WorldWideScience

Sample records for butt welds

  1. Microcomputer Checks Butt-Weld Accuracy

    Science.gov (United States)

    Clisham, W.; Garner, W.; Cohen, C.; Beal, J.; Polen, R.; Lloyd, J.

    1982-01-01

    Electrical gage and microcomputer eliminate time-consuming manual measurements. Alinement and angle of plates on either side of butt weld are measured and recorded automatically by hand-held gage and desk-top microcomputer. Gage/micro-computer quickly determine whether weld is within dimensional tolerances or whether reworking is needed. Microcomputer prints out measurements while operator moves gage from point to point along weld. Out-of-tolerance measurements are marked by an asterisk on printout.

  2. Effect of flash butt welding parameters on weld quality of mooring chain

    OpenAIRE

    Kim, D. C.; W.J. So; Kang, M J

    2009-01-01

    Purpose: The effects of flash butt welding parameters on mechanical properties were explored for mooring chain for offshore structure.Design/methodology/approach: Through the tensile strength, impact energy, hardness of weld, macrosection, microstructure and waveform analysis of the flash butt weld, following the change of the flash mode, flash length, upset mode, and upset length which are the parameters of the flash butt welding, the weld quality has been assessed.Findings: It is confirmed ...

  3. Creep failure analysis of butt welded tubes

    International Nuclear Information System (INIS)

    As part of a major research programme to investigate the influence of butt welds on the life expectancy of tubular components, a series of internal-pressure, stress-rupture tests have been carried out. Thick walled 1/2Cr 1/2Mo 1/4V tube specimens were welded with mild steel, 1Cr 1/2Mo steel, 2 1/4Cr 1Mo steel or nominally matching 1/2Cr 1/2Mo 1/4V steel to give a wide range of weld metal creep strengths relative to the parent tube. The weldments were tested at 5650C at two values of internal pressure, and gave failure lives of up to 44,000 hrs. Finite element techniques have been used to determine the stationary state stress distribution in the weldment which was represented by a three material model. Significant stress redistribution was indicated and these results enabled the position and orientation of cracking and the rupture life to be predicted. The theoretical and experimental results have been used to highlight the limitations of current design methods which are based on the application of the mean diameter hoop stress to the parent material stress rupture data. (author)

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

    NARCIS (Netherlands)

    Kerstens, N.F.H.

    2010-01-01

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

  5. FATIGUE STRENGTH DETERMINATION OF BUTT WELDED JOINTS BY FEM

    Institute of Scientific and Technical Information of China (English)

    M. Szubryt; J. Brózda

    2004-01-01

    The influence of welding parameters of butt joints, made by three processes (MMA, MAG and T.I.M.E), on their geometric characteristics has been evaluated, which in turn caused a change of the fatigue strength. That fore the statistic analysis and FEM were used and a method developed in the Institute of Welding, which consist in a direct connection of parameters used during welding with the fatigue strength of joints welded by various processes. It has been proven, among others, which by using more advanced welding processes (T.I.M.E) the fatigue strength of welded joints can be increased in comparison to joints welded by MMA and MAG.

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

    OpenAIRE

    Kerstens, N.F.H.

    2010-01-01

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

  7. Critical Gap distance in Laser Butt-welding

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove

    1999-01-01

    In a number of systematic laboratory experiments the critical gap distance that results in sound beads in laser butt welding is sought identified. By grinding the edges of the sheets, a number of "reference" welds are made and compared to the sheets with shear cut edges. In the tests the gap...... were also x-ray photographed.Of the weld combinations analysed 80 % were of high quality and 17 % of a non-acceptable quality. 90 % of the bad welds had a gap distance larger than 0.05 mm. The results showed that 85 % of the bad welds were shear cut and only 15 % grinded. Two third of the bad welds...

  8. GAP WIDTH STUDY IN LASER BUTT-WELDING

    DEFF Research Database (Denmark)

    Gong, Hui; Olsen, Flemming Ove

    In this paper the maximum allowable gap width in laser butt-welding is intensively studied. The gap width study (GWS) is performed on the material of SST of W1.4401 (AISI 316) under various welding conditions, which are the gap width : 0.00-0.50 mm, the welding speed : 0.5-2.0 m/min, the laser...... power : 2 and 2.6 kW and the focal point position : 0 and -1.2 mm. Quality of all the butt welds are destructively tested according to ISO 13919-1.Influences of the variable process parameters to the maximum allowable gap width are observed as (1) the maximum gap width is inversely related to the...... welding speed, (2) the larger laser power leads to the bigger maximum allowable gap width and (3) the focal point position has very little influence on the maximum gap width....

  9. Development of Full Automatic Flash Butt Welding with Digital Control

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; SUN Hexu; WANG Hongwen

    2006-01-01

    The hardware and software design of two digital control systems based on 80C196KB MCU for flash butt welder is introduced in this paper. The welding power supply is made of six-phase half-wave rectifier. The welding outer characteristic of welding machine is realized by digital PI algorithm with the voltage close-loop feedback. The flashing curve is finished by electric-hydraulic servo valve .The process control system transfers datum with power supply system by a serial communication interface. The parameters of the control systems are collected by photoelectrical seclusion to avoid the disturbing of the electromagnetism in welding process.

  10. The flash-butt welding of aluminium alloys

    Science.gov (United States)

    Kuchuk-Iatsenko, S. I.; Cherednichok, V. T.; Semenov, L. A.

    Flash-butt welding (FBW) of high-strength aerospace Al alloys is conducted without gaseous-medium shielding and has undergone substantial development in the direction of automated operations. FBW yields virtually no pores, discontinuities, or cracks, and is therefore ideal for gas-impermeable joints. The dimensional accuracies achievable by FBW are a function of weld are inner stresses that are a full order of magnitude smaller than those of arc-welding methods. NDI methods can be incorporated into an automated FBW apparatus for direct inspection of welds.

