive tool for the residual stress evaluation due to its easy implementation, low cost and wide application to different materials. Residual stress would result in the ultrasonic wave velocity variation, which is the so called acoustoelastic effect. In this paper, Laser/EMAT ultrasonic technique was proposed to experimentally study the relative velocity variation ΔV/V of Rayleigh wave, which has the potential to evaluate surface/subsurface longitudinal residual stress developed during the Gas Metal Arc Welding process. Broad band ultrasonic waves were excited by pulsed Q-Switched Nd: YAG laser. An electromagnetic acoustic transducer (EMAT) attached to the welded plates was used to capture the Rayleigh wave signals propagating along the weld seam direction. Different time of flight measurements were conducted by varying the distance between the weld seam and Rayleigh wave propagating path in the range of 0 to 45 mm. The maximum relative velocity difference was found on the weld seam. With the increasing distance away from the weld seam, the relative velocity difference sharply decreased to negative value. With further increase in distance, the relative velocity difference slowly increased and approached zero. The distribution of relative velocity variations indicates that tensile stress appears in the melted zone as it becomes compressive near the heat-affected zone.

Development of technique for laser welding of biological tissues using laser welding device and nanocomposite solder.

Science.gov (United States)

Gerasimenko, A; Ichcitidze, L; Podgaetsky, V; Ryabkin, D; Pyankov, E; Saveliev, M; Selishchev, S

2015-08-01

The laser device for welding of biological tissues has been developed involving quality control and temperature stabilization of weld seam. Laser nanocomposite solder applied onto a wound to be weld has been used. Physicochemical properties of the nanocomposite solder have been elucidated. The nature of the tissue-organizing nanoscaffold has been analyzed at the site of biotissue welding.

Assisting Gas Optimization in CO2 Laser Welding

DEFF Research Database (Denmark)

Gong, Hui; Olsen, Flemming Ove

1996-01-01

High quality laser welding is achieved under the condition of optimizing all process parameters. Assisting gas plays an important role for sound welds. In the conventional welding process assisting gas is used as a shielding gas to prevent that the weld seam oxidates. In the laser welding process...... assisting gas is also needed to control the laser induced plasma.Assisting gas is one of the most important parameters in the laser welding process. It is responsible for obtaining a quality weld which is characterized by deep penetration, no interior imperfections, i.e. porosity, no crack, homogeneous seam...... surface, etc. In this work a specially designed flexible off-axis nozzle capable of adjusting the angle of the nozzle, the diameter of the nozzle, and the distance between the nozzle end and the welding zone is tested. In addition to the nozzle parameters three gases, Nitrogen, Argon, and Helium...

ICT diagnostic method of beryllium welding quality

International Nuclear Information System (INIS)

Sun Lingxia; Wei Kentang; Ye Yunchang

2002-01-01

To avoid the interference of high density material for the quality assay of beryllium welding line, a slice by slice scanning method was proposed based upon the research results of the Industrial Computerized Tomography (ICT) diagnostics for weld penetration, weld width, off-centered deviation and weld defects of beryllium-ring welding seam with high density material inside

Drag resistance of ship hulls: Effects of surface roughness of newly applied fouling control coatings, coating water absorption, and welding seams

DEFF Research Database (Denmark)

Wang, Xueting; Olsen, Stefan Møller; Andrés, Eduardo

2018-01-01

selected, that a so-called fouling release (FR) coating caused approximately 5.6 % less skin friction (torque) over time than traditional biocide-based antifouling (AF) coatings at a tangential speed of 12 knots. Furthermore, results of immersion experiments and supporting “standard” water absorption......Fouling control coatings (FCCs) and irregularities (e.g. welding seams) on ship hull surfaces have significant effects on the overall drag performance of ships. In this work, skin frictions of four newly applied FCCs were compared using a pilot-scale rotary setup. Particular attention was given...

Passive Visual Sensing in Automatic Arc Welding

DEFF Research Database (Denmark)

Liu, Jinchao

For decades much work has been devoted to the research and development of automatic arc welding systems. However, it has remained a challenging problem. Besides the very complex arc welding process itself, the lack of ability to precisely sense the welding process, including the seam geometry...... and the weld pool, has also prevented the realization of a closed-loop control system for many years, even though a variety of sensors have been developed. Among all the sensor systems, visual sensors have the advantage of receiving visual information and have been drawn more and more attentions. Typical...... industrial solutions for seam detection such as using laser scanners suer from several limitations. For instance, it must be positioned some distance ahead to the molten pool and may cause problem when dealing with shiny surfaces. Existing techniques for weld pool sensing mostly rely on auxiliary light...

A comparative study of laser beam welding and laser-MIG hybrid welding of Ti-Al-Zr-Fe titanium alloy

International Nuclear Information System (INIS)

Li Ruifeng; Li Zhuguo; Zhu Yanyan; Rong Lei

2011-01-01

Research highlights: → Ti-Al-Zr-Fe titanium alloy sheets were welded by LBW and LAMIG methods. → LAMIG welded joints have better combination of strength and ductility. → LAMIG welding is proved to be feasible for the production of titanium sheet joints. - Abstract: Ti-Al-Zr-Fe titanium alloy sheets with thickness of 4 mm were welded using laser beam welding (LBW) and laser-MIG hybrid welding (LAMIG) methods. To investigate the influence of the methods difference on the joint properties, optical microscope observation, microhardness measurement and mechanical tests were conducted. Experimental results show that the sheets can be welded at a high speed of 1.8 m/min and power of 8 kW, with no defects such as, surface oxidation, porosity, cracks and lack of penetration in the welding seam. In addition, all tensile test specimens fractured at the parent metal. Compared with the LBW, the LAMIG welding method can produce joints with higher ductility, due to the improvement of seam formation and lower microhardness by employing a low strength TA-10 welding wire. It can be concluded that LAMIG is much more feasible for welding the Ti-Al-Zr-Fe titanium alloy sheets.

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

The effect of axial external magnetic field on tungsten inert gas welding of magnesium alloy

Science.gov (United States)

Li, Caixia; Zhang, Xiaofeng; Wang, Jing

2018-04-01

The influences of axial external magnetic field on the microstructure and mechanical property of the AZ31 magnesium (Mg) alloy joints were studied. The microstructure of Mg alloy joint consisted of the weld seam, heat affected zone and base metal zone. The average grain size of weld seam welded with magnetic field is 39 μm, which is 38% smaller than that of the joint welded with absence of magnetic field. And the microhardness of weld seam increases with the help of magnetic field treatment, owing to the coarse grain refinement. With coil current of 2.0A, the maximum mechanical property of joint increases 6.7% to 255 MPa over the specimen without magnetic field treatment. Furthermore, fracture location is near heat affected area and the fracture surface is characterized with ductile fracture.

Computer Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding

Science.gov (United States)

Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.

2004-01-01

In friction stir welding, a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. This solid-state technique has been successfully used in the joining of materials that are difficult to fusion weld such as aluminum alloys. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and thus tracks the aluminum deformation flow paths in a unique 3-dimensional manner. CT scanning is a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.

Computed Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding

Science.gov (United States)

Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.

2005-01-01

In friction stir welding (FSW), a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and is carried with the macro-flow of the weld metal. By using CT images, a 3-dimensional (3D) image of the lead flow pattern can be reconstructed. CT imaging was found to be a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.

Diffractive beam shaping for enhanced laser polymer welding

Science.gov (United States)

Rauschenberger, J.; Vogler, D.; Raab, C.; Gubler, U.

2015-03-01

Laser welding of polymers increasingly finds application in a large number of industries such as medical technology, automotive, consumer electronics, textiles or packaging. More and more, it replaces other welding technologies for polymers, e. g. hot-plate, vibration or ultrasonic welding. At the same rate, demands on the quality of the weld, the flexibility of the production system and on processing speed have increased. Traditionally, diode lasers were employed for plastic welding with flat-top beam profiles. With the advent of fiber lasers with excellent beam quality, the possibility to modify and optimize the beam profile by beam-shaping elements has opened. Diffractive optical elements (DOE) can play a crucial role in optimizing the laser intensity profile towards the optimal M-shape beam for enhanced weld seam quality. We present results on significantly improved weld seam width constancy and enlarged process windows compared to Gaussian or flat-top beam profiles. Configurations in which the laser beam diameter and shape can be adapted and optimized without changing or aligning the laser, fiber-optic cable or optical head are shown.

Development of automatic laser welding system

International Nuclear Information System (INIS)

Ohwaki, Katsura

2002-01-01

Laser are a new production tool for high speed and low distortion welding and applications to automatic welding lines are increasing. IHI has long experience of laser processing for the preservation of nuclear power plants, welding of airplane engines and so on. Moreover, YAG laser oscillators and various kinds of hardware have been developed for laser welding and automation. Combining these welding technologies and laser hardware technologies produce the automatic laser welding system. In this paper, the component technologies are described, including combined optics intended to improve welding stability, laser oscillators, monitoring system, seam tracking system and so on. (author)

Evaluation of Distortion in Welding Unions of 304 Stainless Steel with Elliptic Trajectory Using a Welding Robot

Science.gov (United States)

Carrasco-González, L. A.; Hurtado-Delgado, E.; Reyes-Valdés, F. A.

The aim of this investigation is to evaluate the distortions generated in welding unions of stainless steel 304 by effect of the welding temperature and the microestructural changes. The joint design is a 100 × 100 mm steel plate of 3 mm thickness. The plate was joined to a tube of 50 mm diameter and 2 mm thickness, which has a defined angular cut; therefore, the trajectory followed by the seam has an elliptic form. Temperature data acquisition was developed by type K thermocouples, placed in pairs at 0°, 90°, 180° and 270° along the welding trajectory and connected to a data acquisition device yo obtain the measures to generate time-temperature plots. The welding process was executed by a KUKA ®; KR16 welding robot with an integrated GMAW (Gas metal arc welding) process where the input parameters of voltage, wire feed and travel speed are set to constant. The distortion of the work piece was measured using a laser scanning technique that generates a point cloud with the VXelements TM software for comparison between the pre and post-weld condition. Microstructural evaluation was performed on transversal sections of the seam, at the mentioned angles for correlation.

Sensor development and integration for robotized laser welding

NARCIS (Netherlands)

Iakovou, D.

2009-01-01

Laser welding requires fast and accurate positioning of the laser beam over the seam trajectory. The task of accurate positioning of the laser tools is performed by robotic systems. It is therefore necessary to teach the robot the path it has to follow. Seam teaching is implemented in several ways:

Measuring weld heat to evaluate weld integrity

Energy Technology Data Exchange (ETDEWEB)

Schauder, V., E-mail: schauder@hks-prozesstechnik.de [HKS-Prozesstechnik GmbH, Halle (Germany)

2015-11-15

Eddy current and ultrasonic testing are suitable for tube and pipe mills and have been used for weld seam flaw detection for decades, but a new process, thermography, is an alternative. By measuring the heat signature of the weld seam as it cools, it provides information about weld integrity at and below the surface. The thermal processes used to join metals, such as plasma, induction, laser, and gas tungsten arc welding (GTAW), have improved since they were developed, and they get better with each passing year. However, no industrial process is perfect, so companies that conduct research in flaw detection likewise continue to develop and improve the technologies used to verify weld integrity: ultrasonic testing (UT), eddy current testing (ET), hydrostatic, X-ray, magnetic particle, and liquid penetrant are among the most common. Two of these are used for verifying the integrity of the continuous welds such as those used on pipe and tube mills: UT and ET. Each uses a transmitter to send waves of ultrasonic energy or electrical current through the material and a receiver (probe) to detect disturbances in the flow. The two processes often are combined to capitalize on the strengths of each. While ET is good at detecting flaws at or near the surface, UT penetrates the material, detecting subsurface flaws. One drawback is that sound waves and electrical current waves have a specific direction of travel, or an alignment. A linear defect that runs parallel to the direction of travel of the ultrasonic sound wave or a flaw that is parallel to the coil winding direction of the ET probe can go undetected. A second drawback is that they don't detect cold welds. An alternative process, thermography, works in a different fashion: It monitors the heat of the material as the weld cools. Although it measures the heat at the surface, the heat signature provides clues about cooling activity deep in the material, resulting in a thorough assessment of the weld's integrity It

Technology of electron beam welding for Zr-4 alloy spacer grid

International Nuclear Information System (INIS)

Pei Qiusheng; Wu Xueyi; Yang Qishun

1989-10-01

The welding technology for Zr-4 alloy spacer grid by using vacuum electron beam was studied. Through a series of welding technological experiments, metallographic examinations of seam structure and detecting tests for welding defect by X-ray defectoscopy, a good welding technology was selected to meet the requirements. The experimental results indicated that the Zr-4 alloy spacer grid welded by vacuum electron beam welding is feasible

Movement of liquid metal in welding bath during welding in longitudinal magnetic field

International Nuclear Information System (INIS)

Kovalev, I.M.; Rybakov, A.S.

1977-01-01

The specific features are considered of liquid metal flow in a bath during welding of steel 12Kh18N10T plates with a non-consumable electrode in argon under interaction of the arc and bath with a longitudinal constant magnetic field. In controlling the velocity field of metal flow, the longitudinal magnetic field permits to form a seam at automatic welding of horizontal joints on a vertical plane

Metals welding by using laser

International Nuclear Information System (INIS)

Al-Qaisy, R.A.W.

1991-01-01

In the present work, same welding ''conduction limited type'' under atmospheric conditions was performed using pulsed Ng:YAG laser to weld; low carbon steel (LCS), stainless steel (304) (SUS304), stainless steel (303) (SUS303), and brass. Microstructure of welded zone, heat affected zone (HAZ), and the laser energy on penetration depth and effective diameter were studied. Tensile test, micro-hardness, and surface roughness of welded and parent metals were also dealt with. Melting efficiency was worked out and an under vacuum seam welding of low carbon steel has been accomplished. Finally spot welding of aluminium tungsten, and platinium wires were employed using different layer energies. 34 tabs.; 82 figs.; 51 refs.; 1 app

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.

Setting reinspection intervals for seam welded piping by use of probabilistic fracture mechanics and target reliability values

International Nuclear Information System (INIS)

Harris, D.O.; Dedhia, D.

1995-01-01

The purpose of this paper is to describe a procedure for the selection of a reinspection interval for defects found during an inspection. The procedure is based on probabilistic fracture mechanics calculations of the reliability of the component into the future and selection of an inspection time based on maintaining the target value reliability. The selection of a target value based on the risk of everyday activities is discussed. The procedure is applied to high temperature seam welded piping as an example, because the probabilistic fracture mechanics tools are relatively readily available and this is a problem of great current interest. The results obtained in the example problem indicate reinspection intervals much shorter than field experience would suggest. This indicates a conservatism in the fracture mechanics procedures and/or lack of accurate characterization of scatter in material properties due to lack of data. The general procedure should prove useful in the disposition of detected cracks in a wide variety of situations

Novel low-cost vision-sensing technology with controllable of exposal time for welding

Science.gov (United States)

Zhang, Wenzeng; Wang, Bin; Chen, Nian; Cao, Yipeng

2005-02-01

In the process of robot Welding, position of welding seam and welding pool shape is detected by CCD camera for quality control and seam tracking in real-time. It is difficult to always get a clear welding image in some welding methods, such as TIG welding. A novel idea that the exposal time of CCD camera is automatically controlled by arc voltage or arc luminance is proposed to get clear welding image. A set of special device and circuits are added to a common industrial CCD camera in order to flexibly control the CCD to start or close exposal by control of the internal clearing signal of the accumulated charge. Two special vision sensors according to the idea are developed. Their exposal grabbing can be triggered respectively by the arc voltage and the variety of the arc luminance. Two prototypes have been designed and manufactured. Experiments show that they can stably grab clear welding images at appointed moment, which is a basic for the feedback control of automatic welding.

Structure and properties of an aluminium alloy welded by electron beam

International Nuclear Information System (INIS)

Ruzimov, Sh.M.; Palvanov, S.R.; Pogrebnjak, A.D.

2005-01-01

Full text: In the given work the experimental results on research of influence of electronic beams on structure of an aluminum alloy are submitted. As a basis of samples the alloy Al-Mg-Zn-Cu by the additives Se-0.5 % and Nb-0.15 % is chosen. Samples from a cast aluminum alloy by thickness of 3 mm such as B-96 were welded with an electronic beam in three different modes at radius circle of a root of a welded seam of 5 mm. The welding was carried out by an alloy Amg 63 and Sv-1571 with application electron team welding joint of parts. The basic influence on the given process makes energy - allocation of an electronic beam. For research of phase structure used of X-ray beams (XRD), DRON-2 in copper K α - Cu measurement. For research of structure and morphology of a surface used optical microscope with increase 800-1500 times and electronic microscope with the microanalysis. On figures of optical microscopy the morphology of a seam sharply differs from morphology of an initial part. The microanalysis carried out with a place of a seam, has shown presence of the whole spectrum of elements, such as, Al; Zn; Na; Mg; Cu; and Mn. All measurements carried out in welding zone and in frontier zones that it was possible to carry out the comparative analysis. The element structure of these zones essentially differs in dependence of a condition of welding

New technology for production of granular adding material with nanomodifying additives for steel arc welding

Directory of Open Access Journals (Sweden)

BOLDYREV Alexander Mikhaylovich

2016-12-01

Full Text Available The chemical analysis of metal seam showed that introduction of titanium dioxide with MCA intensifies transition of Al2O3 from slag into metal pool and provides double concentration of titanium in the seam compared to the one which appears in the interaction of bathtub with melted flux AH-47 without TiO2 additives. The presence of oxides of titanium and aluminium of endogenous origin in the melt leads to formation of refractory particles with the center of TiO2 and Al2O3 in it. These particles are the centers of crystallization in the tail part of the molten pool and they remain in seam metal in the form of evenly distributed fine nonmetallic inclusions, which have crystallographic affinity with a matrix (α-iron. That provides the fine-grained seam structure with the raised and stable strength characteristics. This article compares the existing and developed technologies for production of MCA. The granulometric analysis of the powder TiO2 has demonstrated that when MCA is processed in the planetary mill, particles of titanium dioxide are crushed to a nanodimensional order. It is shown that the preparation of MCA in high-energy planetary mill (due to double increase of durability in coupling of the modifier with granulate provides its stable structure, increases the cold resistance (20–25% and stability of strength characteristics along the length of welded seam. Metalgraphic researches determined that the fine-grained structure which linear size of grain is twice smaller than the one obtained in the old technology welding is formed in a seam. However the direct introduction of nanomodifiers in a molten pool through the flux or an electrode wire is not efficient because of their deactivation and high temperature in welding zone. Therefore it was offered to use modifiers in the mix with the cooling macroparticles in case of automatic welding of a bridge metalware under flux using metalchemical additive (MCA. The MCA consists of a chopped

Metal flow of a tailor-welded blank in deep drawing process

Science.gov (United States)

Yan, Qi; Guo, Ruiquan

2005-01-01

Tailor welded blanks were used in the automotive industry to consolidate parts, reduce weight, and increase safety. In recent years, this technology was developing rapidly in China. In Chinese car models, tailor welded blanks had been applied in a lot of automobile parts such as rail, door inner, bumper, floor panel, etc. Concerns on the properties of tailor welded blanks had become more and more important for automobile industry. A lot of research had shown that the strength of the welded seam was higher than that of the base metal, such that the weld failure in the aspect of strength was not a critical issue. However, formability of tailor welded blanks in the stamping process was complex. Among them, the metal flow of tailor welded blanks in the stamping process must be investigated thoroughly in order to reduce the scrap rate during the stamping process in automobile factories. In this paper, the behavior of metal flow for tailor welded blanks made by the laser welding process with two types of different thickness combinations were studied in the deep drawing process. Simulations and experiment verification of the movement of weld line for tailor welded blanks were discussed in detail. Results showed that the control on the movement of welded seam during stamping process by taking some measures in the aspect of blank holder was effective.

Optical design and development of a fiber coupled high-power diode laser system for laser transmission welding of plastics

Science.gov (United States)

Rodríguez-Vidal, Eva; Quintana, Iban; Etxarri, Jon; Azkorbebeitia, Urko; Otaduy, Deitze; González, Francisco; Moreno, Fernando

2012-12-01

Laser transmission welding (LTW) of thermoplastics is a direct bonding technique already used in different industrial applications sectors such as automobiles, microfluidics, electronics, and biomedicine. LTW evolves localized heating at the interface of two pieces of plastic to be joined. One of the plastic pieces needs to be optically transparent to the laser radiation whereas the other part has to be absorbent, being that the radiation produced by high power diode lasers is a good alternative for this process. As consequence, a tailored laser system has been designed and developed to obtain high quality weld seams with weld widths between 0.7 and 1.4 mm. The developed laser system consists of two diode laser bars (50 W per bar) coupled into an optical fiber using a nonimaging solution: equalization of the beam parameter product (BPP) in the slow and fast axes by a pair of step-mirrors. The power scaling was carried out by means of a multiplexing polarization technique. The analysis of energy balance and beam quality was performed considering ray tracing simulation (ZEMAX) and experimental validation. The welding experiments were conducted on acrylonitrile/butadiene/styrene (ABS), a thermoplastic frequently used in automotive, electronics and aircraft applications, doped with two different concentrations of carbon nanotubes (0.01% and 0.05% CNTs). Quality of the weld seams on ABS was analyzed in terms of the process parameters (welding speed, laser power and clamping pressure) by visual and optical microscope inspections. Mechanical properties of weld seams were analyzed by mechanical shear tests. High quality weld seams were produced in ABS, revealing the potential of the laser developed in this work for a wide range of plastic welding applications.

The use of electromagnetic body forces to enhance the quality of laser welds

Science.gov (United States)

Ambrosy, Guenter; Berger, P.; Huegel, H.; Lindenau, D.

2003-11-01

The use of electromagnetic body forces in laser beam welding of aluminum alloys is a new method to shape the geometry and to enhance the quality of the weld seams. In this new approach, electromagnetic volume forces are utilized by applying magnetic fields and electric currents of various origins. Acting in the liquid metal, they directly affect the flow field and can lead to favourable conditions for the melt dynamics and energy coupling. Numerous welds with full and partial penetration using both CO2 and Nd:YAG lasers demonstrate that this method directly influences the seam geometry and top-bead topography as well as the penetration depth and the evolution of pores and cracks. In the case of full penetration, it is also possible to lift or to lower the weld pool. The method, therefore, can be used to shape the geometry and to enhance the quality of the weld seam. Depending on the orientation of an external magnetic field, significant impacts are achieved in CO2 welding, even without an external current: the shape of the cross-sectional area can be increased of up to 50% and also the seam width is changed. Whereas for such conditions with Nd:YAG lasers no significant effect could be observed, it turned out that, when an external electric current is applied, similar effects are present with both wavelengths. In further investigations, the effect of electromagnetic body forces resulting from the interaction of an external current and its self-induced magnetic field was studied. Hereby, the current was fed into the workpiece via a tungsten electrode or a filler wire. The resulting phenomena are the same independent from wavelength and means of current feed.

Mechanism and Microstructure of Oxide Fluxes for Gas Tungsten Arc Welding of Magnesium Alloy

Science.gov (United States)

Liu, L. M.; Zhang, Z. D.; Song, G.; Wang, L.

2007-03-01

Five single oxide fluxes—MgO, CaO, TiO2, MnO2, and Cr2O3—were used to investigate the effect of active flux on the depth/width ratio in AZ31B magnesium alloy. The microstructure and mechanical property of the tungsten inert gas (TIG) welding seam were studied. The oxygen content in the weld seam and the arc images during the TIG welding process were analyzed. A series of emission spectroscopy of weld arc for TIG welding for magnesium with and without flux were developed. The results showed that for the five single oxide fluxes, all can increase the weld penetration effectively and grain size in the weld seam of alternating current tungsten inert gas (ACTIG) welding of the Mg alloy. The oxygen content of the welds made without flux is not very different from those produced with oxide fluxes not considering trapped oxide. However, welds that have the best penetration have a relatively higher oxygen content among those produced with flux. It was found that the arc images with the oxide fluxes were only the enlarged form of the arc images without flux; the arc constriction was not observed. The detection of arc spectroscopy showed that the metal elements in the oxides exist as the neutral atom or the first cation in the weld arc. This finding would influence the arc properties. When TIG simulation was carried out on a plate with flux applied only on one side, the arc image video showed an asymmetric arc, which deviated toward the flux free side. The thermal stability, the dissociation energy, and the electrical conductivity of oxide should be considered when studying the mechanism for increased TIG flux weld penetration.

The narrow-gap TIG welding concerns the electric power plants manufacturers; Le soudage en joint etroit suscite l'interet des constructeurs de centrales electriques

Energy Technology Data Exchange (ETDEWEB)

Anon

2009-05-15

Polysoude, France, played host to an expert forum on narrow gap welding from 5-7 November 2008. The successful event welcomed around one hundred experts.The power plant construction sector is currently booming worldwide. For plant construction this means using more pressure-resistant, thick-walled pipes made from high temperature steels. The key quality features of this new steel grade are the values for high creep rupture strength that also apply without restriction as the benchmark for every weld seam on these pipes. In particular, the forum on narrow gap welding addressed this area of automated welding technology. During the forum, Mr Hans-Peter Mariner (Polysoude's CEO), has offered an in-depth insight into the latest developments in narrow gap welding. This presentation highlighted that with wall thicknesses of over 60 mm, welding time is shortened by a factor of five to ten in comparison to conventional TIG processes with a traditional V seam. The welding characteristics of the parent material are the decisive factor in the application of the narrow gap process. Technical advances in equipment technology such as automatic centring, HF-free ignition, seam preparation and optimised gas protection further increase the application limits. The geometry and gap width of the weld groove are based on the mechanical properties of the materials being joined, with the shrinkage characteristics of the seam being particularly important. Another key part of the programme was a presentation on the three different narrow gap-welding techniques. The first involves a single pass weld per layer and torch or work-piece revolution. The second is dual pass welding next to one another, when the seam preparation or positioning exceed the required narrow tolerances of a few tenths of a millimetre for one stringer bead per layer. TIG narrow gap welding with a shuttle-motion electrode is ideal with very large wall thicknesses of 150-200 mm. This is particularly the case if the

Infrared temperature measurement and interference analysis of magnesium alloys in hybrid laser-TIG welding process

International Nuclear Information System (INIS)

Huang, R.-S.; Liu, L.-M.; Song, G.

2007-01-01

Infrared (IR) temperature measurement, as a convenient, non-contact method for making temperature field measurements, has been widely used in the fields of welding, but the problem of interference from radiant reflection is a complicating factor in applying IR temperature sensing to welding. The object of this research is to make a deep understand about the formation of interference, explore a new method to eliminate the interfering radiation during laser-TIG hybrid welding of magnesium alloys and to obtain the distribution of temperature field accurately. The experimental results showed that the interferences caused by radiant specular reflection of arc light, ceramic nozzle, electrode and laser nozzle were transferred out of welding seam while the IR thermography system was placed perpendicularly to welding seam. And the welding temperature distribution captured by IR termography system which had been calibrated by thermocouple was reliable by using this method in hybrid laser-TIG welding process of AZ31B magnesium alloy

Thin seam mining

Energy Technology Data Exchange (ETDEWEB)

Sikora, W [Politechnika Slaska, Gliwice (Poland). Instytut Mechanizacji Gornictwa

1989-06-01

Discusses thin seam mining in Poland and its prospects. There were 194 working faces in coal seams to 1.5 m thick in Poland in 1988. Of them, 115 fell on faces with powered supports, 79 on faces with SHC-40 and Valent props; 108 shearer loaders and 45 coal plows were used for longwall mining of thin coal seams. Drilling and blasting was used to mine 21 working faces. Longwall faces in seams to 1.0 m thick gave 2.0% coal output, faces in coal seams 1.01-1.5 m thick gave 12.2% of daily coal output of underground mining. Structure of daily coal output of faces in thin seams was the following: 52 faces below 300 t/day, 42 from 301-500 t/day, 63 from 501 to 1,000 t/day, 17 faces above 1,000 t/day. Prospects for increasing coal output of faces in thin seams are discussed. 7 refs.

Fundamental Laser Welding Process Investigations

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove

1998-01-01

In a number of systematic laboratory investigations the fundamental behavior of the laser welding process was analyzed by the use of normal video (30 Hz), high speed video (100 and 400 Hz) and photo diodes. Sensors were positioned to monitor the welding process from both the top side and the rear...... side of the specimen.Special attention has been given to the dynamic nature of the laser welding process, especially during unstable welding conditions. In one series of experiments, the stability of the process has been varied by changing the gap distance in lap welding. In another series...... video pictures (400 Hz), a clear impact on the seam characteristics has been identified when a hump occurs.Finally, a clear correlation between the position of the focus point, the resultant process type and the corresponding signal intensity and signal variation has been found for sheets welded...

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.

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

Effects of Different Filler Metals on the Mechanical Behaviors of GTA Welded AA7A52(T6)

Science.gov (United States)

Shu, Fengyuan; Lv, Yaohui; Liu, Yuxin; Lin, Jianjun; Sun, Zhe; Xu, Binshi; He, Peng

2014-06-01

ER4043, ER5356, and AA7A52 on behalf of the Al-Si, Al-Mg, and Al-Zn-Mg-based welding material, respectively, were chosen as the filler metal to weld AA7A52(T6) plates by GTAW. The variance in mechanical performances of the joints caused by the various filler materials was investigated with reference to the SEM and EDS test results for the weld seam and the fracture surface. Failure was found in the seam for all the welded joints. With regard to the joint obtained with ER4043 welding wire, the total elongation was limited by the brittle intergranular compound Mg2Si of which Mg was introduced by convection mass transfer. As for the other two welds, the content ratio of Zn and Mg was found to play the dominant role in deciding the mechanical properties of the intergranular Mg-Zn compounds which were responsible for the tensile behavior of the joints. The content ratio (wt.%) of beyond 2:1 gave birth to the strengthening phase MgZn2 leading to a ductile fracture. Cr in the seam obtained with AA7A52 filler metal was found to enhance the strength of the joint through isolated particles.

Welding feasibility study of U-shape lips at ITER Port-Plug with new laser beam sources

Energy Technology Data Exchange (ETDEWEB)

Behr, W., E-mail: w.behr@fz-juelich.de; Faidel, D.; Fischer, K.; Pap, M.; Offermanns, G.

2013-10-15

A “Cut and weld feasibility study of U shape lips” shown on June 2007 was initial of the following investigations. A new solution for Port Plug sealing at ITER was demanded and the experience in laser beam welding of the ZAT (Central Institute of Technology) in Jülich (Research Centre Jülich) offered an alternative solution. Up to now mechanically fixed sealing or sealing by TIG welding is used with typical benefits and problems, as heat input, shrinkage or limited room for tools. New disc-laser application for tight welding (leakage rate < 10{sup −9} mbar l/s) of the sealing lips is presented in the following. Both in the metallographic investigation and by means of leakage rate investigation the suitability of the selected procedure as seal alternative at the ITER Port Plug could be pointed out. The distance between two connections can be reduced to approx. 5 mm. The presented milling process for weld seam removal offers an option additionally to laser beam cutting. Final tests with a new disc-laser source offered additional benefits concerning seam quality, process stability and seam geometry. The distance between two connections will be reduced to less than 3 mm in next investigations. Construction unit near investigations and a demo part in original size underline finally the industrial suitability of the laser-welding-process for Port-Plug sealing at ITER.

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

Laser vision seam tracking system based on image processing and continuous convolution operator tracker

Science.gov (United States)

Zou, Yanbiao; Chen, Tao

2018-06-01

To address the problem of low welding precision caused by the poor real-time tracking performance of common welding robots, a novel seam tracking system with excellent real-time tracking performance and high accuracy is designed based on the morphological image processing method and continuous convolution operator tracker (CCOT) object tracking algorithm. The system consists of a six-axis welding robot, a line laser sensor, and an industrial computer. This work also studies the measurement principle involved in the designed system. Through the CCOT algorithm, the weld feature points are determined in real time from the noise image during the welding process, and the 3D coordinate values of these points are obtained according to the measurement principle to control the movement of the robot and the torch in real time. Experimental results show that the sensor has a frequency of 50 Hz. The welding torch runs smoothly with a strong arc light and splash interference. Tracking error can reach ±0.2 mm, and the minimal distance between the laser stripe and the welding molten pool can reach 15 mm, which can significantly fulfill actual welding requirements.

Low-cycle fatigue of welded joints of alloy AMg5

International Nuclear Information System (INIS)

Modestova, R.V.; Borisenko, V.A.; Parfenova, I.N.; Stepanov, S.V.

1986-01-01

The authors study the low-cycle fatigue of welded joints of aluminum alloy AMg5 in order to determine the cyclic strength coefficient of welded seams. Tests were carried out on cylindrical specimens of the parent metal, welded specimens, and models of welded vessels. The average values of mechanical properties of the specimens and the parent metal are shown. It is shown that when designing welded vessels of aluminum alloy AMg5, the permissible amplitudes of conventional compressive stresses are recommended to be determined as the lower of the two values calculated using the equations presented

Improvement and qualification of ultrasonic testing of dissimilar welds in the primary circuit of NPPs

International Nuclear Information System (INIS)

Mitzscherling, Steffen; Barth, Enrico; Homann, Tobias; Prager, Jens; Goetschel, Sebastian; Weiser, Martin

2017-01-01

The austenitic and dissimilar welds found in the primary circuit of nuclear power plants are not only extremely relevant to safety but also place very high demands on material testing. In addition to limited accessibility, the macroscopic structure of the weld seam is of paramount importance for ultrasound testing. In order to reliably determine material errors in position and size, the grain orientations and the elastic constants of the anisotropic weld bead structure must be known. The following work steps are used for the imaging representation of possible material defects: First, the weld seam is sounded in order to be able to determine important weld seam parameters, such as, for example, the grain orientation, using an inverse method. On the basis of these parameters, the sound paths are simulated in the next step by means of raytracing (RT). Finally, this RT simulation is assigned the measurement data (A-scans) from different transmitter and receiver positions and superimposed according to the Synthetic Aperature Focusing Technique (SAFT) method. The combination of inverse process, RT and SAFT also ensures a correct visualization of the faults in anisotropic materials. We explain these three methods and present the test arrangement of test specimens with artificial test errors. Measurement data as well as their evaluation are compared with the results of a CIVA simulation. [de

Quality assurance on the welding work during the assembly of Wendelstein 7-X

International Nuclear Information System (INIS)

Schroeder, Michael

2011-01-01

At the Max-Planck-Institut fuer Plasmaphysik (IPP) in Greifswald (Germany) the stellarator experiment W7-X is presently being assembled. During this assembly many different weld connections are made, which are very important for the proper functionality of the experiment. This concerns mainly the structural integrity and the leak tightness. The quality requirements for the weld seams are high (mainly class B according to DIN EN ISO 5817), because the complex machine must operate reliably for more than 15 years and the possibility of any repair or change of important components is very small. To guarantee a high quality of the welds they are submitted to different tests. The applied test methods are depending on the function of the weld, the wall thickness, the seam geometry, and the material. The main test methods are visual testing (VT), penetrant testing (PT), radiographic testing (RT), ultrasonic testing (UT), leak testing (LT), permeability testing and macros. The paper will describe the application of these test methods and show their need by examples of typical weld imperfections.

Energy losses estimation during pulsed-laser seam welding

Czech Academy of Sciences Publication Activity Database

Šebestová, Hana; Havelková, M.; Chmelíčková, H.

2014-01-01

Roč. 45, č. 3 (2014), s. 1116-1121 ISSN 1073-5615 R&D Projects: GA MŠk(CZ) LG13007 Institutional support: RVO:68378271 Keywords : laser welding * pulsed-laser * Nd:YAG laser Subject RIV: JP - Industrial Processing Impact factor: 1.461, year: 2014

Pre-Industry-Optimisation of the Laser Welding Process

DEFF Research Database (Denmark)

Gong, Hui

This dissertation documents the investigations into on-line monitoring the CO2 laser welding process and optimising the process parameters for achieving high quality welds. The requirements for realisation of an on-line control system are, first of all, a clear understanding of the dynamic...... phenomena of the laser welding process including the behaviour of the keyhole and plume, and the correlation between the adjustable process parameters: laser power, welding speed, focal point position, gas parameters etc. and the characteristics describing the quality of the weld: seam depth and width......, porosity etc. Secondly, a reliable monitoring system for sensing the laser-induced plasma and plume emission and detecting weld defects and process parameter deviations from the optimum conditions. Finally, an efficient control system with a fast signal processor and a precise feed-back controller...

Behaviour under fatigue of AISI 304-L stainless steel welded joints

International Nuclear Information System (INIS)

Scal, M.W.; Joia, C.J.B.M.; Sousa e Silva, A.S. de

1979-01-01

The fatigue behaviour at room temperature of AISI-304-L stainless steel welded joints obtained by two distinct welding methods was studied. The results obtained were compared to those characteristic of the base metal. The welded joint fatigue samples were rectified in order to eliminate the effect of the welded seam geometry. It was concluded that the mechanisms of fatigue crack start in this case is commanded by the austenitic matrix, there being no influence of the delta ferrite rate and distribution present at the melted zone. (Author) [pt

Welding of stainless steel clad fuel rods for nuclear reactors

International Nuclear Information System (INIS)

Neves, Mauricio David Martins das

1986-01-01

This work describes the obtainment of austenitic stainless steel clad fuel rods for nuclear reactors. Two aspects have been emphasized: (a) obtainment and qualification of AISI 304 and 304 L stainless steel tubes; b) the circumferential welding of pipe ends to end plugs of the same alloy followed by qualification of the welds. Tubes with special and characteristic dimensions were obtained by set mandrel drawing. Both, seamed and seamless tubes of 304 and 304 L were obtained.The dimensional accuracy, surface roughness, mechanical properties and microstructural characteristics of the tubes were found to be adequate. The differences in the properties of the tubes with and without seams were found to be insignificant. The TIG process of welding was used. The influence of various welding parameters were studied: shielding gas (argon and helium), welding current, tube rotation speed, arc length, electrode position and gas flow. An inert gas welding chamber was developed and constructed with the aim of reducing surface oxidation and the heat affected zone. The welds were evaluated with the aid of destructive tests (burst-test, microhardness profile determination and metallographic analysis) and non destructive tests (visual inspection, dimensional examination, radiography and helium leak detection). As a function of the results obtained, two different welding cycles have been suggested; one for argon and another for helium. The changes in the microstructure caused by welding have been studied in greater detail. The utilization of work hardened tubes, permitted the identification by optical microscopy and microhardness measurements, of the different zones: weld zone; heat affected zone (region of grain growth, region of total and partial recrystallization) and finally, the zone not affected by heat. Some correlations between the welding parameters and metallurgical phenomena such as: solidification, recovery, recrystallization, grain growth and precipitation that occurred

Metal Flow in Friction Stir Welding

Science.gov (United States)

Nunes, Arthur C., Jr.

2006-01-01

The plastic deformation field in Friction Stir Welding (FSW) is compared to that in metal cutting. A shear surface around the FSW tool analogous to the metal cutting shear plane is identified and comprises the basis of the "rotating plug" flow field model and the "wiping" model of tool interaction with weld metal. Within the context of these models: The FSW shear rate is estimated to be comparable to metal cutting shear rates. The effect of tool geometry on the FSW shear surface is discussed and related to published torque measurements. Various FS W structural features are explained, including a difference in structure of bimetallic welds when alloys on the advancing and retreating sides of the weld seam are exchanged. The joining mechanism and critical parameters of the FSW process are made clear.

Linear Mathematical Model for Seam Tracking with an Arc Sensor in P-GMAW Processes.

Science.gov (United States)

Liu, Wenji; Li, Liangyu; Hong, Ying; Yue, Jianfeng

2017-03-14

Arc sensors have been used in seam tracking and widely studied since the 80s and commercial arc sensing products for T and V shaped grooves have been developed. However, it is difficult to use these arc sensors in narrow gap welding because the arc stability and sensing accuracy are not satisfactory. Pulse gas melting arc welding (P-GMAW) has been successfully applied in narrow gap welding and all position welding processes, so it is worthwhile to research P-GMAW arc sensing technology. In this paper, we derived a linear mathematical P-GMAW model for arc sensing, and the assumptions for the model are verified through experiments and finite element methods. Finally, the linear characteristics of the mathematical model were investigated. In torch height changing experiments, uphill experiments, and groove angle changing experiments the P-GMAW arc signals all satisfied the linear rules. In addition, the faster the welding speed, the higher the arc signal sensitivities; the smaller the groove angle, the greater the arc sensitivities. The arc signal variation rate needs to be modified according to the welding power, groove angles, and weaving or rotate speed.

Influence of thickness of zinc coating on CMT welding-brazing with AlSi5 alloy wire

Science.gov (United States)

Jin, Pengli; Wang, Zhiping; Yang, Sinan; Jia, Peng

2018-03-01

Effect of thickness of zinc coating on Cold Mattel Transfer (CMT) brazing of aluminum and galvanized steel is investigated. The thickness of zinc coating is 10 μm, 30 μm, and 60 μm, respectively. A high-speed camera was used to capture images of welding process of different specimens; the microstructure and composition analyses of the welding seam were examined by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS); the mechanical properties were measured in the form of Nano-indentation experiments. The results showed that arc characteristics and metal transfer behavior were unsteady at the beginning of welding process and that became stable after two cycles of CMT. With the thickness of zinc coating thickening, arc characteristics and metal transfer behaviors were more deteriorated. Compared with 10 μm and 30 μm, clad appearance of 60 μm was straight seam edges and a smooth surface which wetting angle was 60°. Zinc-rich zone at the seam edges was formed by zinc dissolution and motel pool oscillating, and zinc content of 10 μm and 30 μm were 5.8% and 7.75%. Zinc content of 60 μm was 14.61%, and it was a belt between galvanized steel and welding seam. The thickness of intermetallic compounds layer was in the range of 1-8 μm, and it changed with the thickness of zinc coating. The average hardness of the reaction layer of 60 μm is 9.197 GPa.

Counterrotating-Shoulder Mechanism for Friction Stir Welding

Science.gov (United States)

Nunes, Arthur C., Jr.