  11. Evaluation of tandem gas metal arc welding for low distortion butt-welds in naval shipbuilding

    International Nuclear Information System (INIS)

    Tandem gas metal arc welding (T-GMAW) had been indentified as a welding process that is potentially capable of increasing productivity and minimizing distortion in the butt-welding of steel panels for the shipbuilding industry. In this study, the T-GMAW process has been used to butt-weld DH36 steel plate in order to determine its suitability as a replacement for submerged arc welding (SAW) or standard gas-metal-arc welding (GMAW) in naval shipbuilding applications. Experiments conducted show that the T-GMAW process is feasible and provides a significant improvement ove the SAW process in several respects, including higher travel speed, reduction in filler material, significantly lower post-weld distortion and residual stress, and a smaller heat affected zone (HAZ) with finer weld metal and HAZ microstructures. Furthermore, similar mechanical properties to those of SAW were obtained in the weld metal and HAZ.

  12. 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.

  13. Comparison of Residual Stress Distributions of Similar and Dissimilar Thick Butt-Weld Plates

    Science.gov (United States)

    Suzuki, Hiroshi; Katsuyama, Jinya; Morii, Yukio

    Residual stress distributions of 35 mm thick dissimilar metal butt-weld between A533B ferritic steel and Type 304 austenitic stainless steel (304SS) with Ni alloy welds and similar metal butt-weld of 304SS were measured using neutron diffraction. Effects of differences in thermal expansion coefficients (CTEs) and material strengths on the weld residual stress distributions were discussed by comparison of the residual stress distributions between the similar and dissimilar metal butt-welds. Residual stresses in the similar metal butt-weld exhibited typical distributions found in a thick butt-weld and they were distributed symmetrically on either side of the weld line. Meanwhile, asymmetric residual stress distributions were observed near the root of the dissimilar metal butt-weld, which was caused by differences in CTEs and yield strengths among both parent materials and weld metals. Transverse residual stress distribution of the dissimilar metal butt-weld was similar trend to that of the similar metal butt-weld, since effect of difference in CTEs were negligible, while magnitude of the transverse residual stress near the root depended on the yield strengths of each metal. In contrast, the normal and longitudinal residual stresses in the dissimilar metal butt-weld distributed asymmetrically on either side of weld line due to influence of differences in CTEs.

  14. A Neural Network Approach for GMA Butt Joint Welding

    DEFF Research Database (Denmark)

    Christensen, Kim Hardam; Sørensen, Torben

    2003-01-01

    This paper describes the application of the neural network technology for gas metal arc welding (GMAW) control. A system has been developed for modeling and online adjustment of welding parameters, appropriate to guarantee a certain degree of quality in the field of butt joint welding with full...... penetration, when the gap width is varying during the welding process. The process modeling to facilitate the mapping from joint geometry and reference weld quality to significant welding parameters has been based on a multi-layer feed-forward network. The Levenberg-Marquardt algorithm for non-linear least...... squares has been used with the back-propagation algorithm for training the network, while a Bayesian regularization technique has been successfully applied for minimizing the risk of inexpedient over-training. Finally, a predictive closed-loop control strategy based on a so-called single-neuron self...

  15. Equipment for Preparing Pipeline Position Butts for Welding

    Directory of Open Access Journals (Sweden)

    Lobanov L.M.

    2015-09-01

    Full Text Available The results of developments of the Ye.O.Paton Electric Welding Institute and its specialized departments on the designing national equipment models for preparation during the assembly the edges and butt ends of pipeline position butts with the diameter from 14 up to 159 mm, repair and modernization of power engineering objects, including the power units of nuclear and heat electric stations, in chemical and machine building, at enterprises of oil-gas complex and other branches of industry are presented.

  16. Optimization of laser butt welding parameters with multiple performance characteristics

    Science.gov (United States)

    Sathiya, P.; Abdul Jaleel, M. Y.; Katherasan, D.; Shanmugarajan, B.

    2011-04-01

    This paper presents a study carried out on 3.5 kW cooled slab laser welding of 904 L super austenitic stainless steel. The joints have butts welded with different shielding gases, namely argon, helium and nitrogen, at a constant flow rate. Super austenitic stainless steel (SASS) normally contains high amount of Mo, Cr, Ni, N and Mn. The mechanical properties are controlled to obtain good welded joints. The quality of the joint is evaluated by studying the features of weld bead geometry, such as bead width (BW) and depth of penetration (DOP). In this paper, the tensile strength and bead profiles (BW and DOP) of laser welded butt joints made of AISI 904 L SASS are investigated. The Taguchi approach is used as a statistical design of experiment (DOE) technique for optimizing the selected welding parameters. Grey relational analysis and the desirability approach are applied to optimize the input parameters by considering multiple output variables simultaneously. Confirmation experiments have also been conducted for both of the analyses to validate the optimized parameters.

  17. Diffusion welding in air. [solid state welding of butt joint by fusion welding, surface cleaning, and heating

    Science.gov (United States)

    Moore, T. J.; Holko, K. H. (Inventor)

    1974-01-01

    Solid state welding a butt joint by fusion welding the peripheral surfaces to form a seal is described along with, autogenetically cleaning the faying or mating surfaces of the joint by heating the abutting surfaces to 1,200 C and heating to the diffusion welding temperature in air.

  18. Butt-welding Residual Stress of Heat Treatable Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    C.M. Cheng

    2007-01-01

    This study, taking three types of aluminum alloys 2024-T351, 6061-T6 and 7075-T6 as experimental materials, conducted single V-groove GTAW (gas tungsten arc welding) butt-welding to analyze and compare the magnitude and differences of residual stress in the three aluminum alloys at different single V-groove angles and in restrained or unrestrained conditions. The results show that the larger the grooving angle of butt joint, the higher the residual tensile stress. Too small grooving angle will lead to dramatic differences due to the amount of welding bead filler metal and pre-set joint geometry. Therefore, only an appropriate grooving angle can reduce residual stress. While welding, weldment in restrained condition will lead to a larger residual stress. Also, a residual stress will arise from the restraint position. The ultimate residual stress of weldment is determined by material yield strength at equilibrium temperature. The higher the yield strength at equilibrium temperature, the higher the material residual stress. Because of its larger thermal conductivity, aluminum alloy test specimens have small temperature differential. Therefore, the residual tensile stress of all materials is lower than their yield strength.

  19. Critical Gap distance in Laser Butt-welding

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove

    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...... 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...... % of the bad welds have a gap distance larger than 0.05 mm. The results also show that 85 % of the bad welds are shear cut and only 15 % ground. Furthermore the results show that two third of the bad welds are zinc coated.X-ray pictures revealed that welding at "low" welding speeds (2 m/min. for 0.75 mm and 1...

  20. Superplastic formability of Ti-6Al-4V butt-welded plate by laser beam welding

    Institute of Scientific and Technical Information of China (English)

    WANG Gang; ZHANG Wen-cong; ZHANG Gong-lei; XU Zhi-hang

    2009-01-01

    The superplasticity of Ti-6Al-4V butt-welded plates by laser beam welding (LBW) was studied in virtue of hot tensile tests and superplastic bulging tests. Furthermore, microstructural evolution of weld metal upon superplastie forming was systematically analyzed via metallographical tests and scanning electron microscope (SEM). The relation between the microstructure of weld metal and its superplastic ability was discussed. The experimental results show that Ti-6Al-4V butt-welded plates by LBW possess superplasticity. The maximum elongation is up to 154% and the maximum bulge height can be up to 1.81 times the internal radius of the female die. There is an optimum value of the bulge height for bulging gas pressure.

  1. 75 FR 76025 - Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan

    Science.gov (United States)

    2010-12-07

    ... party responded to the sunset review notice of initiation by the applicable deadline * * *'' (75 FR... COMMISSION Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan AGENCY: United States... stainless steel butt-weld pipe fittings from Japan, Korea, and Taiwan would be likely to lead...

  2. 75 FR 53714 - Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan

    Science.gov (United States)

    2010-09-01

    ... imports of stainless steel butt-weld pipe fittings from Japan (53 FR 9787). On February 23, 1993, Commerce... on imports of stainless steel butt-weld pipe fittings from Japan, Korea, and Taiwan (65 FR 11766... Japan, Korea, and Taiwan (70 FR 61119). The Commission is now conducting third reviews to...

  3. 77 FR 14002 - Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines: Final Results...

    Science.gov (United States)

    2012-03-08

    ...'' section of this notice. \\1\\ See Initiation of Five-Year (``Sunset'') Review, 76 FR 67412 (November 1, 2011... International Trade Administration Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the... duty orders on stainless steel butt-weld pipe fittings (butt-weld pipe fittings) from Italy,...

  4. Fatigue Properties of Welded Butt Joint and Base Metal of MB8 Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Ying-xia YU

    2016-09-01

    Full Text Available The fatigue properties of welded butt joint and base metal of MB8 magnesium alloy were investigated. The comparative fatigue tests were carried out using EHF-EM200K2-070-1A fatigue testing machine for both welded butt joint and base metal specimens with the same size and shape. The fatigue fractures were observed and analyzed by a scanning electron microscope of 6360 LA type. The experimental results show that the fatigue performance of the welded butt joint of MB8 magnesium alloy is sharply decreased. The conditional fatigue limit (1×107 of base metal and welded butt joint is about 69.41 and 32.76 MPa, respectively. The conditional fatigue limit (1×107 of the welded butt joint is 47.2 % of that of base metal. The main reasons are that the welding can lead to stress concentration in the weld toe area, tensile welding residual stress in the welded joint, as well as grain coarsening in the welding seam. The cleavage steps or quasi-cleavage patterns present on the fatigue fracture surface, indicating the fracture type of the welded butt joint belongs to a brittle fracture.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.9132

  5. Characterization of magnetically impelled arc butt welded T11 tubes for high pressure applications

    OpenAIRE

    R. Sivasankari; V. Balusamy; P.R. Venkateswaran; G. Buvanashekaran; K Ganesh Kumar

    2015-01-01

    Magnetically impelled arc butt (MIAB) welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. In this work, MIAB welding of low alloy steel (T11) tubes were carried out to study the microstructural changes occurring in thermo-mechanically affected zone (TMAZ). To qualify the process for the welding applications where pressure could be up to 300 bar, the MIAB welds are studied with variations...

  6. Acoustic Microscope Inspection of Cylindrical Butt Laser Welds

    Science.gov (United States)

    Maev, R. Gr.; Severin, F.

    Presented work was made in order to develop the ultrasound technique for quality control of critical butt laser welds in automotive production. The set of powertrain assemblies was tested by high resolution acoustic microscopy method. The pulse-echo Tessonics AM 1102 scanning acoustic microscope was modified to accommodate cylindrical configuration of the parts. The spherically focused transducers with frequencies 15, 25 and 50 MHz were used; ultrasonic beam was focused on the joint area. Three-dimensional acoustic images were obtained and analyzed. The clear distinction between weld seam and remaining gap was demonstrated on the B- and C-scans representation. Seam depth varying from 0 up to 3.2 mm was measured along the weld. Different types of defects (porosity, cracks, lack of fusion) were detected and classified. The optimized analytical procedures for signal processing and advanced seam visualization were determined. The results were used as a basis for development of specialized instrumentation for inspection of this kind of parts in industrial environment. The technical requirements were established and the general design of new cylindrical acoustical scanner was made.

  7. Electron beam welding technology for butt weld in stainless steel tubes

    International Nuclear Information System (INIS)

    This paper presents an EBW (Electron Beam Welding) technology for butt weld in stainless steel (00Cr17Ni14Mo2) tubes used in an electro-thermal component, which size is Φ22mm x 2.5mm. By carrying out the EBW technology with a low current and a near-focusing manner, the inner convex of the weld is accurately controlled, the problem of external collapse is solved, and the One Side Welding Both Sides Formation technology is implemented. The specimen has passed all the tests required in Code RCC-M, including visual examination, liquid penetrate examination, X-ray inspection, tensile test, bending test, metallography detection, ferrite determination, and inter-granular corrosion test. Each quality above has reached the technological index grade I. (authors)

  8. Experimental investigation on tensile strength of butt welded joint post high temperatures

    Institute of Scientific and Technical Information of China (English)

    Cao Pingzhou; Chen Jianfeng; Zhao Wentao

    2009-01-01

    In order to investigate the laws of variation on tensile strength of butt welded joint post high temperatures, the wide plate tension tests for butt welded joint were conducted after cooling down from different high temperatures. The tests indicate that specimens appear ductile fracture at the steel plate during the tension tests after cooling down. The maximum temperatures undergone and the cooling pattern are major factors influencing tensile strength of butt welded joint post high temperatures. The tensile strength mostly reduces by 8% within 900℃. Based on the experimental results, the paper proposes the calculation formulas of tensile strength of butt welded joint post high temperatures. The conclusions of the paper supply references for evaluation damage and feinforcement of steel structure post fire.