2007-01-01

A counterrotating-shoulder mechanism has been proposed as an alternative to the mechanism and fixtures used in conventional friction stir welding. The mechanism would internally react most or all of the forces and torques exerted on the workpiece, making it unnecessary to react the forces and torques through massive external fixtures. In conventional friction stir welding, a rotating pin tool is inserted into, and moved along, a weld seam. As the pin tool moves, it stirs together material from the opposite sides of the seam to form the weld. A large axial plunge force must be exerted upon the workpiece through and by the pin tool and a shoulder attached above the pin tool in order to maintain the pressure necessary for the process. The workpiece is secured on top of an anvil, which supports the workpiece against the axial plunge force and against the torque exerted by the pin tool and shoulder. The anvil and associated fixtures must be made heavy (and, therefore, are expensive) to keep the workpiece stationary. In addition, workpiece geometries must be limited to those that can be accommodated by the fixtures. The predecessor of the proposed counterrotating-shoulder mechanism is a second-generation, self-reacting tool, resembling a bobbin, that makes it possible to dispense with the heavy anvil. This tool consists essentially of a rotating pin tool with opposing shoulders. Although the opposing shoulders maintain the necessary pressure without need to externally apply or react a large plunge force, the torque exerted on the workpiece remains unreacted in the absence of a substantial external fixture. Depending on the RPM and the thickness of the workpiece, the torque can be large. The proposed mechanism (see figure) would include a spindle attached to a pin tool with a lower shoulder. The spindle would be coupled via splines to the upper one of three bevel gears in a differential drive. The middle bevel gear would be the power-input gear and would be coupled to the

System for evaluating weld quality using eddy currents

Science.gov (United States)

Todorov, Evgueni I.; Hay, Jacob

2017-12-12

Electromagnetic and eddy current techniques for fast automated real-time and near real-time inspection and monitoring systems for high production rate joining processes. An eddy current system, array and method for the fast examination of welds to detect anomalies such as missed seam (MS) and lack of penetration (LOP) the system, array and methods capable of detecting and sizing surface and slightly subsurface flaws at various orientations in connection with at least the first and second weld pass.

ANSYS Simulation of Residual Strains in Butt-welded Joints

Directory of Open Access Journals (Sweden)

A. Atroshenko

2014-07-01

Full Text Available The effect of thermal-strain cycle on residual strains in thin-walled circular seams of cylindrical shells using TIG butt welds was studied. Estimates were calculated using numerical modelling. The structure was made of corrosion-resistant austenitic steels.

Java Persistence Dengan JBoss Seam

OpenAIRE

Utomo, Wiranto Herry; Istiyanto, Jazi Eko

2009-01-01

Seam is based on Java EE, so it satisfies its framework duties in two fundamental ways: 1) Seam  simplifies Java EE: Seam provides a number of  shortcuts and  simplifications  to  the standard  Java EE  framework, making  it  even  easier  to  effectively  use  Java EE web  and business components, 2) Seam extends Java EE: Seam integrates a number of new concepts and tools into the Java EE framework. These extensions b...

Optical sensor for real-time weld defect detection

Science.gov (United States)

Ancona, Antonio; Maggipinto, Tommaso; Spagnolo, Vincenzo; Ferrara, Michele; Lugara, Pietro M.

2002-04-01

In this work we present an innovative optical sensor for on- line and non-intrusive welding process monitoring. It is based on the spectroscopic analysis of the optical VIS emission of the welding plasma plume generated in the laser- metal interaction zone. Plasma electron temperature has been measured for different chemical species composing the plume. Temperature signal evolution has been recorded and analyzed during several CO2-laser welding processes, under variable operating conditions. We have developed a suitable software able to real time detect a wide range of weld defects like crater formation, lack of fusion, excessive penetration, seam oxidation. The same spectroscopic approach has been applied for electric arc welding process monitoring. We assembled our optical sensor in a torch for manual Gas Tungsten Arc Welding procedures and tested the prototype in a manufacturing industry production line. Even in this case we found a clear correlation between the signal behavior and the welded joint quality.

Residual stress measurements in coil, linepipe and girth welded pipe

International Nuclear Information System (INIS)

Law, M.; Prask, H.; Luzin, V.; Gnaeupel-Herold, T.

2006-01-01

Residual stresses in gas pipelines come from forming operations in producing the coil and pipe, seam welding the pipe, and girth welding pipes together to form a gas pipeline. Welding is used extensively in gas pipelines, the welds are made without post weld heat treatment. The three normal stresses were measured by neutron diffraction for three types of sample: coil, unwelded rings cut from the pipe made from this coil, and girth welded rings cut from linepipe. All three specimens came from three thicknesses of manufacture (5.4, 6.4, and 7.1 mm). The welds are manual metal arc cellulosic electrode welds made in X70 linepipe, these were measured at 5 through-thickness positions at 19 locations (from the center of the weld up to 35 mm away from the weld) with a spatial resolution of 1 mm 3 . The coil and unwelded rings were measured at the same five through-thickness positions

Tailor-welded blanks and their production

Science.gov (United States)

Yan, Qi

2005-01-01

Tailor welded blanks had been widely used in the automobile industry. A tailor welded blank consists of several flat sheets that were laser welded together before stamping. A combination of different materials, thickness, and coatings could be welded together to form a blank for stamping car body panels. As for the material for automobile industry, this technology was one of the development trend for automobile industry because of its weight reduction, safety improvement and economical use of materials. In this paper, the characters and production of tailor welded blanks in the market were discussed in detail. There had two major methods to produce tailor welded blanks. Laser welding would replace mesh seam welding for the production of tailor welded blanks in the future. The requirements on the edge preparation of unwelded blanks for tailor welded blanks were higher than the other steel processing technology. In order to produce the laser welded blank, there had the other process before the laser welding in the factory. In the world, there had three kinds of patterns for the large volume production of tailor welded blanks. In China, steel factory played the important role in the promotion of the application of tailor welded blanks. The competition for the supply of tailor welded blanks to the automobile industry would become fierce in the near future. As a result, the demand for the quality control on the production of tailor welded blanks would be the first priority concern for the factory.

Analysis and validation of laser spot weld-induced distortion

Energy Technology Data Exchange (ETDEWEB)

Knorovsky, G.A.; Kanouff, M.P.; Maccallum, D.O.; Fuerschbach, P.W.

1999-12-09

Laser spot welding is an ideal process for joining small parts with tight tolerances on weld size, location, and distortion, particularly those with near-by heat sensitive features. It is also key to understanding the overlapping laser spot seam welding process. Rather than attempting to simulate the laser beam-to-part coupling (particularly if a keyhole occurs), it was measured by calorimetry. This data was then used to calculate the thermal and structural response of a laser spot welded SS304 disk using the finite element method. Five combinations of process parameter values were studied. Calculations were compared to experimental data for temperature and distortion profiles measured by thermocouples and surface profiling. Results are discussed in terms of experimental and modeling factors. The authors then suggest appropriate parameters for laser spot welding.

Critical Gap distance in Laser Butt-welding

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove

of "reference" welds are made and compared to sheets with the edges shear cut. The gap distance is precisely controlled by inserting spacers between the sheets. In the tests the gap is set at 0.00, 0.02, 0.05, 0.08 and 0.10 mm. Mild steel (St 1203) with thickness? of 0.75 and 1.25 mm with and without zinc......When butt-welding metal sheets with high power lasers the gap distance between the sheets determine the final quality of the seam. In a number of systematic laboratory experiments the critical gap distance that results in sound beads is identified. By grinding the edges of the sheets, a number...... coating were analysed. A total of 120 welds are made at different welding speeds.As quality norm DIN 8563 is used to divide the welds into quality classes. Since this norm only deals with surface defects a number of welds are also x-ray photographed.According to DIN 8563 the welds have classes of either B...

Friction stir welding (FSW process of copper alloys

Directory of Open Access Journals (Sweden)

M. Miličić

2016-01-01

Full Text Available The present paper analyzes the structure of the weld joint of technically pure copper, which is realized using friction stir welding (FSW. The mechanism of thermo-mechanical processes of the FSW method has been identified and a correlation between the weld zone and its microstructure established. Parameters of the FSW welding technology influencing the zone of the seam material and the mechanical properties of the resulting joint were analyzed. The physical joining consists of intense mixing the base material along the joint line in the “doughy” phase. Substantial plastic deformations immediately beneath the frontal surface of tool provide fine-grained structure and a good quality joint. The optimum shape of the tool and the optimum welding regime (pressure force, rotation speed and the traverse speed of the tool in the heat affected zone enable the achievement of the same mechanical properties as those of the basic material, which justifies its use in welding reliable structures.

Spline-based automatic path generation of welding robot

Institute of Scientific and Technical Information of China (English)

Niu Xuejuan; Li Liangyu

2007-01-01

This paper presents a flexible method for the representation of welded seam based on spline interpolation. In this method, the tool path of welding robot can be generated automatically from a 3D CAD model. This technique has been implemented and demonstrated in the FANUC Arc Welding Robot Workstation. According to the method, a software system is developed using VBA of SolidWorks 2006. It offers an interface between SolidWorks and ROBOGUIDE, the off-line programming software of FANUC robot. It combines the strong modeling function of the former and the simulating function of the latter. It also has the capability of communication with on-line robot. The result data have shown its high accuracy and strong reliability in experiments. This method will improve the intelligence and the flexibility of the welding robot workstation.

Study of Dynamic Features of Surface Plasma in High-Power Disk Laser Welding

International Nuclear Information System (INIS)

Wang Teng; Gao Xiangdong; Seiji, Katayama; Jin, Xiaoli

2012-01-01

High-speed photography was used to obtain the dynamic changes in the surface plasma during a high-power disk laser welding process. A color space clustering algorithm to extract the edge information of the surface plasma region was developed in order to improve the accuracy of image processing. With a comparative analysis of the plasma features, i.e., area and height, and the characteristics of the welded seam, the relationship between the surface plasma and the stability of the laser welding process was characterized, which provides a basic understanding for the real-time monitoring of laser welding.

Manufacturing and use of spiral welded pipes for high pressure service : state of the art

Energy Technology Data Exchange (ETDEWEB)

Knoop, F.M.; Sommer, B. [Salzgitter GroBrohre GmbH, Salzgitter (Germany)

2004-07-01

This paper provided details of an improved helical seam 2-step (HTS) manufacturing process used to produce spiral welded large diameter pipes for high pressure transmission pipelines. During the process, pipe forming is combined with continuous tack welding and internal and external submerged arc welding at separate welding stations. The pipe forming unit consists of a 3 roll bending system with an outside roller cage used to guarantee the roundness of the pipe. The converging strip edges of the pipe are joined using a continuous shielded arc tack weld. Tack welding is done automatically with a laser-guided weld head. Run-out angles are adjusted by an automatic gap control system. The formed and tack-welded pipes are then fed to computer-controlled welding stations for final welding, where each pipe is rotated with a precise screw-like motion. The same welding materials used for the helical seam are used for the skelp end welding. The process offers more precise root gap control, as well as improved pipe geometry. Use of the process has also increased production rates and improved weld stability. The dimensions of the spiral-weld pipes are adjustable so that any diameter can be produced from a base material of the same width. The pipes can also be coated externally with fusion-bonded epoxy or 3-layer polyethylene/polypropylene. It was concluded that the process is being further refined to support the use of HTS pipes in high-pressure pipelines. New nondestructive testing techniques used to assess the performance of the line pipes were presented, as well as the results from hot and cold bending tests, field weldability trials, and tests related to the safety of spiral pipes. 16 refs., 2 tabs., 12 figs.

An Investigation of the Microstructure of an Intermetallic Layer in Welding Aluminum Alloys to Steel by MIG Process.

Science.gov (United States)

Nguyen, Quoc Manh; Huang, Shyh-Chour

2015-12-02

Butt joints of A5052 aluminum alloy and SS400 steel, with a new type of chamfered edge, are welded by means of metal inert gas welding and ER4043 Al-Si filler metal. The microhardness and microstructure of the joint are investigated. An intermetallic layer is found on the surface of the welding seam and SS400 steel sheet. The hardness of the intermetallic layer is examined using the Vickers hardness test. The average hardness values at the Intermetallic (IMC) layer zone and without the IMC layer zone were higher than that of the welding wire ER4043. The tensile strength test showed a fracture at the intermetallic layer when the tensile strength is 225.9 MPa. The tensile value test indicated the average of welds was equivalent to the 85% tensile strength of the A5052 aluminum alloy. The thickness of the intermetallic layers is non-uniform at different positions with the ranges from 1.95 to 5 μm. The quality of the butt joint is better if the intermetallic layer is minimized. The Si crystals which appeared at the welding seam, indicating that this element participated actively during the welding process, also contributed to the IMC layer's formation.

Advantages and successful use of TIG narrow-gap welding

International Nuclear Information System (INIS)

Loehberg, R.; Pellkofer, D.; Schmidt, J.

1986-01-01

Narrow-gap welding, an advancement of the mechanized TIG impulse welding process with conventional seam geometry (V-shaped and/or U-shaped welds), not only assures great economic efficiency on account of the low weld volume but also offers considerable benefits in terms of quality. Thanks to the low number of beads, the following advantages are gained: less axial and radial shrinkage which reduces the strain in the root area, total heat input and, thus, the dwell time in the critical temperature range from 500 to 800 0 C leading to a chromium depletion at the grain boundaries during the welding process is minimized which markedly reduces the sensitivity of non-stabilized steels to intercrystalline stress corrosion cracking, and a relatively favourable residual welding stress profile in the heat affected zone. The process was used successfully in the past for welds of ferritic and austenitic steel pipes in the construction of nuclear power plants and in the remote-controlled welding during the replacement of piping in plants already in operation. (orig.) [de

Integration of vertical and in-seam horizontal well production analyses with stochastic geostatistical algorithms to estimate pre-mining methane drainage efficiency from coal seams: Blue Creek seam, Alabama.

Science.gov (United States)

Karacan, C Özgen

2013-07-30

Coal seam degasification and its efficiency are directly related to the safety of coal mining. Degasification activities in the Black Warrior basin started in the early 1980s by using vertical boreholes. Although the Blue Creek seam, which is part of the Mary Lee coal group, has been the main seam of interest for coal mining, vertical wellbores have also been completed in the Pratt, Mary Lee, and Black Creek coal groups of the Upper Pottsville formation to degasify multiple seams. Currently, the Blue Creek seam is further degasified 2-3 years in advance of mining using in-seam horizontal boreholes to ensure safe mining. The studied location in this work is located between Tuscaloosa and Jefferson counties in Alabama and was degasified using 81 vertical boreholes, some of which are still active. When the current long mine expanded its operation into this area in 2009, horizontal boreholes were also drilled in advance of mining for further degasification of only the Blue Creek seam to ensure a safe and a productive operation. This paper presents an integrated study and a methodology to combine history matching results from vertical boreholes with production modeling of horizontal boreholes using geostatistical simulation to evaluate spatial effectiveness of in-seam boreholes in reducing gas-in-place (GIP). Results in this study showed that in-seam wells' boreholes had an estimated effective drainage area of 2050 acres with cumulative production of 604 MMscf methane during ~2 years of operation. With horizontal borehole production, GIP in the Blue Creek seam decreased from an average of 1.52 MMscf to 1.23 MMscf per acre. It was also shown that effective gas flow capacity, which was independently modeled using vertical borehole data, affected horizontal borehole production. GIP and effective gas flow capacity of coal seam gas were also used to predict remaining gas potential for the Blue Creek seam.

Electric pulse treatment of welded joint of aluminum alloy

Directory of Open Access Journals (Sweden)

A.A. Mitiaev

2013-08-01

Full Text Available Purpose. Explanation of the redistribution effect of residual strengthes after electric pulse treatment of ark welding seam of the aluminum alloy. Methodology. Alloy on the basis of aluminium of АК8М3 type served as the research material. As a result of mechanical treatment of the ingots after alloy crystallization the plates with 10 mm thickness were obtained. After edge preparation the elements, which are being connected were butt welded using the technology of semiautomatic argon arc welding by the electrode with a diameter of 3 mm of AK-5 alloy. Metal structure of the welded joint was examined under the light microscope at a magnification of 200 and under the scanning electronic microscope «JSM-6360 LA». The Rockwell hardness (HRF was used as a strength characteristic of alloy. Hardness measuring of the phase constituents (microhardness was carried out using the device PМТ-3, with the indenter loadings 5 and 10 g. The crystalline structure parameters of alloy (dislocation density, second kind of the crystalline grid distortion and the scale of coherent scattering regions were determined using the methods of X-ray structural analysis. Electric pulse treatment (ET was carried out on the special equipment in the conditions of the DS enterprise using two modes A and В. Findings. On the basis of researches the previously obtained microhardness redistribution effect in the area of welded connection after ET was confirmed. As a result of use of the indicated treatment it was determined not only the reduction of microhardness gradient but also the simultaneous hardening effect in the certain thermal affected areas near the welding seam. During study of chemical composition of phase constituents it was discovered, that the structural changes of alloy as a result of ET first of all are caused by the redistribution of chemical elements, which form the connections themselves. By the nature of the influence the indicated treatment can be

The effects of alloying elements on microstructures and mechanical properties of tungsten inert gas welded AZ80 magnesium alloys joint

Science.gov (United States)

Li, Hui; Zhang, Jiansheng; Ding, Rongrong

2017-11-01

The effects of alloying elements on the macrostructures, microstructures and tensile strength of AZ80 Mg alloy weldments were studied in the present study. The results indicate that with the decrease of Al element content of filler wire, the welding defects of seam are gradually eliminated and the β-Mg17Al12 phases at α-Mg boundaries are refined and become discontinuous, which are beneficial to the improvement of tensile strength. With AZ31 Mg alloy filler wire, the maximum tensile strength of AZ80 weldment is 220 MPa and fracture occurs at the welding seam of joint. It is experimentally proved that robust AZ80 Mg alloy joints can be obtained by tungsten inert gas (TIG) welding process with AZ31 Mg alloy filler wire. However, further study is required to improve the microstructures and reduce welding defects of joint in order to further improve the joining strength of AZ80 Mg alloy joint.

Electron beam welding of flanges with tubular shafts of steel 40KhNMA

International Nuclear Information System (INIS)

Leskov, G.I.; Zhivaga, L.I.; Shipitsyn, B.N.; Savichev, R.V.

1975-01-01

The results are presented of elaborating the technological process for the electron beam welding of flanges with a tube of the 40KhNMA steel and of investigation into the quality of the welded joints. A welded piece has been fabricated conforming to the technology suggested observing the parameters worked-out in the following sequence: assembling the piece; pre-welding of the edges in some points; welding; high tempering; welds quality control; removal of the seam reinforcement inside of the tube and the weld root to the depth of 2 mm; quenching; tempering; welds quality control; finishing. The welds quality control consists in visual inspection, ultrasonic testing, magnetic flaw detection, as well as X-ray and metallographic analyses. The mechanical properties are studied on notched samples cut out of the welded joints. The test results have shown that the mechanical properties of the welded joints meet the requirements on the same level with the base metal

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.

Welding using soap shielding. Fremgangsmaate til utfoerelse av buesveising samt sveisestang til utoevelse av fremgangmaaten

Energy Technology Data Exchange (ETDEWEB)

Kauppi, M.; Niinivaara, J.; Nurminen, M.

1984-08-06

A procedure is disclosed in the application, for carrying out arc welding under water or in otherwise difficult external conditions. In the procedure, there is introduced in the arc area or in its immediate vicinity, an auxiliary substance having the purpose to boost the ignition of the arc and its burning and to retard the cooling of the weld bead produced, so that the emergence of gases from the welded seam is promoted and the quality of the weld seam improves. The auxiliary substance used consists mainly of soap which is a salt formed by anions of a fatty acid, a fatty acid mixture or a mixture of fatty and resin acids and by metal cations or a mixture of such salts and which may in addition contain water and inorganic salts. Best results have been obtained by using for auxiliary substance soft soaps made of tall oil and which contain salts of both fatty acids, such as oleic and linoleic acid and of resin acids, such as abietic acid. Good results have further been obtained with soft soaps based exclusively on salts of saturated or unsaturated fatty acids. 4 drawings, 3 tables.

Formation of Oxides in the Interior of Friction Stir Welds

Science.gov (United States)

Schneider, Judy; Chen, Po; Nunes, Arthur C., Jr.

2016-01-01

In friction stir welding (FSWing) the actual solid state joining takes place between the faying surfaces which form the weld seam. Thus the seam trace is often investigated for clues when the strength of the weld is reduced. Aluminum and its alloys are known to form a native, protective oxide on the surface. If these native surface oxides are not sufficiently broken up during the FSW process, they are reported to remain in the FSW interior and weaken the bond strength. This type of weld defect has been referred to as a lazy "S", lazy "Z", joint line defect, kissing bond, or residual oxide defect. Usually these defects are mitigated by modification of the process parameters, such as increased tool rotation rate, which causes a finer breakup of the native oxide particles. This study proposes that there may be an alternative mechanism for formation of oxides found within the weld nugget. As the oxidation rate increases at elevated temperatures above 400ºC, it may be possible for enhanced oxidation to occur on the interior surfaces during the FSW process from entrained air entering the seam gap. Normally, FSWs of aluminum alloys are made without a purge gas and it is unknown how process parameters and initial fit up could affect a potential air path into the interior during the processing. In addition, variations in FSW parameters, such as the tool rotation, are known to have a strong influence on the FSW temperature which may affect the oxidation rate if internal surfaces are exposed to entrained air. A series of FSWs were made in 3 different thickness panels of AA2219 (0.95, 1.27 and 1.56 cm) at 2 different weld pitches. As the thickness of the panels increased, there was an increased tendency for a gap to form in advance of the weld tool. If sufficient air is able to enter the workpiece gap prior to consolidation, the weld temperature can increase the oxidation rate on the interior surfaces. These oxidation rates would also be accelerated in areas of localized

Spectroscopic analysis technique for arc-welding process control

Science.gov (United States)

Mirapeix, Jesús; Cobo, Adolfo; Conde, Olga; Quintela, María Ángeles; López-Higuera, José-Miguel

2005-09-01

The spectroscopic analysis of the light emitted by thermal plasmas has found many applications, from chemical analysis to monitoring and control of industrial processes. Particularly, it has been demonstrated that the analysis of the thermal plasma generated during arc or laser welding can supply information about the process and, thus, about the quality of the weld. In some critical applications (e.g. the aerospace sector), an early, real-time detection of defects in the weld seam (oxidation, porosity, lack of penetration, ...) is highly desirable as it can reduce expensive non-destructive testing (NDT). Among others techniques, full spectroscopic analysis of the plasma emission is known to offer rich information about the process itself, but it is also very demanding in terms of real-time implementations. In this paper, we proposed a technique for the analysis of the plasma emission spectrum that is able to detect, in real-time, changes in the process parameters that could lead to the formation of defects in the weld seam. It is based on the estimation of the electronic temperature of the plasma through the analysis of the emission peaks from multiple atomic species. Unlike traditional techniques, which usually involve peak fitting to Voigt functions using the Levenberg-Marquardt recursive method, we employ the LPO (Linear Phase Operator) sub-pixel algorithm to accurately estimate the central wavelength of the peaks (allowing an automatic identification of each atomic species) and cubic-spline interpolation of the noisy data to obtain the intensity and width of the peaks. Experimental tests on TIG-welding using fiber-optic capture of light and a low-cost CCD-based spectrometer, show that some typical defects can be easily detected and identified with this technique, whose typical processing time for multiple peak analysis is less than 20msec. running in a conventional PC.

Fatigue analysis of welding seams in automotive structures

International Nuclear Information System (INIS)

Halaszi, C.; Gaier, C.; Dannbauer, H.; Hofwimmer, K.

2006-01-01

For lightweight automotive structures, the stiffness and the fatigue behavior is greatly influenced by the properties of the joints. The joining technology used and the number and locations of the joints are of high importance for both engineers and cost accountants. An overview of common computational procedures including European and national standards is given for the assessments of the fatigue behavior of thin sheet structures with arc welds. The influence of the quality and size of finite shell elements on the fatigue results are investigated and it is shown how this influence can be minimized. (author)

A Weld Position Recognition Method Based on Directional and Structured Light Information Fusion in Multi-Layer/Multi-Pass Welding

Directory of Open Access Journals (Sweden)

Jinle Zeng

2018-01-01

Full Text Available Multi-layer/multi-pass welding (MLMPW technology is widely used in the energy industry to join thick components. During automatic welding using robots or other actuators, it is very important to recognize the actual weld pass position using visual methods, which can then be used not only to perform reasonable path planning for actuators, but also to correct any deviations between the welding torch and the weld pass position in real time. However, due to the small geometrical differences between adjacent weld passes, existing weld position recognition technologies such as structured light methods are not suitable for weld position detection in MLMPW. This paper proposes a novel method for weld position detection, which fuses various kinds of information in MLMPW. First, a synchronous acquisition method is developed to obtain various kinds of visual information when directional light and structured light sources are on, respectively. Then, interferences are eliminated by fusing adjacent images. Finally, the information from directional and structured light images is fused to obtain the 3D positions of the weld passes. Experiment results show that each process can be done in 30 ms and the deviation is less than 0.6 mm. The proposed method can be used for automatic path planning and seam tracking in the robotic MLMPW process as well as electron beam freeform fabrication process.

A Weld Position Recognition Method Based on Directional and Structured Light Information Fusion in Multi-Layer/Multi-Pass Welding.

Science.gov (United States)

Zeng, Jinle; Chang, Baohua; Du, Dong; Wang, Li; Chang, Shuhe; Peng, Guodong; Wang, Wenzhu

2018-01-05

Multi-layer/multi-pass welding (MLMPW) technology is widely used in the energy industry to join thick components. During automatic welding using robots or other actuators, it is very important to recognize the actual weld pass position using visual methods, which can then be used not only to perform reasonable path planning for actuators, but also to correct any deviations between the welding torch and the weld pass position in real time. However, due to the small geometrical differences between adjacent weld passes, existing weld position recognition technologies such as structured light methods are not suitable for weld position detection in MLMPW. This paper proposes a novel method for weld position detection, which fuses various kinds of information in MLMPW. First, a synchronous acquisition method is developed to obtain various kinds of visual information when directional light and structured light sources are on, respectively. Then, interferences are eliminated by fusing adjacent images. Finally, the information from directional and structured light images is fused to obtain the 3D positions of the weld passes. Experiment results show that each process can be done in 30 ms and the deviation is less than 0.6 mm. The proposed method can be used for automatic path planning and seam tracking in the robotic MLMPW process as well as electron beam freeform fabrication process.

In-seam seismics for coal

Energy Technology Data Exchange (ETDEWEB)

Saviron Cidon, L [OCICARBON, Madrid (Spain)

1989-11-01

The project objective is to assess the degree of applicability of in-seam seismic technology in Spanish coal mines for use as a tool to predict the presence of irregularities in coal seams. By the very nature of coal mining, a large number of in-seam seismic research results are put directly to the test by the ensuing underground operations. The statistics from this continuous process of verification in other countries show this method to be extremely successful. Indeed, the use of the method has become habitual and it is recognised as an efficient instrument for aiding the location of faults and other irregularities in coal seams. 3 figs., 2 tabs.

Numerical microstructural analysis of automotive-grade steels when joined with an array of welding processes

International Nuclear Information System (INIS)

Gould, J.E.; Khurana, S.P.; Li, T.

2004-01-01

Weld strength, formability, and impact resistance for joints on automotive steels is dependent on the underlying microstructure. A martensitic weld area is often a precursor to reduced mechanical performance. In this paper, efforts are made to predict underlying joint microstructures for a range of processing approaches, steel types, and gauges. This was done first by calculating cooling rates for some typical automotive processes [resistance spot welding (RSW), resistance mash seam welding (RMSEW), laser beam welding (LBW), and gas metal arc welding (GMAW)]. Then, critical cooling rates for martensite formation were calculated for a range of automotive steels using an available thermodynamically based phase transformation model. These were then used to define combinations of process type, steel type, and gauge where welds could be formed avoiding martensite in the weld area microstructure

CO2 laser welding of galvanized steel sheets using vent holes

International Nuclear Information System (INIS)

Chen Weichiat; Ackerson, Paul; Molian, Pal

2009-01-01

Joining of galvanized steels is a challenging issue in the automotive industry because of the vaporization of zinc at 906 deg. C during fusion welding of steel (>1530 deg. C). In this work, hot-dip galvanized steel sheets of 0.68 mm thick (24-gage) were pre-drilled using a pulsed Nd:YAG laser to form vent holes along the weld line and then seam welded in the lap-joint configuration using a continuous wave CO 2 laser. The welds were evaluated through optical and scanning electron microscopy and tensile/hardness tests. The vent holes allowed zinc vapors to escape through the weld zone without causing expulsion of molten metal, thereby eliminating the defects such as porosity, spatter, and loss of penetration. In addition, riveting of welds occurred so long as the weld width was greater than the hole diameter that in turn provided much higher strength over the traditional 'joint gap' method

A Plasma Control and Gas Protection System for Laser Welding of Stainless Steel

DEFF Research Database (Denmark)

Juhl, Thomas Winther; Olsen, Flemming Ove

1997-01-01

A prototype shield gas box with different plasma control nozzles have been investigated for laser welding of stainless steel (AISI 316). Different gases for plasma control and gas protection of the weld seam have been used. The gas types, welding speed and gas flows show the impact on process...... stability and protection against oxidation. Also oxidation related to special conditions at the starting edge has been investigated. The interaction between coaxial and plasma gas flow show that the coaxial flow widens the band in which the plasma gas flow suppresses the metal plasma. In this band the welds...... are oxide free. With 2.7 kW power welds have been performed at 4000 mm/min with Ar / He (70%/30%) as coaxial, plasma and shield gas....

Study on the welding process of the CTB outbox prototype of ITER

International Nuclear Information System (INIS)

Liu, Chen; Lu, Kun; Song, Yuntao; Zhu, Rui; Bao, Hongwei; Li, Shoukang; Zhang, Chunjie; Tuo, Fuxing

2015-01-01

Highlights: • Welding progress simulation of ITER CTB outbox by SYSWELD. • 2 m length box mockup welding for R&D. • Special welding tooling and groove design for welding deformation control and improvement of welding quality. • Double torch automatic MIG welding method application. - Abstract: The current study investigated the main welding process of the box. We first performed a simple simulation of the welding process for the four long weld lines on CTB (Coil Terminal Box) outbox by using the finite element analysis mode of SYSWELD. Then a 2 m length mock up box was welded for R&D to optimize the welding parameters and deformation distribution. Base on the R&D experiences, we designed a special tooling of the prototype box which can be used to control the deformation during the welding process. A 8 m length CTB outbox prototype was successfully welded by using double torch automatic MIG (Metal Inert-Gas) welding. The dimension inspection results confirmed that the welding deformation of the box can be controlled within 3 mm on each side. Based on the ultrasonic inspection, all the welding seams met quality level B by standard EN 5817.

Friction Stir Welding of three dissimilar aluminium alloy used in aeronautics industry

Science.gov (United States)

Boşneag, A.; Constantin, M. A.; Niţu, E.; Iordache, M.

2017-10-01

Friction Stir Welding (FSW) is an innovative solid-state joining process. This process was, in first time, develop to join the similar aluminum plates but now the technology can be used to weld a large area of materials similar or dissimilar. Taking these into account FSW process, for dissimilar materials are increasingly required, more than traditional arc welding, in industrial environment. More than that FSW is used in aeronautics industry because of very good result and very good weldability between aluminum alloy used at building of airplanes, where the body of airplane are 20% aluminum alloy and this percent can be increaser in future. In this paper is presented an experimental study which includes welding three dissimilar aluminum alloy, with different properties, used in aeronautics industry, this materials are: AA 2024, AA6061 and AA7075. After welding with different parameters, the welding join and welding process will be analyzed considering process temperature, process vertical force, and roughnessof welding seams, visual aspect and microhardness.

Gas Shielding Technology for Welding and Brazing

Science.gov (United States)

Nunes, Arthur J.; Gradl, Paul R.

2012-01-01

Welding is a common method that allows two metallic materials to be joined together with high structural integrity. When joints need to be leak-tight, light-weight, or free of contaminant-trapping seams or surface asperities, welding tends to be specified. There are many welding techniques, each with its own advantages and disadvantages. Some of these techniques include Forge Welding, Gas Tungsten Arc Welding, Friction Stir Welding, and Laser Beam Welding to name a few. Whichever technique is used, the objective is a structural joint that meets the requirements of a particular component or assembly. A key practice in producing quality welds is the use of shielding gas. This article discusses various weld techniques, quality of the welds, and importance of shielding gas in each of those techniques. Metallic bonds, or joints, are produced when metals are put into intimate contact. In the solid-state "blacksmith welding" process, now called Forge Welding (FOW), the site to be joined is pounded into intimate contact. The surfaces to be joined usually need to be heated to make it easier to deform the metal. The surfaces are sprinkled with a flux to melt surface oxides and given a concave shape so that surface contamination can be squeezed out of the joint as the surfaces are pounded together; otherwise the surface contamination would be trapped in the joint and would weaken the weld. In solid-state welding processes surface oxides or other contamination are typically squeezed out of the joint in "flash."

Experimental and Simulative Investigation of Laser Transmission Welding under Consideration of Scattering

Science.gov (United States)

Devrient, M.; Da, X.; Frick, T.; Schmidt, M.

Laser transmission welding is a well known joining technology for thermoplastics. Because of the needs of lightweight, cost effective and green production thermoplastics are usually filled with glass fibers. These lead to higher absorption and more scattering within the upper joining partner with a negative influence on the welding process. Here an experimental method for the characterization of the scattering behavior of semi crystalline thermoplastics filled with short glass fibers and a finite element model of the welding process capable to consider scattering as well as an analytical model are introduced. The experimental data is used for the numerical and analytical investigation of laser transmission welding under consideration of scattering. The scattering effects of several thermoplastics onto the calculated temperature fields as well as weld seam geometries are quantified.

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

A comparative study of the microstructure and properties of 800 MPa microalloyed C-Mn steel welded joints by laser and gas metal arc welding

Energy Technology Data Exchange (ETDEWEB)

Sun, Qian [The State Key Laboratory of Rolling and Automation of Northeastern University, Shenyang 110819 (China); Di, Hong-Shuang, E-mail: hongshuangdi_ral@126.com [The State Key Laboratory of Rolling and Automation of Northeastern University, Shenyang 110819 (China); Li, Jun-Chen [The State Key Laboratory of Rolling and Automation of Northeastern University, Shenyang 110819 (China); Wu, Bao-Qiang [National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); Misra, R.D.K. [Laboratory for Excellence in Advanced Steel Research, Department of Metallurgical, Material and Biomedical Engineering, University of Texas at El Paso, TX 79968 (United States)

2016-07-04

The differences in microstructure and mechanical properties of laser beam welded (LBW) and gas metal arc welded (GMAW) joints of 800 MPa grade Nb-Ti-Mo microalloyed C-Mn steel of 5 mm thickness were studied. The study suggested that the microstructure in welded seam (WS) of GMAW was acicular ferrite and fine grained ferrite, whereas lath martensite (LM) was obtained in WS of LBW, where inclusions were finer and did not act as nucleation sites for acicular ferrite. The microstructure of coarse-grained HAZ (CGHAZ) obtained using the two welding methods was LM and granular bainite (GB), respectively. The original austenite grain size in CGHAZ of LBW was 1/3 of GMAW. The microstructure of fine-grained HAZ and mixed-grained HAZ using the two welding methods was ferrite and M-A constituents, while that of LBW was significantly fine. The hardness of LBW welded joints was higher than the base metal (BM), which was the initiation site for tensile fracture. The tensile fracture location of GMAW welded joints was in WS. The impact toughness of LBW welded joints was excellent and the impact absorption energy was similar to BM.

Novel welding image processing method based on fractal theory

Institute of Scientific and Technical Information of China (English)

陈强; 孙振国; 肖勇; 路井荣

2002-01-01

Computer vision has come into used in the fields of welding process control and automation. In order to improve precision and rapidity of welding image processing, a novel method based on fractal theory has been put forward in this paper. Compared with traditional methods, the image is preliminarily processed in the macroscopic regions then thoroughly analyzed in the microscopic regions in the new method. With which, an image is divided up to some regions according to the different fractal characters of image edge, and the fuzzy regions including image edges are detected out, then image edges are identified with Sobel operator and curved by LSM (Lease Square Method). Since the data to be processed have been decreased and the noise of image has been reduced, it has been testified through experiments that edges of weld seam or weld pool could be recognized correctly and quickly.

Statistical analysis of process parameters to eliminate hot cracking of fiber laser welded aluminum alloy

Science.gov (United States)

Wang, Jin; Wang, Hui-Ping; Wang, Xiaojie; Cui, Haichao; Lu, Fenggui

2015-03-01

This paper investigates hot cracking rate in Al fiber laser welding under various process conditions and performs corresponding process optimization. First, effects of welding process parameters such as distance between welding center line and its closest trim edge, laser power and welding speed on hot cracking rate were investigated experimentally with response surface methodology (RSM). The hot cracking rate in the paper is defined as ratio of hot cracking length over the total weld seam length. Based on the experimental results following Box-Behnken design, a prediction model for the hot cracking rate was developed using a second order polynomial function considering only two factor interaction. The initial prediction result indicated that the established model could predict the hot cracking rate adequately within the range of welding parameters being used. The model was then used to optimize welding parameters to achieve cracking-free welds.

Application of Factorial Design for Gas Parameter Optimization in CO2 Laser Welding

DEFF Research Database (Denmark)

Gong, Hui; Dragsted, Birgitte; Olsen, Flemming Ove

1997-01-01

The effect of different gas process parameters involved in CO2 laser welding has been studied by applying two-set of three-level complete factorial designs. In this work 5 gas parameters, gas type, gas flow rate, gas blowing angle, gas nozzle diameter, gas blowing point-offset, are optimized...... to be a very useful tool for parameter optimi-zation in laser welding process. Keywords: CO2 laser welding, gas parameters, factorial design, Analysis of Variance........ The bead-on-plate welding specimens are evaluated by a number of quality char-acteristics, such as the penetration depth and the seam width. The significance of the gas pa-rameters and their interactions are based on the data found by the Analysis of Variance-ANOVA. This statistic methodology is proven...

Design of the Intersector Welding Robot for vacuum vessel assembly and maintenance

International Nuclear Information System (INIS)

Jones, L.; Dagenais, J.-F.; Daenner, W.; Maisonnier, D.

2000-01-01

Next Step Fusion Devices require on-site (field weld) joining of sectors of the thick-walled vacuum vessel for structural and vacuum integrity. EFDA (European Fusion Development Agreement) is supporting an R and D programme to investigate processes for assembly of the vacuum vessel and to carry out cutting, re-welding and inspection for remote sector replacement, forming part of the overall VV/blanket research effort. In order to direct the process end-effectors along the field joint zone, a track-mounted Intersector Welding Robot (IWR) on a mock-up of a region of the vacuum vessel has been designed and is described in this paper. A rail-mounted hexapod type robot offers six axes of motion over a limited work envelope with high payload to robot weight ratio. A solution to the production of reduced pressure local vacuum is the installation of short, lightweight segments bolted to each other and the vessel wall. The various process heads can be mounted using end-effectors of special design. To minimise the supply and interface problems for the IWR prototype, its motion control and electronic systems will be embedded locally. A laser scan with camera forms the on-line seam tracking capability to compensate for rail and seam deviations

Corrosion of welded steel piping in domestic hot water: A case history. Corrosion de una instalacion de tubos soldados de acero galvanizado para agua caliente

Energy Technology Data Exchange (ETDEWEB)

Herrera, E J; Soria, L; Gallardo, J M

1993-01-01

Many leaks had occurred after seven years of service in the hot sanitary water system of building. The results of the failure analysis have led to the conclusion that the reduced life of the piping system was primarily promoted by the use of a dissimilar metal (galvanized steel-copper) installation and by an excessive service temperature. Through precuations were taking to electrically insulate both types of tubing by employing dielectric fittings and water flow followed the ''rule of flow'' (zinc[yields] copper), an indirect galvanic attach on galvanized steel took place. Localized corrosion was originated by microcells formed by plating out of soluble copper. Corrosive attack was most severe at weld seams. The microstructure of the weld zone was very different from that of the surrounding pipe. In addition, some pipes presented signs of incomplete fusion (welding without filling metal) and others had protruding weld seams which produced crevice attack and erosion-corrosion, respectively. Author (10 refs.)

Double fillet lap of laser welding of thin sheet AZ31B Mg alloy

Science.gov (United States)

Ishak, Mahadzir; Salleh, M. N. M.

2018-05-01

In this paper, we describe the experimental laser welding of thin sheet AZ31B using double fillet lap joint method. Laser welding is capable of producing high quality weld seams especially for small weld bead on thin sheet product. In this experiment, both edges for upper and lower sheets were subjected to the laser beam from the pulse wave (PW) mode of fiber laser. Welded sample were tested their joint strength by tensile-shear strength method and the fracture loads were studied. Strength for all welded samples were investigated and the effect of laser parameters on the joint strength and appearances were studied. Pulsed energy (EP) from laser process give higher effect on joint strength compared to the welding speed (WS) and angle of irradiation (AOI). Highest joint strength was possessed by sample with high EP with the same value of WS and AOI. The strength was low due to the crack defect at the centre of weld region.

Improvement in properties of welded joints of titanium alloy VT22 by thermocyclic treatment

International Nuclear Information System (INIS)

Lyasotskaya, V.S.; Kulikov, F.R.; Kirillov, Yu.G.; Ravdonikas, N.Yu.

1983-01-01

The results of investigations of the thermocyclic treatment (TCT) effect on the structure and properties of butt welded joints of tubes (with external diameter 180 mm and wall thickness 20-25 mm) of the VT22 alloy are presented. Welded joints have been obtained by means of multipassing automatic argon-arc (ARAW) and electron-beam (ELB) welding. It is shown that TCT of welded joints of the VT22 alloy results in formation in all zones of substructure with disperse precipitations of α-phase which is analogous to the structure of near welded seam zone metal immediately after welding. As a result of TCT and subsequent TT of welded joints poligonization and recrystallization processes of α- and #betta#-phases, changes in parameters of structural components and thin phase structure take place. TCT with strengthening TT or annealing leads to strength increase, while TCT with annealing besides that improves placticity and impact strength of the VT22 alloy welded joints

Solid state welding processes for an oxide dispersion strengthened nickel-chromium-aluminum alloy

Science.gov (United States)

Moore, T. J.

1975-01-01

Solid-state welding processes were evaluated for joining TD-NiCrAl (Ni-16Cr-4Al-2ThO2) alloy sheet. Both hot-press and resistance spot welding techniques were successfully applied in terms of achieving grain growth across the bond line. Less success was achieved with a resistance seam welding process. In stress-rupture shear and tensile shear tests of lap joints at 1100 C, most failures occurred in the parent material, which indicates that the weld quality was good and that the welds were not a plane of weakness. The overall weld quality was not as good as previously attained with TD-NiCr, probably because the presence of alumina at the faying surfaces and the developmental TD-NiCrAl sheet, which was not of the quality of the TD-NiCr sheet in terms of surface flatness and dimensional control.