  9. Remote panoramic radiography of small diameter tubular butt welds

    International Nuclear Information System (INIS)

    The application of low energy isotopes has been considered for the radiographic inspection of tubular butt welds in small diameter thin walled heat exchanger tubing. Four isotopes were selected from an initial list, after consideration of gamma ray energy spectrum, half life, specific activity, availability and cost. The experimental work undertaken to assess image contrast, inherent unsharpness and weld image sensitivity is briefly discussed and the relative insensitivity of conventional British Standard wire type image quality indicators to changes in radiographic definition is demonstrated. A design study undertaken to identify a suitable remote delivery/positioning system for panoramic radiography is also reported. This system is based upon conventional projection equipment with a flexible guide tube and inflatable source positioning device, which can incorporate a suitable image quality indicator. The equipment should prove capable of greatly extending the application of panoramic radiography during heat exchanger manufacture, particularly in situations where geometric restrictions limit the application of ultrasonic techniques, or where clarification of ultrasonic defect indication is required. Thus the system will provide a useful addition to the NDE techniques currently available for the implementation of the stringent quality assurance requirements of the nuclear industry. (author)

  10. Laser welding of butt joints of austenitic stainless steel AISI 321

    OpenAIRE

    A. Klimpel; A. Lisiecki

    2007-01-01

    Purpose: of this paper: A study of an automated laser autogenous welding process of butt joints of austenitic stainless steel AISI 321 sheets 0.5 [mm] and 1.0 [mm] thick using a high power diode laser HPDL has been carried out.Design/methodology/approach: Influence of basic parameters of laser welding on shape and quality of the butt joints and the range of optimal parameters of welding were determined.Findings: It was showed that there is a wide range of laser autogenous welding parameters w...

  11. Evaluation of residual stress distribution in austenitic stainless steel pipe butt-welded joint

    International Nuclear Information System (INIS)

    This paper reports measured and estimated results of residual stress distributions of butt-welded austenitic stainless steel pipe in order to improve estimation accuracy of welding residual stress. Neutron diffraction and strain gauge method were employed for the measurement of the welding residual stress and its detailed distributions on inner and outer surface of the pipe as well as the distributions within the pipe wall were obtained. Finite element method was employed for the estimation. Transient and residual stresses in 3D butt-welded joint model were computed by employing Iterative Substructure Method and also commercial FEM code ABAQUS for a reference. The measured and estimated distributions presented typical characteristic of straight butt-welded pipe which had decreasing trend along the axial direction and bending type distributions through wall of the pipe. Both results were compared and the accuracy of measurement and estimation was discussed. (author)

  12. Laser welding of butt joints of austenitic stainless steel AISI 321

    Directory of Open Access Journals (Sweden)

    A. Klimpel

    2007-11-01

    Full Text Available Purpose: of this paper: A study of an automated laser autogenous welding process of butt joints of austenitic stainless steel AISI 321 sheets 0.5 [mm] and 1.0 [mm] thick using a high power diode laser HPDL has been carried out.Design/methodology/approach: Influence of basic parameters of laser welding on shape and quality of the butt joints and the range of optimal parameters of welding were determined.Findings: It was showed that there is a wide range of laser autogenous welding parameters which ensures high quality joints of mechanical strength not lower than the strength of the base material (BM. The butt joints of austenitic steel AISI 321 sheets welded by the HPDL diode laser at optimal parameters are very high quality, without any internal imperfections and the structure and grain size of weld metal and HAZ is very small and also the HAZ is very narrow and the fusion zone is very regular.Research limitations/implications: Studies of the weldability of stainless steels indicate that the basic influence on the quality of welded joints and reduction of thermal distortions has the heat input of welding, moreover the highest quality of welded joints of austenitic stainless steel sheets are ensured only by laser welding.Practical implications: The technology of laser welding can be directly applied for welding of butt joints of austenitic steel AISI 321 sheets 0.5 and 1.0 [mm] thick.Originality/value: Application of high power diode laser for welding of austenitic stainless steel AISI 321.

  13. 77 FR 42697 - Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines: Continuation...

    Science.gov (United States)

    2012-07-20

    ... Orders: Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines, 66 FR 11257 (February 23, 2001). \\2\\ See Initiation of Five-Year (``Sunset'') Review, 76 FR 67412 (November 1, 2011... Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines, 77 FR 39735 (July 5, 2012),...

  14. 75 FR 60814 - Carbon Steel Butt-Weld Pipe Fittings From Brazil, China, Japan, Taiwan, and Thailand

    Science.gov (United States)

    2010-10-01

    ... butt- 731-TA-309 52 FR 4167. weld pipe fittings/ Japan. 7/6/92 Carbon steel butt- 731-TA-520 57 FR...-weld pipe fittings from Brazil, China, Japan, Taiwan, and Thailand (65 FR 753). Following second five... from Brazil, China, Japan, Taiwan, and Thailand (70 FR 70059). The Commission is now conducting...

  15. Gap Width Study and Fixture Design in Laser Butt-Welding

    DEFF Research Database (Denmark)

    Gong, Hui; Olsen, Flemming Ove

    This paper discusses some practical consideration for design of a mechanical fixture, which enables to accurately measure the width of a gap between two stainless steel workpieces and to steadfastly clamp the workpieces for butt-welding with a high power CO2 laser.With such a fixture, a series of...... butt-welding experiment is successfully carried out in order to find the maximum allowable gap width in laser butt-welding. The gap width study (GWS) is performed on the material of SST of W1.4401 (AISI 316) under various welding conditions, which are the gap width : 0.00-0.50 mm, the welding speed : 0.......5-2.0 m/min, the laser power : 2 and 2.6 kW and the focal point position : 0 and -1.2 mm. Quality of all the butt welds are destructively tested according to ISO 13919-1.Influences of the variable process parameters to the maximum allowable gap width are observed as (1) the maximum gap width is inversely...

  16. A new method to butt weld pipes with laser at different angles

    International Nuclear Information System (INIS)

    Laser butt welding of pipes at different angles may be cumbersome and may require very expensive tooling. The pipe size may not allow using the laser for large volume throughputs. We propose a rotary optical head composed by an adjustable focus lens system and two reflecting mirrors. The laser beam is bent at 90 deg. C. so that weld can be performed inwards outwards. The optic head design compensates the rotary backlash and vibrations, like a penta prism thus ensuring a perfect follow up of the weld track. The optic head can be inclined at 45 deg. C. to laser butt weld pipe each other at 90 deg. C. In this case the laser beam focus position is computer controlled in order to keep the focus point always on the elliptical weld profile. The paper covers theoretical and practical aspects of the proposed device. (author)

  17. Verification of residual stresses in flash-butt-weld rails using neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Tawfik, David [Mechanical Engineering Department, Monash University, Melbourne (Australia)]. E-mail: david.tawfik@eng.monash.edu.au; Kirstein, Oliver [Bragg Institute, Australian Nuclear Science Technology Organisation, Sydney (Australia); Mutton, Peter John [Institute of Railway Technology, Monash University, Melbourne (Australia); Chiu, Wing Kong [Mechanical Engineering Department, Monash University, Melbourne (Australia)

    2006-11-15

    Residual stresses developed during flash-butt welding may play a crucial role in prolonging the fatigue life of the welded tracks under service loading conditions. The finished welds typically exhibit high levels of tensile residual stresses in the web region of the weld. Moreover, the surface condition of the web may contain shear drag or other defects resulting from the shearing process which may lead to the initiation and propagation of fatigue cracks in a horizontal split web failure mode under high axle loads. However, a comprehensive understanding into the residual stress behaviour throughout the complex weld geometry remains unclear and is considered necessary to establish the correct localised post-weld heat treatment modifications intended to lower tensile residual stresses. This investigation used the neutron diffraction technique to analyse residual stresses in an AS60 flash-butt-welded rail cooled under normal operating conditions. The findings will ultimately contribute to developing modifications to the flash-butt-welding procedure to lower tensile residual stresses which may then improve rail performance under high axle load.

  18. Verification of residual stresses in flash-butt-weld rails using neutron diffraction

    Science.gov (United States)

    Tawfik, David; Kirstein, Oliver; Mutton, Peter John; Chiu, Wing Kong

    2006-11-01

    Residual stresses developed during flash-butt welding may play a crucial role in prolonging the fatigue life of the welded tracks under service loading conditions. The finished welds typically exhibit high levels of tensile residual stresses in the web region of the weld. Moreover, the surface condition of the web may contain shear drag or other defects resulting from the shearing process which may lead to the initiation and propagation of fatigue cracks in a horizontal split web failure mode under high axle loads. However, a comprehensive understanding into the residual stress behaviour throughout the complex weld geometry remains unclear and is considered necessary to establish the correct localised post-weld heat treatment modifications intended to lower tensile residual stresses. This investigation used the neutron diffraction technique to analyse residual stresses in an AS60 flash-butt-welded rail cooled under normal operating conditions. The findings will ultimately contribute to developing modifications to the flash-butt-welding procedure to lower tensile residual stresses which may then improve rail performance under high axle load.

  19. Flexible solution of the fixturing problem in sheet metal laser butt welding

    Science.gov (United States)

    Olsen, Flemming O.

    1994-09-01

    In 20 years laser welding of sheet metal has been demonstrated as a possible high-tech metal joining process. However, the major obstacle to the introduction of laser welding in for example car body manufacturing has been and is the fixturing problem. In case of laser butt welding of 0.5 - 1 mm thick steel sheets, the maximum acceptable gab between the sheets to be welded is in the range of 40 - 50 micrometer. Out of this demand two major problems arise: (1) the high precision required in weld preparation in terms of precise shape of the two sheets to be welded. (2) the problem of maintaining a narrow gab under welding, where thermal distortions, even though they are relatively small in this process, still will open the gap as the welding beam proceeds along the seam. In this paper a unique technique to overcome these problems will be described. The results of the experimental work described in this paper demonstrates the technique in 2D welding, where high quality butt welds has been demonstrated with virtually no clamping forces applied by utilizing a special seam preparation technique. Possibilities in car body manufacturing and other 3D sheet metal assembly by means of the flexible laser welding technique will be discussed.

  20. Thermal Analysis on Butt Welded Aluminium Alloy AA7075 Plate Using FEM

    Directory of Open Access Journals (Sweden)

    M. Pal Pandi

    2014-03-01

    Full Text Available Thermo-mechanical finite element analysis has been performed to assess the residual stress in the butt weld joints of aluminium Alloy AA7075 plates by utilizing the commercial software package ABAQUS. This paper presents an efficient FE technique using equivalent load to precisely predict welding deformations and residual stresses in butt joints. The radial heat flux distribution is considered on the top surface of the weldment. Convective and radiative heat losses are taken into account through boundary conditions for the outward heat flux. Linear FE transient thermal analysis is performed using surface heat source model with Gaussian distribution to compute highest temperature in AA7075 plates. The objective of this project is to simulate the welding process by using the finite element method. After the model is built and verified, the main objective of this project is to study the effects of varying the welding process parameters on the thermo-mechanical responses. In addition to that, the aim of this research is also to find a relationship between welding parameters and the responses of single pass butt welding are evaluated through the finite element analysis. The study of this paper covers the effects of varying heat input, welding speed on the thermo-mechanical responses of the weldment after cooling down to room temperature.

  1. Fracture analysis of U71Mn rail flash-butt welding joint

    OpenAIRE

    Xuemei Yu; Lichao Feng; Shijie Qin; Yuanliang Zhang; Yiqiang He

    2015-01-01

    This paper mainly investigates the fracture problem of U71Mn rail flash-butt welding joint. Fracture surface morphology, microstructure and micro hardness are analyzed by using the scanning electron microscopy (SEM/EDS), the optical microscope (OM) and the micro Vickers hardness tester (Vickers-tester). The analysis results show that the welding joint is fatigue fracture, and the fracture surface morphology is the cleavage fracture characteristics. The metallographic morphology, inclusions an...