Effect of Local Post Weld Heat Treatment on Tensile Properties in Friction Stir Welded 2219-O Al Alloy

Science.gov (United States)

Chu, Guannan; Sun, Lei; Lin, Caiyuan; Lin, Yanli

2017-11-01

To improve the formability of the aluminum alloy welds and overcome the size limitation of the bulk post weld heat treatment (BPWHT) on large size friction stir welded joints, a local post weld heat treatment method (LPWHT) was proposed. In this method, the resistance heating as the moving heat source is adopted to only heat the weld seam. The temperature field of LPWHT and its influence on the mechanical properties and formability of FSW 2219-O Al alloy joints was investigated. The evaluation of the tensile properties of FSW samples was also examined by mapping the global and local strain distribution using the digital image correlation methodology. The results indicated that the formability was improved greatly after LPWHT, while the hardness distribution of the FSW joint was homogenized. The maximum elongation can reach 1.4 times that of as-welded joints with increase the strength and the strain of the nugget zone increased from 3 to 8% when annealing at 300 °C. The heterogeneity on the tensile deformation of the as-welded joints was improved by the nugget zone showing large local strain value and the reason was given according to the dimple fracture characteristics at different annealing temperatures. The tensile strength and elongation of LPWHT can reach 93.3 and 96.1% of the BPWHT, respectively. Thus, the LPWHT can be advantageous compared to the BPWHT for large size welds.

Analysis of US underground thin seam mining potential. Volume 1. Text. Final technical report, December 1978. [In thin seams

Energy Technology Data Exchange (ETDEWEB)

Pimental, R. A; Barell, D.; Fine, R. J.; Douglas, W. J.

1979-06-01

An analysis of the potential for US underground thin seam (< 28'') coal mining is undertaken to provide basic information for use in making a decision on further thin seam mining equipment development. The characteristics of the present low seam mines and their mining methods are determined, in order to establish baseline data against which changes in mine characteristics can be monitored as a function of time. A detailed data base of thin seam coal resources is developed through a quantitative and qualitative analysis at the bed, county and state level. By establishing present and future coal demand and relating demand to production and resources, the market for thin seam coal has been identified. No thin seam coal demand of significance is forecast before the year 2000. Current uncertainty as to coal's future does not permit market forecasts beyond the year 2000 with a sufficient level of reliability.

Multiple pass and multiple layer friction stir welding and material enhancement processes

Science.gov (United States)

Feng, Zhili [Knoxville, TN; David, Stan A [Knoxville, TN; Frederick, David Alan [Harriman, TN

2010-07-27

Processes for friction stir welding, typically for comparatively thick plate materials using multiple passes and multiple layers of a friction stir welding tool. In some embodiments a first portion of a fabrication preform and a second portion of the fabrication preform are placed adjacent to each other to form a joint, and there may be a groove adjacent the joint. The joint is welded and then, where a groove exists, a filler may be disposed in the groove, and the seams between the filler and the first and second portions of the fabrication preform may be friction stir welded. In some embodiments two portions of a fabrication preform are abutted to form a joint, where the joint may, for example, be a lap joint, a bevel joint or a butt joint. In some embodiments a plurality of passes of a friction stir welding tool may be used, with some passes welding from one side of a fabrication preform and other passes welding from the other side of the fabrication preform.

Aluminized film, seam sealing tests and observations. Final report

Energy Technology Data Exchange (ETDEWEB)

1994-06-16

The purpose of this work was to investigate various seam sealing techniques, reinforcing methods, fitting installations, seam tolerances and geometric configurations pertinent to an aluminized plastic laminate. The program seeks a successful fabricating method for producing low-diffusion, cylindrical, spar liners to contain pressurized GH{sub 2} and GO{sub 2}. The test plan included: (1) seaming techniques on metallized Mylar film; (2) ``double patches`` for end fittings; (3) stainless steel bulkhead fitting assembly with seals; (4) minimum run tolerance on linear shear seam; (5) peel seam vs. inverted seal seam fabrication.

Using active contour models for feature extraction in camera-based seam tracking of arc welding

DEFF Research Database (Denmark)

Liu, Jinchao; Fan, Zhun; Olsen, Søren

2009-01-01

of the processes requires the extraction of characteristic parameters of the welding groove close to the molten pool, i.e. in an environment dominated by the very intense light emission from the welding arc. The typical industrial solution today is a laser-scanner containing a camera as well as a laser source......In the recent decades much research has been performed in order to allow better control of arc welding processes, but the success has been limited, and the vast majority of the industrial structural welding work is therefore still being made manually. Closed-loop and nearly-closed-loop control...... illuminating the groove by a light curtain and thus allowing details of the groove geometry to be extracted by triangulation. This solution is relatively expensive and must act several centimetres ahead of the molten pool. In addition laser-scanners often show problems when dealing with shiny surfaces...

Ultrasonic examination for safe end to nozzle dissimilar metal welds of steam generator

International Nuclear Information System (INIS)

Wang Zhuowei; Yu Jingsheng; Wang Jianjun

2014-01-01

The safe-end weld of steam generator is narrow seam weld with dissimilar metal, the filling material is nickel alloy 152/182 (material 690). The interior structure is of great anisotropic, and fake signal may occur during the defect detection by ultrasonic wave and the error for defect location may be increased. Stratified inspection by ultrasonic transducers with different angle and focus is a practical method which is verified by the real inspection while the linear indication in the inside surface besides the interior flaws are detected. (authors)

Investigation of subsidence event over multiple seam mining area

International Nuclear Information System (INIS)

Kohli, K.K.

1999-01-01

An investigation was performed to determine the sequence of events which caused the 1987 surface subsidence and related damage to several homes in Walker County, Alabama, USA. Surface affects compared to mine maps indicated the subsidence to be mine related. However, two coal seams had been worked under this area. The upper seam, the American seam, ranged from 250 to 280 feet beneath the surface in the area in question. It was mined-out before 1955 by room-and-pillar method leaving in place narrow-long pillars to support the overburden strata, and abandoned in 1955. The lower seam, the Mary Lee seam, ranged from 650 to 700 feet beneath the surface. The Mary Lee seam had been abandoned in 1966 and subsequently became flooded. The dewatering of the Mary Lee seam workings in 1985 caused the submerged pillars to be exposed to the atmosphere. Due to multiple seam mining and the fact that workings had been inundated then dewatered, a subsurface investigation ensued to determine the sequence and ultimate cause of surface subsidence. Core sample tests with fracture analysis in conjunction with down-the-hole TV camera inspections provided necessary information to determine that the subsidence started in the lower seam and progressed through the upper coal seam to the surface. Evidence from the investigation program established that dewatering of the lower seam workings caused the marginally stable support pillars and the roof to collapse. This failure triggered additional subsidence in the upper seam which broadened the area of influence at the surface

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

Requirements to gap widths and clamping for CO2 laser butt welding

DEFF Research Database (Denmark)

Gong, Hui; Juhl, Thomas Winther

1999-01-01

In the experimental study of fixturing and gap width requirements a clamping device for laser butt welding of steel sheets has been developed and tested. It has fulfilled the work and made the gap width experiments possible.It has shown that the maximum allowable gap width to some extent...... is inversely related to the welding speed. Also larger laser power leads to bigger allowable gap widths. The focal point position, though, has little influence on the maximum allowable gap width.During analysis X-ray photos show no interior porosity in the weld seam. Other methods have been applied to measure...... responses from variations in welding parameters.The table below lists the results of the study, showing the maximum allowable gap widths and some corresponding welding parameters.Maximum allowable Gap Width; Welding Speed; Laser Power:0.10 mm2 m/min2, 2.6 kW0.15 mm1 m/min2 kW0.20 mm1 m/min2.6 kW0.30 mm0.5 m...

Effect of Seams on Drape of Fabrics | Sukumar | African Research ...

African Journals Online (AJOL)

In this study drape of ten fabrics are analyzed with three types of seams and three stitch densities. Sample without seam is a control sample and drape of seamed samples are compared with control sample to analyse the drape behavior of seamed fabrics. This paper presents a fundamental drape analysis of seamed fabrics ...

Studies of Hot Crack Properties of Laser Welded Stainless Steel

DEFF Research Database (Denmark)

Juhl, Thomas Winther

During the present work crack testing concerning small and fast solidifying laser welds in austenitic stainless steel has been studied. A set of methods has been applied to investigate alloy properties, including ·Application of known information to predict solidification phases from the alloy...... composition. ·Weld metal solidification rate measurements for prediction of phases. ·Various crack tests to assess the crack susceptibility of alloys. ·A combination of the above for selection of suitable, weldable alloys. The possibility of using such specific methods for alloys and applications has been...... to the crack behaviour, but do not show an expected correlation between the crack resistance and the solidification rate. The employment of pulsed seams is therefore assessed not to be usable in the present selection methods. From evaluation of several crack tests, the Weeter spot weld test has been chosen...

Method and apparatus for welding workpieces along a seam with the aid of a filler material deposited in the seam

International Nuclear Information System (INIS)

1979-01-01

A method and apparatus for welding a nuclear reactor core barrel in a very precise and controlled manner is given. The power employed to preheat the filler material at its operating level is automatically controlled as a continuous non-linear function of the filler feed speed. (UK)

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.

49 CFR 230.30 - Lap-joint seam boilers.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Lap-joint seam boilers. 230.30 Section 230.30..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Inspection and Repair § 230.30 Lap-joint seam boilers. Every boiler having lap-joint longitudinal seams...

Microstructural Evolution in Friction Stir Welding of Ti-6Al-4V

Science.gov (United States)

Rubisoff, H.; Querin, J.; Magee, D.; Schneider, J.

2008-01-01

Friction stir welding (FSW) is a thermo-mechanical process that utilizes a nonconsumable rotating pin tool to consolidate a weld joint. In the conventional FSW process, the pin tool is responsible for generating both the heat required to soften the material and the forces necessary to deform and combine the weld seam. As such, the geometry of the pin tool is important to the quality of the weld and the process parameters required to produce the weld. Because the geometry of the pin tool is limitless, a reduced set of pin tools was formed to systematically study their effect on the weldment with respect to mechanical properties and resultant microstructure. In this study 0deg, 15deg, 30deg, 45deg, and 60deg tapered, microwave sintered, tungsten carbide (WC) pin tools were used to FSW Ti-6Al-4V. Transverse sections of the weld were used to test for mechanical properties and to document the microstructure using optical microscopy. X-ray diffraction (XRD) was also used to characterize the microstructure in the welds. FSW results for the 45deg and 60deg pin tools are reported in this paper.

Analysis of rail welding methods for mine rail access with the use of modern technologies

Science.gov (United States)

Usoltsev, A. A.; Shevchenko, R. A.; Kozyrev, N. A.; Kriukov, R. E.; Shishkin, P. E.

2017-09-01

Welded joint zones are weak sections of the railway track for all traffic cases (in the case of high-speed traffic and heavy traffic). In the paper advantages and disadvantages of the basic ways of rails welding, which are widely used today, are considered: electrocontact and aluminothermic. Carefully selected mode of differentially thermally strengthened rails string will allow the process of correction after heat treatment to be minimized and internal residual compressive stresses to be kept. Particular attention should be paid to the method of rails welding, in which after rails welding during their cooling it is offered to perform quasi-isothermal exposure in the temperature range of fine structure formation by passing pulses of alternating electric current through the welded joint maintaining this temperature until the end of the transformation. The use of quasi-isothermal exposure at a temperature of 600 - 650 °C makes it possible to obtain a finely dispersed structure of the welded seam of rails without additional heat treatment.

Mining the 510 coal seam prone to rock bursts and below a coal support pillar in a seam above

Energy Technology Data Exchange (ETDEWEB)

Major, M; Gebala, W

1983-10-01

The 510 coal seam, situated at a depth of 760 m below a support pillar left in an overlying coal seam, was mined by a system of longwall faces from 1979 to 1982. The seam was prone to rock bursts. Energy of rock bursts which occurred in the mine ranged from 10/SUP/5 to 10/SUP/6 J. The coal seam, 10 m thick, was mined by slicing. Faces were 140 m long. Stress concentrations caused by the suppport pillar left in the overlying coal seam were calculated. Curves which describe stress fluctuations were plotted. Rock burst hazards were determined by drilling. Drilling intervals depended on hazard degree and position of the test site in relation to the support pillar in the overlying coal seam. The face was 3 m high. Supports used in 2 gate roads were reinforced by steel and timber supports. Strong timber boards were placed at canopies of powered supports used at the working face. The face was situated at an angle of 10 degrees to the pillar axis. In the zone of critical stresses water infusion and shock blasting were used for rock burst prevention. These methods, plus reinforcement of the supports in gate roads and at the working face, guaranteed safe mining and prevented rock bursts. (8 refs.)

System for ultrasonic testing of welded seams. Einrichtung zur Ultraschallpruefung von Schweissnaehten

Energy Technology Data Exchange (ETDEWEB)

Bondarenko, J K; Troizkij, V A; Agronskaja, E V; Vasiliev, L N; Orel, V G; Naida, V L; Baldakov, V F; Ustjusanin, J V; Litvinenko, V A; Petrovskij, S N

1984-07-12

The invention concerns a device for the ultrasonic testing of welded joints which can be used in particular for quality control of multi-layer weldments. The testing equipment consists of probe, material testing device, amplitude discriminator, recording device, up and down counters and threshold value stages. (GSCH).

Double-Sided Single-Pass Submerged Arc Welding for 2205 Duplex Stainless Steel

Science.gov (United States)

Luo, Jian; Yuan, Yi; Wang, Xiaoming; Yao, Zongxiang

2013-09-01

The duplex stainless steel (DSS), which combines the characteristics of ferritic steel and austenitic steel, is used widely. The submerged arc welding (SAW) method is usually applied to join thick plates of DSS. However, an effective welding procedure is needed in order to obtain ideal DSS welds with an appropriate proportion of ferrite (δ) and austenite (γ) in the weld zone, particularly in the melted zone and heat-affected zone. This study evaluated the effectiveness of a high efficiency double-sided single-pass (DSSP) SAW joining method for thick DSS plates. The effectiveness of the converse welding procedure, characterizations of weld zone, and mechanical properties of welded joint are analyzed. The results show an increasing appearance and continuous distribution feature of the σ phase in the fusion zone of the leading welded seam. The converse welding procedure promotes the σ phase to precipitate in the fusion zone of leading welded side. The microhardness appears to significantly increase in the center of leading welded side. Ductile fracture mode is observed in the weld zone. A mixture fracture feature appears with a shear lip and tears in the fusion zone near the fusion line. The ductility, plasticity, and microhardness of the joints have a significant relationship with σ phase and heat treatment effect influenced by the converse welding step. An available heat input controlling technology of the DSSP formation method is discussed for SAW of thick DSS plates.

Design guidelines for multi-seam mining at Elliot Lake

International Nuclear Information System (INIS)

Hedley, D.G.F.

1978-04-01

With the current expansion in uranium mining, multi-seam mining could again be practised at Elliot Lake as it was in the 1960s. Information on the dimensions of stopes, pillars, and parting zone was gathered from plans and sections of the relevant closed mines. Discussions were held with personnel familiar with these mines to establish instances of pillar, roof, and parting zone failures. Design guidelines are formulated for stope and pillar dimensions in multi-seam mining for a range of orebody configurations using past practice in a back-analysis approach. Constraints imposed by dip and seam thickness on the choice of equipment and mining layout are evaluated. An attempt is made to bring together the engineering aspects, including rock mechanics, of multi-seam mine design with uranium recovery and other economic factors for three alternative mine layouts: single-seam mining, double-seam mining, and seams-and-parting mining. A series of examples are worked through, showing how the design guidelines can be applied for typical orebody configurations

Seam Pucker

CSIR Research Space (South Africa)

Galuszynski, S

1986-05-01

Full Text Available pucker. The bestexam~leofsucha stitch is the lockstitch lFie.4). Astitch withabilitv to stretch and react to thread contraction without prk&kg ~ i g ~ c a n t changes in stitch length, is unlikely to produce seam pucker. The double locked chain...

Assessment of The Cracking Properties of Stainless Steel Alloys and their Usability for Laser Welding in Production

DEFF Research Database (Denmark)

Juhl, Thomas Winther

2001-01-01

Methods to assess stainless steel alloys’ cracking properties and usability for laser welding has been studied. Also tests to assess alloys’ susceptibility to hot cracking has been conducted. Among these is the so-called Weeter test which assesses the alloy by executing a number of spot welds...... to provoke cracking in the alloy. In this work the Weeter test has been modified and changed in order to develop a faster and easier test also applicable to small specimens. The new test, called a Groove test differs from the Weeter test by its procedure in which linear seam welds are conducted instead...... of spot welds. The Groove test has the advantage of an easier microscopy and analysis in the welds. Results from crack tests was partly confirmed by predictions made on the basis of the alloy’s constituents and solidification growth rate....

Multipurpose ANSYS FE procedure for welding processes simulation

Energy Technology Data Exchange (ETDEWEB)

Capriccioli, Andrea [ENEA CR Frascati, Via Enrico Fermi 45, 00044 Frascati (Italy); Frosi, Paolo [ENEA CR Frascati, Via Enrico Fermi 45, 00044 Frascati (Italy)], E-mail: frosi@frascati.enea.it

2009-06-15

ANSYS FE procedures and 3D models for thermal and mechanical simulation of both Laser and TIG welding processes are presented. The special features are the applicability to a non uniform gap and the use of a fast iterative procedure that assures the constancy of the fixed maximum temperature along the single pass and between each pass and the following, apart from their shapes and sizes. All the thermal and mechanical material properties of both INCONEL 625 and AISI 316 are described till to liquid phase; convection and radiation effects are considered. The 3D ANSYS models use both brick and non linear contact elements and elastic and elastic-plastic materials. Two full simulation are presented: a laser welding test (taken from ENEA) and a TIG welding one (source W7-X) with the root seam plus 14 passes; thermal and mechanical results are reported in the two cases and for the latter an extensive sensitivity analysis, changing mesh size of the filling material, welding speed and material properties, is explained with results and comparisons. This large sensitivity analysis has been executed for TIG welding because in this case (multi-pass welding) the reduction of CPU time is a strong requirement; but some conclusions are helpful for laser welding too. The mechanical calculation results very sensitive to the mesh shape: this fact implies very fine and regular meshes. The specimens are first restrained and then welded with the foreseen welding procedure; after that it is released and the final linear and angular shrinkages are calculated. The ANSYS birth and death procedure is used and the CPU time was strongly reduced.

Multipurpose ANSYS FE procedure for welding processes simulation

International Nuclear Information System (INIS)

Capriccioli, Andrea; Frosi, Paolo

2009-01-01

ANSYS FE procedures and 3D models for thermal and mechanical simulation of both Laser and TIG welding processes are presented. The special features are the applicability to a non uniform gap and the use of a fast iterative procedure that assures the constancy of the fixed maximum temperature along the single pass and between each pass and the following, apart from their shapes and sizes. All the thermal and mechanical material properties of both INCONEL 625 and AISI 316 are described till to liquid phase; convection and radiation effects are considered. The 3D ANSYS models use both brick and non linear contact elements and elastic and elastic-plastic materials. Two full simulation are presented: a laser welding test (taken from ENEA) and a TIG welding one (source W7-X) with the root seam plus 14 passes; thermal and mechanical results are reported in the two cases and for the latter an extensive sensitivity analysis, changing mesh size of the filling material, welding speed and material properties, is explained with results and comparisons. This large sensitivity analysis has been executed for TIG welding because in this case (multi-pass welding) the reduction of CPU time is a strong requirement; but some conclusions are helpful for laser welding too. The mechanical calculation results very sensitive to the mesh shape: this fact implies very fine and regular meshes. The specimens are first restrained and then welded with the foreseen welding procedure; after that it is released and the final linear and angular shrinkages are calculated. The ANSYS birth and death procedure is used and the CPU time was strongly reduced.

Development and application of high-precision laser welding technology for manufacturing Ti alloy frames of glasses

International Nuclear Information System (INIS)

Kim, S. S.; Yang, M. S.; Kim, W. K.; Lee, D. Y.; Kim, J. M.; Leem, B. C.; Shin, J. S.; Lee, D. H.

1999-12-01

The research and development efforts of the high precision laser welding technology for manufacturing titanium alloy frames of glasses. For this purpose, laser welding device with the high beam quality is designed and fabricated, which consists of a optical fiber transmission part, a welding monitoring part and a welding controller. The welding nozzle and holding fixtures for manufacturing titanium and shape memory alloy frames of glasses. Titanium and shape memory alloy frames of glasses to be developed were experimentally manufactured by utilizing the laser welding using the optical fiber of GI 400 μm. As a result, the seam welding with the bead width of 0.3 mm or less and the weld penetration of 0.3-0.4mm could be accomplished. The fundamental technology was established through design of welding jigs with a variety of configurations and adequate welding conditions. Also, for the purpose to enable the companies participating in this project to commercialize the developed technology acceleratedly, a training program for the engineers belonging to such companies was conducted along with the technology transfer through joint experiments with the engineers. (author)

Study of hybrid laser / MAG welding process: characterization of the geometry and the hydrodynamics of the melt pool and development of a 3D thermal model

International Nuclear Information System (INIS)

Le Guen, E.

2010-11-01

Hybrid laser/MIG-MAG welding shows high advantages compared to laser welding or GMAW arc welding used separately. Thanks to this process, higher productivity can be gained through higher welding speed, higher squeeze tolerance moreover possible improvement of the metallurgical properties of the weld seam can be obtained. However, many operating parameters have to be set up in order to achieve optimal process. The complex physical phenomena, which govern welding process, have to be understood in order to use efficiently this technique in mass production. Understanding of these phenomena is also necessary to program numerical simulations which fit to this process. In the first step, experimental studies have been carried out with GMAW, laser and hybrid welding on samples of S355 steel. Influence of operating parameters has been analyzed through films performed with speed camera and macro-graphies of weld seam cross section. Surface deformations of the melt pool, induced by the arc pressure, weld pool length, droplet detachment and welding speed, have been analyzed precisely from images of the surface melt pool. In a second step, a numerical model was developed using the COMSOL Multiphysics software for MAG, laser and hybrid laser/MAG welding processes. A 3D quasi-stationary model has been calculated from the temperature field within the metal. The originality of the MAG and hybrid model lies in the prediction of the melt pool surface profile used to determine the 3D geometry, by taking into account the material input. The influence of different parameters such as arc power and speed welding on the efficiency as well as the distribution radius of the arc power and the arc pressure are analyzed through validations with different experimental results and different calculation configurations. (author)

Effects of clay-seam behavior on WIPP repository design

International Nuclear Information System (INIS)

Stone, C.M.; Krieg, R.D.; Branstetter, L.J.

1981-07-01

The geology at the southeastern New Mexico WIPP site consists of bedded layers of rock salt, anhydrite, polyhalite, mixtures of those materials, and thin clay seams. In spite of their very small (0.005 m to 0.05 m) thickness, clay seams are important to structural characterization of the WIPP stratigraphy since slip might possibly take place across them. Results of a study to determine the effects of clay seam frictional slip on the closure of a well-defined drift configuration are described. A Mohr-Coulomb dry friction model was used to model the active clay seams. The main thrust of the study was to determine the effects of friction coefficient variability on drift closure. Results show that the drift closure varies by a factor of 3.0 over the range of friction coefficients studied. The maximum slip observed along any clay seam was 0.12 m. For values of μ > .7, virtually no slip occurs along any clay seam

The Light Plane Calibration Method of the Laser Welding Vision Monitoring System

Science.gov (United States)

Wang, B. G.; Wu, M. H.; Jia, W. P.

2018-03-01

According to the aerospace and automobile industry, the sheet steels are the very important parts. In the recent years, laser welding technique had been used to weld the sheet steel part. The seam width between the two parts is usually less than 0.1mm. Because the error of the fixture fixed can’t be eliminated, the welding parts quality can be greatly affected. In order to improve the welding quality, the line structured light is employed in the vision monitoring system to plan the welding path before welding. In order to improve the weld precision, the vision system is located on Z axis of the computer numerical control (CNC) tool. The planar pattern is placed on the X-Y plane of the CNC tool, and the structured light is projected on the planar pattern. The vision system stay at three different positions along the Z axis of the CNC tool, and the camera shoot the image of the planar pattern at every position. Using the calculated the sub-pixel center line of the structure light, the world coordinate of the center light line can be calculated. Thus, the structured light plane can be calculated by fitting the structured light line. Experiment result shows the effective of the proposed method.

Development of a one side automatic TIG arc welding system in horizontal position for annular vessels in nuclear fuel cycle factory

International Nuclear Information System (INIS)

Ohtsuka, Takao; Ohsawa, Morihiko; Nakashima, Hiroyuki; Habuta, Susumu; Hori, Tomiji; Fujiwara, Katsusi; Kitaguchi, Yoshihisa.

1995-01-01

Various annular vessels are planned to be equipped as a part of the plutonium refining facility in the nuclear fuel cycle factory. For manufacturing the high quality vessels, a one side automatic TIG arc welding system which is applied to the circumferencial joints in horizontal welding position have been completed. The automatic welding system is confirmed to be effective for improving the joint qualities and saving the manufacturing cost by our Mockup test. The main points of our welding system are as follows. (1) Low pulsed TIG arc welding process with a mixed shielding gas of Ar+5%H 2 is being employed. (2) Mechanical seam trucking system for the carriage and welding torch is equipped in the welding machine. (3) Arc voltage controlling system is employed for stabilizing the welding condition. (4) Magnetic wheels are equipped at the carriage for travelling without rails. The weight of this welding machine is designed to be less than 15 kg. (author)

Cryogenic Testing of Different Seam Concepts for Multilayer Insulation Systems

Science.gov (United States)

Johnson, Wesley L.; Fesmire, J. E.

2009-01-01

Recent testing in a cylindrical, comparative cryostat at the Cryogenics Test Laboratory has focused on various seam concepts for multilayer insulation systems. Three main types of seams were investigated: straight overlap, fold-over, and roll wrapped. Each blanket was comprised of 40 layer pairs of reflector and spacer materials. The total thickness was approximately 12.5-mm, giving an average layer density of 32 layers per centimeter. The blankets were tested at high vacuum, soft vacuum, and no vacuum using liquid nitrogen to maintain the cold boundary temperature at 77 K. Test results show that all three seam concepts are all close in thermal performance; however the fold-over method provides the lowest heat flux. For the first series of tests, seams were located 120 degrees around the circumference of the cryostat from the previous seam. This technique appears to have lessened the degradation of the blanket due to the seams. In a follow-on test, a 20 layer blanket was tested in a roll wrapped configuration and then cut down the side of the cylinder, taped together, and re-tested. This test result shows the thermal performance impact of having the seams all in one location versus having the seams clocked around the vessel. This experimental investigation indicates that the method of joining the seams in multilayer insulation systems is not as critical as the quality of the installation process.

Current status of thin seam longwall mining in the US

Energy Technology Data Exchange (ETDEWEB)

Peng, S.S. [West Virginia Univ., Morgantown, WV (United States); Orndorff, A.

1996-12-31

Thin seams in this paper refers to those seams the economic mining height of which is below 50-55 in. that are traditionally considered to be the proprietary of plowing and present a whole net set of problems for longwall mining. In thin seams it is difficult to design and manufacture an efficient high capacity cutting machine for maintenance and production operations. Thin seam mining by longwall plowing began in the late fifties in southern West Virginia, and continues to the present time. In the seventies when longwall mining began to take off a large percentage of U.S. longwalls were operating in the thin seams. Tables 1 and 2 show the historical trends of cutting machines used for seams less than 55 in and 50 in, respectively. In addition to the plow system, the single-ended fixed drum and single-ended ranging drum shearers were introduced in the mid and late seventies and operated continuously until 2-4 years ago. The double-ended ranging drum shearers have also been employed for thin seam longwall mining during this period including several in-web (or off-pan) shearers between late seventies and early eighties. In this paper three thin-seam longwalls in three states employing the latest thin-seam longwall technology will be reviewed. However only two of them are still in operation while the third one ceased operation recently.

High-power Laser Welding of Thick Steel-aluminum Dissimilar Joints

Science.gov (United States)

Lahdo, Rabi; Springer, André; Pfeifer, Ronny; Kaierle, Stefan; Overmeyer, Ludger

According to the Intergovernmental Panel on Climate Change (IPCC), a worldwide reduction of CO2-emissions is indispensable to avoid global warming. Besides the automotive sector, lightweight construction is also of high interest for the maritime industry in order to minimize CO2-emissions. Using aluminum, the weight of ships can be reduced, ensuring lower fuel consumption. Therefore, hybrid joints of steel and aluminum are of great interest to the maritime industry. In order to provide an efficient lap joining process, high-power laser welding of thick steel plates (S355, t = 5 mm) and aluminum plates (EN AW-6082, t = 8 mm) is investigated. As the weld seam quality greatly depends on the amount of intermetallic phases within the joint, optimized process parameters and control are crucial. Using high-power laser welding, a tensile strength of 10 kN was achieved. Based on metallographic analysis, hardness tests, and tensile tests the potential of this joining method is presented.

Investigation of Microstructure and Microhardness in Self-Reacting Friction Stir Welded AA2014-T6 and AA2219-T87

Science.gov (United States)

Horton, K. Renee; McGill, Preston; Barkey, Mark

2011-01-01

Friction stir welding (FSW) is a solid state welding process with potential advantages for aerospace and automotive industries dealing with light alloys. Self-reacting friction stir welding (SR-FSW) is one variation of the FSW process being developed at the National Aeronautics and Space Administration (NASA) for use in the fabrication of propellant tanks. This work reports on the microstructure and microhardness of SR-FSW between two dissimilar aluminum alloys. Specifically, the study examines the cross section of the weld joint formed between an AA2014-T6 plate on the advancing side and an AA2219-T87 plate on the retreating side. The microstructural analysis shows an irregularly displaced weld seam from the advancing side past the thermo-mechanical affected zone (TMAZ) into the weld nugget region. There are sharp variations in the microhardness across the weld. These variations are described in the paper and mechanisms for their formation are discussed.

Effects of process variables on characteristics of Nd:YAG laser welds of Inconel 600

Energy Technology Data Exchange (ETDEWEB)

Lee, Chang Hee [Hanyang University, Seoul (Korea)

1998-04-01

This report described a basic study of the pulse shaping effects on weld dimension and weld discontinuities in the continuous seam welds of STS 310S using Nd:YAG laser. Further, laser weldability tests for STS 310S and Inconel 600 was carried out. Pulse shapes used in this experiment were general type, which has been applied generally in laser material processing, ramped-up type (3 steps) and ramped-down type (3 steps). The pulse energy was constant regardless of types of pulse shape. The penetration of laser welds became deeper as the pulse width was longer and the peak power was increased. The pulse of ramped-up type was most effective for deep penetration compared with others. With regard to the laser weldability and reduction of weld discontinuities such as porosity and hot cracking, the general type pulse was the worst and the ramped-down type pulse was the best among 3 types of pulse shape studied in this investigation. (author). 36 refs., 25 figs., 5 tabs.

Numerical Analysis of Crack Progress in Different Areas of a Friction Stir Welded Bead for an 5251 H14 Aluminum Alloy Specimen

Directory of Open Access Journals (Sweden)

Y. Kambouz

2014-02-01

Full Text Available The assemblies welded by Friction Stir Welding have a major advantage which is the absence of a metal filler. This process contributes to the welding of materials that are known to be difficult to weld using the conventional techniques often employed in the field of transport, for example in the automobile body by applying a spot welding. The numerical modeling of this type of process is complex, not only in terms of the variety of physical phenomena which must be considered, but also because of the experimental procedure that must be followed in order to verify and validate numerical predictions. In this work, a finite element model is proposed in order to simulate the crack propagation under monotonic loading in different areas of the weld seam of a strain hardening CT-50 aluminum alloy 5251H14 specimen.

Sensor controlled robotic welding for nuclear applications. Annual progress report

International Nuclear Information System (INIS)

Chin, B.A.; Madsen, N.H.; Goodling, J.S.

1986-01-01

Significant accomplishments towards the development of an adaptive robotic welding system have been made during the first eight months of the project. The project is currently within budget and on schedule. Accomplishments were both scientific and programmatic in form. A list of the scientific accomplishments follows: demonstrated that the thermal profiles generated for intentionally induced defects during the welding process are similar in steel, aluminum and stainless steel. The conclusion is therefore that infrared sensing is applicable to the welding of over 90% of all materials used in the energy industry. Completed design and testing of a first generation communication system used to transfer information from the infrared camera to the computer in a near real time form. This demonstrates that information can be obtained, sorted, transferred and received in a time frame consistent with on-line process control. Demonstrated rudimentary seam tracking using infrared sensing and closed loop logic routines. A linear relationship exists between measured peak surface temperature and depth of penetration. Similarily, a linear relationship exists between measured infrared width and weld bead width. These relations suggest that penetration parameters may be controlled using surface measurements as obtained by infrared thermography

A new optimal seam method for seamless image stitching

Science.gov (United States)

Xue, Jiale; Chen, Shengyong; Cheng, Xu; Han, Ying; Zhao, Meng

2017-07-01

A novel optimal seam method which aims to stitch those images with overlapping area more seamlessly has been propos ed. Considering the traditional gradient domain optimal seam method and fusion algorithm result in bad color difference measurement and taking a long time respectively, the input images would be converted to HSV space and a new energy function is designed to seek optimal stitching path. To smooth the optimal stitching path, a simplified pixel correction and weighted average method are utilized individually. The proposed methods exhibit performance in eliminating the stitching seam compared with the traditional gradient optimal seam and high efficiency with multi-band blending algorithm.

Analysis of a multi pass weld of a thick walled tube made of austenitic stainless steel X6 CrNiNb 18 10

International Nuclear Information System (INIS)

Scholtes, B.; Zinn, W.; Ilg, U.; Backfisch, W.; Gibmeier, J.; Kirch, D.

2006-01-01

In this paper, microstructure and residual stresses of a multi pass welding of a thick-walled tube made of austenitic stainless steel X6 CrNiNb 18 10 (1.4550) are systematically characterized and assessed. Results of microstructural and phase analyses, residual stress and hardness measurements as well as of a tensile test using micro specimen and SEM analyses are presented. Using these data, plastic deformations occurring during the welding process in the vicinity of the weld seam are evaluated. Finally, consequences of an additional heat treatment at 400 C/24 h are studied. (Abstract Copyright [2006], Wiley Periodicals, Inc.) [de

Investigation of the Weld Properties of Dissimilar S32205 Duplex Stainless Steel with AISI 304 Steel Joints Produced by Arc Stud Welding

Directory of Open Access Journals (Sweden)

Aziz Barış Başyiğit

2017-03-01

Full Text Available UNS S32205 duplex stainless steel plates with a thickness of 3 mm are arc stud welded by M8 × 40 mm AISI 304 austenitic stainless steel studs with constant stud lifts in order to investigate the effects of welding arc voltages on mechanical and microstructural behaviors of the joints. As the welding arc voltage increases starting from 140 V, the tensile strength of the weldment also increases but the higher arc values results in more spatters around the weld seam up to 180 V. Conversely, the lower arc voltages causes poor tensile strength values to weldments. Tensile tests proved that all of the samples are split from each other in the welding zone but deformation occurs in duplex plates during the tensile testing of weldments so that the elongation values are not practically notable. The satisfactory tensile strength and bending values are determined by applying 180 volts of welding arc voltage according to ISO 14555 standard. Peak values of micro hardness occurred in weld metal most probably as a consequence of increasing heat input decreasing the delta ferrite ratios. As the arc voltage increases, the width of the heat affected zone increases. Coarsening of delta-ferrite and austenite grains was observed in the weld metal peak temperature zone but it especially becomes visible closer to the duplex side in all samples. The large voids and unwelded zones up to approximately 1 mm by length are observed by macro-structure inspections. Besides visual tests and micro-structural surveys; bending and microhardness tests with radiographic inspection were applied to samples for maintaining the correct welding parameters in obtaining well-qualified weldments of these two distinct groups of stainless steel materials.

On the quantitative determination of coal seam thickness by means of in-seam seismic surveys

Czech Academy of Sciences Publication Activity Database

Schott, W.; Waclawik, Petr

2015-01-01

Roč. 52, č. 10 (2015), s. 1496-1504 ISSN 0008-3674. [International Colloquium on Geomechanics and Geophysics /5./. Karolinka, 25.06.2014-27.06.2014] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : in-seam seismic (ISS) * ISS wave * Love wave * coal seam thickness * dispersion Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 1.877, year: 2015 http://www.nrcresearchpress.com/doi/full/10.1139/cgj-2014-0466#.VgqE1Zc70mt

Effects of aging treatment and heat input on the microstructures and mechanical properties of TIG-welded 6061-T6 alloy joints

Science.gov (United States)

Peng, Dong; Shen, Jun; Tang, Qin; Wu, Cui-ping; Zhou, Yan-bing

2013-03-01

Aging treatment and various heat input conditions were adopted to investigate the microstructural evolution and mechanical properties of TIG welded 6061-T6 alloy joints by microstructural observations, microhardness tests, and tensile tests. With an increase in heat input, the width of the heat-affected zone (HAZ) increases and grains in the fusion zone (FZ) coarsen. Moreover, the hardness of the HAZ decreases, whereas that of the FZ decreases initially and then increases with an increase in heat input. Low heat input results in the low ultimate tensile strength of the welded joints due to the presence of partial penetrations and pores in the welded joints. After a simple artificial aging treatment at 175°C for 8 h, the microstructure of the welded joints changes slightly. The mechanical properties of the welded joints enhance significantly after the aging process as few precipitates distribute in the welded seam.

Influence of Filler Alloy Composition and Process Parameters on the Intermetallic Layer Thickness in Single-Sided Cold Metal Transfer Welding of Aluminum-Steel Blanks

Science.gov (United States)

Silvayeh, Zahra; Vallant, Rudolf; Sommitsch, Christof; Götzinger, Bruno; Karner, Werner; Hartmann, Matthias

2017-11-01

Hybrid components made of aluminum alloys and high-strength steels are typically used in automotive lightweight applications. Dissimilar joining of these materials is quite challenging; however, it is mandatory in order to produce multimaterial car body structures. Since especially welding of tailored blanks is of utmost interest, single-sided Cold Metal Transfer butt welding of thin sheets of aluminum alloy EN AW 6014 T4 and galvanized dual-phase steel HCT 450 X + ZE 75/75 was experimentally investigated in this study. The influence of different filler alloy compositions and welding process parameters on the thickness of the intermetallic layer, which forms between the weld seam and the steel sheet, was studied. The microstructures of the weld seam and of the intermetallic layer were characterized using conventional optical light microscopy and scanning electron microscopy. The results reveal that increasing the heat input and decreasing the cooling intensity tend to increase the layer thickness. The silicon content of the filler alloy has the strongest influence on the thickness of the intermetallic layer, whereas the magnesium and scandium contents of the filler alloy influence the cracking tendency. The layer thickness is not uniform and shows spatial variations along the bonding interface. The thinnest intermetallic layer (mean thickness < 4 µm) is obtained using the silicon-rich filler Al-3Si-1Mn, but the layer is more than twice as thick when different low-silicon fillers are used.

In situ laser-induced breakdown spectroscopy measurements of chemical compositions in stainless steels during tungsten inert gas welding

Science.gov (United States)

Taparli, Ugur Alp; Jacobsen, Lars; Griesche, Axel; Michalik, Katarzyna; Mory, David; Kannengiesser, Thomas

2018-01-01

A laser-induced breakdown spectroscopy (LIBS) system was combined with a bead-on-plate Tungsten Inert Gas (TIG) welding process for the in situ measurement of chemical compositions in austenitic stainless steels during welding. Monitoring the weld pool's chemical composition allows governing the weld pool solidification behavior, and thus enables the reduction of susceptibility to weld defects. Conventional inspection methods for weld seams (e.g. ultrasonic inspection) cannot be performed during the welding process. The analysis system also allows in situ study of the correlation between the occurrence of weld defects and changes in the chemical composition in the weld pool or in the two-phase region where solid and liquid phase coexist. First experiments showed that both the shielding Ar gas and the welding arc plasma have a significant effect on the selected Cr II, Ni II and Mn II characteristic emissions, namely an artificial increase of intensity values via unspecific emission in the spectra. In situ investigations showed that this artificial intensity increase reached a maximum in presence of weld plume. Moreover, an explicit decay has been observed with the termination of the welding plume due to infrared radiation during sample cooling. Furthermore, LIBS can be used after welding to map element distribution. For austenitic stainless steels, Mn accumulations on both sides of the weld could be detected between the heat affected zone (HAZ) and the base material.

Sturdy on Orbital TIG Welding Properties for Nuclear Fuel Test Rod

International Nuclear Information System (INIS)

Joung, Changyoung; Hong, Jintae; Kim, Kahye; Huh, Sungho

2014-01-01

We developed a precision TIG welding system that is able to weld the seam between end-caps and a fuel cladding tube for the nuclear fuel test rod and rig. This system can be mainly classified into an orbital TIG welder (AMI, M-207A) and a pressure chamber. The orbital TIG welder can be independently used, and it consists of a power supply unit, a microprocessor, water cooling unit, a gas supply unit and an orbital weld head. In this welder, the power supply unit mainly supplies GTAW power for a welding specimen and controls an arc starting of high frequency, supping of purge gas, arc rotation through the orbital TIG welding head, and automatic timing functions. In addition, the pressure chamber is used to make the welded surface of the cladding specimen clean with the inert gas filled inside the chamber. To precisely weld the cladding tube, a welding process needs to establish a schedule program for an orbital TIG welding. Therefore, the weld tests were performed on a cladding tube and dummy rods under various conditions. This paper describes not only test results on parameters of the purge gas flow rates and the chamber gas pressures for the orbital TIG welding, but also test results on the program establishment of an orbital TIG welding system to weld the fuel test rods. Various welding tests were performed to develop the orbital TIG welding techniques for the nuclear fuel test rod. The width of HAZ of a cladding specimen welded with the identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a weld end-point because of heat accumulation. The welding effect of the PGFR and CGP shows a relatively large difference for FSS and LSS. Each hole on the cladding specimens was formed in the 1bar CGP with the 20L/min PGFR but not made in the case of the PGFR of 10L/min in the CGP of 2bar. The optimum schedule program of the orbital TIG welding system to weld the nuclear fuel test rod was established through the program

Sturdy on Orbital TIG Welding Properties for Nuclear Fuel Test Rod

Energy Technology Data Exchange (ETDEWEB)

Joung, Changyoung; Hong, Jintae; Kim, Kahye; Huh, Sungho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

We developed a precision TIG welding system that is able to weld the seam between end-caps and a fuel cladding tube for the nuclear fuel test rod and rig. This system can be mainly classified into an orbital TIG welder (AMI, M-207A) and a pressure chamber. The orbital TIG welder can be independently used, and it consists of a power supply unit, a microprocessor, water cooling unit, a gas supply unit and an orbital weld head. In this welder, the power supply unit mainly supplies GTAW power for a welding specimen and controls an arc starting of high frequency, supping of purge gas, arc rotation through the orbital TIG welding head, and automatic timing functions. In addition, the pressure chamber is used to make the welded surface of the cladding specimen clean with the inert gas filled inside the chamber. To precisely weld the cladding tube, a welding process needs to establish a schedule program for an orbital TIG welding. Therefore, the weld tests were performed on a cladding tube and dummy rods under various conditions. This paper describes not only test results on parameters of the purge gas flow rates and the chamber gas pressures for the orbital TIG welding, but also test results on the program establishment of an orbital TIG welding system to weld the fuel test rods. Various welding tests were performed to develop the orbital TIG welding techniques for the nuclear fuel test rod. The width of HAZ of a cladding specimen welded with the identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a weld end-point because of heat accumulation. The welding effect of the PGFR and CGP shows a relatively large difference for FSS and LSS. Each hole on the cladding specimens was formed in the 1bar CGP with the 20L/min PGFR but not made in the case of the PGFR of 10L/min in the CGP of 2bar. The optimum schedule program of the orbital TIG welding system to weld the nuclear fuel test rod was established through the program

Utilisation of thin-seam drum shearer loaders at Bergbau AG Niederrhein

Energy Technology Data Exchange (ETDEWEB)

Wenzel, W.; Klimek, K.H.