  2. Crack growth analysis due to PWSCC in dissimilar metal butt weld for reactor piping considering hydrostatic and normal operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hwee Sueng; Huh, Nam Su [Seoul Nat' l Univ., Seoul (Korea, Republic of); Lee, Seung Gun; Park, Heung Bae [KEPCO Engineering and Construction Company, Gyeonggi (Korea, Republic of); Lee, Sung Ho [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2013-01-15

    This study investigates the crack growth behavior due to primary water stress corrosion cracking (PWSCC) in the dissimilar metal butt weld of a reactor piping using Alloy 82/182. First, detailed finite element stress analyses were performed to predict the stress distribution of the dissimilar metal butt weld in which the hydrostatic and the normal operating loads as well as the weld residual stresses were considered to evaluate the stress redistribution due to mechanical loadings. Based on the stress distributions along the wall thickness of the dissimilar metal butt weld, the crack growth behavior of the postulated axial and circumferential cracks were predicted, from which the crack growth diagram due to PWSCC was proposed. The present results can be applied to predict the crack growth rate in the dissimilar metal butt weld of reactor piping due to PWSCC.

  3. Mechanical properties of friction stir butt-welded Al-5086 H32 plate

    Directory of Open Access Journals (Sweden)

    G. Çam

    2008-10-01

    Full Text Available Purpose: The purpose of the paper is to study Al-5086 H32 plates with a thickness of 3 mm friction stir butt-welded using different welding speeds at a tool rotational speed of 1600 rpm. Design/methodology/approach: The effect of welding speed on the weld performance of the joints was investigated by conducting optical microscopy, microhardness measurements and mechanical tests (i.e. tensile and bend tests. The effect of heat input during friction stir welding on the microstructure, and thus mechanical properties, of cold-rolled Al- 5086 plates was also determined.Findings: The experimental results indicated that the maximum tensile strength of the joints, which is about 75% that of the base plate, was obtained with a traverse speed of 200 mm/min at the tool rotational speed used, e.g. 1600 rpm, and the maximum bending angle of the joints can reach 180º. The maximum ductility performance of the joints was, on the other hand, relatively low, e.g. about 20%. These results are not unexpected due to the loss of the cold-work strengthening in the weld region as a result of the heat input during welding, and thus the confined plasticity within the stirred zone owing to strength undermatching. Higher joint performances can also be achieved by increasing the penetration depth of the stirring probe in butt-friction stir welding of Al-5086 H32 plates.Research limitations/implications: The results suggest that both strength and ductility performances can be increased by optimizing the tool penetration depth.Originality/value: Examination of mechanical properties of friction stir butt-welded Al-5086 H32 plate.

  4. Control of GMA Butt Joint Welding Based on Neural Networks

    DEFF Research Database (Denmark)

    Christensen, Kim Hardam; Sørensen, Torben

    2004-01-01

    This paper presents results from an experimentally based research on Gas Metal Arc Welding (GMAW), controlled by the artificial neural network (ANN) technology. A system has been developed for modeling and online adjustment of welding parameters, appropriate to guarantee a high degree of quality...

  5. The microstructure of aluminum A5083 butt joint by friction stir welding

    Energy Technology Data Exchange (ETDEWEB)

    Jasri, M. A. H. M.; Afendi, M. [School of Mechatronic Engineering, Universiti Malaysia Perlis, Pauh, 02600, Arau, Perlis (Malaysia); Ismail, A. [UniKL MIMET, JalanPantaiRemis, 32200, Lumut, Perak (Malaysia); Ishak, M. [Faculty of Mechanical Engineering, Universiti Malaysia Pahang, 02600, Pekan, Pahang (Malaysia)

    2015-05-15

    This study presents the microstructure of the aluminum A5083 butt joint surface after it has been joined by friction stir welding (FSW) process. The FSW process is a unique welding method because it will not change the chemical properties of the welded metals. In this study, MILKO 37 milling machine was modified to run FSW process on 4 mm plate of aluminum A5083 butt joint. For the experiment, variables of travel speed and tool rotational speed based on capability of machine were used to run FSW process. The concentrated heat from the tool to the aluminum plate changes the plate form from solid to plastic state. Two aluminum plates is merged to become one plate during plastic state and return to solid when concentrated heat is gradually further away. After that, the surface and cross section of the welded aluminum were investigated with a microscope by 400 x multiplication zoom. The welding defect in the FSW aluminum was identified. Then, the result was compared to the American Welding Society (AWS) FSW standard to decide whether the plate can be accepted or rejected.

  6. Characterization of magnetically impelled arc butt welded T11 tubes for high pressure applications

    Directory of Open Access Journals (Sweden)

    R. Sivasankari

    2015-09-01

    Full Text Available Magnetically impelled arc butt (MIAB welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. In this work, MIAB welding of low alloy steel (T11 tubes were carried out to study the microstructural changes occurring in thermo-mechanically affected zone (TMAZ. To qualify the process for the welding applications where pressure could be up to 300 bar, the MIAB welds are studied with variations of arc current and arc rotation time. It is found that TMAZ shows higher hardness than that in base metal and displays higher weld tensile strength and ductility due to bainitic transformation. The effect of arc current on the weld interface is also detailed and is found to be defect free at higher values of arc currents. The results reveal that MIAB welded samples exhibits good structural property correlation for high pressure applications with an added benefit of enhanced productivity at lower cost. The study will enable the use of MIAB welding for high pressure applications in power and defence sectors.

  7. Microstructure and fatigue performance of butt-welded joints in advanced high-strength steels

    International Nuclear Information System (INIS)

    This study presents a comparative analysis of the high-cycle fatigue behaviors of butt weld joints in advanced high-strength steels with different strength levels and weld bead geometry. Welded joints were made using a gas metal arc welding (GMAW) process on dual-phase steels (DP440 and DP590) and martensitic steel (MS) with tensile strengths of 440, 590, and 1500 MPa, respectively. The microstructures with the lowest hardness were found at the base metal, the sub-critical heat-affected zone (HAZ), and the fusion zone for DP440, DP590, and MS weldments, respectively. Fatigue failure of specimens without weld beads occurred at the points of lowest hardness, and fatigue life exhibited the order MS>DP590>DP440, similar to the order of lowest hardness values in each weldment. However, the introduction of high weld beads resulted in very short, similar fatigue lives for all welded joints and fracture occurred at weld toe due to the overwhelming stress concentration effect. A transition from geometry-governed fracture toward microstructure-governed fracture was investigated by varying weld bead heights

  8. The long-term behaviour of butt fusion welds in polyethylene pipeline systems

    OpenAIRE

    Parmar, Ravindra

    1986-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The objective of the study was to examine factors that influence the strength of butt welds and gain an understanding of the process of failure. The study was divided into several sectors. The first and primary part of the programme was to determine the extent to which the pipe system's long-term strength under both internal fluctuating and constant pressure is reduced by the presence o...

  9. NUMERICAL SIMULATION OF TEMPERATURE FIELD ON FLASH BUTT WELDING FOR HIGH MANGANESE STEELS

    Institute of Scientific and Technical Information of China (English)

    B.D. Yu; W.D. Song; F.C. Zhang

    2005-01-01

    An axial symmetry finite element model coupled with electricity-thermal effect was developed to study the temperature field distribution in process of the flash butt welding (FBW) of frog highmanganese steel. The influence of temperature dependent material properties and the contact resistance were taken into account in FEMsimulation. Meanwhile, the lost materials due to splutter was resolved by using birth and death element. The result of analyzing data shows that the model in the FBW flashing is reasonable and feasible, and can exactly simulate the temperature field distribution. The modeling provides reference for analysis of welding technologies on the temperature field of high-manganese steel in FBW.

  10. Simplified inelastic analysis procedure to evaluate a butt-welded elbow end

    International Nuclear Information System (INIS)

    In a thin-walled piping network, the end of an elbow welded to a straignt pipe constitutes one of the highly stressed cross-sections that require structural evaluation. Explicit rules are not provided in the ASME Code for structural evaluation of the elbow ovalization and fabrication effects at the welded end. This paper presents a conservative semi-analytical procedure that can be used with simplified inelastic analysis to evaluate the elbow cross section welded to the straight pipe. The concept of carry-over factors is used to obtain ovalization stresses or strains at the elbow end. The stresses introduced by material and geometric nonuniformities in the fabrication process are then added to the ovalization stresses to complete structural evluation of the girth butt-welded elbow joint

  11. Joining of the AMC Composites Reinforced with Ti3Al Intermetallic Particles by Resistance Butt Welding

    Directory of Open Access Journals (Sweden)

    Adamiak M.

    2016-06-01

    Full Text Available The introduction of new reinforcing materials continues to be investigated to improve the final behaviour of AMCs as well as to avoid some drawbacks of using ceramics as reinforcement. The present work investigates the structure, properties and ability of joining aluminium EN-AW 6061 matrix composite materials reinforced with Ti3Al particles by resistance butt welding as well as composite materials produced by mechanical milling, powder metallurgy and hot extrusion techniques. Mechanically milled and extruded composites show finer and better distribution of reinforcement particles, which leads to better mechanical properties of the obtained products. Finer microstructure improves mechanical properties of obtained composites. The hardness increases twice in the case of mechanically milled composites also, a higher reinforcement content results in higher particle dispersion hardening, for 15 wt.% of intermetallics reinforcement concentration composites reach about 400 MPa UTS. Investigation results of joints show that best hardness and tensile properties of joints can be achieved by altering soft conditions of butt welding process e.g. current flow time 1.2 s and current 1400 A. To improve mechanical properties of butt welding joints age hardening techniques can also be used.

  12. Hybrid laser/arc welding of advanced high strength steel in different butt joint configurations

    International Nuclear Information System (INIS)

    Highlights: • Feasibility of joining thick steel by HLAW process was studied. • Design of butt joint configurations satisfied ballistic test requirement. • Heat input and microstructure were changed by groove geometry. - Abstract: An experimental procedure was developed to join thick advanced high strength steel plates by using the hybrid laser/arc welding (HLAW) process, for different butt joint configurations. The geometry of the weld groove was optimized according to the requirements of ballistic test, where the length of the softened heat affected zone should be less than 15.9 mm from the weld centerline. The cross-section of the welds was examined by microhardness test. The microstructure of welds was investigated by scanning electron microscopy and an optical microscope for further analysis of the microstructure of fusion zone and heat affected zone. It was demonstrated that by changing the geometry of groove, and increasing the stand-off distance between the laser beam and the tip of wire in gas metal arc welding (GMAW) it is possible to reduce the width of the heat affected zone and softened area while the microhardness stays within the acceptable range. It was shown that double Y-groove shape can provide the optimum condition for the stability of arc and laser. The dimensional changes of the groove geometry provided substantial impact on the amount of heat input, causing the fluctuations in the hardness of the weld as a result of phase transformation and grain size. The on-line monitoring of HLAW of the advanced high strength steel indicated the arc and laser were stable during the welding process. It was shown that less plasma plume was formed in the case where the laser was leading the arc in the HLAW, causing higher stability of the molten pool in comparison to the case where the arc was leading

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

    Science.gov (United States)

    Zeng, Jinle; Chang, Baohua; Du, Dong; Hong, Yuxiang; Chang, Shuhe; Zou, Yirong

    2016-01-01

    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. PMID:27649173

  14. Effect of defects on the burst failure of butt fusion welded polyethylene pipes

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Huan Sheng; Tun, Nwe Ni; Yoon, Kee Bong [Chung-Ang University, Seoul (Korea, Republic of); Kil, Seong Hee [Korea Gas Safety Corporation, Eumseong (Korea, Republic of)

    2016-05-15

    With the increasing demand of Medium density polyethylene (MDPE) pipes for gas transmission, the safety concern related with welding defects is becoming a serious matter. In this paper, experimental burst tests and finite element analyses were employed to study butt fusion welded MDPE pipe joints with spherical and planar defects of various sizes. These defects were used to simulate lack of bonding during the welding. Test results showed that in all pipe test cases, the failure location originated from pipe substrates, even though the defect size was increased to 45% of the pipe's wall thickness. The burst pressure could be estimated by the expression employed in the ASME BPVC, and in the burst pressure, the hoop stress was 20.28 MPa. Simulation results showed that the failure position was not only affected by the defect size, but also by the welding bead. It can be argued that a single welding defect whose maximum size is smaller than 15% of the thickness can be used without failure during short-term usage, even when there is no welding bead in the welded joint.