1983-03-10

Conventional shearer loaders which travel on the AFC can only be used in seams more than 1.6 m thick in the conditions of the Ruhr coalfield. Low design shearers have been developed for seams below 1.6 m, and can work in conditions down to 1.0 m seam thickness. At Bergbau AG Niederrhein these machines have been adapted to prevailing conditions and requirements. The demand for a high drive rating led to a thin-seam shearer thickness from 1.3 m upwards. The need for minimum feasible machine height with adequate drive rating has been obtained with another machine. Currently under development is a machine which should lower the utilisation limit of thin-seam shearers. With planning and the use of suitable types of supports, it is possible to work faces by shearer in seams of 1.0 m upwards, even under difficult extraction conditions.

The Evolution of Friction Stir Welding Theory at Marshall Space Flight Center

Science.gov (United States)

Nunes, Arthur C.

2012-01-01

From 1995 to the present the friction stir welding (FSW) process has been under study at Marshall Space Flight Center (MSFC). This is an account of the progressive emergence of a set of conceptual tools beginning with the discovery of the shear surface, wiping metal transfer, and the invention of a kinematic model and making possible a treatment of both metallurgical structure formation and process dynamics in friction stir welding from a unified point of view. It is generally observed that the bulk of the deformation of weld metal around the FSW pin takes place in a very narrow, almost discontinuous zone with high deformation rates characteristic of metal cutting. By 1999 it was realized that this zone could be treated as a shear surface like that in simple metal cutting models. At the shear surface the seam is drawn out and compressed and pressure and flow conditions determine whether or not a sound weld is produced. The discovery of the shear surface was followed by the synthesis of a simple 3- flow kinematic model of the FSW process. Relative to the tool the flow components are: (1) an approaching translational flow at weld speed V, (2) a rotating cylindrical plug flow with the angular velocity of the tool , and (3) a relatively slow ring vortex flow (like a smoke ring) encircling the tool and driven by shoulder scrolls and pin threads. The rotating plug flow picks up an element of weld metal, rotates it around with the tool, and deposits it behind the tool ( wiping metal transfer ); it forms plan section loops in tracers cut through by the tool. Radially inward flow from the ring vortex component retains metal longer in the rotating plug and outward flow expels metal earlier; this interaction forms the looping weld seam trace and the tongue and groove bimetallic weld contour. The radial components of the translational and ring vortex flows introduce parent metal intrusions into the small grained nugget material close to the tool shoulder; if this feature is

Classification of coal seam outburst hazards and evaluation of the importance of influencing factors

OpenAIRE

Shi Xianzhi; Song Dazhao; Qian Ziwei

2017-01-01

Coal and gas outbursts are the result of several geological factors related to coal seam gas (coal seam gas pressure P, coal seam sturdiness coefficient f and coal seam gas content W), and these parameters can be used to classify the outburst hazard level of a coal seam.

Residual stresses determination in an 8 mm Incoloy 800H weld via neutron diffraction

International Nuclear Information System (INIS)

Chen, Xizhang; Zhang, Shu Yan; Wang, Jingjun; Kelleher, Joe F.

2015-01-01

Highlights: • Stress through thickness at 5 mm from weld centerline indicates a “U” distribution. • Declining of tensile stress through thickness occurred at weld centerline. • Residual stress between layers is the lowest. - Abstract: To investigate the distribution of residual stresses, the 8 mm 800H alloy was joined by multi-layer butt TIG process. Residual stresses in the longitudinal, transverse and normal directions were measured via neutron diffraction. These residual stress measurements were taken at a series of points 2 mm below the top surface, covering the fusion zone, heat affected zone (HAZ) and base metal. In addition, two lines of longitudinal residual stress values at the weld centerline and 5 mm from weld centerline through thickness were measured. Results show that both the longitudinal and transverse stresses from the weld centerline to base metal are mainly tensile stresses. The longitudinal residual stress is the largest, with a maximum value of 330 MPa. As for the normal residual stress, the weld zone shows tensile stress, while the HAZ shows compressive stress. The middle of the thickness shows compressive residual stress along the thickness direction. The longitudinal stress at weld centerline through thickness reveals the interlayer heat treat effects leads to a declining of tensile stress. While the stress at 5 mm from weld centerline indicates a “U” distribution due to the mixed microstructure close to fusion line. With the increasing distance from weld seam, the residual stress decreases gradually

18 CFR 270.302 - Occluded natural gas produced from coal seams.

Science.gov (United States)

2010-04-01

... produced from coal seams. 270.302 Section 270.302 Conservation of Power and Water Resources FEDERAL ENERGY... produced from coal seams. A person seeking a determination that natural gas is occluded natural gas produced from coal seams must file an application with the jurisdictional agency which contains the...

Influence of deformation on structural-phase state of weld material in St3 steel

Energy Technology Data Exchange (ETDEWEB)

Smirnov, Alexander, E-mail: galvas.kem@gmail.ru; Ababkov, Nicolay, E-mail: n.ababkov@rambler.ru; Ozhiganov, Yevgeniy, E-mail: zhigan84@mail.ru [Kuzbass State Technical University, 25-54, Krasnaya Str., 650000, Kemerovo (Russian Federation); LLC “Kuzbass Center of Welding and Control”, 33/2, Lenin Str., 650055, Kemerovo (Russian Federation); Kozlov, Eduard, E-mail: kozlov@tsuab.ru [Kuzbass State Technical University, 25-54, Krasnaya Str., 650000, Kemerovo (Russian Federation); Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Popova, Natalya, E-mail: natalya-popova-44@mail.ru [Kuzbass State Technical University, 25-54, Krasnaya Str., 650000, Kemerovo (Russian Federation); Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); Institute of Strength Physics and Materials Science, SB RAS, 2/4, Akademicheskii Ave., 634021, Tomsk (Russian Federation); Nikonenko, Elena, E-mail: vilatomsk@mail.ru [Kuzbass State Technical University, 25-54, Krasnaya Str., 650000, Kemerovo (Russian Federation); Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30, Lenin Str., 634050, Tomsk (Russian Federation); Zboykova, Nadezhda, E-mail: tezaurusn@gmail.com; Koneva, Nina, E-mail: koneva@tsuab.ru [Tomsk State University of Architecture and Building, 2, Solyanaya Sq., 634003, Tomsk (Russian Federation)

2016-01-15

The structural-phase condition of the weld material subjected to the plastic deformation was investigated using the translucent diffraction electron microscopy method. The investigations were carried out near the joint of the weld and the base metal. The seam was done by the method of manual arc welding without artificial defects. The St3 steel was taken as the welded material. Influence of the plastic deformation on morphology, phase composition, defect structure and its parameters of weld metal was revealed. All investigations were done at the distance of 0.5 mm from the joint of the weld and the base metal at the deformation degrees from 0 to 5% and after destruction of a sample. It was established that deformation of the sample did not lead to qualitative changes in the structure (the structure is still presented by ferrite-pearlite mixture) but changed the quantitative parameters of the structure, namely, with the increase of plastic deformation a part of the pearlite component becomes more and more imperfect. In the beginning it turns into the destroyed pearlite then into ferrite, the volume fraction of pearlite is decreased. The polarization of dislocation structure takes place but it doesn’t lead to the internal stresses that can destroy the sample.

Palaeoenvironmental reconstruction of Hüsamlar coal seam, SW

Indian Academy of Sciences (India)

The Ören and Yatağan Basins in SW Turkey host several Miocene coal deposits currently under exploitation for power generation. The present study aims to provide insight into the palaeoenvironmental conditions, which controlled the formation of the Hüsamlar coal seam located in Ören Basin. The coal seam displays ...

Wavelength dependency in high power laser cutting and welding

Science.gov (United States)

Havrilla, David; Ziermann, Stephan; Holzer, Marco

2012-03-01

Laser cutting and welding have been around for more than 30 years. Within those three decades there has never been a greater variety of high power laser types and wavelengths to choose from than there is today. There are many considerations when choosing the right laser for any given application - capital investment, cost of ownership, footprint, serviceability, along with a myriad of other commercial & economic considerations. However, one of the most fundamental questions that must be asked and answered is this - "what type of laser is best suited for the application?". Manufacturers and users alike are realizing what, in retrospect, may seem obvious - there is no such thing as a universal laser. In many cases there is one laser type and wavelength that clearly provides the highest quality application results. This paper will examine the application fields of high power, high brightness 10.6 & 1 micron laser welding & cutting and will provide guidelines for selecting the laser that is best suited for the application. Processing speed & edge quality serve as key criteria for cutting. Whereas speed, seam quality & spatter ejection provide the paradigm for welding.

Evaluation of bending rigidity behaviour of ultrasonic seaming on woven fabrics

Science.gov (United States)

Şevkan Macit, Ayşe; Tiber, Bahar

2017-10-01

In recent years ultrasonic seaming that is shown as an alternative method to conventional seaming has been investigated by many researchers. In our study, bending behaviour of this alternative method is examined by changing various parameters such as fabric type, seam type, roller type and seaming velocity. For this purpose fifteen types of sewn fabrics were tested according to bending rigidity test standard before and after washing processes and results were evaluated through SPSS statistical analyze programme. Consequently, bending length values of the ultrasonically sewn fabrics are found to be higher than the bending length values of conventionally sewn fabrics and the effects of seam type on bending length are seen statistically significant. Also it is observed that bending length values are in relationship with the rest of the parameters excluding roller type.

Laser patterning and welding of transparent polymers for microfluidic device fabrication

Science.gov (United States)

Pfleging, W.; Baldus, O.

2006-02-01

CO II-laser-assisted micro-patterning of polymethylmethacrylate (PMMA) or cyclo-olefin copolymer (COC) has a great potential for the rapid manufacturing of polymeric devices including cutting and structuring. Channel widths of about 50 μm as well as large area patterning of reservoir structures or drilling of vias are established. For this purpose a high quality laser beam is necessary as well as an appropriate beam forming system. In combination with laser transmission welding a fast fabrication of two- and three-dimensional micro-fluidic devices was possible. Welding as well as multilayer welding of transparent polymers was investigated for different polymers such as PMMA, polyvinylidene fluoride (PVDF), COC, and polystyrene (PS). The laser transmission welding process is performed with a high-power diode laser (wavelength 940 nm). An absorption layer with a thickness of several nanometers is deposited onto the polymer surfaces. The welding process has been established for the welding of polymeric parts containing microchannels, if the width of the channels is equal or larger than 100μm. For smaller feature sizes the absorption layer is structured by UV-laser radiation in order to get a highly localized welding seam, e.g., for the limitation of thermal penetration and thermal damaging of functional features such as channels, thin walls or temperature-sensitive substances often contained in micro-fluidic devices. This process strategy was investigated for the welding of capillary electrophoresis chips and capillary blood separation chips, including channel widths of 100 μm and 30 μm. Analysis of the thickness of the absorption layer was carried out with optical transmission spectroscopy.

A Comprehensive Overview of CO2 Flow Behaviour in Deep Coal Seams

Directory of Open Access Journals (Sweden)

Mandadige Samintha Anne Perera

2018-04-01

Full Text Available Although enhanced coal bed methane recovery (ECBM and CO2 sequestration are effective approaches for achieving lower and safer CO2 levels in the atmosphere, the effectiveness of CO2 storage is greatly influenced by the flow ability of the injected CO2 through the coal seam. A precious understanding of CO2 flow behaviour is necessary due to various complexities generated in coal seams upon CO2 injection. This paper aims to provide a comprehensive overview on the CO2 flow behaviour in deep coal seams, specifically addressing the permeability alterations associated with different in situ conditions. The low permeability nature of natural coal seams has a significant impact on the CO2 sequestration process. One of the major causative factors for this low permeability nature is the high effective stresses applying on them, which reduces the pore space available for fluid movement with giving negative impact on the flow capability. Further, deep coal seams are often water saturated where, the moisture behave as barriers for fluid movement and thus reduce the seam permeability. Although the high temperatures existing at deep seams cause thermal expansion in the coal matrix, reducing their permeability, extremely high temperatures may create thermal cracks, resulting permeability enhancements. Deep coal seams preferable for CO2 sequestration generally are high-rank coal, as they have been subjected to greater pressure and temperature variations over a long period of time, which confirm the low permeability nature of such seams. The resulting extremely low CO2 permeability nature creates serious issues in large-scale CO2 sequestration/ECBM projects, as critically high injection pressures are required to achieve sufficient CO2 injection into the coal seam. The situation becomes worse when CO2 is injected into such coal seams, because CO2 movement in the coal seam creates a significant influence on the natural permeability of the seams through CO2

Refinement of Out of Circularity and Thickness Measurements of a Cylinder for Finite Element Analysis

Science.gov (United States)

2016-09-01

refined finite element model. Note that the longitudinal seam weld at θ = 0° (= 360°) runs along the green area and through the centre of the red...Longitudinal seam weld is a theta = 0/360 deg UNCLASSIFIED DST-Group-TN-1521 UNCLASSIFIED 7 Figure 2. Example of thickness distribution in the... weld seam at 0° is clearly evident. Inspection of similar graphs for all sections indicates similarly good comparison between the measured and

Geomechanics of subsidence above single and multi-seam coal mining

Directory of Open Access Journals (Sweden)

A.M. Suchowerska Iwanec

2016-06-01

Full Text Available Accurate prediction of surface subsidence due to the extraction of underground coal seams is a significant challenge in geotechnical engineering. This task is further compounded by the growing trend for coal to be extracted from seams either above or below previously extracted coal seams, a practice known as multi-seam mining. In order to accurately predict the subsidence above single and multi-seam longwall panels using numerical methods, constitutive laws need to appropriately represent the mechanical behaviour of coal measure strata. The choice of the most appropriate model is not always straightforward. This paper compares predictions of surface subsidence obtained using the finite element method, considering a range of well-known constitutive models. The results show that more sophisticated and numerically taxing constitutive laws do not necessarily lead to more accurate predictions of subsidence when compared to field measurements. The advantages and limitations of using each particular constitutive law are discussed. A comparison of the numerical predictions and field measurements of surface subsidence is also provided.

Gas Permeability Evolution Mechanism and Comprehensive Gas Drainage Technology for Thin Coal Seam Mining

Directory of Open Access Journals (Sweden)

Fangtian Wang

2017-09-01

Full Text Available A thin coal seam mined as a protective coal seam above a gas outburst coal seam plays a central role in decreasing the degree of stress placed on a protected seam, thus increasing gas permeability levels and desorption capacities to dramatically eliminate gas outburst risk for the protected seam. However, when multiple layers of coal seams are present, stress-relieved gas from adjacent coal seams can cause a gas explosion. Thus, the post-drainage of gas from fractured and de-stressed strata should be applied. Comprehensive studies of gas permeability evolution mechanisms and gas seepage rules of protected seams close to protective seams that occur during protective seam mining must be carried out. Based on the case of the LongWall (LW 23209 working face in the Hancheng coal mine, Shaanxi Province, this paper presents a seepage model developed through the FLAC3D software program (version 5.0, Itasca Consulting Group, Inc., Minneapolis, MI, USA from which gas flow characteristics can be reflected by changes in rock mass permeability. A method involving theoretical analysis and numerical simulation was used to analyze stress relief and gas permeability evolution mechanisms present during broken rock mass compaction in a goaf. This process occurs over a reasonable amount of extraction time and in appropriate locations for comprehensive gas extraction technologies. In using this comprehensive gas drainage technological tool, the safe and efficient co-extraction of thin coal seams and gas resources can be realized, thus creating a favorable environment for the safe mining of coal and gas outburst seams.

Temperature field distribution of coal seam in heat injection

OpenAIRE

Zhang Zhizhen; Peng Weihong; Shang Xiaoji; Wang Kun; Li Heng; Ma Wenming

2017-01-01

In this article, we present a natural boundary element method (NBEM) to solve the steady heat flow problem with heat sources in a coal seam. The boundary integral equation is derived to obtain the temperature filed distribution of the coal seam under the different injecting conditions.

Electron Beam Welding of IN792 DS: Effects of Pass Speed and PWHT on Microstructure and Hardness.

Science.gov (United States)

Angella, Giuliano; Barbieri, Giuseppe; Donnini, Riccardo; Montanari, Roberto; Richetta, Maria; Varone, Alessandra

2017-09-05

Electron Beam (EB) welding has been used to realize seams on 2 mm-thick plates of directionally solidified (DS) IN792 superalloy. The first part of this work evidenced the importance of pre-heating the workpiece to avoid the formation of long cracks in the seam. The comparison of different pre-heating temperatures (PHT) and pass speeds ( v ) allowed the identification of optimal process parameters, namely PHT = 300 °C and v = 2.5 m/min. The microstructural features of the melted zone (MZ); the heat affected zone (HAZ), and base material (BM) were investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), electron back-scattered diffraction (EBSD), X-ray diffraction (XRD), and micro-hardness tests. In the as-welded condition; the structure of directionally oriented grains was completely lost in MZ. The γ' phase in MZ consisted of small (20-40 nm) round shaped particles and its total amount depended on both PHT and welding pass speed, whereas in HAZ, it was the same BM. Even if the amount of γ' phase in MZ was lower than that of the as-received material, the nanometric size of the particles induced an increase in hardness. EDS examinations did not show relevant composition changes in the γ' and γ phases. Post-welding heat treatments (PWHT) at 700 and 750 °C for two hours were performed on the best samples. After PWHTs, the amount of the ordered phase increased, and the effect was more pronounced at 750 °C, while the size of γ' particles in MZ remained almost the same. The hardness profiles measured across the joints showed an upward shift, but peak-valley height was a little lower, indicating more homogeneous features in the different zones.

Airbag Seams Leave Trails

Science.gov (United States)

2004-01-01

This image taken by the Mars Exploration Rover Opportunity's panoramic camera shows where the rover's airbag seams left impressions in the martian soil. The drag marks were made after the rover successfully landed at Meridiani Planum and its airbags were retracted. The rover can be seen in the foreground.

Ultrasonic inspection recess in heat exchanger and nuclear steam generator tubesheets

International Nuclear Information System (INIS)

Parkinson, J.K.; Ruhe, A.

1975-01-01

A vessel with a butted weld seam is provided with an access slot in its surface at a selected distance from the weld seam. An ultrasonic probe engages with a wall of the slot which is aligned with the weld and signals generated by the probe cross the axis of the weld frontally without substantial reflection from adjacent vessel surfaces

In-seam seismic surveys at Polio and Santiago collieries during the month of January

Energy Technology Data Exchange (ETDEWEB)

1987-01-01

In-seam seismic surveys were carried out over the last two weekends in January in order to assess two coal panels, one in seam Cuatro at Polio colliery between levels 4 and 5 of the Centella field and the other in the Mariana seam at Santiago colliery between levels 3,5, and 7 in the Desquite zone. Geological research called in-seam seismics, which is just being developed in Spain, is a geophysical method developed specially for detailed investigation of coal seams.

Methods for working thick seams and research on increasing their effectiveness

Energy Technology Data Exchange (ETDEWEB)

Sikora, W

1976-01-01

In Poland nearly 40 per cent of all coal is extracted from seams more than 3 m. thick. In absolute figures this represents about 70 million tons of coal per year. Working seams with thicknesses up to 3.5 m. does not present, at present, major difficulties. Working thicker seams calls for a steady improvement in order to increase the degree of utilizaion of the deposit and to enlarge the concentration of output. The seams are worked under protected surface structures which compels the mines to use hydraulic stowing with all its advantages and disadvantages. Rock burst hazard, the control of which is the basic problem hindering the mining, is a further problem. 3 refs.

On the problem of technological innovations in driving preparatory workings in thin coal seams

Energy Technology Data Exchange (ETDEWEB)

Peknik, J

1980-03-01

Possibilities of mechanizing preparation of thin coal seams for longwall mining are discussed. Until now preparatory workings in the Ostrava Karvina coal region have been driven mainly by manual work or blasting. Tables show the total length of preparatory workings driven in the period 1973-1978 and the average advance of preparatory working per day and per shift. Factors influencing mechanization of preparatory working drivage are: geological disturbances, angle of seam inclination and its changes, thickness of the seam and strength of coal. Some types of mining machines which can be used for driving preparatory workings in thin, horizontal and inclined coal seams and produced in the USSR and United Kingdom are reviewed. Two sets of machines used in coal seams inclined up to 18 or 20 degrees are presented: KN produced in the USSR and 'In seam Miner' produced by the Dosco firm in the UK. Parameters of both machines are compared. The following Soviet machines for driving preparatory workings in inclined seams are also reviewed: 2 KNP (slope 45-80 degrees), KMD-72 (slope 45-80 degrees, height of the seam 0.6 m to 1.2 m), MRS-2 (slope 45-90 degrees, height of the seam 0.55 m to 1.0 m). (7 refs.) (In Czech)

Refined Analysis of Fatigue Crack Initiation Life of Beam-to-Column Welded Connections of Steel Frame under Strong Earthquake

Directory of Open Access Journals (Sweden)

Weilian Qu

2017-01-01

Full Text Available This paper presents a refined analysis for evaluating low-cycle fatigue crack initiation life of welded beam-to-column connections of steel frame structures under strong earthquake excitation. To consider different length scales between typical beam and column components as well as a few crucial beam-to-column welded connections, a multiscale finite element (FE model having three different length scales is formulated. The model can accurately analyze the inelastic seismic response of a steel frame and then obtain in detail elastoplastic stress and strain field near the welded zone of the connections. It is found that the welded zone is subjected to multiaxial nonproportional loading during strong ground motion and the elastoplastic stress-strain field of the welded zone is three-dimensional. Then, using the correlation of the Fatemi-Socie (FS parameter versus fatigue life obtained by the experimental crack initiation fatigue data of the structural steel weldment subjected to multiaxial loading, the refined evaluation approach of fatigue crack initiation life is developed based on the equivalent plastic strain at fatigue critical position of beam end seams of crucial welded connections when the steel frame is subjected to the strong earthquake excitation.

In Situ SEM Observations of Fracture Behavior of Laser Welded-Brazed Al/Steel Dissimilar Joint

Science.gov (United States)

Xia, Hongbo; Tan, Caiwang; Li, Liqun; Ma, Ninshu

2018-03-01

Laser welding-brazing of 6061-T6 aluminum alloy to DP590 dual-phase steel with Al-Si12 flux-cored filler wire was performed. The microstructure at the brazing interface was characterized. Fracture behavior was observed and analyzed by in situ scanning electron microscope. The microstructure of the brazing interface showed that inhomogeneous intermetallic compounds formed along the thickness direction, which had a great influence on the crack initiation and propagation. In the top region, the reaction layer at the interface consisted of scattered needle-like Fe(Al,Si)3 and serration-shaped Fe1.8Al7.2Si. In the middle region, the compound at the interface was only serration-shaped Fe1.8Al7.2Si. In the bottom region, the interface was composed of lamellar-shaped Fe1.8Al7.2Si. The cracks were first detected in the bottom region and propagated from bottom to top along the interface. At the bottom region, the crack initiated and propagated along the Fe1.8Al7.2Si/weld seam interface during the in situ tensile test. When the crack propagated into the middle region, a deflection of crack propagation appeared. The crack first propagated along the steel/Fe1.8Al7.2Si interface and then moved along the weld seam until the failure of the joint. The tensile strength of the joint was 146.5 MPa. Some micro-cracks were detected at Fe(Al,Si)3 and the interface between the steel substrate and Fe(Al,Si)3 in the top region while the interface was still connected.

Application of the diode laser for welding in tairoled blanks

International Nuclear Information System (INIS)

Bocos, J. L.; Zubiri, F.; Garciandia, F.; Pena, J.; Cortiella, A.; Berrueta, J. M.; Zapirain, F.

2004-01-01

During the last years, one of the most interesting subjects in the automotive industry is the weight reduction of the automobile, and so to diminish the fuel consumption. Among other performance, the use in the body car of materials which have high mechanical resistance must be considered for the weight reduction of the automobile and maintaining high benefits. In this work, it has been studied the utilization of the diode laser for high resistance steel sheets welding, concretely microalloying steels (ZStE), DP dual phase and TRIP transformation induced plasticity. These steels can be employed in tailored blanks, which are defined as two or more separate pieces of flat material of dissimilar thickness and/or physical properties joined together before forming, to provide superior qualities in the finished stamped part. In this study, the metallographic characterization has been realised in the welding seams, and the mechanical behaviour has been analysed employing the following tests: microhardenss, drawing, tensile and fatigue. (Author) 15 refs

Study of CW Nd-Yag laser welding of Zn-coated steel sheets

International Nuclear Information System (INIS)

Fabbro, Remy; Coste, Frederic; Goebels, Dominique; Kielwasser, Mathieu

2006-01-01

The welding of Zn-coated steel thin sheets is a great challenge for the automotive industry. Previous studies have defined the main physical processes involved. For non-controlled conditions, the zinc vapour expelled from the interface of the two sheets violently expands inside the keyhole and expels the melt pool. When using CO 2 lasers, we have previously shown that an elongated laser spot produces an elongated keyhole, which is efficient for suppressing this effect. We have adopted a similar approach for CW Nd : Yag laser welding and we observe that an elongated spot is not necessary for achieving good weld seams. Several diagnostics were used in order to understand these interesting results. High-speed video camera visualizations of the top and the bottom of the keyhole during the process show the dynamics of the keyhole hydrodynamic behaviour. It appears that the role of the reflected beam on the front keyhole wall for generating a characteristic rear wall deformation is crucial for an efficient stabilization of the process. Our dynamic keyhole modelling, which includes ray tracing, totally confirms this interpretation and explains the results for very different experimental conditions (effect of welding speed, laser intensity, variable sheet thickness, laser beam intensity distribution) that will be presented

A Study on the compensation margin on butt welding joint of Large Steel plates during Shipbuilding construction

International Nuclear Information System (INIS)

Kim, J; Jeong, K; Chung, H; Jeong, H; Ji, M; Yun, C; Lee, J

2015-01-01

This paper examines the characteristics of butt welding joint shrinkage for shipbuilding and marine structures main plate. The shrinkage strain of butt welding joint which is caused by the process of heat input and cooling, results in the difference between dimensions of the actual parent metal and the dimensions of design. This, in turn, leads to poor quality in the production of ship blocks and reworking through period of correction brings about impediment on improvement of productivity. Through experiments on butt welding joint's shrinkage strain on large structures main plate, the deformation of welding residual stress in the form of I, Y, V was obtained. In addition, the results of experiments indicate that there is limited range of shrinkage in the range of 1 ∼ 2 mm in 11t ∼ 21.5t thickness and the effect of heat transfer of weld appears to be limited within 1000 mm based on one side of seam line so there was limited impact of weight of parent metal on the shrinkage. Finally, it has been learned that Shrinkage margin needs to be applied differently based on groove phenomenon in the design phase in order to minimize shrinkage. (paper)

Dissimilar Joining of Stainless Steel and 5083 Aluminum Alloy Sheets by Gas Tungsten Arc Welding-Brazing Process

Science.gov (United States)

Cheepu, Muralimohan; Srinivas, B.; Abhishek, Nalluri; Ramachandraiah, T.; Karna, Sivaji; Venkateswarlu, D.; Alapati, Suresh; Che, Woo Seong

2018-03-01

The dissimilar joining using gas tungsten arc welding - brazing of 304 stainless steel to 5083 Al alloy had been conducted with the addition of Al-Cu eutectic filler metal. The interface microstructure formation between filler metal and substrates, and spreading of the filler metal were studied. The interface microstructure between filler metal and aluminum alloy characterized that the formation of pores and elongated grains with the initiation of micro cracks. The spreading of the liquid braze filler on stainless steel side packed the edges and appeared as convex shape, whereas a concave shape has been formed on aluminum side. The major compounds formed at the fusion zone interface were determined by using X-ray diffraction techniques and energy-dispersive X-ray spectroscopy analysis. The micro hardness at the weld interfaces found to be higher than the substrates owing to the presence of Fe2Al5 and CuAl2 intermetallic compounds. The maximum tensile strength of the weld joints was about 95 MPa, and the tensile fracture occurred at heat affected zone on weak material of the aluminum side and/or at stainless steel/weld seam interface along intermetallic layer. The interface formation and its effect on mechanical properties of the welds during gas tungsten arc welding-brazing has been discussed.

Utilization of thin-seam drum shearer loaders at Bergbau AG Niederrhein

Energy Technology Data Exchange (ETDEWEB)

Wenzel, W.; Klimek, K.H.

1983-03-10

Low design shearers have been developed for seams under 1.6 m, which can be introduced in thicknesses to 1.0 m in the Ruhr conditions. The opposed demands for high drive rating and low machine height produced a two-pronged development. The priority need for high drive rating led to the EDW 230-2 LN thin-seam shearer for seam thicknesses from 1.3 m upwards. The second demand for minimum feasible machine height with adequate drive rating is most closely matched so far by the EDW 200/230 LN. It is anticipated that the EDW 300 LN at present being developed is another stage in lowering the lower utilization limit of thin-seam shearers. For the best possible use of LN shearers the LN mode of shearing should also be adhered to in the majority of likely applications. With thorough planning and the use of suitable types of supports it is possible to work faces with shearing in seam thicknesses from 1.0 m even under difficult extraction conditions.

The relation between district raise in the multiple coal seams and its pillars

Energy Technology Data Exchange (ETDEWEB)

Zhai, X. [Jiaozuo Institute of Technology, Jiaozuo (China). Dept. of Mining Engineering

2002-02-01

Based on the geological condition of multiple coal seams mining in No.8 Colliery of Pingdingshan Coal Group, the behaviours of the front abutment pressure in each of the coal seams and the fixed abutment pressure are observed. The main cause of deformation and damage to the galleries is the increasing value of the valid load coefficient of the surrounding rock. The rational pillar width of the district raise is studied when its two side seams have been mined, and the layout question of district raise in the different set of seams is also studied. The conclusions derived from the study are useful guiding reference for the design of district raise layout in deep multiple coal seams mining. 6 refs., 3 figs., 1 tab.

Variability of Mercury Content in Coal Matter From Coal Seams of The Upper Silesia Coal Basin

Science.gov (United States)

Wierzchowski, Krzysztof; Chećko, Jarosław; Pyka, Ireneusz

2017-12-01

The process of identifying and documenting the quality parameters of coal, as well as the conditions of coal deposition in the seam, is multi-stage and extremely expensive. The taking and analyzing of seam samples is the method of assessment of the quality and quantity parameters of coals in deep mines. Depending on the method of sampling, it offers quite precise assessment of the quality parameters of potential commercial coals. The main kind of seam samples under consideration are so-called "documentary seam samples", which exclude dirt bands and other seam contaminants. Mercury content in coal matter from the currently accessible and exploited coal seams of the Upper Silesian Coal Basin (USCB) was assessed. It was noted that the mercury content in coal seams decreases with the age of the seam and, to a lesser extent, seam deposition depth. Maps of the variation of mercury content in selected lithostratigraphic units (layers) of the Upper Silesian Coal Basin have been created.

Stochastic reservoir simulation for the modeling of uncertainty in coal seam degasification

Science.gov (United States)

Karacan, C. Özgen; Olea, Ricardo A.

2015-01-01

Coal seam degasification improves coal mine safety by reducing the gas content of coal seams and also by generating added value as an energy source. Coal seam reservoir simulation is one of the most effective ways to help with these two main objectives. As in all modeling and simulation studies, how the reservoir is defined and whether observed productions can be predicted are important considerations.

Exploitation of the in-seam miner and operational experience

Energy Technology Data Exchange (ETDEWEB)

Wilson, W I.S.; Morris, A H

1977-12-01

The In-seam Miner started as an investigatory project at MRDE in 1969. Since that time it has passed through the classic development stages of design of prototype, surface trials, underground trials, modification, production of more machines, assessment of experience and then wider exploitation. At the present time well over 100 machines have been supplied to the National Coal Board. The original machine was hydraulically driven and all but five of the machines supplied to date are of this type. The variety of applications that the machine has found in the mining industry has caused derivative development to embrace machines of length varying from 12-ft centers to 44-ft centers, to work in seams ranging from 40 in. up to 68 in. The range of applications has included face drivages, stablehole operations, in-seam retreat roadways and dirt-absorbing headings. Five electrically driven machines are now coming onto the market and experience with them, though limited, is very encouraging. The paper concentrates on two major aspects of the overall development process: first, the management of exploitation; and second, some operational experience of the In-seam Miner in South Midlands area.

A Precise Visual Method for Narrow Butt Detection in Specular Reflection Workpiece Welding

Directory of Open Access Journals (Sweden)

Jinle Zeng

2016-09-01

Full Text Available During the complex path workpiece welding, it is important to keep the welding torch aligned with the groove center using a visual seam detection method, so that the deviation between the torch and the groove can be corrected automatically. However, when detecting the narrow butt of a specular reflection workpiece, the existing methods may fail because of the extremely small groove width and the poor imaging quality. This paper proposes a novel detection method to solve these issues. We design a uniform surface light source to get high signal-to-noise ratio images against the specular reflection effect, and a double-line laser light source is used to obtain the workpiece surface equation relative to the torch. Two light sources are switched on alternately and the camera is synchronized to capture images when each light is on; then the position and pose between the torch and the groove can be obtained nearly at the same time. Experimental results show that our method can detect the groove effectively and efficiently during the welding process. The image resolution is 12.5 μm and the processing time is less than 10 ms per frame. This indicates our method can be applied to real-time narrow butt detection during high-speed welding process.

Solid Coal Stability with Regards to Seam Thickness or Bench mined

Directory of Open Access Journals (Sweden)

Bukovanský Stanislav

1998-03-01

Full Text Available In the paper the problem of working unit stability, showing a limit state of a rock tension with the Mohr envelope known from a theory of failure, is described. It is obvious that a load of building units in mountain massives can be expressed easily either by simple or multiaxial compressions, and then, on the basis of individual states characteristics, individual conditions of stability can be observed. So we may understand that such building units can be broken even in case of a certain discharge, i.e. lowering of one of main tensions of both of them as well. Combined methods of discharge and surchage can be used too. Another reactive power of an enormous value is caused by pre-fault then. In the OKR district it means even 10% of the seam thickness with common conditions (e.g. saddle seams. An area of a contact between a seam, original rocks and seam thickness should be taken into consideration as serious conditions of rock bumps origin. If this contact area is wavy of the seam thickness is small (possibly both conditions are valid, there will be no risk of any rock bump.

Workability of coal seams in the Upper Silesian Coal Basin

Energy Technology Data Exchange (ETDEWEB)

Sikora, W; Fels, M; Soltysik, K

1978-04-01

This paper presents results of an investigation on workability of coal seams of stratigraphic groups from 100 to 700 in the: Upper Silesian Coal Basin. Analyzed are 2900 petrographic logs taken in the longwall workings and in narrow openings as well as about 9000 individual samples. Workability of coal seams, floors and partings is determined. Workability is described by the indicator f, (according to the Protodyakonov shatter method) and the indicator U, (compression strength of the unshaped test samples). The mean percentage content of indivi dual petrographic groups of coal as well as the mean workability indicator, f, of coals in the stratigraphic groups of coal seams in Upper Silesia are also determined.

Improved Seam-Line Searching Algorithm for UAV Image Mosaic with Optical Flow.

Science.gov (United States)

Zhang, Weilong; Guo, Bingxuan; Li, Ming; Liao, Xuan; Li, Wenzhuo

2018-04-16

Ghosting and seams are two major challenges in creating unmanned aerial vehicle (UAV) image mosaic. In response to these problems, this paper proposes an improved method for UAV image seam-line searching. First, an image matching algorithm is used to extract and match the features of adjacent images, so that they can be transformed into the same coordinate system. Then, the gray scale difference, the gradient minimum, and the optical flow value of pixels in adjacent image overlapped area in a neighborhood are calculated, which can be applied to creating an energy function for seam-line searching. Based on that, an improved dynamic programming algorithm is proposed to search the optimal seam-lines to complete the UAV image mosaic. This algorithm adopts a more adaptive energy aggregation and traversal strategy, which can find a more ideal splicing path for adjacent UAV images and avoid the ground objects better. The experimental results show that the proposed method can effectively solve the problems of ghosting and seams in the panoramic UAV images.

Process for opening up carboniferous seams for underground gasification by drilling production holes downwards

Energy Technology Data Exchange (ETDEWEB)

Lokschin, J L; Volk, A F; Starinskii, A A

1977-12-01

This process will reduce drilling costs and times by 20 to 25% and will improve gasification under the influence of a thin liquid medium connecting adjacent holes. After determining the approximate depth and thickness of the seam to be opened up, e.g. by geological means, production holes of 100 to 400 mm (diameter) are made down to a depth of 400 m or more, by well-known boring bars and chisels. After passing the top of the seam (the roof of the seam), which can be recognised by discoloration of the drilling liquid, one goes 1/2 to 1 metre deeper and one determines the depth of the roof the seam exactly by the reduced natural radioactivity at the boundary layer, by introducing a gamma sensor on to the boring bar. The production holes are taken down in a second borehold to a free space 0.6 to 2 metres above the floor of the seam (bottom of the seam), according to the thickness of the seam. After replacing the boring bar by a feedpipe one continues to drill using a boring bar of smaller cutting diameter inside this tube. This hole reaches from the foot of the pipe of the feedpipe to the floor of the seam. It is preferably flushed with gas but may be flushed with liquid. A thin liquid introduced into this hole penetrates the surrounding mass of the seam horizontally (unhindered by any armouring) and represents the required connection to neighbouring bores for gasification. The process is suitable for mining coal, combustible shale oil, bituminous rock, heavy natural oil where this process is based on gasification, melting or dissolving of those deposits.

Experimental verification of tailor welded joining partners for hot stamping and analytical modeling of TWBs rheological constitutive in austenitic state

Energy Technology Data Exchange (ETDEWEB)

Tang, Bingtao, E-mail: tbtsh@hotmail.com [School of Materials Science and Engineering, Shandong Jianzhu University, Shandong, Jinan 250101 (China); State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Hunan, Changsha 410082 (China); Yuan, Zhengjun; Cheng, Gang [School of Mechanical and Electronic Engineering, Shandong Jianzhu University, Jinan 250101 (China); Huang, Lili; Zheng, Wei [School of Materials Science and Engineering, Shandong Jianzhu University, Shandong, Jinan 250101 (China); Xie, Hui [State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Hunan, Changsha 410082 (China)

2013-11-15

Hot stamping of quenchable ultra high strength steels currently represents a standard forming technology in the automotive industry for the manufacture of safety and crash relevant components. Recently, hot stamping of Tailor-Welded Blanks (TWBs) is proposed to meet the environmental and safety requirements by supplying car structural body components with functionally optimized and tailored mechanical properties. In this paper, an appropriate partner material for the quenchenable boron steel B1500HS based on the phase transformation and deformation behavior under process relevant conditions is determined. It is generally accepted that the mechanical properties for joint partner after quenching process should meet the following requirements. The value of yield strength (YS) should be between 350 and 500 MPa. The ultimate tensile strength (UTS) should be within the limits of 500–650 MPa, and the total elongation (TEL) until rupture should be higher than 13%. Two kinds of High Strength Low Alloy (HSLA) cold rolled steels B340LA and B410LA are chosen for verification of which one is appropriate as joint partner. Microhardness is measured and metallographic is investigated on different base materials and corresponding weld seams. It is pointed out that the B340LA steel is an appropriate joint partner with ideal thermal and mechanical properties. An optimized Arrhenius constitutive law is implemented to improve the characterization and description of the mechanical properties of the base and joint partner, as well as the weld seam in austenitic state. The comparisons with simplified Hensel–Spittel constitutive model show the optimized Arrhenius constitutive law describes the experimental data fairly well.

Experimental verification of tailor welded joining partners for hot stamping and analytical modeling of TWBs rheological constitutive in austenitic state

International Nuclear Information System (INIS)

Tang, Bingtao; Yuan, Zhengjun; Cheng, Gang; Huang, Lili; Zheng, Wei; Xie, Hui

2013-01-01

Hot stamping of quenchable ultra high strength steels currently represents a standard forming technology in the automotive industry for the manufacture of safety and crash relevant components. Recently, hot stamping of Tailor-Welded Blanks (TWBs) is proposed to meet the environmental and safety requirements by supplying car structural body components with functionally optimized and tailored mechanical properties. In this paper, an appropriate partner material for the quenchenable boron steel B1500HS based on the phase transformation and deformation behavior under process relevant conditions is determined. It is generally accepted that the mechanical properties for joint partner after quenching process should meet the following requirements. The value of yield strength (YS) should be between 350 and 500 MPa. The ultimate tensile strength (UTS) should be within the limits of 500–650 MPa, and the total elongation (TEL) until rupture should be higher than 13%. Two kinds of High Strength Low Alloy (HSLA) cold rolled steels B340LA and B410LA are chosen for verification of which one is appropriate as joint partner. Microhardness is measured and metallographic is investigated on different base materials and corresponding weld seams. It is pointed out that the B340LA steel is an appropriate joint partner with ideal thermal and mechanical properties. An optimized Arrhenius constitutive law is implemented to improve the characterization and description of the mechanical properties of the base and joint partner, as well as the weld seam in austenitic state. The comparisons with simplified Hensel–Spittel constitutive model show the optimized Arrhenius constitutive law describes the experimental data fairly well

Residual stress characterization of a fabrication weld from the VICTORIA-Class submarine pressure hull: revealing the unseen

International Nuclear Information System (INIS)

McGregor, R.J.; Rogge, R.B.

2010-01-01

Explicit understanding of the residual-stress character of primary submarine pressure hull weldments will improve the fidelity of numerical analysis and experimentation supporting operational envelope and design life. A length of circumferential-seam closure weld was contained within a section of hull plate removed from the HMCS VICTORIA during the extended docking work period (EDWP) refit operations. This has provided a rare opportunity for detailed characterization of the as-received condition of this common weld-type from original vessel assembly. In collaboration with the Canadian Neutron Beam Centre of the National Research Council (NRC), a program was conducted to study this weld using neutron diffraction. Neutron diffraction is able to survey nondestructively through the section thickness, providing a three-dimensional characterization, while leaving the specimen intact for complementary study by other methods. Results indicate tensile stress peaks of up to 80% of the base-material yield stress. Understanding the three-dimensional behaviour of residual stress in this type of weld provides a valuable resource to the numerical modelling community. The results can also support fatigue and fracture experimental work and serve to confirm and improve the interpretation of the existing body of 'surface-only' work conducted on similar welds. (author)

Exploiting Seams and Closing Gaps: Lessons from Mumbai and Beyond

Directory of Open Access Journals (Sweden)

Dr. Andrea J. Dew

2012-01-01

Full Text Available This article analyzes a single event—the 2008 Mumbai attacks—in order to consider the strategic and operational lessons for dealing with other armed groups. How and why was Lashkar-e-Tayyiba (LeT able to carry out such a sophisticated attack in the heart of Mumbai? And what lessons does Mumbai hold for strategists seeking to counter other armed groups around the world? While tactical level lessons from Mumbai have been well documented, it is important to also consider what the Mumbai attacks tell us at the strategic and operational levels. Specifically, the Mumbai attacks provide valuable insight into how armed groups use the maritime environment, and how they use surprise, denial, and deception to mask intention and invite over-reaction by states. In addition, studying the Mumbai attacks provides insight into some of the strategic and operational seams and gaps that armed groups seek to exploit. These include environmental and geographical factors; institutional, bureaucratic, and jurisdictional seams and gaps between agencies; cognitive seams and gaps that made the use of the sea by LeT so difficult to conceptualize; and the diplomatic seams and gaps that led to heightened tensions among states— in this case, India, Pakistan, and the United States. This article discusses how to categorize these seams and gaps in order to better address the problems they create, and how states might best direct and focus their limited resources when faced with similar challenges.

Polymer Drilling Fluid with Micron-Grade Cenosphere for Deep Coal Seam

Directory of Open Access Journals (Sweden)

Peng Xu

2015-01-01

Full Text Available Traditional shallow coal seam uses clean water, solid-free system, and foam system as drilling fluid, while they are not suitable for deep coal seam drilling due to mismatching density, insufficient bearing capacity, and poor reservoir protection effect. According to the existing problems of drilling fluid, micron-grade cenosphere with high bearing capacity and ultralow true density is selected as density regulator; it, together with polymer “XC + CMC” and some other auxiliary agents, is jointly used to build micron-grade polymer drilling fluid with cenosphere which is suitable for deep coal seam. Basic performance test shows that the drilling fluid has good rheological property, low filtration loss, good density adjustability, shear thinning, and thixotropy; besides, drilling fluid flow is in line with the power law rheological model. Compared with traditional drilling fluid, dispersion stability basically does not change within 26 h; settlement stability evaluated with two methods only shows a small amount of change; permeability recovery rate evaluated with Qinshui Basin deep coal seam core exceeds 80%. Polymer drilling fluid with cenosphere provides a new thought to solve the problem of drilling fluid density and pressure for deep coal seam drilling and also effectively improves the performance of reservoir protection ability.

Influence of Mining Thickness on the Rationality of Upward Mining in Coal Seam Group

Directory of Open Access Journals (Sweden)

Y. Li

2016-04-01

Full Text Available This study aimed to determine the influence of mining thickness on the rationality of upward mining in coal seam group. Numerical simulation and theoretical analysis were performed to investigate the influence of the mining thicknesses of initial mining seam on the destruction and pressure relief effect of the upper coal seam in a high-gas coal seam group. The mechanical model of the roof failure based on the mining thickness was established by assuming that the gob formed after adjacent panels have fully been caved is the infinite plane. On the basis of this model, an equation was derived to calculate the roof failure height of the panel. Considering the geological conditions of No. 9 and No. 12 coal seams of Zhaogezhuang Coal Mine, economic effectiveness, and proposed techniques, we concluded that the top layer (4 m of the No. 12 coal seam should be mined first. The top layer of the No. 9 coal seam should be subsequently mined. The topcaving technique was applied to the exploitation of the lower layer of the No. 12 coal seam. Practically monitored data revealed that the deformation and failure of the No. 2699 panel roadway was small and controllable, the amount of gas emission was reduced significantly, and the effect of upward mining was active. The results of this study provide theory basics for mine designing, and it is the provision of a reference for safe and efficient coal exploitation under similar conditions.

Improvement and qualification of ultrasonic testing of dissimilar welds in the primary circuit of NPPs; Verbesserung und Qualifizierung der Ultraschallpruefung von Mischnaehten im Primaerkreis von KKW

Energy Technology Data Exchange (ETDEWEB)

Mitzscherling, Steffen; Barth, Enrico; Homann, Tobias; Prager, Jens [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany); Goetschel, Sebastian; Weiser, Martin [Konrad-Zuse-Zentrum fuer Informationstechnik Berlin (ZIB) (Germany)

2017-08-01

The austenitic and dissimilar welds found in the primary circuit of nuclear power plants are not only extremely relevant to safety but also place very high demands on material testing. In addition to limited accessibility, the macroscopic structure of the weld seam is of paramount importance for ultrasound testing. In order to reliably determine material errors in position and size, the grain orientations and the elastic constants of the anisotropic weld bead structure must be known. The following work steps are used for the imaging representation of possible material defects: First, the weld seam is sounded in order to be able to determine important weld seam parameters, such as, for example, the grain orientation, using an inverse method. On the basis of these parameters, the sound paths are simulated in the next step by means of raytracing (RT). Finally, this RT simulation is assigned the measurement data (A-scans) from different transmitter and receiver positions and superimposed according to the Synthetic Aperature Focusing Technique (SAFT) method. The combination of inverse process, RT and SAFT also ensures a correct visualization of the faults in anisotropic materials. We explain these three methods and present the test arrangement of test specimens with artificial test errors. Measurement data as well as their evaluation are compared with the results of a CIVA simulation. [German] Die im Primaerkreislauf von Kernkraftwerken anzutreffenden austenitischen Schweiss- und Mischnaehte sind nicht nur extrem sicherheitsrelevant, sondern stellen auch sehr hohe Anforderungen an die Materialpruefung. Neben der eingeschraenkten Zugaenglichkeit ist das makroskopische Gefuege der Schweissnaht fuer die Pruefung mit Ultraschall von hoechster Bedeutung. Um Materialfehler zuverlaessig in Position und Groesse bestimmen zu koennen, muessen die Kornorientierungen und die elastischen Konstanten des anisotropen Schweissnahtgefueges bekannt sein. Fuer die bildgebende Darstellung

Investigation on dissimilar laser welding of advanced high strength steel sheets for the automotive industry

Energy Technology Data Exchange (ETDEWEB)

Rossini, M., E-mail: matteo.rossini@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Spena, P. Russo, E-mail: pasquale.russospena@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Cortese, L., E-mail: luca.cortese@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Matteis, P., E-mail: paolo.matteis@polito.it [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Firrao, D., E-mail: donato.firrao@polito.it [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

2015-03-25

To support the use of advanced high strength steels in car body design and fabrication, an investigation was carried out on dissimilar butt laser welding between TWinning Induced Plasticity (TWIP) steels, Dual Phase (DP) steels, hot stamping boron (22MnB5) steels, and TRansformation Induced Plasticity (TRIP) steels. The base materials and the weldments were fully characterized by means of metallography, microhardness, and tensile tests. Digital image analysis was also used to provide additional information on the local strain field in the joint during the tensile tests. Fractographic examination was finally performed on the fracture surfaces of the tensile samples. The dissimilar joints between the DP, 22MnB5, and TRIP steels exhibit good resistance properties. On the contrary, the dissimilar joints encompassing the TWIP steel exhibit poor mechanical strength and fail along the weld seam by intergranular fracture, probably due to presence of Mn segregations. Therefore, the laser welding of TWIP steel with other advanced high strength steels is not recommended without the use of proper metal fillers. Dissimilar laser welding of DP, TRIP and 22MnB5 combinations, on the contrary, can be a solution to assemble car body parts made of these steel grades.

Effect of geometric construction on residual stress distribution in designing a nuclear rotor joined by multipass narrow gap welding

International Nuclear Information System (INIS)

Tan, Long; Zhang, Linjie; Zhang, Jianxun; Zhuang, Dong

2014-01-01

Highlights: • The internal stress of the pipe is measured using local material removal method. • Bottom protrusion at weld seam can release the stress and mitigate stress evolution. The through-wall axial stress is bending type under the effect of the rotor discs. • The impact of geometric construction on the stress evolution begins after pass 15. - Abstract: The purpose of this study is to investigate the effect of geometric construction on the distribution of residual stresses before and after heat treatment in designing a nuclear welded rotor. The local material removal method was used to measure internal residual stress of the experimental pipe after post weld heat treatment. Three finite element models were employed as follows: a model of experimental pipe, a model with a bottom protrusion existed at the weld region, and a model of two rotor discs butt-welded with a bottom protrusion at the weld region. Investigated results showed that the bottom protrusion existed at the weld region can decrease the residual stress and mitigate the stress evolution significantly on the inner surface. Under the binding effect of the rotor discs, the axial stress of inner surface region is compressive stress; the through-wall axial stress at the weld center line can be deemed to a bending type; both the hoop stress and axial stress at the weld center line on the inner surface are compressive. The impact of geometric construction on the stress evolution at the root bead begins after pass 15 deposited

In-process monitoring and adaptive control for gap in micro butt welding with pulsed YAG laser

International Nuclear Information System (INIS)

Kawahito, Yousuke; Kito, Masayuki; Katayama, Seiji

2007-01-01

A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 μm spot diameter. It was revealed that a 45 μm narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 μm gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam

Modeling of Three Flat Coal Seams Strata Developing at Open Pit Miming

Science.gov (United States)

Gvozdkova, Tatiana; Markov, Sergey; Demirel, Nuray; Anyona, Serony

2017-11-01

The use of low-cost direct dumpling technology, as is well known, has a relatively limited field of application: flat coal seams, and the higher the dip angle of the seam, the more difficult it is to place the necessary volume of overburden rock in the dumping layers. For this, we have to pour four-tier dumps. In this article, four possible options for piling the dump have been studied and prerequisites have been made for further research aimed at improving the efficiency of the use of direct dumpling technology in the development of flat coal seams.

Online NIR diagnostic of laser welding processes and its potential for quality assuring sensor systems

Science.gov (United States)

Dorsch, Friedhelm; Braun, Holger; Keβler, Steffen; Pfitzner, Dieter; Rominger, Volker

2014-02-01

We have integrated an imaging thermographic sensor into commercial welding optics for observation of the weld zone. Key element of the sensor is an InGaAs-camera that detects the thermal radiation of the welding process in the wavelength range of 1,200 to 1,700 nm. This is well suited to record images of the keyhole, the melt pool and the thermal trace. The sensor was integrated to the welding heads for on-axis observation to minimize the interfering contour to ensure easy adaption to industrial processes. The welding heads used were established industrial-grade TRUMPF optics: a BEO fixed optics with 280 mm focal length, or a TRUMPF PFO-3D scanner optics with 450 mm focal length. We used a TRUMPF TruDisk 16002 16kW-thin disk laser that transmits its power through a 200 μm core diameter light cable. The images were recorded and features of the various process zones were evaluated by image processing. It turns out that almost all weld faults can be clearly detected in the NIR images. Quantitative features like the dimension of the melt pool and the thermal trace can be derived from the captured images. They are correlated to process input parameters as well as to process results. In contrast to observation in the visible spectrum the NIR camera records the melt pool without auxiliary illumination. As an unrivaled attribute of the NIR sensor it supports an online heat flow thermography of the seam and allows identifying missing fusion ("false friends") of lap joints virtually during the welding process. Automated weld fault detection and documentation is possible by online image processing which sets the basis for comprehensive data documentation for quality assurance and traceability.

Simulation of double-seaming in a two-piece aluminum can

International Nuclear Information System (INIS)

Romanko, Anne; Berry, Dale; Fox, David

2004-01-01

The aluminum can industry in the United States and Canada manufactures over 100 billion cans per year. Two-piece aluminum cans are commonly used to seal and deliver foodstuffs such as soft drinks, beer, pet food, and other perishable items. In order to ensure product safety and performance, the double seam between the can body and lid is a critical component of the package. Double-seaming is a method by which the flange of the can body and the curl of the end are folded over together such that the final joint is composed of five metal thicknesses. There are a number of design challenges involved with the art of double seaming, especially with the push to lightweight. Although the requirements vary by product, the typical beer package must be able to hold pressures in excess of 90psi. In addition, in production, double seaming is a high-speed operation with speeds as high as 3000 cans/minute on an 18-spindle seamer. For this high volume, low cost industry, understanding and optimizing the seaming process can advance the industry as well as help prevent various manufacturing problems that produce a poor seal between the two pieces of the can.To aid in understanding the mechanics of the can parts during double-seaming, a simulation procedure was developed and carried out on a 202 diameter beverage can and lid. Simulations were run with the explicit dynamics solver ABAQUS/Explicit using the continuum shell element technology available in the ABAQUS general purpose FEA program. The continuum shell is a shear-deformable shell element with the topology of an eight node brick. The element's formulation allows continuously varying, solution-dependent shell thickness and through-thickness pinching stress. One important advantage of using the continuum shell as opposed to a traditional shell element is that true contact interactions at the top and bottom surfaces of the can body and lid can be accurately modeled. With a conventional shell element, contact is performed at the

Simulation of Double-Seaming in a Two-piece Aluminum Can

Science.gov (United States)

Romanko, Anne; Berry, Dale; Fox, David

2004-06-01

The aluminum can industry in the United States and Canada manufactures over 100 billion cans per year. Two-piece aluminum cans are commonly used to seal and deliver foodstuffs such as soft drinks, beer, pet food, and other perishable items. In order to ensure product safety and performance, the double seam between the can body and lid is a critical component of the package. Double-seaming is a method by which the flange of the can body and the curl of the end are folded over together such that the final joint is composed of five metal thicknesses. There are a number of design challenges involved with the art of double seaming, especially with the push to lightweight. Although the requirements vary by product, the typical beer package must be able to hold pressures in excess of 90psi. In addition, in production, double seaming is a high-speed operation with speeds as high as 3000 cans/minute on an 18-spindle seamer. For this high volume, low cost industry, understanding and optimizing the seaming process can advance the industry as well as help prevent various manufacturing problems that produce a poor seal between the two pieces of the can. To aid in understanding the mechanics of the can parts during double-seaming, a simulation procedure was developed and carried out on a 202 diameter beverage can and lid. Simulations were run with the explicit dynamics solver ABAQUS/Explicit using the continuum shell element technology available in the ABAQUS general purpose FEA program. The continuum shell is a shear-deformable shell element with the topology of an eight node brick. The element's formulation allows continuously varying, solution-dependent shell thickness and through-thickness pinching stress. One important advantage of using the continuum shell as opposed to a traditional shell element is that true contact interactions at the top and bottom surfaces of the can body and lid can be accurately modeled. With a conventional shell element, contact is performed at the

Study of physiocochemical processes liable to affect methane drainage from an anthracite seam

Energy Technology Data Exchange (ETDEWEB)

Artemov, A V

1976-01-01

The molecular structure of anthracites is discussed, and liquids suitable for improving gas emission from anthracite seams are suggested. Infusion of the seam with ethylene glycol solution makes it possible to increase methane emission in drainage boreholes by eight or nine times.

The Method of Validity Evaluation of Hard Coal Excavation in Residual Seam Parts

Science.gov (United States)

Wodarski, Krzysztof; Bijańska, Jolanta; Gumiński, Adam

2017-12-01

The excavation of residual seam parts should be justified by positive assessment of the purposefulness, technical feasibility and economic effectiveness. The results of the profitability evaluation are crucial in a decision making process. The excavation of residual seam parts, even if it is possible from a technical point of view, should not be implemented if it is economically inefficient or when accompanied by a very high risk of non-recovery of invested capital resources. The article presents the evaluation method of possibilities of excavating hard coal from residual seam parts, and the example of its use in one of collieries in the Upper Silesian Coal Basin. Working in line with the developed method, allows to indicate the variant of residual seam part exploitation, which is feasible to implement from a technical point of view, and which is characterized by the highest economic effectiveness and lowest risk.

Lining seam elimination algorithm and surface crack detection in concrete tunnel lining

Science.gov (United States)

Qu, Zhong; Bai, Ling; An, Shi-Quan; Ju, Fang-Rong; Liu, Ling

2016-11-01

Due to the particularity of the surface of concrete tunnel lining and the diversity of detection environments such as uneven illumination, smudges, localized rock falls, water leakage, and the inherent seams of the lining structure, existing crack detection algorithms cannot detect real cracks accurately. This paper proposed an algorithm that combines lining seam elimination with the improved percolation detection algorithm based on grid cell analysis for surface crack detection in concrete tunnel lining. First, check the characteristics of pixels within the overlapping grid to remove the background noise and generate the percolation seed map (PSM). Second, cracks are detected based on the PSM by the accelerated percolation algorithm so that the fracture unit areas can be scanned and connected. Finally, the real surface cracks in concrete tunnel lining can be obtained by removing the lining seam and performing percolation denoising. Experimental results show that the proposed algorithm can accurately, quickly, and effectively detect the real surface cracks. Furthermore, it can fill the gap in the existing concrete tunnel lining surface crack detection by removing the lining seam.

Eddy-current guidance of the automatic inspection machine for the main vessel of the superphenix reactor

International Nuclear Information System (INIS)

David, B.; Pigeon, M.

1985-01-01

The weld detector device is an eddy-current measurement system consisting of four dual sensors (absolute + differential types), and a control cabinet with eight analog channels. The system delivers all the signals required for computing the correct track of the MIR machine along the welds, irrespective of bend, temperature, width and type of the seam, junctions of seams

Diode laser welding of aluminum to steel

International Nuclear Information System (INIS)

Santo, Loredana; Quadrini, Fabrizio; Trovalusci, Federica

2011-01-01

Laser welding of dissimilar materials was carried out by using a high power diode laser to join aluminum to steel in a butt-joint configuration. During testing, the laser scan rate was changed as well as the laser power: at low values of fluence (i.e. the ratio between laser power and scan rate), poor joining was observed; instead at high values of fluence, an excess in the material melting affected the joint integrity. Between these limiting values, a good aesthetics was obtained; further investigations were carried out by means of tensile tests and SEM analyses. Unfortunately, a brittle behavior was observed for all the joints and a maximum rupture stress about 40 MPa was measured. Apart from the formation of intermeltallic phases, poor mechanical performances also depended on the chosen joining configuration, particularly because of the thickness reduction of the seam in comparison with the base material.

Interanal seam loss in Asian turtles of the Cuora flavomarginata complex (Testudines, Geoemydidae)

Science.gov (United States)

Ernst, Carl H.; Lovich, Jeffrey E.

2015-01-01

The taxonomy of Asian box turtles of the genus Cuora is complicated by the description of numerous valid and invalid taxa over the last several decades. However, some characteristics used to differentiate species are questionable. Members of the C. flavomarginata complex are defined by some, but not all, taxonomists as having reduced interanal seam lengths relative to other species. We examined the ratio of interanal scute seam length divided by midline anal scute length in C. flavomarginata and C. evelynae. Hatchlings show a seam that divides 100% of the anal scute along the midline. As individuals increase in carapace length, there is a tendency for the percentage to decrease, especially in females, although there is considerable overlap. We suggest that the decrease in interanal seam length is due to abrasion of the plastron on the substrate as turtles grow larger and older. Differences in habitat substrates across the range of the species may contribute to the wide variation we observed.

IASCC susceptibility under BWR conditions of welded 304 and 347 stainless steels

Energy Technology Data Exchange (ETDEWEB)

Castano, M.L. [CIEMAT, Complutense 22, 28040 Madrid (Spain); Schaaf, B. van der [NRG, Petten (Netherlands); Roth, A. [Framatome ANP, Erlangen (Germany); Ohms, C. [JRC-IE, Petten (Netherlands); Gavillet, D. [PSI, Villigen (Switzerland); Dyck, S. van [SCK - CEN, Mol (Belgium)

2004-07-01

performed. Measurements of residual stresses by Neutron Diffraction, mechanical properties, sensitization degree and microstructural and microchemical characterization are carried out. To evaluate the stress corrosion behaviour of the irradiated weld materials, Slow Strain Rate Tensile (SSRT) tests were used. Flat tensile samples, containing the weld seam and the HAZ of the weld were fabricated from the 304 and 347 weldments. Stress corrosion tests were performed at 290 deg. C in low conductivity water with 200 ppb dissolved oxygen. In addition, tests in inert gas at the same temperature were carried out as a reference. This paper describes the obtained testing results. (authors)

Characterization of bond line discontinuities in a high-Mn TWIP steel pipe welded by HF-ERW

Energy Technology Data Exchange (ETDEWEB)

Park, Gitae; Kim, Bongyoon; Kang, Yongjoon [Division of Materials Science and Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 04763 (Korea, Republic of); Kang, Heewoong [RD Team, Husteel, 131 Bugokgongdan-ro, Songak-eup, Dangjin-si, Chungnam 31721 (Korea, Republic of); Lee, Changhee, E-mail: chlee@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 04763 (Korea, Republic of)

2016-08-15

In this work, the microstructure and defects in a high-frequency electrical resistance welded (HF-ERW) pipe of high-Mn twinning-induced plasticity (TWIP) steel were characterized. The microstructure of the base metal and the bond line were examined using both optical microscopy and scanning electron microscopy. The features of the bond line were similar to those of conventional steel. Simultaneously, the circumferential ductility was evaluated via a flaring test. It was concluded that the deterioration of the circumferential ductility in a high-Mn TWIP steel pipe was caused by irregular shaped oxide defects and a penetrator that had been formed during welding. Specifically, the penetrator, which is composed of MnO and Mn{sub 2}SiO{sub 4}, was found to be the most influential on the circumferential ductility of the welded pipe. The penetrator was analyzed using both an electron probe micro analyzer and transmission electron microscopy, and the formation sequence of the penetrator was evaluated. - Highlights: •This study focused on applying the HF-ERW process to the seam welding of expandable pipe using TWIP steels. •For improvement of the circumferential ductility, deterioration factors were characterized. •Penetrator which would mainly deteriorate the circumferential ductility consisted of round MnO and Mn{sub 2}SiO{sub 4}. •Metallurgical evidence of existing theory regarding the mechanism of defect formation during the HF-ERW was characterized.

Experience with dust suppression in mining a thick, dirty seam

Energy Technology Data Exchange (ETDEWEB)

Siepmann, D; Kohlhauer, H

1975-11-20

Dust suppression measures used when mining a thick, dirty seam are described. Dust sprays inside and outside the shearer drum helped to reduce coarse dust, but the resulting increase in moisture content of the coal limits the extent to which this method can be used. The shields were also fitted with sprays. Because of the dirt in the seam, continuous, remotely controlled deep infusion was used. This reduced the dust concentration from more than 10 mg/m/sup 3/ to between 3.9 and 6.6 mg/m/sup 3/.

Investigation of residual stress in laser welding between carbon steel AISI 1010 and stainless AISI 304

International Nuclear Information System (INIS)

Mirim, Denilson de Camargo

2011-01-01

The dissimilar materials union has the residual stress formation as one of the most critical problems, which occurs mainly because these materials have both different thermal expansion coefficients and thermal conductivities. In this study, it was investigated the laser welding technique between steels, AISI 1010 and AISI 304. The materials were joined by butt autogenous welding with a continuous Nd:YAG laser. The main objective was to identify the welding parameters influence by the residual stresses analysis in the heat affected zone (HAZ). It was executed a factorial design with three-factor at two levels with a replica, which were varied power, welding speed and focal position of the laser beam. Residual stress measurements by the diffraction of X-rays were performed on the sample surface, to study their variation as a function of the parameters investigated. The blind hole method was also used to evaluate the residual stress along the samples depth, up to depth of 1mm. Besides residual stress measurement, weld seams were evaluated by optical and scanned electron microscopy, which were aimed to determine the weld geometry and changes in the microstructure. It was also made Vickers hardness measurements to evaluate the extent of HAZ. To evaluate the mechanical properties of the union were performed tensile and fatigue test. The MINITAB 15 software was used to analyze the residual stresses obtained by the blind hole method at different depths of the HAZ. It was also used statistical regression based on both the influences different and the combination of this input factors, in the residual stress of union. The results indicate that the models can satisfactorily predict the responses and provide users a guide to better define the welding parameters. (author)

Improving extraction technology of level seams. Sovershenstvovanie tekhnologii razrabotki pologikh plastov

Energy Technology Data Exchange (ETDEWEB)

Shetser, M G; Spitsyn, Yu G

1985-01-01

This report deals with conditions and prospects for intensifying extraction of level and inclined seams and improving extraction technology. Reviews mechanization of excavation of stables with automatic cutter-loaders (KA80 in conjunction with KD80); coal extraction using two cutter-loaders in seams 0.9 - 1.9 m thick and up to 20 degrees inclination (pillar mining); reciprocating method of coal cutting; one-sided method of coal extraction (KMK97 cutter loaders). Discusses strengthening of junctions of faces with gate roads (KSU and KSU3M props); improved types of props (hydraulic props SUG-30, SUG-V and GVD); roof control methods (induced caving, advance torpedoing or using KM87UMP and KMT power supports). Deals in detail with introduction of new extraction technology and strengthening of unstable rock by injecting polyurethene compounds, extraction of seams with wide-web cutter-loaders (Kirovets, IK101) and plowing. (3 refs.)

In-line process control for laser welding of titanium by high dynamic range ratio pyrometry and plasma spectroscopy

Science.gov (United States)

Lempe, B.; Taudt, C.; Baselt, T.; Rudek, F.; Maschke, R.; Basan, F.; Hartmann, P.

2014-02-01

The production of complex titanium components for various industries using laser welding processes has received growing attention in recent years. It is important to know whether the result of the cohesive joint meets the quality requirements of standardization and ultimately the customer requirements. Erroneous weld seams can have fatal consequences especially in the field of car manufacturing and medicine technology. To meet these requirements, a real-time process control system has been developed which determines the welding quality through a locally resolved temperature profile. By analyzing the resulting weld plasma received data is used to verify the stability of the laser welding process. The determination of the temperature profile is done by the detection of the emitted electromagnetic radiation from the material in a range of 500 nm to 1100 nm. As detectors, special high dynamic range CMOS cameras are used. As the emissivity of titanium depends on the wavelength, the surface and the angle of radiation, measuring the temperature is a problem. To solve these a special pyrometer setting with two cameras is used. That enables the compensation of these effects by calculating the difference between the respective pixels on simultaneously recorded images. Two spectral regions with the same emissivity are detected. Therefore the degree of emission and surface effects are compensated and canceled out of the calculation. Using the spatially resolved temperature distribution the weld geometry can be determined and the laser process can be controlled. The active readjustment of parameters such as laser power, feed rate and inert gas injection increases the quality of the welding process and decreases the number of defective goods.

An experimental study of assessment of weld quality on fatigue reliability analysis of a nuclear pressure vessel

International Nuclear Information System (INIS)

Dai Shuhe

1993-01-01

The steam generator in PWR primary coolant system China of Qinshan Nuclear Power Plant is a crucial unit belonging to the category of nuclear pressure vessel. The purpose of this research work is to make an examination of the weld quality of the steam generator under fatigue loading and to assess its reliability by using the experimental results of fatigue test of material of nuclear pressure vessel S-271 (Chinese Standard) and of qualified tests of welded seams of a simulated prototype of bottom closure head of the steam generator. A guarantee of weld quality is proposed as a subsequent verification for China National Nuclear Safety Supervision Bureau. The results of reliability analysis reported in this work can be taken as a supplementary material of Probabilistic Safety Assessment (PSA) of Qinshan Nuclear Power Plant. According to the requirement of Provision II-1500 cyclic testing, ASME Boiler and Pressure Vessel Code, Section III, Rules for Construction of Nuclear Power Plant Components, a simulated prototype of the bottom closure head of the steam generator was made for qualified tests. To find the quantified results of reliability assessment by using the testing data, two proposals are presented

Influence of Zn Interlayer on Interfacial Microstructure and Mechanical Properties of TIG Lap-Welded Mg/Al Joints

Science.gov (United States)

Gao, Qiong; Wang, Kehong

2016-03-01

This study explored 6061 Al alloy and AZ31B Mg alloy joined by TIG lap welding with Zn foils of varying thicknesses, with the additional Zn element being imported into the fusion zone to alloy the weld seam. The microstructures and chemical composition in the fusion zone near the Mg substrate were examined by SEM and EDS, and tensile shear strength tests were conducted to investigate the mechanical properties of the Al/Mg joints, as well as the fracture surfaces, and phase compositions. The results revealed that the introduction of an appropriate amount of Zn transition layer improves the microstructure of Mg/Al joints and effectively reduces the formation of Mg-Al intermetallic compounds (IMCs). The most common IMCs in the fusion zone near the Mg substrate were Mg-Zn and Mg-Al-Zn IMCs. The type and distribution of IMCs generated in the weld zone differed according to Zn additions; Zn interlayer thickness of 0.4 mm improved the sample's mechanical properties considerably compared to thicknesses of less than 0.4 mm; however, any further increase in Zn interlayer thickness of above 0.4 mm caused mechanical properties to deteriorate.

Characterization of Coal Quality Based On Ash Content From M2 Coal-Seam Group, Muara Enim Formation, South Sumatra Basin

Directory of Open Access Journals (Sweden)

Frillia Putri Nasution

2017-09-01

Full Text Available Muara Enim Formation is well known as coal-bearing formation in South Sumatra Basin. As coal-bearing formation, this formation was subjects of many integrated study. Muara Enim Formation can be divided into four coal-seam group, M1, M2, M3, and M4. The M2 group comprising of Petai (C, Suban (B, Lower Mangus (A2, and Upper Mangus (A1. Depositional environments of Group M2 is transitional lower delta plain with sub-depositional are crevasse splay and distributary channel. The differentiation of both sub-depositional environments can be caused the quality of coal deposit. One of quality aspects is ash content. This research conducted hopefully can give better understanding of relationship between depositional environments to ash content. Group M2 on research area were found only Seam C, Seam B, and Seam A2, that has distribution from north to central so long as 1400 m. Coal-seam thickness C ranged between 3.25-9.25 m, Seam B range 7.54-13.43 m, and Seam C range 1.53-8.37 m, where all of coal-seams thickening on the central part and thinning-splitting to northern part and southern part. The ash content is formed from burning coal residue material. Ash contents on coal seam caused by organic and inorganic compound which resulted from mixing modified material on surrounded when transportation, sedimentation, and coalification process. There are 27 sample, consists of 9 sample from Seam C, 8 sample from Seam B, and 10 sample from Seam A2. Space grid of sampling is 100-150 m. Ash content influenced by many factors, but in research area, main factor is existence of inorganic parting. Average ash content of Seam C is 6,04%, Seam B is 5,05%, and Seam A2 is 3,8%. Low ash content influenced by settle environment with minor detrital material. High ash content caused by oxidation and erosional process when coalification process. Ash content on coal in research area originated from detritus material carried by channel system into brackish area or originated

Laser beam welding of high strength aluminium-lithium alloys; Laserstrahlschweissen von hochfesten Aluminium-Lithium Legierungen

Energy Technology Data Exchange (ETDEWEB)

Enz, Josephin

2012-07-01

The present development in aircraft industry determined by the demand for a higher cost-effectiveness. Laser beam welding is one of the most promising joining technologies for the application in the aircraft industry through the considerable reduction of the production costs. Furthermore the weight of an aircraft structure can be reduced by the use of light and high strength aluminium alloys. This paper deals with the development of a process for the laser beam welding of a skin-stringer-joint where the Al-Li-alloy AA2196 is used as stringer material and the Al-Li-alloy AA2198 is used as skin and stringer material. By the use of design of experiments the optimal welding process parameters for different material combinations were determined which will be used for the welding of a 5-stringer panel. Therefore the weld seams of the joints were tested for irregularities and microstructural characteristics. In addition several mechanical tests were performed, which define the quality of the welded joint. Furthermore the influence of the oxide layer and the welding preparation on the welding performance was investigated. (orig.) [German] Die derzeitigen Entwicklungen im Flugzeugbau werden durch die allgemeine Forderung nach einer Steigerung der Wirtschaftlichkeit bestimmt. Das Laserstrahlschweissen ist dabei eines der vielversprechendsten Fuegeverfahren fuer die Anwendung im Flugzeugbau durch das die Herstellungskosten deutlich reduziert werden koennen. Zudem kann durch die Verwendung von leichten und hochfesten Aluminium-Legierungen das Gewicht einer Flugzeugstruktur zusaetzlich reduziert werden. Die vorliegende Arbeit befasst sich mit der Entwicklung eines Prozesses zum Laserstrahlschweissen einer Skin-Stringer-Verbindung aus den Aluminium-Lithium-Legierungen AA2196 (als Stringer-Werkstoff) und AA2198 (als Skin- und Stringer-Werkstoff). Unter Verwendung der statistischen Versuchsplanung wurden die optimalen Einstellungen der Schweissprozessparameter fuer die

Microhardness, strength and strain field characterization of self-reacting friction stir and plug welds of dissimilar aluminum alloys

Science.gov (United States)

Horton, Karla Renee

Friction stir welding (FSW) is a solid state welding process with potential advantages for aerospace and automotive industries dealing with light alloys. Self-reacting friction stir welding (SR-FSW) is one variation of the FSW process being developed at the National Aeronautics and Space Administration (NASA) for use in the fabrication of propellant tanks. Friction plug welding is used to seal the exit hole that remains in a circumferential SR-FSW. This work reports on material properties and strain patterns developed in a SR-FSW with a friction plug weld. Specifically, this study examines the behavior of a SR-FSW formed between an AA2014-T6 plate on the advancing side and an AA2219-T87 plate on the retreating side and a SR-FSW (AA2014-T6 to AA2219-T87) with a 2219-T87 plug weld. This study presents the results of a characterization of the micro-hardness, joint strength, and strain field characterization of SR-FSW and FPW joints tested at room temperature and cryogenic temperatures. The initial weld microstructure analysis showed a nugget region with fine grains and a displaced weld seam from the advancing side past the thermo-mechanical affected zone (TMAZ) into the nugget region. The displaced material shared the same hardness as the parent material. Dynamic recrystallization was observed in the SR-FSW zone and the displaced weld seam region. The welds revealed a fine grain structure in the SR-FSW zone with a sharp demarcation seen on the advancing side and fairly diffuse flow observed on the retreating side. The parent material hardness is 145 HV700g with a drop in hardness starting at the HAZ to 130 HV700g. The hardness further drops in the TMAZ to118 HV700g with an increase representing a dispersed interface of AA2014-T6 material to 135 HV700g. The hardness then drops significantly within the nugget region to 85 HV700g followed by an increase through the retreating side TMAZ into the HAZ to 135 HV 700g. There was a sharp increase in the hardness value within

Effects of Nd:YAG laser pulse frequency on the surface treatment of Ti 6Al 4V alloys

Energy Technology Data Exchange (ETDEWEB)

Gursel, Ali [International University of Sarajevo (Bosnia and Herzegovina). Dept. of Mechanical Engineering

2016-07-01

The desirable properties of titanium and titanium alloys, including excellent corrosion resistance, high strength to weight ratio and high operating temperature, have led to their successful application in various fields such as the medical and aerospace industries. Among the reliable treatment techniques, laser welding can provide significant advantages for the titanium alloys because of its precision, rapid processing capability and ability to control the welding parameters and their effects. The morphology and the quality of pulsed seam welds are directly or synergistically influenced by the Nd:YAG laser parameters of pulse shape, energy, duration, travel speed, peak power and frequency of repetition. In this study, a 1.5 mm thick Ti-6Al-4V alloy sheet surface was treated by SigmaLaser {sup registered} 300 Nd:YAG pulsed laser. The influence of the pulse frequency on seam morphology and surface effects was then investigated. The seam and surface quality were characterized in terms of weld morphology and microhardness. The results showed that, for Nd:YAG laser seams used for surface treatment, pulse repetition was more effective on the cooling rate than had been expected.

Computer-aided planning of brown coal seam mining in regard to coal quality

Energy Technology Data Exchange (ETDEWEB)

Ciesielski, R.; Lehmann, A.; Rabe, H.; Richter, S.

1988-09-01

Discusses features of the geologic SORVER software developed at the Freiberg Fuel Institute, GDR. The program processes geologic data from exploratory wells, petrographic characteristics of a coal seam model, technological mining parameters and coal quality requirements of consumers. Brown coal reserves of coking coal, gasification coal, briquetting coal and steam coal are calculated. Vertical seam profiles and maps of seam horizon isolines can be plotted using the program. Coal quality reserves along the surface of mine benches, mining block widths and lengths for excavators, maximum possible production of individual coal qualities by selective mining, and coal quality losses due to mining procedures are determined. The program is regarded as a means of utilizing deposit reserves more efficiently. 5 refs.

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…

The seam visual tracking method for large structures

Science.gov (United States)

Bi, Qilin; Jiang, Xiaomin; Liu, Xiaoguang; Cheng, Taobo; Zhu, Yulong

2017-10-01

In this paper, a compact and flexible weld visual tracking method is proposed. Firstly, there was the interference between the visual device and the work-piece to be welded when visual tracking height cannot change. a kind of weld vision system with compact structure and tracking height is researched. Secondly, according to analyze the relative spatial pose between the camera, the laser and the work-piece to be welded and study with the theory of relative geometric imaging, The mathematical model between image feature parameters and three-dimensional trajectory of the assembly gap to be welded is established. Thirdly, the visual imaging parameters of line structured light are optimized by experiment of the weld structure of the weld. Fourth, the interference that line structure light will be scatters at the bright area of metal and the area of surface scratches will be bright is exited in the imaging. These disturbances seriously affect the computational efficiency. The algorithm based on the human eye visual attention mechanism is used to extract the weld characteristics efficiently and stably. Finally, in the experiment, It is verified that the compact and flexible weld tracking method has the tracking accuracy of 0.5mm in the tracking of large structural parts. It is a wide range of industrial application prospects.

Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network.

Science.gov (United States)

De Filippis, Luigi Alberto Ciro; Serio, Livia Maria; Facchini, Francesco; Mummolo, Giovanni; Ludovico, Antonio Domenico

2016-11-10

A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW) process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable) and the mechanical properties (output responses) of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls). The simulation model was based on the adoption of the Artificial Neural Networks (ANNs) characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration.

Prediction of the Vickers Microhardness and Ultimate Tensile Strength of AA5754 H111 Friction Stir Welding Butt Joints Using Artificial Neural Network

Directory of Open Access Journals (Sweden)

Luigi Alberto Ciro De Filippis

2016-11-01

Full Text Available A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable and the mechanical properties (output responses of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls. The simulation model was based on the adoption of the Artificial Neural Networks (ANNs characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration.

The Investigation of Knitted Materials Bonded Seams Behaviour upon Cyclical Fatigue Loading

Directory of Open Access Journals (Sweden)

Gita BUSILIENĖ

2017-08-01

Full Text Available In this research uniaxial tension behaviour of PES knitted materials with bonded seams is analysed. The objects of the investigation were two types of knitted materials, having the same fibre composition (93 % PES, 7 % EL, but different in knitting pattern, i. e. plain single jersey and rib 1 × 1. Bonded overlap seams were formed by changing the orientation of knitted materials strips, i. e. parallel/parallel, parallel/bias, parallel/perpendicular, bias/bias and bias/perpendicular. The strips of each knitted material were joined by two types of thermoplastic polyurethane (PU films different in thickness (75 mm and 150 mm. Mechanical characteristics of bonded seams were defined in longitudinal direction. During uniaxial tension such parameters as maximal force Fmax (N and maximal elongation ɛmax (% were recorded from typical tension diagrams. The changes of tested specimens strength and deformation were compared before and after cyclical fatigue tension the conditions of which were 50 cycles up to tension force F equal 24.5 N. The results have shown that changes before and after cyclical fatigue tension are mostly determined by the structure of knitted materials, the orientation of knitted materials strips in bonded seam, but not effected by thermoplastic polyurethane film. These results are opposite compared to the results of biaxial tension of the same type of specimens, which have shown that changes before and after cyclical fatigue punching are mostly determined by the type of thermoplastic film, but not effected by the orientation of knitted materials strips in bonded seams. DOI: http://dx.doi.org/10.5755/j01.ms.23.2.16065

ARTIFICIAL NEURAL NETWORK AND FUZZY LOGIC CONTROLLER FOR GTAW MODELING AND CONTROL

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

An artificial neural network(ANN) and a self-adjusting fuzzy logic controller(FLC) for modeling and control of gas tungsten arc welding(GTAW) process are presented. The discussion is mainly focused on the modeling and control of the weld pool depth with ANN and the intelligent control for weld seam tracking with FLC. The proposed neural network can produce highly complex nonlinear multi-variable model of the GTAW process that offers the accurate prediction of welding penetration depth. A self-adjusting fuzzy controller used for seam tracking adjusts the control parameters on-line automatically according to the tracking errors so that the torch position can be controlled accurately.

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

The C. elegans engrailed homolog ceh-16 regulates the self-renewal expansion division of stem cell-like seam cells.

Science.gov (United States)

Huang, Xinxin; Tian, E; Xu, Yanhua; Zhang, Hong

2009-09-15

Stem cells undergo symmetric and asymmetric division to maintain the dynamic equilibrium of the stem cell pool and also to generate a variety of differentiated cells. The homeostatic mechanism controlling the choice between self-renewal and differentiation of stem cells is poorly understood. We show here that ceh-16, encoding the C. elegans ortholog of the transcription factor Engrailed, controls symmetric and asymmetric division of stem cell-like seam cells. Loss of function of ceh-16 causes certain seam cells, which normally undergo symmetric self-renewal expansion division with both daughters adopting the seam cell fate, to divide asymmetrically with only one daughter retaining the seam cell fate. The human engrailed homolog En2 functionally substitutes the role of ceh-16 in promoting self-renewal expansion division of seam cells. Loss of function of apr-1, encoding the C. elegans homolog of the Wnt signaling component APC, results in transformation of self-renewal maintenance seam cell division to self-renewal expansion division, leading to seam cell hyperplasia. The apr-1 mutation suppresses the seam cell division defect in ceh-16 mutants. Our study reveals that ceh-16 interacts with the Wnt signaling pathway to control the choice between self-renewal expansion and maintenance division and also demonstrates an evolutionarily conserved function of engrailed in promoting cell proliferation.

Resistance of Type 5 chemical protective clothing against nanometric airborne particles: Behavior of seams and zipper.

Science.gov (United States)

Vinches, Ludwig; Hallé, Stéphane

2017-12-01

In the field of dermal protection, the use of chemical protective clothing (CPC) (including coveralls) are considered as the last barrier against airborne engineered nanomaterials (ENM). In the majority of cases, Type 5 CPC, used against solid particles (ISO 13982-1), perform well against ENM. But in a recent study, a penetration level (PL) of up to 8.5% of polydisperse sodium chloride airborne nanoparticles has been measured. Moreover, in all the previous studies, tests were performed on a sample of protective clothing material without seams or zippers. Thus, the potential for permeation through a zipper or seams has not yet been determined, even though these areas would be privileged entry points for airborne ENM. This work was designed to evaluate the PL of airborne ENM through coveralls and specifically the PL through the seams on different parts of the CPC and the zipper. Eight current models of CPC (Type 5) were selected. The samples were taken from places with and without seams and with a zipper. In some cases, a cover strip can be added to the zipper to enhance its sealing. Polydisperse nanoparticles were generated by nebulization of a sodium chloride solution. A penetration cell was developed to expose the sample to airborne nanometric particles. The NaCl particle concentration in number was measured with an ultrafine particle counter and the PL was defined as the downstream concentration divided by the upstream concentration. The results obtained show that the PL increased significantly in the presence of seams and could reach up to 90% depending on the seam's design. Moreover, this study classifies the different types of seams by their resistance against airborne ENM. As for the penetration of airborne NaCl particles through the zipper, the PL was greatly attenuated by the presence of a cover strip, but only for certain models of coveralls. Finally, the values of the pressure drop were directly linked to the type of seam. All of these conclusions provide

Microstructure and mechanical performance of autogenously fibre laser beam welded Ti-6242 butt joints

Energy Technology Data Exchange (ETDEWEB)

Kashaev, Nikolai, E-mail: nikolai.kashaev@hzg.de; Pugachev, Dmitry; Ventzke, Volker; Fomin, Fedor; Burkhardt, Irmela; Enz, Josephin; Riekehr, Stefan

2017-05-10

This work deals with the effects of laser beam power, focus position and advance speed on the geometry, microstructure and mechanical properties such as the tensile strength and microhardness of autogenously fibre laser beam welded Ti-6Al-2Sn-4Zr-2Mo (denoted as Ti-6242) butt joints used for high temperature applications. The Ti-6242 sheet employed here is characterized by a globular (α+β) microstructure. Laser beam welded butt joints consisted of a martensitic fusion zone, inhomogeneous heat affected zones and equiaxed base materials. The microhardness increased from 330 HV 0.3 in base material to 430 HV 0.3 in fusion zone due to the martensitic transformation. Butt joints showed the base material level of strength in tensile test. The local increase in microhardness provided a shielding effect that protected the Ti-6242 butt joint against mechanical damage during the static tensile load test. The predicted critical total underfill depth that does not reduce the tensile strength of the weld was determined to be 25% of the specimen thickness. - Highlights: • Autogenous fibre LBW of Ti-6242 was successfully achieved. • Butt joints showed low levels of porosity and an appropriate seam geometry. • Base material level of strength achieved for tensile strength. • Predicted critical underfill depth is 25% of the specimen thickness.

Detecting voids in coal seams in surface mining by means of a biophysical method

Energy Technology Data Exchange (ETDEWEB)

Bek, E.

1985-07-01

Soviet research institutes, in cooperation with research intitutes from other countries, developed the Radar 1 system for detecting abandoned workings in coal seams in surface mines. The system will be used for detecting voids in seams at depths to 50 m. The Academy of Sciences of Czechoslovakia tested use of dowsing for detecting abandoned workings in the Pohranicni straz, the Brezova and the Medard coal surface mines. The workings were situated at depths from 2 to 12 m from the ground surface (dowser position). The dowser was not informed of position or dimensions of the workings. Accuracy of determining position of abandoned workings in coal seams was high. Results of dowsing were checked by drilling. 4 references.

保护层开采被保护层卸压增透效果的应用研究%Effect of protective seam mining on pressure relief and permeability enhancement of protected coal seam

Institute of Scientific and Technical Information of China (English)

冯拥军; 周玉军; 张喜传

2014-01-01

In view of the coal seam occurrence condition and geological condition of the west-ern region of Henan Province,the gas pressure releasing and drainage in protective coal seam was designed and the drilling design was investigated. In addition,the gas parameters and the dis-placement of roof and floor of B1 coal seam were determined. The research results showed that after the protective seam mining,coal seam gas pressure was decreased from the original 0.9 MPa to 0.12 MPa,the original gas content was reduced from the previous 6.52 m3/t to 3.1 m3/t,the expansion deformation of roof and floor reached 20.6 ‰,and the coal seam permeability coefficient was increased 810 times,so that the outburst danger at No. 12112 working face of B1 coal seam was eliminated in the pressure released area.%针对豫西煤田煤层赋存情况及地质状况,设计了被保护层的卸压抽采方案及考察钻孔,对瓦斯基础参数和二1煤层的煤层顶底板移近量进行了测定.研究结果表明,二1煤层在受到保护层开采后,煤层瓦斯压力由原始的0.9 MP a降为0.12 MP a ,原始瓦斯含量由以前的6.52 m3/t降为3.1 m3/t,顶底板膨胀变形量达到20.6‰,煤层透气性系数增大了810倍,在卸压区内完全消除了二1煤层12112工作面的突出危险性.

Method of gas emission control for safe working of flat gassy coal seams

Science.gov (United States)

Vinogradov, E. A.; Yaroshenko, V. V.; Kislicyn, M. S.

2017-10-01

The main problems at intensive flat gassy coal seam longwall mining are considered. For example, mine Kotinskaja JSC “SUEK-Kuzbass” shows that when conducting the work on the gassy coal seams, methane emission control by means of ventilation, degassing and insulated drain of methane-air mixture is not effective and stable enough. It is not always possible to remove the coal production restrictions by the gas factor, which leads to financial losses because of incomplete using of longwall equipment and the reduction of the technical and economic indicators of mining. To solve the problems, the authors used a complex method that includes the compilation and analysis of the theory and practice of intensive flat gassy coal seam longwall mining. Based on the results of field and numerical researches, the effect of parameters of technological schemes on efficiency of methane emission control on longwall panels, the non-linear dependence of the permissible according to gas factor longwall productivity on parameters of technological schemes, ventilation and degassing during intensive mining flat gassy coal seams was established. The number of recommendations on the choice of the location and the size of the intermediate section of coal heading to control gassing in the mining extracted area, and guidelines for choosing the parameters of ventilation of extracted area with the help of two air supply entries and removal of isolated methane-air mixture are presented in the paper. The technological scheme, using intermediate entry for fresh air intake, ensuring effective management gassing and allowing one to refuse from drilling wells from the surface to the mined-out space for mining gas-bearing coal seams, was developed.

Innovative technology summary report: Sealed-seam sack suits

International Nuclear Information System (INIS)

1998-09-01

Sealed-seam sack suits are an improved/innovative safety and industrial hygiene technology designed to protect workers from dermal exposure to contamination. Most of these disposable, synthetic-fabric suits are more protective than cotton suits, and are also water-resistant and gas permeable. Some fabrics provide a filter to aerosols, which is important to protection against contamination, while allowing air to pass, increasing comfort level of workers. It is easier to detect body-moisture breakthrough with the disposable suits than with cotton, which is also important to protecting workers from contamination. These suits present a safe and cost-effective (6% to 17% less expensive than the baseline) alternative to traditional protective clothing. This report covers the period from October 1996 to August 1997. During that time, sealed-seam sack suits were demonstrated during daily activities under normal working conditions at the C Reactor and under environmentally controlled conditions at the Los Alamos National Laboratory (LANL)

Detrimental Cr-rich Phases Precipitation on SAF 2205 Duplex Stainless Steels Welds After Heat Treatment

Directory of Open Access Journals (Sweden)

Argelia Fabiola Miranda Pérez

Full Text Available Abstract The austeno-ferritic Stainless Steels are commonly employed in various applications requiring structural performances with enhanced corrosion resistance. Their characteristics can be worsened if the material is exposed to thermal cycles, since the high-temperature decomposition of ferrite causes the formation of detrimental secondary phases. The Submerged Arc Welding (SAW process is currently adopted for joining DSS owing to its relatively simple execution, cost savings, and using molten slag and granular flux from protecting the seam of atmospheric gases. However, since it produces high contents of δ-ferrite in the heat affected zone and low content of γ-austenite in the weld, high-Ni filler materials must be employed, to avoid excessive ferritization of the joint. The present work is aimed to study the effect of 3 and 6 hours isothermal heat treatments at 850°C and 900°C in a SAF 2205 DSS welded joint in terms of phases precipitation. The results showed the presence of σ-phase at any time-temperature combination, precipitating at the δ/γ interphases and often accompanied by the presence of χ-phase. However, certain differences in secondary phases amounts were revealed among the different zones constituting the joint, ascribable both to peculiar elements partitioning and to the different morphology pertaining to each microstructure.

New standards for digital radiography and qualification of detectors; Neue Standards zur Digitalen Radiographie und Qualifizierung von Detektoren

Energy Technology Data Exchange (ETDEWEB)

Ewert, Uwe; Zscherpel, Uwe [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

2017-08-01

The contribution describes the most important standards for radiographic examinations that are revised in different committees. Information is given on new requirements esp. on revised parameters that have to be considered in practical testing procedures and classification. Actually for the revision of ISO 17636-1/2 in 2018 user questions are collected concerning weld seam testing. The DIN 25435 standards for weld seam testing in nuclear technology have been translated into English. Revisions of ASTM standards have to be considered in the actual EN and ISO standards. Since several years the International Institute of Welding (IIW) is also revising the international standards.

Simulation of a welding process in polyduct pipelines resolved with a finite elements computational model. Comparison with analytical solutions and tests with thermocouples

International Nuclear Information System (INIS)

Sanzi, H; Elvira, G; Kloster, M; Asta, E; Zalazar, M

2006-01-01

All welding processes induce deformations and thermal tensions, which must be evaluated correctly since they can influence a component's structural integrity. This work determines the distribution of temperatures that develop during a manual welding process with shielded electrodes (SMAW), on the circumference seam of a pipe for use in polyducts. A simplified model of Finite Elements (FEA) using three dimensional solids is proposed for the study. The analysis considers that while the welding process is underway, no heat is lost into the environment, that is, adiabatic conditions are considered, and the transformations produced in the material due to phase changes do not produce modifications in the properties of the supporting or base materials. The results of the simulation are compared with those obtained by recent analytical studies developed by different investigators, such as Nguyen, Ohta, Matsuoka, Suzuki and Taeda, where a continuously moving three dimensional double ellipsoidal source was used. The results are then compared with the experimental results by measuring with thermocouples. This study reveals the sensitivity and the validity of the proposed computer model, and in a second stage optimizes the engineering times for the resolution of a problem like the one presented in order to design the corresponding welding procedure (CW)

Image resizing using saliency strength map and seam carving for white blood cell analysis

Directory of Open Access Journals (Sweden)

Nam JaeYeal

2010-09-01

Full Text Available Abstract Background A new image-resizing method using seam carving and a Saliency Strength Map (SSM is proposed to preserve important contents, such as white blood cells included in blood cell images. Methods To apply seam carving to cell images, a SSM is initially generated using a visual attention model and the structural properties of white blood cells are then used to create an energy map for seam carving. As a result, the energy map maximizes the energies of the white blood cells, while minimizing the energies of the red blood cells and background. Thus, the use of a SSM allows the proposed method to reduce the image size efficiently, while preserving the important white blood cells. Results Experimental results using the PSNR (Peak Signal-to-Noise Ratio and ROD (Ratio of Distortion of blood cell images confirm that the proposed method is able to produce better resizing results than conventional methods, as the seam carving is performed based on an SSM and energy map. Conclusions For further improvement, a faster medical image resizing method is currently being investigated to reduce the computation time, while maintaining the same image quality.

Image resizing using saliency strength map and seam carving for white blood cell analysis.

Science.gov (United States)

Ko, ByoungChul; Kim, SeongHoon; Nam, JaeYeal

2010-09-20

A new image-resizing method using seam carving and a Saliency Strength Map (SSM) is proposed to preserve important contents, such as white blood cells included in blood cell images. To apply seam carving to cell images, a SSM is initially generated using a visual attention model and the structural properties of white blood cells are then used to create an energy map for seam carving. As a result, the energy map maximizes the energies of the white blood cells, while minimizing the energies of the red blood cells and background. Thus, the use of a SSM allows the proposed method to reduce the image size efficiently, while preserving the important white blood cells. Experimental results using the PSNR (Peak Signal-to-Noise Ratio) and ROD (Ratio of Distortion) of blood cell images confirm that the proposed method is able to produce better resizing results than conventional methods, as the seam carving is performed based on an SSM and energy map. For further improvement, a faster medical image resizing method is currently being investigated to reduce the computation time, while maintaining the same image quality.

Coal seam has boom - powering North Queensland industrial growth

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-06-01

Reduced operating costs, lower greenhouse gas emissions and security of supply are being cited by North Queensland industry leaders as the reasons for investing more than A$550 million to expand operations and convert to coal seam gas as their preferred fuel source. The article, by Enertrade, reports that just a few months after commissioning its North Queensland Gas Pipeline to transport coal seam gas from Moranbah to Townsville, Enertrade has signed contracts that will see combined cycle gas-fired baseload electricity generated in Townsville and the Queensland Nickel Refinery, and Xstrata Copper Refinery switch from liquid fuels to gas. The development has been driven by state government policy that 13% of Queensland's electricity be sourced from gas-fired power generation from 1 January 2005. Further information is available from Enertrade on Tel +617 3331 9929. 2 photos.

Influence of Industrial Washing and Cyclic Fatigue on Slippage of Linen Fabric Threads along the Seam

Directory of Open Access Journals (Sweden)

Irina KORUNČAK

2014-04-01

Full Text Available All seams of garments shall withstand the established force effect in the longitudinal and transverse directions. Resistance to thread slippage along the seam is a major property of fabrics that is regulated by strict guidelines. In many research works, lining fabrics are chosen as the object of research as thread slippage is the most typical of them. What concerns the reports exploring slippage of linen fabric threads along the seam, just very few papers are available. Studies dealing with the influence made by industrial washing and cyclic load on the defect under investigation, thereby taking into account operational properties of garments are not readily available at all. The objective of the paper is to define the influence of industrial washing and cyclic tensile on slippage of linen fabric threads along the seam. For the research, five 100 % linen fabrics of plain weave have been selected. Control test specimens, unwashed and processed with different washing methods, have been analysed. Cyclic tensile of the test specimens has been carried out by a tensile machine “Tinius Olsen” at tensile force P = 20 N, tensile speed of 12.55 mm/s, number of cycles of 100. The carried-out testing has demonstrated that industrial washing decreased resistance of linen fabrics to thread slippage along the seam in the most cases. Analysis of the results obtained has shown that cyclic tensile led to particularly significant increase in the seam gap. DOI: http://dx.doi.org/10.5755/j01.ms.20.1.2486

Impacts of Coal Seam Gas (Coal Bed Methane) Extraction on Water Resources in Australia

Science.gov (United States)

Post, David

2017-04-01

While extraction of methane from shale gas deposits has been the principal source of the recent expansion of the industry in the United States, in Australia extraction of methane from coal bed methane deposits (termed 'coal seam gas' in Australia) has been the focus to date. The two sources of methane share many of the same characteristics including the potential requirement for hydraulic fracturing. However, as coal seam gas deposits generally occur at shallower depths than shale gas, the potential impacts of extraction on surface and groundwater resources may be of even greater concern. In Australia, an Independent Expert Scientific Committee (IESC) has been established to provide scientific advice to federal and state government regulators on the impact that coal seam gas and large coal mining developments may have on water resources. This advice is provided to enable decisions to be informed by the best available science about the potential water-related impacts associated with these developments. To support this advice, the Australian Government Department of the Environment has implemented a programme of research termed 'bioregional assessments' to investigate these potential impacts. A bioregional assessment is defined as a scientific analysis of the ecology, hydrology, geology and hydrogeology of a bioregion with explicit assessment of the potential direct, indirect and cumulative impacts of coal seam gas and large coal mining development on water resources. These bioregional assessments are currently being carried out across large portions of eastern Australia underlain by coal reserves. Further details of the programme and results to date can be found at http://www.bioregionalassessments.gov.au. The bioregional assessment programme has modelled the impacts of coal seam gas development on surface and groundwater resources in three regions of eastern Australia, namely the Clarence-Moreton, Gloucester, and Namoi regions. This presentation will discuss the

The development of the rotational friction welding process for the welding of γ-TiAl-casting alloy Ti-47Al-3.5(Mn+Cr+Nb)-0.8(B+Si) to Ti6Al4V. Pt. II; Prozessentwicklung zum Rotationsreibschweissen der γ-TiAl-Feingusslegierung Ti-47Al-3.5(Mn+Cr+Nb)-0.8(B+Si) mit Ti6Al4V. T. II

Energy Technology Data Exchange (ETDEWEB)

Ventzke, Volker; Riekehr, Stefan; Horstmann, Manfred; Kashaev, Nikolai; Brokmeier, Heinz-Guenter; Huber, Norbert [Helmholtz-Zentrum Geesthacht GmbH, Zentrum fuer Material- und Kuestenforschung, Geesthacht (Germany). Inst. fuer Werkstoffforschung, Werkstoffmechanik

2014-07-01

At process temperatures of T > T{sub β}, the globular and fine grained microstructure of the Titanium alloy Ti6Al4V supports the occurrence of super-plasticity and deformation within the β phase region. This led to one sided shortening of the welded joints combined with the formation of weld flash. As a result of this no evening out of temperature across the forging surface between the γ-TAB cast alloy and Ti6Al4V alloy sides of the joint was able to take place, as a result of which the friction weld seam produced became symmetrically wedge shaped about the axis of rotation. Thereby the γ-TAB cast alloy side of the joint became only slightly compressed exhibiting no appreciable signs of deformation. In the radial direction on the γ-TAB side of the joint close to the forged surface neither the hardness nor the microstructure were homogeneous. Without pre-heating the fine ground, lapped and homogenised γ-TAB weld specimens at a temperature of 800 C above the brittle - ductile transformation transition temperature it was not possible to prevent the occurrence of boundary surface cracking on the outside, micro-voids and inter-lamellar cracking on the γ-TAB side solely by varying the welding parameters. The pre-heating of the γ-TAB friction weld specimens was a necessary pre-requisite to support the deformation of the γ-TAB side of the welded joint and the formation of weld flash during the friction welding process. (orig.)

Sequence stratigraphy, organic petrology and chemistry applied to the upper and lower coal seams in the Candiota Coalfield, Parana Basin, RS, Brazil

Energy Technology Data Exchange (ETDEWEB)

Oliveira, J.S. de; Kalkreuth, W. [Instituto de Geociencias, UFRGS, Porto Alegre (Brazil)

2010-12-01

The Permian age coal seams in the Candiota Coalfield represent the largest coal deposit of the country. Currently two seams are mined, called ''Camada Candiota Superior'' and ''Camada Candiota Inferior''. The other coal seams of the coalfield, seams S1-S9 (upper seams) and I1-I5 (lower seams) have as yet not been exploited. The objective of this paper is to perform a detailed sequence stratigraphic, petrologic and chemical study of the upper and lower coal seams, thereby generating data for assisting in the development and better use of the coal-bearing interval. The methodology includes application of the concepts of sequence stratigraphy, which includes the lithological interpretation of the core to establish the depositional environments and genetic correlation between facies associations to define parasequences and bounding surfaces; coal petrology (analysis of the reflectance of vitrinite, determination of the petrographic composition of the coals by maceral analyses), and chemical analyses such as sulphur determination, proximate analyses (ash, moisture, volatile matter, and fixed carbon), and elemental analyses. Three main depositional systems were so far identified: alluvial fan, fluvial system, lagoonal estuary system. This study shows that coal development was controlled by accommodation/accumulation rates, with coal seams with greater thickness and lateral continuity being formed within the transgressive systems tract (lagoonal depositional system) of parasequence 2 (PS2), indicating that the accumulation rates of the peat and distribution of the coal seams were controlled by stratigraphic setting. Vitrinite reflectances for the upper and lower coal seams are indicative of subbituminous rank (Rrandom = 0.36-0.47%), with evidence that anomalously low reflectance values are related to high mineral-matter contents. Maceral composition is highly variable, with some coal seams being extremely rich in inertinite (up to

Prediction of Weld Residual Stress of Narrow Gap Welds

International Nuclear Information System (INIS)

Yang, Jun Seog; Huh, Nam Su

2010-01-01

The conventional welding technique such as shield metal arc welding has been mostly applied to the piping system of the nuclear power plants. It is well known that this welding technique causes the overheating and welding defects due to the large groove angle of weld. On the other hand, the narrow gap welding(NGW) technique has many merits, for instance, the reduction of welding time, the shrinkage of weld and the small deformation of the weld due to the small groove angle and welding bead width comparing with the conventional welds. These characteristics of NGW affect the deformation behavior and the distribution of welding residual stress of NGW, thus it is believed that the residual stress results obtained from conventional welding procedure may not be applied to structural integrity evaluation of NGW. In this paper, the welding residual stress of NGW was predicted using the nonlinear finite element analysis to simulate the thermal and mechanical effects of the NGW. The present results can be used as the important information to perform the flaw evaluation and to improve the weld procedure of NGW

Law of Strata Pressure Behavior in Shallow Coal Seam

Science.gov (United States)

Zhao, Jian; Liu, Leibin; Zheng, Zhiyang

2018-02-01

The law of strata pressure behavior in shallow coal seam is analyzed, according to the load data of Jinjie Coal Mine 31109 working face hydraulic supports. The first weighting distance of main roof is 80 m, and the periodic weighting distance of main roof is about 20 m. And according to the load data in the middle and both ends of the working face, the working resistance of hydraulic supports and the setting load are a bit small, so they couldn’t meet the needs of supporting roof. Then, the front abutment pressure of working face is analyzed by numerical simulation. It does not only explain the reason that the load is too big, but also explains the reason that the strata pressure behavior in shallow coal seam is serious. The length of undamaged main roof rock beam verifies the correctness of the periodic weighting distance.

Effects of nano-particles strengthening activating flux on the microstructures and mechanical properties of TIG welded AZ31 magnesium alloy joints

International Nuclear Information System (INIS)

Xie, Xiong; Shen, Jun; Cheng, Liang; Li, Yang; Pu, Yayun

2015-01-01

Highlights: • Increased nano-particles strengthening activating flux degraded TIGed seams. • The reaction between SiC particles and Mg alloy produced Al 4 C 3 and Mg 2 Si phases. • Al 4 C 3 and SiC particles promoted the nucleation and suppressed the growth of α-Mg. • Refined α-Mg grains, precipitated phase and SiC particles enhanced TIGed joints. - Abstract: In this paper, AZ31 magnesium alloy joints were processed by nano-particles strengthening activating flux tungsten inert gas (NSA-TIG) welding, which was achieved by the mixed TiO 2 and nano-SiC particles coated on the samples before welding tests. The macro/micro structural observation and mechanical properties evaluation of the welding joints were conducted by using optical microscope, scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction and tension and microhardness tests. The results showed that nano-particles strengthening activating flux effective improved the microstructure, microhardness in fusion zone, ultimate tensile strength of the TIG welding joints. In addition, the chemical reaction between part of SiC particles and AZ31 magnesium alloy produced Al 4 C 3 and Mg 2 Si in the joints. The Al 4 C 3 performed as nucleating agents for α-Mg and the dispersed Mg 2 Si and SiC particles enhanced the mechanical properties of the NSA-TIG welding joints. However, large heat input induced by the increase of the surface coating density of the nano-particles strengthening activating flux, increased the α-Mg grain sizes and weakened the mechanical properties of the welded joints. Therefore, the grain size of α-Mg, distribution of β-Mg 17 Al 12 , Mg 2 Si and SiC particles together influenced the evolution of the mechanical properties of the NSA-TIG welded AZ31 magnesium alloy joints

Assessment of the influence of surface finishing and weld joints on the corrosion/oxidation behaviour of stainless steels in lead bismuth eutectic

Energy Technology Data Exchange (ETDEWEB)

Martin-Munoz, F.J., E-mail: fco.javier@ciemat.es [Structural Materials Division, CIEMAT, Building 30, Avda. Complutense 22, Madrid 28040 (Spain); Soler-Crespo, L.; Gomez-Briceno, D. [Structural Materials Division, CIEMAT, Building 30, Avda. Complutense 22, Madrid 28040 (Spain)

2011-09-01

The objective of this paper is to gain some insight into the influence of the surface finishing in the oxidation/corrosion behaviour of 316L and T91 steels in lead bismuth eutectic (LBE). Specimens of both materials with different surface states were prepared (as-received, grinded, grinded and polished, and electrolitically polished) and oxidation tests were carried out at 775 and 825 K from 100 to 2000 h for two different oxygen concentrations and for H{sub 2}/H{sub 2}O molar ratios of 3 and 0.03. The general conclusion for these tests is that the effect of surface finishing on the corrosion/protection processes is not significant under the tested conditions. In addition the behaviour of weld joints, T91-T91 Tungsten Inert Gas (TIG) and T91-316L have been also studied under similar conditions. The conclusions are that, whereas T91-T91 welded joint shows the same corrosion properties as the parent materials for the conditions tested, AISI 316L-T91 welded joint, present an important dissolution over seam area that it associated to the electrode 309S used for the fabrication process.

Assessment of the influence of surface finishing and weld joints on the corrosion/oxidation behaviour of stainless steels in lead bismuth eutectic

Science.gov (United States)

Martín-Muñoz, F. J.; Soler-Crespo, L.; Gómez-Briceño, D.

2011-09-01

The objective of this paper is to gain some insight into the influence of the surface finishing in the oxidation/corrosion behaviour of 316L and T91 steels in lead bismuth eutectic (LBE). Specimens of both materials with different surface states were prepared (as-received, grinded, grinded and polished, and electrolitically polished) and oxidation tests were carried out at 775 and 825 K from 100 to 2000 h for two different oxygen concentrations and for H 2/H 2O molar ratios of 3 and 0.03. The general conclusion for these tests is that the effect of surface finishing on the corrosion/protection processes is not significant under the tested conditions. In addition the behaviour of weld joints, T91-T91 Tungsten Inert Gas (TIG) and T91-316L have been also studied under similar conditions. The conclusions are that, whereas T91-T91 welded joint shows the same corrosion properties as the parent materials for the conditions tested, AISI 316L-T91 welded joint, present an important dissolution over seam area that it associated to the electrode 309S used for the fabrication process.

Assessment of the influence of surface finishing and weld joints on the corrosion/oxidation behaviour of stainless steels in lead bismuth eutectic

International Nuclear Information System (INIS)

Martin-Munoz, F.J.; Soler-Crespo, L.; Gomez-Briceno, D.

2011-01-01

The objective of this paper is to gain some insight into the influence of the surface finishing in the oxidation/corrosion behaviour of 316L and T91 steels in lead bismuth eutectic (LBE). Specimens of both materials with different surface states were prepared (as-received, grinded, grinded and polished, and electrolitically polished) and oxidation tests were carried out at 775 and 825 K from 100 to 2000 h for two different oxygen concentrations and for H 2 /H 2 O molar ratios of 3 and 0.03. The general conclusion for these tests is that the effect of surface finishing on the corrosion/protection processes is not significant under the tested conditions. In addition the behaviour of weld joints, T91-T91 Tungsten Inert Gas (TIG) and T91-316L have been also studied under similar conditions. The conclusions are that, whereas T91-T91 welded joint shows the same corrosion properties as the parent materials for the conditions tested, AISI 316L-T91 welded joint, present an important dissolution over seam area that it associated to the electrode 309S used for the fabrication process.

Three-dimensional modelling of arc behaviour and gas shield quality in tandem gas-metal arc welding using anti-phase pulse synchronization

International Nuclear Information System (INIS)

Schnick, M; Lohse, M; Fuessel, U; Wilhelm, G; Murphy, A B

2011-01-01

The paper presents a transient three-dimensional model of an anti-phase-synchronized pulsed tandem gas-metal arc welding process, which is used to analyse arc interactions and their influence on the gas shield flow. The shielding gases considered are pure argon and a mixture of argon with 18% CO 2 . Comparison of the temperature fields predicted by the model with high-speed images indicates that the essential features of the interactions between the arcs are captured. The paper demonstrates strong arc deflection and kinking, especially during the low-current phase of the pulse, in agreement with experimental observations. These effects are more distinct for the argon mixture with 18% CO 2 . The second part of the paper demonstrates the effects of arc deflection and instabilities on the shielding gas flow and the occurrence of air contamination in the process region. The results allow an improved understanding of the causes of periodic instabilities and weld seam imperfections such as porosity, spatter, heat-tint oxidation and fume deposits.

Application of the diode laser for welding in tairoled blanks; Aplicaciond el lase de diodo para la soldadura en tailored blanks

Energy Technology Data Exchange (ETDEWEB)

Bocos, J. L.; Zubiri, F.; Garciandia, F.; Pena, J.; Cortiella, A.; Berrueta, J. M.; Zapirain, F.

2004-07-01

During the last years, one of the most interesting subjects in the automotive industry is the weight reduction of the automobile, and so to diminish the fuel consumption. Among other performance, the use in the body car of materials which have high mechanical resistance must be considered for the weight reduction of the automobile and maintaining high benefits. In this work, it has been studied the utilization of the diode laser for high resistance steel sheets welding, concretely microalloying steels (ZStE), DP dual phase and TRIP transformation induced plasticity. These steels can be employed in tailored blanks, which are defined as two or more separate pieces of flat material of dissimilar thickness and/or physical properties joined together before forming, to provide superior qualities in the finished stamped part. In this study, the metallographic characterization has been realised in the welding seams, and the mechanical behaviour has been analysed employing the following tests: microhardenss, drawing, tensile and fatigue. (Author) 15 refs.

Principles of integrated modeling of coal seam mining

Energy Technology Data Exchange (ETDEWEB)

Magda, R

1983-01-01

Mathematical modeling of underground coal mining is discussed. Construction of a mathematical model of an underground mine is analyzed. The model is based on integrating the elementary units (modules). A so-called elementary mining field is defined with the example of a longwall face. A model of an elementary coal seam zone is constructed by integrating the elementary mining fields (in time and space) and supplementing them with a suitable model of mine roadway structure. By integrating the elementary coal seam zones a model of mining level is constructed. Such a mathematical model is used for optimizing the selected mining parameters e.g. structure of mine roadways, size of a coal mine, and organizational scheme of underground mining in a mine or in a mine section using the standardized optimization criterion e.g. investment. Use of the integration model of underground mining for optimizing coal mine construction is evaluated. The following elements of investment and operating cost are considered: shaft excavation, shaft equipment, investment in mining sections, ventilation, mine draining etc. 1 reference.

Investigation on mechanical properties of welded material under different types of welding filler (shielded metal arc welding)

Science.gov (United States)

Tahir, Abdullah Mohd; Lair, Noor Ajian Mohd; Wei, Foo Jun

2018-05-01

The Shielded Metal Arc Welding (SMAW) is (or the Stick welding) defined as a welding process, which melts and joins metals with an arc between a welding filler (electrode rod) and the workpieces. The main objective was to study the mechanical properties of welded metal under different types of welding fillers and current for SMAW. This project utilized the Design of Experiment (DOE) by adopting the Full Factorial Design. The independent variables were the types of welding filler and welding current, whereas the other welding parameters were fixed at the optimum value. The levels for types of welding filler were by the models of welding filler (E6013, E7016 and E7018) used and the levels for welding current were 80A and 90A. The responses were the mechanical properties of welded material, which include tensile strength and hardness. The experiment was analyzed using the two way ANOVA. The results prove that there are significant effects of welding filler types and current levels on the tensile strength and hardness of the welded metal. At the same time, the ANOVA results and interaction plot indicate that there are significant interactions between the welding filler types and the welding current on both the hardness and tensile strength of the welded metals, which has never been reported before. This project found that when the amount of heat input with increase, the mechanical properties such as tensile strength and hardness decrease. The optimum tensile strength for welded metal is produced by the welding filler E7016 and the optimum of hardness of welded metal is produced by the welding filler E7018 at welding current of 80A.

Online process monitoring at quasi-simultaneous laser transmission welding using a 3D-scanner with integrated pyrometer

Science.gov (United States)

Schmailzl, A.; Steger, S.; Dostalek, M.; Hierl, S.

2016-03-01

Quasi-simultaneous laser transmission welding is a well-known joining technique for thermoplastics and mainly used in the automotive as well as in the medical industry. For process control usually the so called set-path monitoring is used, where the weld is specified as "good" if the irradiation time is inside a defined confidence interval. However, the detection of small-sized gaps or thermal damaged zones is not possible with this technique. The analyzation of the weld seam temperature during welding offers the possibility to overcome this problem. In this approach a 3D-scanner is used instead of a scanner with flat-field optic. By using a pyrometer in combination with a 3D-scanner no color-corrected optic is needed in order to provide that laser- and detection-spot are concentric. Experimental studies on polyethylene T-joints have shown that the quality of the signal is adequate, despite the use of an optical setup with a long working distance and a small optical aperture. The effects on temperature are studied for defects like a gap in the joining zone. Therefore a notch was milled into the absorbent polymer. In case of producing housings for electronic parts the effect of an electrical wire between the joining partners is also investigated. Both defects can be identified by a local temperature deviation even at a feed rate of four meters per second. Furthermore a strategy for signal-processing is demonstrated. By this, remaining defects can be identified. Consequently an online detection of local defects is possible, which makes a dynamic process control feasible.

Innovative Extraction Method for a Coal Seam with a Thick Rock-Parting for Supporting Coal Mine Sustainability

Directory of Open Access Journals (Sweden)

Meng Li

2017-10-01

Full Text Available As thick rock partings delay the efficient mining of coal seams and constrain the sustainable development of coal mines, an innovative extraction method for a coal seam with thick rock parting was proposed. The coal seams were divided into different sub-zones according to the thickness of rock parting and then the sub-zones were mined by separately using three mining schemes involving full-seam mining, combined mining using backfill and caving (CMBC, and reducing height mining. Afterwards, the study introduced the basic mechanism and key devices for the CMBC and analysed the working state of the backfill support in detail. Moreover, the method for calculating the length of the backfill zone was proposed to design the length of backfill zone and the influences of four factors (including bulking coefficient of rock parting on the length of the backfill zone were also explored. By taking the No. 22203 panel, Buertai mine, Inner Mongolia, China as an example, the mined coal resource by using the CMBC extraction method will increase by 1.83 × 106 tons and the recovery ratio will rise from 56.2% to 92.4% compared with mining of the 2-2 upper coal seam alone. Moreover, by applying CMBC, a series of environmental and ecological problems caused by rock parting is reduced, which can improve the environment in mined areas. The research can provide technological guidance for mining panels of a coal seam with a thick rock parting and the disposal thereof under similar conditions.

Petrographic properties of major coal seams in Turkey and their formation

Energy Technology Data Exchange (ETDEWEB)

Toprak, Selami [Mineral Research and Exploration Directorate (MTA), 06520 Ankara (Turkey)

2009-06-01

Most types of coal in Turkey are generally low in rank: lignite, and subbituminous. Most of the coal was formed during the Miocene, Eocene, and Pliocene ages. There are only a few thin Jurassic-age coal occurrences in Turkey. Pennsylvanian age bituminous coal is found on the Black Sea coast. General implications of the petrographic properties of Turkey's coal seams and coal deposits have not yet been taken into consideration comparatively or as a whole. For this study, about 190 channel samples were collected from different locales. The composite profile samples of the seams were taken into considerations. The content and depositional properties as well as some chemical and physical properties of the main coal seams are compared. All coal samples tend to have similar coal petrographic properties and were deposited in intermontane lacustrine basins. Later, they were affected by faulting and post-depositional volcanic activity. As a result, there are variations in the properties and rank of the coal samples. The most abundant coal maceral group is huminite and the most abundant maceral is gelinite. The liptinite and inertinite contents of the coal are low and the maceral contents of the coals show great similarity. The depositional environments of the all coals are lacustrine dominated. (author)

Manufacture of power station heat exchangers using modern production technology

International Nuclear Information System (INIS)

Genzlinger, W.; Hoffmann, J.; Ohlhaeuser, K.

1986-01-01

Heat exchangers of high quality and operational safety can only be fabricated economically if fabrication is as 'simple' as possible and can be controlled and if, through value analysis, the work flows can be mechanized and automated and the following requirements are met: use of materials that are easy to work with for the application considered, choice of product designs and wall thicknesses that offer favourable conditions for processing and non-destructive testing, placing of seams in such a way that good accessibility for welding and minimum residual welding stresses are assured, minimizing the number of welding seams, use of automatic welding machines for submerged-arc welding and electronically controlled sources of welding current - semi-automatic equipment for spatter-free interfaces (pulse technique), electronically controlled equipment for welding in rollers and pipes and CNC-controlled machining centres for drilling pipe galleries (deep-hole drilling) and baffle plates and for machining the sealing elements after welding. Continuous inspections in each phase of fabrication assures that heat exchangers are made which fully meet the requirements of nuclear power station operators. (orig.)

Effects of TiO2 coating on the microstructures and mechanical properties of tungsten inert gas welded AZ31 magnesium alloy joints

International Nuclear Information System (INIS)

Wang Linzhi; Shen Jun; Xu Nan

2011-01-01

Highlights: → The weld penetration and the D/W ratio could be improved dramatically by increasing of the amount of the TiO 2 coating. → The average grain size of the α-Mg grains increased and the β-Mg 17 Al 12 IMC transformed from granular structure to continuous structure with an increase of the amount of the TiO 2 coating. → With an increase of the amount of the TiO 2 coating, the microhardness of the FZ of the AZ31 magnesium alloy welded joints decreased slightly at first and then decreased sharply. → The UTS value of the welded joints increased with an increase of the amount of the TiO 2 coating. → However, too much TiO 2 coating caused a significant decrease of the UTS value of the welded joints. - Abstract: The effects of TiO 2 coating on the macro-morphologies, microstructures and mechanical properties of tungsten inert gas (TIG) welded AZ31 magnesium alloy joints were investigated by microstructural observations, microhardness tests and tensile tests. The results showed that an increase in the amount of the TiO 2 coating resulted in an increase in the weld penetration and the depth/width (D/W) ratio of the TIG welded AZ31 magnesium alloy seams. Moreover, the average grain size of the α-Mg grains increased and the β-Mg 17 Al 12 intermetallic compound (IMC) was coarser in the case of higher amount of the TiO 2 coating. With an increase in the amount of the TiO 2 coating, the microhardness of the fusion zone (FZ) of the AZ31 magnesium alloy welded joints decreased slightly initially and then decreased sharply. In addition, with an increase in the amount of the TiO 2 coating, the ultimate tensile strength (UTS) value and elongation of the welded joints increased at first and then decreased sharply.

Palynological dating of a coal seam in Ayyanapalem area, Khamman District, Andhra Pradesh, India

Energy Technology Data Exchange (ETDEWEB)

Rao, M.R.; Lakshminarayana, G.; Ramanujam, C.G.K. (Geological Survey of India, Hyderabad (India). Southern Region)

1990-05-25

A palynological study of five subsurface samples of a coal seam near Ayyanapalem, Chintalapudi sub-basin of Godavari valley, Andhra Pradesh, was carried out. Twenty-five genera, including monosaccate, striate and nonstriate bisaccate, and trilete sporomorphs were identified; striate bisaccates predominate. Based on occurrence of {ital Rhizomaspora, Microbaculispora, Indotriradites, Crucisaccites ital} and {ital Corisaccites}, the coal seam is inferred to be similar in age to the Permian age Barakar Formation of the Lower Gondwana. 3 refs., 2 figs.

Weld Nugget Temperature Control in Thermal Stir Welding

Science.gov (United States)

Ding, R. Jeffrey (Inventor)

2014-01-01

A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

Transition welds in welding of two-ply steels

International Nuclear Information System (INIS)

Fartushnyj, V.G.; Evsyukov, Yu.G.

1977-01-01

Studied were physico-mechanical properties of welds made by various welding wires of chromium-nickel and nickel-chromium steels in submerged arc welding of double-layer steels with main layer of the VSt.3sp. carbon steel. It is shown that service-reliable structures welded of two-layer steels are obtained by providing the content from 11 to 20 % Ni in the automatically welded transition layer

Weld controller for automated nuclear service welding

International Nuclear Information System (INIS)

Barfield, K.L.; Strubhar, P.M.; Green, D.I.

1995-01-01

B and W Nuclear Technologies (BWNT) uses many different types of weld heads for automated welding in the commercial nuclear service industry. Some weld heads are purchased as standard items, while others are custom designed and fabricated by BWNT requiring synchronized multiaxis motion control. BWNT recently completed a development program to build a common weld controller that interfaces to all types of weld heads used by BWNT. Their goal was to construct a system that had the flexibility to add different modules to increase the capability of the controller as different application needs become necessary. The benefits from having a common controller are listed. This presentation explains the weld controller system and the types of applications to which it has been applied

3D Discrete element approach to the problem on abutment pressure in a gently dipping coal seam

Science.gov (United States)

Klishin, S. V.; Revuzhenko, A. F.

2017-09-01

Using the discrete element method, the authors have carried out 3D implementation of the problem on strength loss in surrounding rock mass in the vicinity of a production heading and on abutment pressure in a gently dripping coal seam. The calculation of forces at the contacts between particles accounts for friction, rolling resistance and viscosity. Between discrete particles modeling coal seam, surrounding rock mass and broken rocks, an elastic connecting element is introduced to allow simulating coherent materials. The paper presents the kinematic patterns of rock mass deformation, stresses in particles and the graph of the abutment pressure behavior in the coal seam.

The Single Needle Lockstitch Machine. [Sewing Seams.] Module 4.

Science.gov (United States)

South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

This module on sewing seams, one in a series on the single needle lockstitch sewing machine for student self-study, contains three sections. Each section includes the following parts: an introduction, directions, an objective, learning activities, student information, student self-check, check-out activities, and an instructor's final checklist.…

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)

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.)

Mechanism of Rock Burst Occurrence in Specially Thick Coal Seam with Rock Parting

Science.gov (United States)

Wang, Jian-chao; Jiang, Fu-xing; Meng, Xiang-jun; Wang, Xu-you; Zhu, Si-tao; Feng, Yu

2016-05-01

Specially thick coal seam with complex construction, such as rock parting and alternative soft and hard coal, is called specially thick coal seam with rock parting (STCSRP), which easily leads to rock burst during mining. Based on the stress distribution of rock parting zone, this study investigated the mechanism, engineering discriminant conditions, prevention methods, and risk evaluation method of rock burst occurrence in STCSRP through setting up a mechanical model. The main conclusions of this study are as follows. (1) When the mining face moves closer to the rock parting zone, the original non-uniform stress of the rock parting zone and the advancing stress of the mining face are combined to intensify gradually the shearing action of coal near the mining face. When the shearing action reaches a certain degree, rock burst easily occurs near the mining face. (2) Rock burst occurrence in STCSRP is positively associated with mining depth, advancing stress concentration factor of the mining face, thickness of rock parting, bursting liability of coal, thickness ratio of rock parting to coal seam, and difference of elastic modulus between rock parting and coal, whereas negatively associated with shear strength. (3) Technologies of large-diameter drilling, coal seam water injection, and deep hole blasting can reduce advancing stress concentration factor, thickness of rock parting, and difference of elastic modulus between rock parting and coal to lower the risk of rock burst in STCSRP. (4) The research result was applied to evaluate and control the risk of rock burst occurrence in STCSRP.

Spatio-temporal evolution of apparent resistivity during coal-seam hydraulic flushing

Science.gov (United States)

Li, Dexing; Wang, Enyuan; Song, Dazhao; Qiu, Liming; Kong, Xiangguo

2018-06-01

Hydraulic flushing in gas predrainage is widely used, but the hydraulic-flushing effect is evaluated in a traditional way, by determining the desorption volume, moisture content, gas drainage rate and other conventional indices. To verify the rationality and feasibility of the multielectrode resistivity method in the evaluation of coal-seam hydraulic flushing and to research the spatio-temporal evolution of apparent resistivity during hydraulic flushing, a field test was conducted in 17# coal seam at Nuodong Mine, Guizhou. During hydraulic flushing, four stages were defined according to the variation in coal rock resistivity with time, namely, the preparation stage, the sharply decreasing stage, the rapidly increasing stage and the steady stage. The apparent resistivity of the coal rock mass is affected mainly by its own degree of fragmentation and flushing volume. A more serious rupture and a greater flushing volume yield a smaller apparent resistivity during the sharply decreasing stage and a higher resistivity during the stable stage. After three months of gas predrainage, the residual gas content and the gas pressure at different points in the expected affected area decrease below the critical value. Changes in the residual gas content and gas pressure at these points are consistent with the apparent resistivity, which validates the rationality and feasibility of the multielectrode resistivity method in evaluating coal-seam hydraulic flushing.

Creep-fatigue evaluation method for weld joint of Mod.9Cr-1Mo steel Part II: Plate bending test and proposal of a simplified evaluation method

Energy Technology Data Exchange (ETDEWEB)

Ando, Masanori, E-mail: ando.masanori@jaea.go.jp; Takaya, Shigeru, E-mail: takaya.shigeru@jaea.go.jp

2016-12-15

Highlights: • Creep-fatigue evaluation method for weld joint of Mod.9Cr-1Mo steel is proposed. • A simplified evaluation method is also proposed for the codification. • Both proposed evaluation method was validated by the plate bending test. • For codification, the local stress and strain behavior was analyzed. - Abstract: In the present study, to develop an evaluation procedure and design rules for Mod.9Cr-1Mo steel weld joints, a method for evaluating the creep-fatigue life of Mod.9Cr-1Mo steel weld joints was proposed based on finite element analysis (FEA) and a series of cyclic plate bending tests of longitudinal and horizontal seamed plates. The strain concentration and redistribution behaviors were evaluated and the failure cycles were estimated using FEA by considering the test conditions and metallurgical discontinuities in the weld joints. Inelastic FEA models consisting of the base metal, heat-affected zone and weld metal were employed to estimate the elastic follow-up behavior caused by the metallurgical discontinuities. The elastic follow-up factors determined by comparing the elastic and inelastic FEA results were determined to be less than 1.5. Based on the estimated elastic follow-up factors obtained via inelastic FEA, a simplified technique using elastic FEA was proposed for evaluating the creep-fatigue life in Mod.9Cr-1Mo steel weld joints. The creep-fatigue life obtained using the plate bending test was compared to those estimated from the results of inelastic FEA and by a simplified evaluation method.

Creep-fatigue evaluation method for weld joint of Mod.9Cr-1Mo steel Part II: Plate bending test and proposal of a simplified evaluation method

International Nuclear Information System (INIS)

Ando, Masanori; Takaya, Shigeru

2016-01-01

Highlights: • Creep-fatigue evaluation method for weld joint of Mod.9Cr-1Mo steel is proposed. • A simplified evaluation method is also proposed for the codification. • Both proposed evaluation method was validated by the plate bending test. • For codification, the local stress and strain behavior was analyzed. - Abstract: In the present study, to develop an evaluation procedure and design rules for Mod.9Cr-1Mo steel weld joints, a method for evaluating the creep-fatigue life of Mod.9Cr-1Mo steel weld joints was proposed based on finite element analysis (FEA) and a series of cyclic plate bending tests of longitudinal and horizontal seamed plates. The strain concentration and redistribution behaviors were evaluated and the failure cycles were estimated using FEA by considering the test conditions and metallurgical discontinuities in the weld joints. Inelastic FEA models consisting of the base metal, heat-affected zone and weld metal were employed to estimate the elastic follow-up behavior caused by the metallurgical discontinuities. The elastic follow-up factors determined by comparing the elastic and inelastic FEA results were determined to be less than 1.5. Based on the estimated elastic follow-up factors obtained via inelastic FEA, a simplified technique using elastic FEA was proposed for evaluating the creep-fatigue life in Mod.9Cr-1Mo steel weld joints. The creep-fatigue life obtained using the plate bending test was compared to those estimated from the results of inelastic FEA and by a simplified evaluation method.

Effect of Seams on Drape of Fabrics (Pp. 62-72)

African Journals Online (AJOL)

Nekky Umera

Jinlian ... Drape profile of fabrics with seams provide guidance for garment designs ... holder consists of flat plates, circular in shape, mounted on a shaft coming through ... The image of this draped pattern is cast onto a sheet by means of a lens.

Stress distribution characteristics in the vicinity of coal seam floor

Science.gov (United States)

Cui, Zimo; Chanda, Emmanuel; Zhao, Jingli; Wang, Zhihe

2018-01-01

Although longwall top-coal caving (LTCC) has been a popular, more productive and cost-effective method in recent years, roadway floor heave and rock bursts frequently appear when exploiting such coal seams with large dip angle. This paper proposes addressing this problem by adopting three-dimensional roadway layout of stagger arrangement (3-D RLSA). In this study, the first step was to analyse the stress distribution characteristics in the vicinity of coal seam floor based on the stress slip line field theory. In the second step, numerical calculation using FLAC3D was conducted. Finally, an evaluation of the 3-D RLSA for solving this particular issue was given. Results indicate that for this particular mine the proposed 3-D RLSA results in 24% increase in the coal recovery ratio and a modest reduction in excavation and maintenance costs compared to the conventional LTCC method.

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.

SEAM PUCKERING EVALUATION METHOD FOR SEWING PROCESS

Directory of Open Access Journals (Sweden)

BRAD Raluca

2014-07-01

Full Text Available The paper presents an automated method for the assessment and classification of puckering defects detected during the preproduction control stage of the sewing machine or product inspection. In this respect, we have presented the possible causes and remedies of the wrinkle nonconformities. Subjective factors related to the control environment and operators during the seams evaluation can be reduced using an automated system whose operation is based on image processing. Our implementation involves spectral image analysis using Fourier transform and an unsupervised neural network, the Kohonen Map, employed to classify material specimens, the input images, into five discrete degrees of quality, from grade 5 (best to grade 1 (the worst. The puckering features presented in the learning and test images have been pre-classified using the seam puckering quality standard. The network training stage will consist in presenting five input vectors (derived from the down-sampled arrays, representing the puckering grades. The puckering classification consists in providing an input vector derived from the image supposed to be classified. A scalar product between the input values vectors and the weighted training images is computed. The result will be assigned to one of the five classes of which the input image belongs. Using the Kohonen network the puckering defects were correctly classified in proportion of 71.42%.

Welding method, and welding device for use therein, and method of analysis for evaluating welds

NARCIS (Netherlands)

Aendenroomer, A.J.; Den Ouden, G.; Xiao, Y.H.; Brabander, W.A.J.

1995-01-01

Described is a method of automatically welding pipes, comprising welding with a pulsation welding current and monitoring, by means of a sensor, the variations occurring in the arc voltage caused by weld pool oscillations. The occurrence of voltage variations with only frequency components below 100

Comparison of Welding Residual Stresses of Hybrid Laser-Arc Welding and Submerged Arc Welding in Offshore Steel Structures

DEFF Research Database (Denmark)

Andreassen, Michael Joachim; Yu, Zhenzhen; Liu, Stephen

2016-01-01

In the offshore industry, welding-induced distortion and tensile residual stresses have become a major concern in relation to the structural integrity of a welded structure. Particularly, the continuous increase in size of welded plates and joints needs special attention concerning welding induced...... residual stresses. These stresses have a negative impact on the integrity of the welded joint as they promote distortion, reduce fatigue life, and contribute to corrosion cracking and premature failure in the weld components. This paper deals with the influence and impact of welding method on the welding...... induced residual stresses. It is also investigated whether the assumption of residual stresses up to yield strength magnitude are present in welded structures as stated in the design guidelines. The fatigue strength for welded joints is based on this assumption. The two welding methods investigated...

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.

Determination of mineral matter distribution in a coal seam using O sub 2 chemisorption technique

Energy Technology Data Exchange (ETDEWEB)

Palmer, A.D.; Goulet, J.-C.; Grandsen, J.; Price, J.T.; Furimsky, E. (CANMET, Ottawa, ON (Canada). Energy Research Laboratories)

1990-08-01

A series of samples taken from different depths of the seam of a bituminous coal in Western Canada was used to determine the mineral matter distribution. The measurements were carried out using the O{sub 2} chemisorption based on a thermogravimetric technique. The O{sub 2} chemisorption increased with decreasing mineral matter content. The employed technique was found to be suitable for identifying the portion of coal seam least contaminated with mineral matter. 5 refs., 3 figs., 1 tab.

Numerical analysis of weld pool oscillation in laser welding

Energy Technology Data Exchange (ETDEWEB)

Cho, Jung Ho [Chungbuk National University, Cheongju (Korea, Republic of); Farson, Dave F [The Ohio State University, Columbus (United States); Hollis, Kendall; Milewski, John O. [Los Alamos National Laboratory, Los Alamos (United States)

2015-04-15

Volume of fluid (VOF) numerical simulation was used to investigate melt flow and volumetric oscillation of conduction-mode pulsed laser weld pools. The result is compared to high speed video stream of titanium laser spot welding experiment. The total simulation time is 10ms with the first 5 ms being heating and melting under constant laser irradiation and the remaining 5 ms corresponding to resolidification of the weld pool. During the melting process, the liquid pool did not exhibit periodic oscillation but was continually depressed by the evaporation recoil pressure. After the laser pulse, the weld pool was excited into volumetric oscillation by the release of pressure on its surface and oscillation of the weld pool surface was analyzed. The simulation model suggested adjusting thermal diffusivity to match cooling rate and puddle diameter during solidification which is distinguishable from previous weld pool simulation. The frequency continuously increased from several thousand cycles per second to tens of thousands of cycles per second as the weld pool solidified and its diameter decreased. The result is the first trial of investigation of small weld pool oscillation in laser welding although there have been several reports about arc welding.

Alternate Welding Processes for In-Service Welding

Science.gov (United States)

2009-04-24

Conducting weld repairs and attaching hot tap tees onto pressurized pipes has the advantage of avoiding loss of service and revenue. However, the risks involved with in-service welding need to be managed by ensuring that welding is performed in a rep...

Hybrid laser-TIG welding, laser beam welding and gas tungsten arc welding of AZ31B magnesium alloy

International Nuclear Information System (INIS)

Liu Liming; Wang Jifeng; Song Gang

2004-01-01

Welding of AZ31B magnesium alloy was carried out using hybrid laser-TIG (LATIG) welding, laser beam welding (LBW) and gas tungsten arc (TIG) welding. The weldability and microstructure of magnesium AZ31B alloy welded using LATIG, LBW and TIG were investigated by OM and EMPA. The experimental results showed that the welding speed of LATIG was higher than that of TIG, which was caught up with LBW. Besides, the penetration of LATIG doubles that of TIG, and was four times that of LBW. In addition, arc stability was improved in hybrid of laser-TIG welding compared with using the TIG welding alone, especially at high welding speed and under low TIG current. It was found that the heat affect zone of joint was only observed in TIG welding, and the size of grains in it was evidently coarse. In fusion zone, the equiaxed grains exist, whose size was the smallest welded by LBW, and was the largest by TIG welding. It was also found that Mg concentration of the fusion zone was lower than that of the base one by EPMA in three welding processes

Closing the weld gap with laser/mig hybrid welding process

DEFF Research Database (Denmark)

Bagger, Claus; Olsen, Flemming Ove; Wiwe, Bjarne David

2003-01-01

In this article, laboratory tests are demonstrated that systematically accesses the critical gap distance when welding CMn 2.13 mm steel with a 2.6 kW CO2 laser, combined with a MIG energy source. In the work, the welding speed is varied at gap distances from 0 to 0.8 mm such that the limits...... for obtaining sound welds are identified. The welds are quality assessed according to ISO 13.919-1 and EN25817, transversal hardness measurements are made and the heat input to the workpiece is calculated. The results show that the critical gap is 0.1 mm for a laser weld alone. With hybrid welding, this can...... be increased to 0.6 mm, even at a welding speed of 3.5 m/min. The maximum welding speed with the hybrid process is comparable to laser welding alone, 4.5 m/min. The measured hardness is comparable to MIG welding, and this corresponds to a 33 percent reduction compared to laser welding alone. The heat input...

LASER WELDING WITH MICRO-JET COOLING FOR TRUCK FRAME WELDING

Directory of Open Access Journals (Sweden)

Jan PIWNIK

2017-12-01

Full Text Available The aim of this paper is to analyse the mechanical properties of the weld steel structure of car body truck frames after laser welding. The best welding conditions involve the use of proper materials and alloy elements in steel and filer materials, in addition to welding technology, state of stress and temperature of exploitation. We present for the first time the properties of steel track structures after laser welding with micro-jet cooling. Therefore, good selection of both welding parameters and micro-jet cooling parameters is very important to achieve a proper steel structure. In this study, the metallographic structure, tensile results and impact toughness of welded joints have been analysed in terms of welding parameters.

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.

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...

Electrochemical corrosion behaviors of the X90 linepipe steel in NS4 solution

Directory of Open Access Journals (Sweden)

Jinheng Luo

2016-10-01

Full Text Available Oil and gas line pipes are laid underground and run through different areas in the laying process, so they will be subjected to different degrees of corrosion and even crack, leading to enormous casualties and economic losses. In order to guarantee the safe operation of line pipes, therefore, it is significant to investigate the electrochemical corrosion behaviors of pipe steel in a simulated soil environment. In this paper, the electrochemical corrosion behaviors of the base metals and welding materials of API 5L X90 steel longitudinally submerged arc welding pipes in near-neutral simulated soil solution (NS4 were studied by means of the electrochemical impedance spectroscopy (EIS and the potentiodynamic polarization testing technology. It is shown that the typical characteristic of anodic dissolution is presented but with no passivation phenomenon when X90 linepipe steel is put in NS4 solution. The base material is thermodynamically more stable than the seam weld material. The base material and seam weld samples were polarized under −850 mV polarization potential for different durations. It is demonstrated that with the proceeding of polarization, the polarization resistance and the corrosion resistance increase while the corrosion current density decreases. And the corrosion resistance of base material is better than that of seam weld material.

Cu-Fe welding techniques by electromagnetic and electron beam welding processes

International Nuclear Information System (INIS)

Kumar, Satendra; Saroj, P.C.; Kulkarni, M.R.; Sharma, A.; Rajawat, R.K.; Saha, T.K.

2015-01-01

Electromagnetic welding being a solid state welding process has been found suitable for welding Copper and Iron which are conventionally very tricky. Owing to good electrical conductivity of both copper and iron, they are best suited combination for EM welding. For the experimental conditions presented above, 1.0 mm wall thickness of Cu tube was lap welded to Fe disc. A heavy duty four disc stainless steel coil was used for electromagnetic welding of samples. MSLD of the welded samples indicated leak proof joints. Metallographic examination of the welds also revealed defect free interfaces. Electron beam welding is also a non-conventional welding process used for joining dissimilar materials. Autogenous welding of the above specimen was carried out by EBW method for the sake of comparison. A characterization analysis of the above mentioned joining processes will be discussed in the paper. (author)

Brittleness, microcracking and crack propagation in stress-relief annealing of welded low-alloyed NiMoCr steels

International Nuclear Information System (INIS)

Chen, H.Y.

1976-01-01

It in possible to produce the essentially corresponding microstructural states as well as micro or macro crack formation by simulation welding of the coarse grain zone of welded seams and to analyze the conditions for brittleness and crack formation. The metallurgical procedures in the heat affected zone of a welded joint are described. It could be seen from metallographic polished specimens that the crack formation can persue the triple point theory as well as the carity theory. The heating and relaxing process was analyzed on a model and the latter described by the pure relaxation test, relaxation test according to Murray and time-fracture test. The time-fracture test was mainly applied to investigate a possible decrease in toughness and crack formation because it normally does not work in relaxation tests - contrary to the component - to produce crack formation. In order to determine how long it takes for the first micro cracks to occur at a defined stress in short time-fracture testing, metallographic specimens were prepared as well as notched bar impact beneting tests performed. There is a distinct dependence between lasting expansion in the short time-fracture test, notched bar impact strength and the number of cracks; the notched bar impact strength decreases with increasing microcracking (increasing permanent expansion). One must note here that the microstructure can still carry full load although its toughness value has decreased. The maximum brittleness state of the materials depends on time and temperature. (orig.) [de

Deconvoluting the Friction Stir Weld Process for Optimizing Welds

Science.gov (United States)

Schneider, Judy; Nunes, Arthur C.

2008-01-01

In the friction stir welding process, the rotating surfaces of the pin and shoulder contact the weld metal and force a rotational flow within the weld metal. Heat, generated by the metal deformation as well as frictional slippage with the contact surface, softens the metal and makes it easier to deform. As in any thermo-mechanical processing of metal, the flow conditions are critical to the quality of the weld. For example, extrusion of metal from under the shoulder of an excessively hot weld may relax local pressure and result in wormhole defects. The trace of the weld joint in the wake of the weld may vary geometrically depending upon the flow streamlines around the tool with some geometry more vulnerable to loss of strength from joint contamination than others. The material flow path around the tool cannot be seen in real time during the weld. By using analytical "tools" based upon the principles of mathematics and physics, a weld model can be created to compute features that can be observed. By comparing the computed observations with actual data, the weld model can be validated or adjusted to get better agreement. Inputs to the model to predict weld structures and properties include: hot working properties ofthe metal, pin tool geometry, travel rate, rotation and plunge force. Since metals record their prior hot working history, the hot working conditions imparted during FSW can be quantified by interpreting the final microstructure. Variations in texture and grain size result from variations in the strain accommodated at a given strain rate and temperature. Microstructural data from a variety of FSWs has been correlated with prior marker studies to contribute to our understanding of the FSW process. Once this stage is reached, the weld modeling process can save significant development costs by reducing costly trial-and-error approaches to obtaining quality welds.

Residual stress reduction in the penetration nozzle weld joint by overlay welding

International Nuclear Information System (INIS)

Jiang, Wenchun; Luo, Yun; Wang, B.Y.; Tu, S.T.; Gong, J.M.

2014-01-01

Highlights: • Residual stress reduction in penetration weld nozzle by overlay welding was studied. • The overlay weld can decrease the residual stress in the weld root. • Long overlay welding is proposed in the actual welding. • Overlay weld to decrease residual stress is more suitable for thin nozzle. - Abstract: Stress corrosion cracking (SCC) in the penetration nozzle weld joint endangers the structural reliability of pressure vessels in nuclear and chemical industries. How to decrease the residual stress is very critical to ensure the structure integrity. In this paper, a new method, which uses overlay welding on the inner surface of nozzle, is proposed to decrease the residual stresses in the penetration joint. Finite element simulation is used to study the change of weld residual stresses before and after overlay welding. It reveals that this method can mainly decrease the residual stress in the weld root. Before overlay welding, large tensile residual stresses are generated in the weld root. After overlay weld, the tensile hoop stress in weld root has been decreased about 45%, and the radial stress has been decreased to compressive stress, which is helpful to decrease the susceptibility to SCC. With the increase of overlay welding length, the residual stress in weld root has been greatly decreased, and thus the long overlay welding is proposed in the actual welding. It also finds that this method is more suitable for thin nozzle rather than thick nozzle

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...

A comparison of geochemical features of extracts from coal-seams source rocks with different polarity solvents

Energy Technology Data Exchange (ETDEWEB)

Chen, Jianping; Deng, Chunping; Wang, Huitong

2009-02-15

There exists a great difference in group-type fractions and biomarker distributions of chloroform extracts from coals and coal-seams oils, which makes the source identification of coal-seams oils in sedimentary basins rather difficult. The experiment, in which four different polarity solvents, n-hexane, benzene, dichloromethane and chloroform, were used to extract 9 coal-seams source rocks and 3 typical lacustrine source rocks, showed that the yield of extracts increased gradually with increasing solvent polarity. The distribution features of their n-alkanes, isoprenoids and sterane and terpane biomarkers remained, in general, similar, showing no distinct enrichment or depletion for a certain fraction by any solvent. The compositional analysis on n-hexane and chloroform extracts showed that the absolute amount (concentration) of biomarkers was relatively low for the n-hexane extract but comparatively high for the chloroform extract, this difference became great among coal-seams source rocks but small among lacustrine mudstones. The statistical analysis on the relative amount of the 18 major biomarkers in n-hexane and chloroform extracts from 10 source rock samples showed that extracts with a proportional error for the same biomarker of less than 5% (including the analytical error) accounted for 84% while those with a proportional error over 10% amounted to below 5%. This suggested that the outcome of oil-source correlation made by these biomarkers will be independent of variations in amounts of saturates and biomarkers arising from solvent polarity. Therefore, biomarkers obtained from organic-rich source rocks including coals by the extraction with the commonly used chloroform solvent can be applied for the oilsource correlation of coal-seams petroliferous basins.

Adult Education and Radical Habitus in an Environmental Campaign: Learning in the Coal Seam Gas Protests in Australia

Science.gov (United States)

Ollis, Tracey; Hamel-Green, Michael

2015-01-01

This paper examines the adult learning dimensions of protestors as they participate in a campaign to stop coal seam gas exploration in Gippsland in Central Victoria, Australia. On a global level, the imposition of coal seam gas exploration by governments and mining companies has been the trigger for movements of resistance from environmental…

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.…

Analysis of support installation and strata control in ventilation tunnels and coal chutes in steep seams

Energy Technology Data Exchange (ETDEWEB)

Moroz, V D; Belyaev, A N; Kostyuk, I S

1984-01-01

The VNIMI and the Donugi branch in Gorlovka developed and tested a system for strata control in gate roads for ventilation and in coal chutes in inclined and steep medium and thick coal seams. The roof is supported by cribbings made of slabs of reinforced concrete with yielding elements. Timber is used as yielding material. Tests showed that thickness of yielding layers between concrete slabs should range from 15 to 20% of coal seam thickness. Yielding elements increase yield strength of the system to about 2 MN (load distribution is more regular). The tests show that the cribbings are an efficient system for strata control in workings driven in coal seams with dip angle from 35 to 60 degrees. Performance of concrete cribbings in ventilation gate roads and coal chutes in selected mines of the Ukrainian SSR is analyzed.

The migration law of overlay rock and coal in deeply inclined coal seam with fully mechanized top coal caving.

Science.gov (United States)

Liu, Jian; Chen, Shan-Le; Wang, Hua-Jun; Li, Yu-Cheng; Geng, Xiaowei

2015-07-01

In a mine area, some environment geotechnics problems always occure, induced by mined-out region such as the subsidence and cracks at ground level, deformation and destruction of buildings, landslides destruction of water resources and the ecological environment. In order to research the migration of surrounding rock and coal in steeply inclined super high seams which used fully mechanized top coal caving, a working face of a certain mine was made as an example, analyzed the migration law of the overlay rock and coal under different caving ratio of fully mechanized top coal caving with numerical simulation analysis. The results suggest that the laws of overlay rock deformation caused by deeply inclined coal seam were different from horizontal coal seam. On the inclined direction, with an increase of dip angle and caving ratio, the vertical displacement of overlay rock and coal became greater, the asymmetric phenomenon of vertical displacement became obvious. On the trend direction, active region and transition region in goaf became smaller along with the increase of mining and caving ratio. On the contrary, the stable region area became greater. Therefore, there was an essential difference between the mechanism of surface movement deformation with deeply inclined coal seam and that with horizontal coal seam.

In-pile inspections of the Calder and Chapelcross nuclear reactors

International Nuclear Information System (INIS)

Stewart, G.

1984-01-01

The subject is discussed under the headings: introduction (relevant data about the reactors); inspection policy; photographic inspection (equipment; inspection results (vessel seam welds and plates; top dome welds; top dome internals)); ultrasonic equipment; manipulator; television inspections; concluding remarks. (U.K.)

LASER WELDING WITH MICRO-JET COOLING FOR TRUCK FRAME WELDING

OpenAIRE

Jan PIWNIK; Bożena SZCZUCKA-LASOTA; Tomasz WĘGRZYN; Wojciech MAJEWSKI

2017-01-01

The aim of this paper is to analyse the mechanical properties of the weld steel structure of car body truck frames after laser welding. The best welding conditions involve the use of proper materials and alloy elements in steel and filer materials, in addition to welding technology, state of stress and temperature of exploitation. We present for the first time the properties of steel track structures after laser welding with micro-jet cooling. Therefore, good selection of both welding paramet...

Fabrication of fine-grain tantalum diffusion barrier tube for Nb3Sn conductors

International Nuclear Information System (INIS)

Hartwig, K. T.; Balachandran, S.; Mezyenski, R.; Seymour, N.; Robinson, J.; Barber, R. E.

2014-01-01

Diffusion barriers used in Nb 3 Sn wire are often fabricated by wrapping Ta sheet into a tube with an overlap seam. A common result of such practice is non-uniform deformation in the Ta sheet as it thins by wire drawing because of non-uniform grain size and texture in the original Ta sheet. Seamless Ta tube with a fine-grain and uniform microstructure would be much better for the diffusion barrier application, but such material is expensive and difficult to manufacture. This report presents results on a new fabrication strategy for Ta tube that shows promise for manufacture of less costly tube with an improved microstructure. The fabrication method begins with seam-welded tube but gives a fine-grain uniform microstructure with little difference between the longitudinal seam weld region and the parent metal after post-weld processing. Severe plastic deformation processing (SPD) applied by area reduction extrusion and tube equal channel angular extrusion (tECAE) are used to refine and homogenize the microstructure. Microstructure and mechanical property results are presented for Ta tubes fabricated by this new processing strategy

Fabrication of fine-grain tantalum diffusion barrier tube for Nb3Sn conductors

Science.gov (United States)

Hartwig, K. T.; Balachandran, S.; Mezyenski, R.; Seymour, N.; Robinson, J.; Barber, R. E.

2014-01-01

Diffusion barriers used in Nb3Sn wire are often fabricated by wrapping Ta sheet into a tube with an overlap seam. A common result of such practice is non-uniform deformation in the Ta sheet as it thins by wire drawing because of non-uniform grain size and texture in the original Ta sheet. Seamless Ta tube with a fine-grain and uniform microstructure would be much better for the diffusion barrier application, but such material is expensive and difficult to manufacture. This report presents results on a new fabrication strategy for Ta tube that shows promise for manufacture of less costly tube with an improved microstructure. The fabrication method begins with seam-welded tube but gives a fine-grain uniform microstructure with little difference between the longitudinal seam weld region and the parent metal after post-weld processing. Severe plastic deformation processing (SPD) applied by area reduction extrusion and tube equal channel angular extrusion (tECAE) are used to refine and homogenize the microstructure. Microstructure and mechanical property results are presented for Ta tubes fabricated by this new processing strategy.

Thermal Stir Welding: A New Solid State Welding Process

Science.gov (United States)

Ding, R. Jeffrey

2003-01-01

Thermal stir welding is a new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating, stirring and forging elements of the process are all independent of each other and are separately controlled. Furthermore, the heating element of the process can be either a solid-state process (such as a thermal blanket, induction type process, etc), or, a fusion process (YG laser, plasma torch, etc.) The separation of the heating, stirring, forging elements of the process allows more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

C. elegans GATA factors EGL-18 and ELT-6 function downstream of Wnt signaling to maintain the progenitor fate during larval asymmetric divisions of the seam cells.

Science.gov (United States)

Gorrepati, Lakshmi; Thompson, Kenneth W; Eisenmann, David M

2013-05-01

The C. elegans seam cells are lateral epithelial cells arrayed in a single line from anterior to posterior that divide in an asymmetric, stem cell-like manner during larval development. These asymmetric divisions are regulated by Wnt signaling; in most divisions, the posterior daughter in which the Wnt pathway is activated maintains the progenitor seam fate, while the anterior daughter in which the Wnt pathway is not activated adopts a differentiated hypodermal fate. Using mRNA tagging and microarray analysis, we identified the functionally redundant GATA factor genes egl-18 and elt-6 as Wnt pathway targets in the larval seam cells. EGL-18 and ELT-6 have previously been shown to be required for initial seam cell specification in the embryo. We show that in larval seam cell asymmetric divisions, EGL-18 is expressed strongly in the posterior seam-fated daughter. egl-18 and elt-6 are necessary for larval seam cell specification, and for hypodermal to seam cell fate transformations induced by ectopic Wnt pathway overactivation. The TCF homolog POP-1 binds a site in the egl-18 promoter in vitro, and this site is necessary for robust seam cell expression in vivo. Finally, larval overexpression of EGL-18 is sufficient to drive expression of a seam marker in other hypodermal cells in wild-type animals, and in anterior hypodermal-fated daughters in a Wnt pathway-sensitized background. These data suggest that two GATA factors that are required for seam cell specification in the embryo independently of Wnt signaling are reused downstream of Wnt signaling to maintain the progenitor fate during stem cell-like divisions in larval development.

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.

Enabling high speed friction stir welding of aluminum tailor welded blanks

Science.gov (United States)

Hovanski, Yuri

Current welding technologies for production of aluminum tailor-welded blanks (TWBs) are utilized in low-volume and niche applications, and have yet to be scaled for the high-volume vehicle market. This study targeted further weight reduction, part reduction, and cost savings by enabling tailor-welded blank technology for aluminum alloys at high-volumes. While friction stir welding (FSW) has traditionally been applied at linear velocities less than one meter per minute, high volume production applications demand the process be extended to higher velocities more amenable to cost sensitive production environments. Unfortunately, weld parameters and performance developed and characterized at low to moderate welding velocities do not directly translate to high speed linear friction stir welding. Therefore, in order to facilitate production of high volume aluminum FSW components, parameters were developed with a minimum welding velocity of three meters per minute. With an emphasis on weld quality, welded blanks were evaluated for post-weld formability using a combination of numerical and experimental methods. Evaluation across scales was ultimately validated by stamping full-size production door inner panels made from dissimilar thickness aluminum tailor-welded blanks, which provided validation of the numerical and experimental analysis of laboratory scale tests.

Contribution to a research on electron beam welding of metals

International Nuclear Information System (INIS)

Stohr, J.

1964-03-01

such conditions that the molten zone shows a small section, which is the main characteristic of this method. These tests have also established that the hollow cut by the electron beam, is free of molten metal, which allows a flow of electrons, whose penetration into the material is negligible. This way of looking has been confirmed by macro-graphies of mixtures, where very short welding points have been performed. These macro-graphies show the existence of a central hole. Tests made under dynamic operating confirm also the existence of a hole, when during the welding process, the electron beam pressure, the molten metal is pushed against the height, then existence of a hole, when during the welding process, the electron beam is suddenly cut off. Therefore, the welding process can be explained as follows: Through electron beam pressure, the molten metal is pushed against the height, then flows down, once the electron beam has moved away, and fills the previously made hole. The existence of a welding seam corroborates this point of view: autoradiographic of straight sections of parts containing radiotracers, show well the mixing due to metal flow. As a matter of fact, the filling of the hole is made by the molten metal coming as well from the higher part, as the lateral back part of the hole (on grounds of way of moving); The penetrating depth also depends on material's characteristics. Tests made with pieces of Cu, Fe, Al show that the penetrating depth is almost proportional to specific heat and in this particular case, one gets: h(Al) / C(Al) = h (Fe) / C (Fe) = h (Cu) / C (Cu) This proportionality comes to an end, welding alloys with one or several additional elements show a high vapour pressure at the melting pint. Tests made with Aluminium and an Al-Mg alloy show indeed a considerable increase of penetrating depth for the latter, in spite of the fact, that the specific heat is practically the same. This increase of penetrating depth can be explained by the pressure

Selection of an Appropriate Mechanized Mining Technical Process for Thin Coal Seam Mining

Directory of Open Access Journals (Sweden)

Chen Wang

2015-01-01

Full Text Available Mechanized mining technical process (MMTP related to the control method of the shearer is a vital process in thin coal seam mining operations. An appropriate MMTP is closely related to safety, productivity, labour intensity, and efficiency. Hence, the evaluation of alternative MMTP is an important part of the mining design. Several parameters should be considered in MMTP evaluation, so the evaluation is complex and must be compliant with a set of criteria. In this paper, two multiple criteria decision-making (MCDM methods, Analytic Hierarchy Process (AHP and Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE, were adopted for this evaluation. Then, the most appropriate MMTP for a thin coal seam working face was selected in China.

The Influence of Friction Stir Weld Tool Form and Welding Parameters on Weld Structure and Properties: Nugget Bulge in Self-Reacting Friction Stir Welds

Science.gov (United States)

Schneider, Judy; Nunes, Arthur C., Jr.; Brendel, Michael S.

2010-01-01

Although friction stir welding (FSW) was patented in 1991, process development has been based upon trial and error and the literature still exhibits little understanding of the mechanisms determining weld structure and properties. New concepts emerging from a better understanding of these mechanisms enhance the ability of FSW engineers to think about the FSW process in new ways, inevitably leading to advances in the technology. A kinematic approach in which the FSW flow process is decomposed into several simple flow components has been found to explain the basic structural features of FSW welds and to relate them to tool geometry and process parameters. Using this modelling approach, this study reports on a correlation between the features of the weld nugget, process parameters, weld tool geometry, and weld strength. This correlation presents a way to select process parameters for a given tool geometry so as to optimize weld strength. It also provides clues that may ultimately explain why the weld strength varies within the sample population.

Automatic orbital GTAW welding: Highest quality welds for tomorrow's high-performance systems

Science.gov (United States)

Henon, B. K.

1985-01-01

Automatic orbital gas tungsten arc welding (GTAW) or TIG welding is certain to play an increasingly prominent role in tomorrow's technology. The welds are of the highest quality and the repeatability of automatic weldings is vastly superior to that of manual welding. Since less heat is applied to the weld during automatic welding than manual welding, there is less change in the metallurgical properties of the parent material. The possibility of accurate control and the cleanliness of the automatic GTAW welding process make it highly suitable to the welding of the more exotic and expensive materials which are now widely used in the aerospace and hydrospace industries. Titanium, stainless steel, Inconel, and Incoloy, as well as, aluminum can all be welded to the highest quality specifications automatically. Automatic orbital GTAW equipment is available for the fusion butt welding of tube-to-tube, as well as, tube to autobuttweld fittings. The same equipment can also be used for the fusion butt welding of up to 6 inch pipe with a wall thickness of up to 0.154 inches.

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.

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

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.

Advantages of new micro-jet welding technology on weld microstructure control

Directory of Open Access Journals (Sweden)

Jan PIWNIK

2013-01-01

Full Text Available An innovative apparatus to welding process with micro-jet cooling of the weld made it possible to carry out technological tests, which have proved theoretical considerations about this problem. This project gives real opportunities for professional development in the field of welding with controlling the parameters of weld structure. These tests have proved that the new micro-jet technology has the potential for growth. It may be great achievement of welding technology in order to increase weld metal strength. The new technology with micro-jet cooling may have many practical applications in many fields, for example such as in the transport industry or to repair damaged metal elements. The advantages of the new device over the traditional system are the ability to control the structure of the weld, the weld mechanical performance increases and improve the quality of welded joints.

TECHNOLOGICAL ISSUES IN MECHANISED FEED WIG/TIG WELDING SURFACING OF WELDING

Directory of Open Access Journals (Sweden)

BURCA Mircea

2016-09-01

manual welding tests in the light of using the process for welding surfacing being known that in such applications mechanised operations are recommended whenever possible given the latter strengths i.e. increased productivity and quality deposits. The research also aims at achieving a comparative a study between wire mechanised feed based WIG manual welding and the manual rod entry based manual welding in terms of geometry deposits, deposits aesthetics, operating technique, productivity, etc . In this regard deposits were made by means of two welding procedures, and subsequently welding surfacing was made with the optimum values of the welding parameters in this case.

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.

Versatile Friction Stir Welding/Friction Plug Welding System

Science.gov (United States)

Carter, Robert

2006-01-01

A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

Effect of Welding Parameters on Dilution and Weld Bead Geometry in Cladding

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The effect of pulsed gas metal arc welding (GMAW) variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a full factorial method, a series of experiments were carried out to know the effect of wire feed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of welding on dilution and weld bead geometry. The findings indicate that the dilution of weld metal and its dimension i.e. width, height and depth increase with the feed rate, but the contact angle of the bead decreases first and then increases. Meantime, welding speed has an opposite effect except for dilution. There is an interaction effect between welding parameters at the contact angle. The results also show forehand welding or decreasing electrode extension decrease the angle of contact. Finally,a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

Permeability Prediction in Deep Coal Seam: A Case Study on the No. 3 Coal Seam of the Southern Qinshui Basin in China

Science.gov (United States)

2013-01-01

The coal permeability is an important parameter in mine methane control and coal bed methane (CBM) exploitation, which determines the practicability of methane extraction. Permeability prediction in deep coal seam plays a significant role in evaluating the practicability of CBM exploitation. The coal permeability depends on the coal fractures controlled by strata stress, gas pressure, and strata temperature which change with depth. The effect of the strata stress, gas pressure, and strata temperature on the coal (the coal matrix and fracture) under triaxial stress and strain conditions was studied. Then we got the change of coal porosity with strata stress, gas pressure, and strata temperature and established a coal permeability model under tri-axial stress and strain conditions. The permeability of the No. 3 coal seam of the Southern Qinshui Basin in China was predicted, which is consistent with that tested in the field. The effect of the sorption swelling on porosity (permeability) firstly increases rapidly and then slowly with the increase of depth. However, the effect of thermal expansion and effective stress compression on porosity (permeability) increases linearly with the increase of depth. The most effective way to improve the permeability in exploiting CBM or extracting methane is to reduce the effective stress. PMID:24396293

Modeling of welded bead profile for rapid prototyping by robotic MAG welding

Institute of Scientific and Technical Information of China (English)

CAO Yong; ZHU Sheng; WANG Tao; WANG Wanglong

2009-01-01

As a deposition technology, robotic metal active gas(MAG) welding has shown new promise for rapid prototyping (RP) of metallic parts. During the process of metal forming using robotic MAG welding, sectional profile of single-pass welded bead is critical to formed accuracy and quality of metal pans. In this paper, the experiments of single-pass welded bead for rapid prototyping using robotic MAG welding were carried out. The effect of some edge detectors on the cross-sectional edge of welded bead was discussed and curve fitting was applied using leat square fitting. Consequently, the mathematical model of welded bead profile was developed. The experimental results show that good shape could be obtained under suitable welding parameters. Canny operawr is suitable to edge detection of welded bead profile, and the mathematical model of welded bead profile developed is approximately parabola.

An influence function method based subsidence prediction program for longwall mining operations in inclined coal seams

Energy Technology Data Exchange (ETDEWEB)

Yi Luo; Jian-wei Cheng [West Virginia University, Morgantown, WV (United States). Department of Mining Engineering

2009-09-15

The distribution of the final surface subsidence basin induced by longwall operations in inclined coal seam could be significantly different from that in flat coal seam and demands special prediction methods. Though many empirical prediction methods have been developed, these methods are inflexible for varying geological and mining conditions. An influence function method has been developed to take the advantage of its fundamentally sound nature and flexibility. In developing this method, significant modifications have been made to the original Knothe function to produce an asymmetrical influence function. The empirical equations for final subsidence parameters derived from US subsidence data and Chinese empirical values have been incorporated into the mathematical models to improve the prediction accuracy. A corresponding computer program is developed. A number of subsidence cases for longwall mining operations in coal seams with varying inclination angles have been used to demonstrate the applicability of the developed subsidence prediction model. 9 refs., 8 figs.

Fusion welding process

Science.gov (United States)

Thomas, Kenneth C.; Jones, Eric D.; McBride, Marvin A.

1983-01-01

A process for the fusion welding of nickel alloy steel members wherein a ferrite containing pellet is inserted into a cavity in one member and melted by a welding torch. The resulting weld nugget, a fusion of the nickel containing alloy from the members to be welded and the pellet, has a composition which is sufficiently low in nickel content such that ferrite phases occur within the weld nugget, resulting in improved weld properties. The steel alloys encompassed also include alloys containing carbon and manganese, considered nickel equivalents.

Improved coal winning in Zollverein 7/8 seam by toe-in plough 9. 30 v supplied by GEW Luenen

Energy Technology Data Exchange (ETDEWEB)

Schwolow, G; Dornack, M; Plich, H

1982-04-01

The project aimed at mining Zollverein 7/8 seam more efficiently than with drag-hook ploughs. Zollverein 7/8 seam is characterized by mechanically tough coal changing, seam thickness, a somewhat 'corrugated' shape, and a soft floor. Comparative investigations on one toe-in plough face and one drag-hook plough face in two neighbouring panels of said seam were made for individual plough travels as well as over several months of operation. These investigations were backed up by measuring. The measuring conditions were identical in both panels. The face equipments were identical except for the plough systems. The energy pick-up relative to the web is by 43% lower with the toe-in plough compared to the drag-hook plough. As to wear, for the toe-in plough in comparison to the drag-hook plough twice the longevity of the latter was recorded. For the noise level on the plough guides only marginal difference in favor to the toe-in plough could be recorded. Analyses of dust and particle-size distribution showed no obvious advantages for either of both plough systems.

Imaging techniques for ultrasonic testing

International Nuclear Information System (INIS)

2013-01-01

These seminar proceedings contain 16 lectures on the following topics: 1. From imaging to quantification - ultrasound methods in medical diagnostics; 2. SAFT, TOFD, Phased Array - classical applications and recent developments in ultrasonic imaging; 3. Innovative ultrasonic imaging methods in research and application; 4. Industrial ultrasonic testing of fibre-reinforced structures of complex geometry; 5. Visualisation of crack tips in the inspection of wheel set shafts with longitudinal boreholes as a means of avoiding unnecessary wheel set changes; 6. Areal analysis of the propagation of Lamb waves on curved, anisotropic structures; 7. High-resolution representation in immersion technique testing; 8. Variants in generating images from phased array measurement data - practical examples involving copper, carbon-fibre reinforced plastic and other materials; 9. GIUM - an unconventional method of microstructure imaging using ultrasonic stimulation and laser vibrometry scanning; 10. Innovative air-ultrasonic testing concepts for improved imaging; 11. Use of imaging methods for improving the quality of test results from nondestructive testing; 12. Modelling and visualisation of EMUS stimulation for transducer optimisation; 13. Use of SAFT in the manufacture of energy conversion machines; 14. Ultrasonic imaging tests for improved defect characterisation during weld seam inspection on longitudinally welded large-diameter pipes; 15. SAFT reconstruction for testing austenitic weld seams and dissimilar metal weld seams for transverse cracks; 16. Imaging-based optimisation method for quantitative ultrasonic testing of anisotropic inhomogeneous austenitic welded joints with determination and utilisation of their elastic properties. One contribution has been abstracted separately. [de

MAG narrow gap welding - an economic way to minimize welding expenses

International Nuclear Information System (INIS)

Kast, W.; Scholz, E.; Weyland, F.

1982-01-01

The thicker structural components are, the more important it is to take measures to reduce the volume of the weld. The welding process requiring the smallest possible weld section is the so-called narrow gap process. In submerged arc narrow gap welding as well as in MAG narrow gap welding different variants are imaginable, some of them already in practical use. With regard to efficiency and weld quality an optimum variant of the MAG narrow gap welding process is described. It constitutes a two wire system in which two wire electrodes of 1.2 mm diameter are arranged one behind the other. In order to avoid lack of fusion, the wire guides are slightly pointed towards each groove face. Thus, by inclining the two arcs burning one behind the other in the direction of weld progress, it is achieved that two separately solidifying weld pools and two beads per layer are simultaneously formed. Welding parameters are selected in such a way that a heat input of 16-20 kJ/cm and a deposition rate of 11-16 kgs/h are obtained. In spite of this comparatively high deposition rate, good impact values are found both in the weld and HAZ (largely reduced coarse-grain zone) which is due to an optimum weld build-up. With the available welding equipment the process can be applied to structural members having a thickness of 40-400 mm. The width of gap is 13 mm (root section) with a bevel angle of 1 0 . As filler metal, basic flux-cored wires are used which, depending on the base metal to be welded and the required tensile properties, can be of the Mn-, MnMo-, MnCrMo-, MnNi-, or MnNiMo-alloyed types. (orig.)

Advanced Welding Applications

Science.gov (United States)

Ding, Robert J.

2010-01-01

Some of the applications of advanced welding techniques are shown in this poster presentation. Included are brief explanations of the use on the Ares I and Ares V launch vehicle and on the Space Shuttle Launch vehicle. Also included are microstructural views from four advanced welding techniques: Variable Polarity Plasma Arc (VPPA) weld (fusion), self-reacting friction stir welding (SR-FSW), conventional FSW, and Tube Socket Weld (TSW) on aluminum.

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.

Friction stir welding tool and process for welding dissimilar materials

Science.gov (United States)

Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

2013-05-07

A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

Dynamic mapping of conical intersection seams: A general method for incorporating the geometric phase in adiabatic dynamics in polyatomic systems.

Science.gov (United States)

Xie, Changjian; Malbon, Christopher L; Yarkony, David R; Guo, Hua

2017-07-28

The incorporation of the geometric phase in single-state adiabatic dynamics near a conical intersection (CI) seam has so far been restricted to molecular systems with high symmetry or simple model Hamiltonians. This is due to the fact that the ab initio determined derivative coupling (DC) in a multi-dimensional space is not curl-free, thus making its line integral path dependent. In a recent work [C. L. Malbon et al., J. Chem. Phys. 145, 234111 (2016)], we proposed a new and general approach based on an ab initio determined diabatic representation consisting of only two electronic states, in which the DC is completely removable, so that its line integral is path independent in the simply connected domains that exclude the CI seam. Then with the CIs included, the line integral of the single-valued DC can be used to construct the complex geometry-dependent phase needed to exactly eliminate the double-valued character of the real-valued adiabatic electronic wavefunction. This geometry-dependent phase gives rise to a vector potential which, when included in the adiabatic representation, rigorously accounts for the geometric phase in a system with an arbitrary locus of the CI seam and an arbitrary number of internal coordinates. In this work, we demonstrate this approach in a three-dimensional treatment of the tunneling facilitated dissociation of the S 1 state of phenol, which is affected by a C s symmetry allowed but otherwise accidental seam of CI. Here, since the space is three-dimensional rather than two-dimensional, the seam is a curve rather than a point. The nodal structure of the ground state vibronic wavefunction is shown to map out the seam of CI.

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…

Latest MIG, TIG arc-YAG laser hybrid welding systems for various welding products

Science.gov (United States)

Ishide, Takashi; Tsubota, Shuho; Watanabe, Masao

2003-03-01

Laser welding is capable of high-efficiency low-strain welding, and so its applications are started to various products. We have also put the high-power YAG laser of up to 10 kW to practical welding use for various products. On the other hand the weakest point of this laser welding is considered to be strict in the welding gap aiming allowance. In order to solve this problem, we have developed hybrid welding of TIG, MIG arc and YAG laser, taking the most advantages of both the laser and arc welding. Since the electrode is coaxial to the optical axis of the YAG laser in this process, it can be applied to welding of various objects. In the coaxial MIG, TIG-YAG welding, in order to make irradiation positions of the YAG laser beams having been guided in a wire or an electrode focused to the same position, the beam transmitted in fibers is separated to form a space between the separated beams, in which the laser is guided. With this method the beam-irradiating area can be brought near or to the arc-generating point. This enables welding of all directions even for the member of a three-dimensional shape. This time we carried out welding for various materials and have made their welding of up to 1 mm or more in welding groove gap possible. We have realized high-speed 1-pass butt welding of 4m/min in welding speed with the laser power of 3 kW for an aluminum alloy plate of approximately 4 mm thick. For a mild steel plate also we have realized butt welding of 1m/min with 5 kW for 6 mm thick. Further, in welding of stainless steel we have shown its welding possibility, by stabilizing the arc with the YAG laser in the welding atmosphere of pure argon, and shown that this welding is effective in high-efficiency welding of various materials. Here we will report the fundamental welding performances and applications to various objects for the coaxial MIG, TIG-YAG welding we have developed.

"Knitting Nannas" and "Frackman": A Gender Analysis of Australian Anti-Coal Seam Gas Documentaries (CSG) and Implications for Environmental Adult Education

Science.gov (United States)

Larri, Larraine J.; Newlands, Maxine

2017-01-01

"Frackman" ("FM") and "Knitting Nannas" ("KN") are two documentaries about the anti-coal seam gas movement in Australia. "Frackman" features a former construction worker turned eco-activist, Dayne Pratzky (DP), fighting coal seam gas extraction. "Knitting Nannas" follows a group of women…

Ultrasonic testing of austenitic welds and its dependency on the welding process

International Nuclear Information System (INIS)

Tabatabaeipour, S.M.; Honarvar, F.

2009-01-01

This paper describes the ultrasonic testing of austenitic welds prepared by two different welding processes. The tests were carried out by the ultrasonic Time-of-Flight Diffraction (ToFD) technique. Shielded Metal Arc Welding (SMAW) and Gas Tungsten Arc Welding (GTAW) are the welding processes used for preparing the specimens. Identical artificial defects were implanted in both welds during the welding process. Both specimens were examined by the ToFD technique under similar conditions. Metallographic images were also obtained from the cross sectional plane of both the SMA and GTA welds. These images show that the grain orientation in the two welded specimens are different. D-scan images obtained by the ToFD technique from these welds indicates that inspecting the specimens prepared by the SMAW process is easier than the one made by the GTAW process. The results also show that the D-scan images cannot reveal the small vertical drilled holes implanted in the specimens. (author)

Friction Stir Welding of Tapered Thickness Welds Using an Adjustable Pin Tool

Science.gov (United States)

Adams, Glynn; Venable, Richard; Lawless, Kirby

2003-01-01

Friction stir welding (FSW) can be used for joining weld lands that vary in thickness along the length of the weld. An adjustable pin tool mechanism can be used to accomplish this in a single-pass, full-penetration weld by providing for precise changes in the pin length relative to the shoulder face during the weld process. The difficulty with this approach is in accurately adjusting the pin length to provide a consistent penetration ligament throughout the weld. The weld technique, control system, and instrumentation must account for mechanical and thermal compliances of the tooling system to conduct tapered welds successfully. In this study, a combination of static and in-situ measurements, as well as active control, is used to locate the pin accurately and maintain the desired penetration ligament. Frictional forces at the pin/shoulder interface were a source of error that affected accurate pin position. A traditional FSW pin tool design that requires a lead angle was used to join butt weld configurations that included both constant thickness and tapered sections. The pitch axis of the tooling was fixed throughout the weld; therefore, the effective lead angle in the tapered sections was restricted to within the tolerances allowed by the pin tool design. The sensitivity of the FSW process to factors such as thickness offset, joint gap, centerline offset, and taper transition offset were also studied. The joint gap and the thickness offset demonstrated the most adverse affects on the weld quality. Two separate tooling configurations were used to conduct tapered thickness welds successfully. The weld configurations included sections in which the thickness decreased along the weld, as well as sections in which the thickness increased along the weld. The data presented here include weld metallography, strength data, and process load data.

The technology and welding joint properties of hybrid laser-tig welding on thick plate

Science.gov (United States)

Shenghai, Zhang; Yifu, Shen; Huijuan, Qiu

2013-06-01

The technologies of autogenous laser welding and hybrid laser-TIG welding are used on thick plate of high strength lower alloy structural steel 10CrNiMnMoV in this article. The unique advantages of hybrid laser-TIG welding is summarized by comparing and analyzing the process parameters and welding joints of autogenous laser welding laser welding and hybrid laser-TIG welding. With the optimal process parameters of hybrid welding, the good welding joint without visible flaws can be obtained and its mechanical properties are tested according to industry standards. The results show that the hybrid welding technology has certain advantages and possibility in welding thick plates. It can reduce the demands of laser power, and it is significant for lowering the aspect ratio of weld during hybrid welding, so the gas in the molten pool can rise and escape easily while welding thick plates. Therefore, the pores forming tendency decreases. At the same time, hybrid welding enhances welding speed, and optimizes the energy input. The transition and grain size of the microstructure of hybrid welding joint is better and its hardness is higher than base material. Furthermore, its tensile strength and impact toughness is as good as base material. Consequently, the hybrid welding joint can meet the industry needs completely.

Effects of post weld heat treatment and weld overlay on the residual stress and mechanical properties in dissimilar metal weld

International Nuclear Information System (INIS)

Campos, Wagner R.C.; Ribeiro, Vladimir S.; Vilela, Alisson H.F.; Almeida, Camila R.O.; Rabello, Emerson G.

2017-01-01

The object of this work is a dissimilar metal weld (DMW) pipe joint between carbon steel (A-106 Gr B) and stainless steel (A-312 TP316L) pipes and filler metals of Nickel alloy (82/182), which find wide application in the field of chemical, oil, petroleum industries, fossil fuel and nuclear power plant. A lot of the failures that have occurred in dissimilar metal welded are affected greatly by residual stresses. Residual stress is often a cause of premature failure of critical components under normal operation of welded components. Several methods have been tested and developed for removing the tensile residual stresses. The aim of the methods is to reduce the tensile stress state or to create compressive stresses at a predefined area, such as the inner surface of a welded pipe joint. Post weld heat treatment (PWHT) and weld overlay (WOL) are two of the residual stress mitigation methods which reduce the tensile residual stress, create compressive stresses and arrest crack initiation and crack growth. The technique used to substantially minimized or eliminated this failure development in the root weld is the post weld heat treatments (stress relief heat treatment) or the weld overlay. In this work was studied the effectiveness in reducing internal residual stress in dissimilar metal welded pipe joints subjected to post weld heat treatment and weld overlay, measurement by hole-drilling strain-gage method of stress relaxation. Also held was mechanical characterization of the welded pipe joint itself. (author)

Effects of post weld heat treatment and weld overlay on the residual stress and mechanical properties in dissimilar metal weld

Energy Technology Data Exchange (ETDEWEB)

Campos, Wagner R.C.; Ribeiro, Vladimir S.; Vilela, Alisson H.F.; Almeida, Camila R.O.; Rabello, Emerson G., E-mail: wrcc@cdtn.br, E-mail: camilarezende.cr@gmail.com, E-mail: egr@cdtn.br, E-mail: vladimirsoler@hotmail.com, E-mail: ahfv02@outlook.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

The object of this work is a dissimilar metal weld (DMW) pipe joint between carbon steel (A-106 Gr B) and stainless steel (A-312 TP316L) pipes and filler metals of Nickel alloy (82/182), which find wide application in the field of chemical, oil, petroleum industries, fossil fuel and nuclear power plant. A lot of the failures that have occurred in dissimilar metal welded are affected greatly by residual stresses. Residual stress is often a cause of premature failure of critical components under normal operation of welded components. Several methods have been tested and developed for removing the tensile residual stresses. The aim of the methods is to reduce the tensile stress state or to create compressive stresses at a predefined area, such as the inner surface of a welded pipe joint. Post weld heat treatment (PWHT) and weld overlay (WOL) are two of the residual stress mitigation methods which reduce the tensile residual stress, create compressive stresses and arrest crack initiation and crack growth. The technique used to substantially minimized or eliminated this failure development in the root weld is the post weld heat treatments (stress relief heat treatment) or the weld overlay. In this work was studied the effectiveness in reducing internal residual stress in dissimilar metal welded pipe joints subjected to post weld heat treatment and weld overlay, measurement by hole-drilling strain-gage method of stress relaxation. Also held was mechanical characterization of the welded pipe joint itself. (author)

On use of weld zone temperatures for online monitoring of weld quality in friction stir welding of naturally aged aluminium alloys

International Nuclear Information System (INIS)

Imam, Murshid; Biswas, Kajal; Racherla, Vikranth

2013-01-01

Highlights: • FSWs for 6063-T4 AA are done at different process parameters and sheet thicknesses. • Weld nugget zone and heat affected zone temperatures are monitored for each case. • Microstructural and mechanical characterisation of welds is done in all cases. • Weld ductility is found to be particularly sensitive to weld zone temperatures. • Strong correlation is found between WNZ and HAZ temperatures and weld properties. - Abstract: 6063-T4 aluminium alloy sheets of 3 and 6 mm thicknesses were friction stir butt welded using a square tool pin at a wide range of tool rotational speeds. Properties of obtained welds were characterised using tensile tests, optical micrographs, X-ray diffraction, and transmission electron microscopy. Shape, size, and distribution of precipitates in weld zones, and strength and ductility of welds were seen to directly correlate with peak temperatures in weld nugget and heat affected zones, independent of sheet thickness. In addition, fluctuations in measured temperature profiles, for 3 mm sheets, were seen to correlate with an increase in scatter of weld nugget zone properties for 3 mm sheets. Optimal weld strength and ductility were obtained for peak weld nugget zone temperatures of around 450 °C and corresponding peak heat affected zone temperatures of around 360–380 °C. Results obtained suggest that, at least for naturally aged aluminium alloys, nature of temperature evolution and magnitudes of peak temperatures in weld nugget and heat affected zones provide information on uniformity of properties in weld zones, overaging of heat affected zones, and formation of tunnel defects from improper material mixing at low weld zone temperatures

The effect of post-welding conditions in friction stir welds: From weld simulation to Ductile Failure

DEFF Research Database (Denmark)

Hattel, Jesper Henri; Nielsen, Kim Lau; Tutum, Cem Celal

2012-01-01

software ANSYS, a thermo-mechanical model is employed to predict the thermally induced stresses and strains during welding, while an in-house finite element code is used to study the plastic flow localization and failure in a subsequent structural analysis. The coupling between the two models is made......The post-welding stress state, strain history and material conditions of friction stir welded joints are often strongly idealized when used in subsequent modeling analyses, typically by neglecting one or more of the features above. But, it is obvious that the conditions after welding do influence......, showed the largest influence of the post-welding conditions, even though significant relaxation of the residual stress state was predicted....

Nitrogen And Oxygen Amount In Weld After Welding With Micro-Jet Cooling

Directory of Open Access Journals (Sweden)

Węgrzyn T.

2015-06-01

Full Text Available Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was presented in terms of nitrogen and oxygen amount in WMD (weld metal deposit.

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.

Welding and cutting

International Nuclear Information System (INIS)

Drews, P.; Schulze Frielinghaus, W.

1978-01-01

This is a survey, with 198 literature references, of the papers published in the fields of welding and cutting within the last three years. The subjects dealt with are: weldability of the materials - Welding methods - Thermal cutting - Shaping and calculation of welded joints - Environmental protection in welding and cutting. (orig.) [de

Automated concept and relationship extraction for the semi-automated ontology management (SEAM) system.

Science.gov (United States)

Doing-Harris, Kristina; Livnat, Yarden; Meystre, Stephane

2015-01-01

We develop medical-specialty specific ontologies that contain the settled science and common term usage. We leverage current practices in information and relationship extraction to streamline the ontology development process. Our system combines different text types with information and relationship extraction techniques in a low overhead modifiable system. Our SEmi-Automated ontology Maintenance (SEAM) system features a natural language processing pipeline for information extraction. Synonym and hierarchical groups are identified using corpus-based semantics and lexico-syntactic patterns. The semantic vectors we use are term frequency by inverse document frequency and context vectors. Clinical documents contain the terms we want in an ontology. They also contain idiosyncratic usage and are unlikely to contain the linguistic constructs associated with synonym and hierarchy identification. By including both clinical and biomedical texts, SEAM can recommend terms from those appearing in both document types. The set of recommended terms is then used to filter the synonyms and hierarchical relationships extracted from the biomedical corpus. We demonstrate the generality of the system across three use cases: ontologies for acute changes in mental status, Medically Unexplained Syndromes, and echocardiogram summary statements. Across the three uses cases, we held the number of recommended terms relatively constant by changing SEAM's parameters. Experts seem to find more than 300 recommended terms to be overwhelming. The approval rate of recommended terms increased as the number and specificity of clinical documents in the corpus increased. It was 60% when there were 199 clinical documents that were not specific to the ontology domain and 90% when there were 2879 documents very specific to the target domain. We found that fewer than 100 recommended synonym groups were also preferred. Approval rates for synonym recommendations remained low varying from 43% to 25% as the

Simplified welding distortion analysis for fillet welding using composite shell elements

Directory of Open Access Journals (Sweden)

Mingyu Kim

2015-05-01

Full Text Available This paper presents the simplified welding distortion analysis method to predict the welding deformation of both plate and stiffener in fillet welds. Currently, the methods based on equivalent thermal strain like Strain as Direct Boundary (SDB has been widely used due to effective prediction of welding deformation. Regarding the fillet welding, however, those methods cannot represent deformation of both members at once since the temperature degree of freedom is shared at the intersection nodes in both members. In this paper, we propose new approach to simulate deformation of both members. The method can simulate fillet weld deformations by employing composite shell element and using different thermal expansion coefficients according to thickness direction with fixed temperature at intersection nodes. For verification purpose, we compare of result from experiments, 3D thermo elastic plastic analysis, SDB method and proposed method. Compared of experiments results, the proposed method can effectively predict welding deformation for fillet welds.

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…

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.…

Orbital welding technique

International Nuclear Information System (INIS)

Hoeschen, W.

2003-01-01

The TIG (Tungsten-inert gas) orbital welding technique is applied in all areas of pipe welding. The process is mainly used for austenitic and ferritic materials but also for materials like aluminium, nickel, and titanium alloys are commonly welded according to this technique. Thin-walled as well as thick-walled pipes are welded economically. The application of orbital welding is of particular interest in the area of maintenance of thick-walled pipes that is described in this article. (orig.) [de

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

Reduction of Biomechanical and Welding Fume Exposures in Stud Welding.

Science.gov (United States)

Fethke, Nathan B; Peters, Thomas M; Leonard, Stephanie; Metwali, Mahmoud; Mudunkotuwa, Imali A

2016-04-01

The welding of shear stud connectors to structural steel in construction requires a prolonged stooped posture that exposes ironworkers to biomechanical and welding fume hazards. In this study, biomechanical and welding fume exposures during stud welding using conventional methods were compared to exposures associated with use of a prototype system that allowed participants to weld from an upright position. The effect of base material (i.e. bare structural beam versus galvanized decking) on welding fume concentration (particle number and mass), particle size distribution, and particle composition was also explored. Thirty participants completed a series of stud welding simulations in a local apprenticeship training facility. Use of the upright system was associated with substantial reductions in trunk inclination and the activity levels of several muscle groups. Inhalable mass concentrations of welding fume (averaged over ~18 min) when using conventional methods were high (18.2 mg m(-3) for bare beam; 65.7 mg m(-3) for through deck), with estimated mass concentrations of iron (7.8 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), zinc (0.2 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), and manganese (0.9 mg m(-3) for bare beam; 1.5 mg m(-3) for through deck) often exceeding the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs). Number and mass concentrations were substantially reduced when using the upright system, although the total inhalable mass concentration remained above the TLV when welding through decking. The average diameters of the welding fume particles for both bare beam (31±17 nm) through deck conditions (34±34 nm) and the chemical composition of the particles indicated the presence of metallic nanoparticles. Stud welding exposes ironworkers to potentially high levels of biomechanical loading (primarily to the low back) and welding fume. The upright system used in this study improved exposure

High-Speed Friction-Stir Welding to Enable Aluminum Tailor-Welded Blanks

Science.gov (United States)

Hovanski, Yuri; Upadhyay, Piyush; Carsley, John; Luzanski, Tom; Carlson, Blair; Eisenmenger, Mark; Soulami, Ayoub; Marshall, Dustin; Landino, Brandon; Hartfield-Wunsch, Susan

2015-05-01

Current welding technologies for production of aluminum tailor-welded blanks (TWBs) are utilized in low-volume and niche applications, and they have yet to be scaled for the high-volume vehicle market. This study targeted further weight reduction, part reduction, and cost savings by enabling tailor-welded blank technology for aluminum alloys at high volumes. While friction-stir welding (FSW) has been traditionally applied at linear velocities less than 1 m/min, high-volume production applications demand the process be extended to higher velocities more amenable to cost-sensitive production environments. Unfortunately, weld parameters and performance developed and characterized at low-to-moderate welding velocities do not directly translate to high-speed linear FSW. Therefore, to facilitate production of high-volume aluminum FSW components, parameters were developed with a minimum welding velocity of 3 m/min. With an emphasis on weld quality, welded blanks were evaluated for postweld formability using a combination of numerical and experimental methods. An evaluation across scales was ultimately validated by stamping full-size production door inner panels made from dissimilar thickness aluminum TWBs, which provided validation of the numerical and experimental analysis of laboratory-scale tests.

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

Nitrogen And Oxygen Amount In Weld After Welding With Micro-Jet Cooling

OpenAIRE

Węgrzyn T.; Piwnik J.

2015-01-01

Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was pr...

Element geochemistry and cleaning potential of the No. 11 coal seam from Antaibao mining district

Energy Technology Data Exchange (ETDEWEB)

Wang, W.F.; Qin, Y.; Song, D.Y.; Sang, S.X.; Jiang, B.; Zhu, Y.M.; Fu, X.H. [China University of Mining & Technology, Xuzhou (China). College for Resources & Geoscience

2005-12-15

Based on the analyses of sulfur and 41 other elements in 8 channel samples of the No. 11 coal seam from Antaibao surface mine, Shanxi, China and 4 samples from the coal preparation plant of this mine, the distribution of the elements in the seam profile, their geochemical partitioning behavior during the coal cleaning and the genetic relationships between the both are studied. The coal-forming environment was probably invaded by sea water during the post-stage of peatification, which results in the fact that the contents of As, Fe, S, etc. associated closely with sea water tend to increase toward the top of the seam. These elements studied are dominantly associated with kaolinite, pyrite, illite, montmorillonite, etc., of which the As, Pb, Mn, Cs, Co, Ni, etc. are mainly associated with sulfides, the Mo, V, Nb, Hf, REEs, Ta etc. mainly with kaolinite, the Mg, Al etc. mainly with epigenetic montmorillonite, and the Rb, Cr, Ba, Cu, K, Hg, etc. mainly with epigenetic illite. The physical coal cleaning is not only effective in the removal of ash and sulfur, but also in reducing the concentration of most major and trace elements. The elements Be, U, Sb, W, Br, Se, P, etc. are largely or partly organically bound showing a relatively low removability, while the removability of the other elements studied is more than 20%, of which the Mg, Mn, Hg, Fe, As, K, AI, Cs, and Cr associated mostly with the coarser or epigenetic minerals show a higher removability than that of ash. The distribution of the elements in the seam profile controls their partitioning behavior to a great degree during the coal cleaning processes.

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.)

Welded joints integrity analysis and optimization for fiber laser welding of dissimilar materials

Science.gov (United States)

Ai, Yuewei; Shao, Xinyu; Jiang, Ping; Li, Peigen; Liu, Yang; Liu, Wei

2016-11-01

Dissimilar materials welded joints provide many advantages in power, automotive, chemical, and spacecraft industries. The weld bead integrity which is determined by process parameters plays a significant role in the welding quality during the fiber laser welding (FLW) of dissimilar materials. In this paper, an optimization method by taking the integrity of the weld bead and weld area into consideration is proposed for FLW of dissimilar materials, the low carbon steel and stainless steel. The relationships between the weld bead integrity and process parameters are developed by the genetic algorithm optimized back propagation neural network (GA-BPNN). The particle swarm optimization (PSO) algorithm is taken for optimizing the predicted outputs from GA-BPNN for the objective. Through the optimization process, the desired weld bead with good integrity and minimum weld area are obtained and the corresponding microstructure and microhardness are excellent. The mechanical properties of the optimized joints are greatly improved compared with that of the un-optimized welded joints. Moreover, the effects of significant factors are analyzed based on the statistical approach and the laser power (LP) is identified as the most significant factor on the weld bead integrity and weld area. The results indicate that the proposed method is effective for improving the reliability and stability of welded joints in the practical production.

Fault capability problem about seams in Shika NPP

International Nuclear Information System (INIS)

Katagawa, H.

2016-01-01

Against the opinion of the Nuclear Regulation Authority that insists that the on-site seams of Shika Nuclear Power Plant is fault, Hokuriku Electric Power Company shows the view that they are not the fault. Additional survey result was submitted by Hokuriku Electric Power Company, and the evaluation draft for it by the expert meeting of Nuclear Regulation Authority, as well as the peer review were published. The evaluation draft mentioned that the seams cannot be denied for the possibility to become active, and the peer review issued many evaluations different from the evaluation draft. This paper describes the contents of the evaluation draft and peer review summarized by Hokuriku Electric Power Company. Against the three major points of the evaluation draft, the peer review pointed out the defect of fact recognition in every issue of discussion that lacks in examination on the points that should have been checked, and questioned the eligibility of the contents of evaluation. Many of the suggestions and comments of the peer review were the contents that approved the on-site survey and the report at the expert meeting made by Hokuriku Electric Power Company. In addition, this paper summarizes the focal points of the evaluation draft, and points out the question for fault assumption and discrepancies in the case of existence of fault. Hokuriku Electric Power Company has published a rebuttal to the evaluation draft as the written opinion. (A.O.)

THE EFFECTS OF DIFFERENT WORK-LOADING APPLIED TO THE WORKERS THAT WORK PRODUCING OF SHIRT TO THE SEAM FAULT RATES

Directory of Open Access Journals (Sweden)

Önder YÜCEL

2001-03-01

Full Text Available Human efficiency is of big importance in the clothing industry. So as to provide high quality and productivity stabilized work –loading must be given to the workers that work in the cloth production lines. In addition to it, the kind of work must be paid attention in the studies to be done on stabilized work-loading. The aim of this study is to determine the effects of different work-loading to the seam fault rates. For this purpose, four different work-loading had been applied to the workers and determined seam faults on the clothes had been recorded. As a result of this study, seam fault rates in the different work-loading had been evaluated.

Production methods and costs of oxygen free copper canisters for nuclear waste disposal

International Nuclear Information System (INIS)

Rajainmaeki, H.; Nieminen, M.; Laakso, L.

1991-08-01

The fabrication technology and costs of various manufacturing alternatives to make large copper canisters for spent fuel repository are discussed. The capsule design is based on the TVO's new advanced cold process concept where a steel canister is surrounded by the oxygen free copper canister. This study shows that already at present there exist several possible manufacturing routes, which result in consistently high quality canisters. Hot rolling, bending and EB-welding the seam is the best way to assure the small grain size which is preferable for the best inspectability of the final EB-welded seam of the lid. The same route turns out also to be the most economical

Production methods and costs of oxygen free copper canisters for nuclear waste disposal

International Nuclear Information System (INIS)

Rajainmaeki, H.; Nieminen, M.; Laakso, L.

1991-06-01

The fabrication technology and costs of various manufacturing alternatives to make large copper canisters for spent fuel repository are discussed. The capsule design is based on the TVO's new advanced cold process concept where a steel canister is surrounded by the oxygen free copper canister. This study shows that already at present there exist several possible manufacturing routes, which results in consistently high quality canisters. Hot rolling, bending and EB-welding the seam is the best way to assure the small grain size which is preferable for the best inspectability of the final EB-welded seam of the lid. The same route turns out also to be the most economical. (au)

Laser Welding Test Results with Gas Atmospheres in Welding Chamber

Energy Technology Data Exchange (ETDEWEB)

Joung, Chang-Young; Hong, Jin-Tae; Ahn, Sung-Ho; Heo, Sung-Ho; Jang, Seo-Yun; Yang, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

The weld beads of specimens welded under identical conditions in the helium and argon gas were cleaner, more regular, and steadier than those in a vacuum. The penetration depth of the FZ in the vacuum was much deeper than those in the helium and argon gas. To measure the irradiation properties of nuclear fuel in a test reactor, a nuclear fuel test rod instrumented with various sensors must be fabricated with assembly processes. A laser welding system to assemble the nuclear fuel test rod was designed and fabricated to develop various welding technologies of the fuel test rods to joint between a cladding tube and end-caps. It is an air-cooling optical fiber type and its emission modes are a continuous (CW) mode of which the laser generates continuous emission, and pulse (QCW) mode in which the laser internally generates sequences of pulses. We considered the system welding a sample in a chamber that can weld a specimen in a vacuum and inert gas atmosphere, and the chamber was installed on the working plate of the laser welding system. In the chamber, the laser welding process should be conducted to have no defects on the sealing area between a cladding tube and an end-cap.

Welding of Thin Steel Plates by Hybrid Welding Process Combined TIG Arc with YAG Laser

Science.gov (United States)

Kim, Taewon; Suga, Yasuo; Koike, Takashi

TIG arc welding and laser welding are used widely in the world. However, these welding processes have some advantages and problems respectively. In order to improve problems and make use of advantages of the arc welding and the laser welding processes, hybrid welding process combined the TIG arc with the YAG laser was studied. Especially, the suitable welding conditions for thin steel plate welding were investigated to obtain sound weld with beautiful surface and back beads but without weld defects. As a result, it was confirmed that the shot position of the laser beam is very important to obtain sound welds in hybrid welding. Therefore, a new intelligent system to monitor the welding area using vision sensor is constructed. Furthermore, control system to shot the laser beam to a selected position in molten pool, which is formed by TIG arc, is constructed. As a result of welding experiments using these systems, it is confirmed that the hybrid welding process and the control system are effective on the stable welding of thin stainless steel plates.

Hybrid laser-arc welding

DEFF Research Database (Denmark)

Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

[New welding processes and health effects of welding].

Science.gov (United States)

La Vecchia, G Marina; Maestrelli, Piero

2011-01-01

This paper describes some of the recent developments in the control technology to enhance capability of Pulse Gas Metal Arc Welding. Friction Stir Welding (FSW) processing has been also considered. FSW is a new solid-state joining technique. Heat generated by friction at the rotating tool softens the material being welded. FSW can be considered a green and energy-efficient technique without deleterious fumes, gas, radiation, and noise. Application of new welding processes is limited and studies on health effects in exposed workers are lacking. Acute and chronic health effects of conventional welding have been described. Metal fume fever and cross-shift decline of lung function are the main acute respiratory effects. Skin and eyes may be affected by heat, electricity and UV radiations. Chronic effects on respiratory system include chronic bronchitis, a benign pneumoconiosis (siderosis), asthma, and a possible increase in the incidence of lung cancer. Pulmonary infections are increased in terms of severity, duration, and frequency among welders.

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

Fine tuning of dwelling time in friction stir welding for preventing material overheating, weld tensile strength increase and weld nugget size decrease

Directory of Open Access Journals (Sweden)

Mijajlović Miroslav M.

2016-01-01

Full Text Available After successful welding, destructive testing into test samples from Al 2024-T351 friction stir butt welds showed that tensile strength of the weld improve along the joint line, while dimensions of the weld nugget decrease. For those welds, both the base material and the welding tool constantly cool down during the welding phase. Obviously, the base material became overheated during the long dwelling phase what made conditions for creation of joints with the reduced mechanical properties. Preserving all process parameters but varying the dwelling time from 5-27 seconds a new set of welding is done to reach maximal achievable tensile strength. An analytical-numerical-experimental model is used for optimising the duration of the dwelling time while searching for the maximal tensile strength of the welds

Time-lapse analysis of methane quantity in Mary Lee group of coal seams using filter-based multiple-point geostatistical simulation

Science.gov (United States)

Karacan, C. Özgen; Olea, Ricardo A.

2013-01-01

Coal seam degasification and its success are important for controlling methane, and thus for the health and safety of coal miners. During the course of degasification, properties of coal seams change. Thus, the changes in coal reservoir conditions and in-place gas content as well as methane emission potential into mines should be evaluated by examining time-dependent changes and the presence of major heterogeneities and geological discontinuities in the field. In this work, time-lapsed reservoir and fluid storage properties of the New Castle coal seam, Mary Lee/Blue Creek seam, and Jagger seam of Black Warrior Basin, Alabama, were determined from gas and water production history matching and production forecasting of vertical degasification wellbores. These properties were combined with isotherm and other important data to compute gas-in-place (GIP) and its change with time at borehole locations. Time-lapsed training images (TIs) of GIP and GIP difference corresponding to each coal and date were generated by using these point-wise data and Voronoi decomposition on the TI grid, which included faults as discontinuities for expansion of Voronoi regions. Filter-based multiple-point geostatistical simulations, which were preferred in this study due to anisotropies and discontinuities in the area, were used to predict time-lapsed GIP distributions within the study area. Performed simulations were used for mapping spatial time-lapsed methane quantities as well as their uncertainties within the study area.

Optimum welding condition of 2017 aluminum similar alloy friction welded joints

Energy Technology Data Exchange (ETDEWEB)

Tsujino R.; Ochi, H. [Osaka Inst. of Tech., Osaka (Japan); Morikawa, K. [Osaka Sangyo Univ., Osaka (Japan); Yamaguchi, H.; Ogawa, K. [Osaka Prefecture Univ., Osaka (Japan); Fujishiro, Y.; Yoshida, M. [Sumitomo Metal Technology Ltd., Hyogo (Japan)

2002-07-01

Usefulness of the statistical analysis for judging optimization of the friction welding conditions was investigated by using 2017 aluminum similar alloy, where many samples under fixed welding conditions were friction welded and analyzed statistically. In general, selection of the optimum friction welding conditions for similar materials is easy. However, it was not always the case for 2017 aluminum alloy. For optimum friction welding conditions of this material, it is necessary to apply relatively larger upset pressure to obtain high friction heating. Joint efficiencies obtained under the optimum friction welding conditions showed large shape parameter (m value) of Weibull distribution as well as in the dissimilar materials previously reported. The m value calculated on the small number of data can be substituted for m value on the 30 data. Therefore, m value is useful for practical use in the factory for assuming the propriety of the friction welding conditions. (orig.)

Dual wire welding torch and method

Science.gov (United States)

Diez, Fernando Martinez; Stump, Kevin S.; Ludewig, Howard W.; Kilty, Alan L.; Robinson, Matthew M.; Egland, Keith M.

2009-04-28

A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

TIG welding method and TIG welding device

International Nuclear Information System (INIS)

Yoneda, Eishi

1998-01-01

The present invention provides a method of TIG welding for members having different heat capacities including a cladding tube and an end plug of a fuel rod to be used, for example, in a reactor, and a device therefor. Namely, in the TIG welding method, the flow rate of a sealed gas to the side of a member having smaller heat capacity is made greater than that on the side of the member having greater heat capacity bordered on the top end of a welding electrode. Since the sealed gas is jetted being localized relative to the welding electrode, arc is restricted in a region of the member having smaller heat capacity and is increased at a region having a larger heat capacity. As a result, the arc is localized, so that the heat input amount to the region having a large heat capacity is increased, and then a plurality of members at the abutting portion are melted uniformly thereby capable of obtaining a uniform molten pool. A bead is formed at the abutting portion thereby capable of obtaining a welded portion with less unevenness and having large strength. (I.S.)

Study of geological and technologic evaluation for steeply inclined coal seams

Energy Technology Data Exchange (ETDEWEB)

Zhang Xiao-bing; Wang Zhong-qiang; Zhang Wei (and others) [China University of Mining & Technology, Beijing (China). School of Resources and Safety Engineering

2007-07-01

In order to predict the mining effect and choice of the technical decision comprehensive evaluation on steep coal seams was taken. Based on technical test, mining practice and analysis of statistic data, the hierarchical structure of evaluation about steeply inclined coal seam was obtained. In the structure, there are 8 multiple factors, which can divide 13 fundamental factors. Using the method of comprehensive evaluation with multi-index and fuzzy mathematics, the evaluation functions of the influencing factors are structured, and the model of fuzzy evaluation is proposed. 289 mining faces in Datai mine were evaluated using this model and the single outputs of these faces were predicted. The result shows that the number of mining faces in the first class is 27, covering 9.43% of the total, the number of the second class is 87, covering 30.1% of the total, the number of the third class is 112, covering 38.75%, and the number of the fourth class is 63, covering 21.8%.The evaluation and the reality are largely uniform. 8 refs., 3 tabs.

Experimental investigation on the weld pool formation process in plasma keyhole arc welding

Science.gov (United States)

Van Anh, Nguyen; Tashiro, Shinichi; Van Hanh, Bui; Tanaka, Manabu

2018-01-01

This paper seeks to clarify the weld pool formation process in plasma keyhole arc welding (PKAW). We adopted, for the first time, the measurement of the 3D convection inside the weld pool in PKAW by stereo synchronous imaging of tungsten tracer particles using two sets of x-ray transmission systems. The 2D convection on the weld pool surface was also measured using zirconia tracer particles. Through these measurements, the convection in a wide range of weld pools from the vicinity of the keyhole to the rear region was successfully visualized. In order to discuss the heat transport process in a weld pool, the 2D temperature distribution on the weld pool surface was also measured by two-color pyrometry. The results of the comprehensive experimental measurement indicate that the shear force due to plasma flow is found to be the dominant driving force in the weld pool formation process in PKAW. Thus, heat transport in a weld pool is considered to be governed by two large convective patterns near the keyhole: (1) eddy pairs on the surface (perpendicular to the torch axis), and (2) eddy pairs on the bulk of the weld pool (on the plane of the torch). They are formed with an equal velocity of approximately 0.35 m s-1 and are mainly driven by shear force. Furthermore, the flow velocity of the weld pool convection becomes considerably higher than that of other welding processes, such as TIG welding and GMA welding, due to larger plasma flow velocity.

Automatization of welding

International Nuclear Information System (INIS)

Iwabuchi, Masashi; Tomita, Jinji; Nishihara, Katsunori.

1978-01-01

Automatization of welding is one of the effective measures for securing high degree of quality of nuclear power equipment, as well as for correspondence to the environment at the site of plant. As the latest ones of the automatic welders practically used for welding of nuclear power apparatuses in factories of Toshiba and IHI, those for pipes and lining tanks are described here. The pipe welder performs the battering welding on the inside of pipe end as the so-called IGSCC countermeasure and the succeeding butt welding through the same controller. The lining tank welder is able to perform simultaneous welding of two parallel weld lines on a large thin plate lining tank. Both types of the welders are demonstrating excellent performance at the shops as well as at the plant site. (author)

Electric arc welding gun

Science.gov (United States)

Luttrell, Edward; Turner, Paul W.

1978-01-01

This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

Coiled-tubing fracturing of coal seams on the Vermejo Park Ranch

Energy Technology Data Exchange (ETDEWEB)

Bybee, K.

2003-06-01

Coiled-tubing (CT) fracturing currently is used to stimulate the Vermejo and Raton coal seams on the Vermejo Park Ranch in northern New Mexico. The CT fracturing process increased the number of stimulation stages from 4 to 18 per well. CT fracturing results in more accurate proppant placement and more effective stimulation of the producing zones.

Investigation into Variations of Welding Residual Stresses and Redistribution Behaviors for Different Repair Welding Widths

International Nuclear Information System (INIS)

Park, Chiyong; Lee, Hweesueng; Huh, Namsu

2014-01-01

In this study, we investigated the variations in welding residual stresses in dissimilar metal butt weld due to width of repair welding and re-distribution behaviors resulting from similar metal welding (SMW) and mechanical loading. To this end, detailed two-dimensional axi-symmetric finite element (FE) analyses were performed considering five different repair welding widths. Based on the FE results, we first evaluated the welding residual stress distributions in repair welding. We then investigated the re-distribution behaviors of the residual stresses due to SMW and mechanical loads. It is revealed that large tensile welding residual stresses take place in the inner surface and that its distribution is affected, provided repair welding width is larger than certain value. The welding residual stresses resulting from repair welding are remarkably reduced due to SMW and mechanical loading, regardless of the width of the repair welding

Certification of a weld produced by friction stir welding

Science.gov (United States)

Obaditch, Chris; Grant, Glenn J

2013-10-01

Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

Laser beam welding and friction stir welding of 6013-T6 aluminium alloy sheet