  15. Numerical simulation of side heating for controlling angular distortion in multipass MMAW butt welded plates

    Indian Academy of Sciences (India)

    Adinath V Damale; Keshav N Nandurkar

    2015-04-01

    Distortion is a severe problem in weld products.It depends on various process parameters like plate thickness, current, voltage, type of weld joint and restraints put on. If distortion is not properly dealt during welding then the product may become useless from geometric accuracy point of view. In the present study, a 3-D coupled transient thermal analysis model with auxiliary side heating (parallel heating) is developed to control angular distortion. During analysis, parallel heating flames are placed at several locations from weld line in cross direction. A user defined subroutine is used to apply transient heat source and side heating flames. Element birth and death technique is used to simulate the filler material deposition. One side multipass 'V' butt weld configuration is used for this study. A series of observational tests are done with a special experimental fixture using Manual Metal Arc Welding (MMAW) to validate the proposed FEA model. It is found that the angular distortion has decreased from 2 mm to 0.4 mm with change in side heating distance from 50 to 90 mm from the weld line.

  16. High power laser welding of thick steel plates in a horizontal butt joint configuration

    Science.gov (United States)

    Atabaki, M. Mazar; Yazdian, N.; Ma, J.; Kovacevic, R.

    2016-09-01

    In this investigation, two laser-based welding techniques, autogenous laser welding (ALW) and laser welding assisted with a cold wire (LWACW), were applied to join thick plates of a structural steel (A36) in a horizontal narrow gap butt joint configuration. The main practical parameters including welding method and laser power were varied to get the sound weld with a requirement to achieve a full penetration with the reinforcement at the back side of weld in just one pass. The weld-bead shape, cross-section and mechanical properties were evaluated by profilometer, micro-hardness test and optical microscope. In order to investigate the stability of laser-induced plasma plume, the emitted optical spectra was detected and analyzed by the spectroscopy analysis. It was found that at the laser power of 7 kW a fully penetrated weld with a convex back side of weld could be obtained by the LWACW. The microstructural examinations showed that for the ALW the acicular ferrite and for the LWACW the pearlite were formed in the heat affected zone (HAZ). The prediction of microstructure based on continuous cooling transformation (CCT) diagram and cooling curves obtained by thermocouple measurement were in good agreement with each other. According to the plasma ionization values obtained from the spectroscopy analysis the plume for both processes was recognized as dominated weakly ionized plasma including the main vaporized elemental composition. At the optimum welding condition (LWACW at the laser power of 7 kW) the fluctuation of the electron temperature was reduced. The spectroscopy analysis demonstrated that at the higher laser power more of the elemental compositions such as Mn and Fe were evaporated.

  17. Mechanical and metallurgical properties of DP 1000 steel square butt welded joints with GMAW

    Directory of Open Access Journals (Sweden)

    Ianto Rocha

    2014-12-01

    Full Text Available In this work, Gas Metal Arc Welding (GMAW was used to study the influence of heat input (i.e. cooling rate on mechanical/metallurgical properties of square butt welded joints of DP 1000 sheets. The influence of filler metals of different strengths on the mechanical properties of joints was also tested. A significant decrease in hardness was observed in the Heat Affected Zone (HAZ due to martensite tempering, in regions where peak temperature was close to isotherm AC1 (calculated in 735 oC for these steel; coincidently, fracture in every tensile test occurred in regions where martensite was tempered, even when a wire of less strength was used. It was noticed that the decrease in ultimate tensile and yield strength of base metal was inherent to welding. When minimum heat input was used, deterioration in mechanical properties was less pronounced, once degree of HAZ softening was smaller. Elongation of joints increased with increasing heat input.

  18. Fracture analysis of U71Mn rail flash-butt welding joint

    Directory of Open Access Journals (Sweden)

    Xuemei Yu

    2015-10-01

    Full Text Available This paper mainly investigates the fracture problem of U71Mn rail flash-butt welding joint. Fracture surface morphology, microstructure and micro hardness are analyzed by using the scanning electron microscopy (SEM/EDS, the optical microscope (OM and the micro Vickers hardness tester (Vickers-tester. The analysis results show that the welding joint is fatigue fracture, and the fracture surface morphology is the cleavage fracture characteristics. The metallographic morphology, inclusions and micro-hardness near the fracture surface are all in the normal levels. On the other side, the free solidification microstructure which extended from the outside to inside in the joint of the left side of the rail web and the rail head is the crack source of the rail welding joint fatigue fracture. Under the action of bending stress, the crack firstly generates in this area, and gradually extended to the rail web, to final fracture.

  19. 移动式交流钢轨闪光焊机%Mobile Rail AC Flash Butt Welding Machine

    Institute of Scientific and Technical Information of China (English)

    高振坤; 丁韦; 李力; 宋宏图

    2011-01-01

    移动式钢轨闪光焊机是无缝线路建设施工中的重要设备,其性能直接影响钢轨焊接接头的质量。鉴于进口的移动式闪光焊机价格昂贵,我国铁路科研院所进行了移动式交流钢轨闪光焊机的研制工作。从焊机总体结构、焊接主电路、系统控制、液压传动等方面,介绍移动式交流钢轨闪光焊机的组成及原理,概括我国自主开发研制的该种焊机的特性。%Mobile flash butt welding machine is an important equipment of continuously-welding-rail(CWR) building because its performance directly affects the quality of rail welding joints.Due to the fact that imported mobile flash butt welding machine is too expensive,China railway research institutes carry out the research and development of a new mobile flash butt welding machine.This article introduces the component and principle of the mobile AC flash butt welding machine which is developed by our country independently and summarize the features from the aspects of structure,main welding circuit,control system and hydraulic drive.

  20. 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...

  1. Residual stresses at girth-butt welds in pipes and pressure vessels. Final report, April 1, 1976--June 30, 1977

    International Nuclear Information System (INIS)

    A research program directed at developing a model or models to predict residual stress distributions due to girth-butt welds in pressure vessels and pipes is described. The program consisted of three tasks. In task 1, a critical review of the literature was conducted to obtain relevant information for developing and verifying the residual stress models. Task 2 was to provide specific experimental data for the purpose of checking the model capabilities and identifying characteristics of residual stress distributions in girth-butt welds. In task 3, residual stress models were developed

  2. Analysis on the joint tensile strength and fractography of TiNi shape memory alloy precise pulse resistance butt welding

    Institute of Scientific and Technical Information of China (English)

    赵熹华; 韩立军; 赵蕾

    2002-01-01

    This paper studies mechanical property and fractography of the welded joints obtained in different welding parameters such as welding heat and welding press with/without gas shield in TiNi shape memory alloy precise pulse resistance butt welding using tensile strength test, XRD, SEM and TEM measures. The optimum welding parameters obtaining high tensile strength welded joint are got. On the condition of welding press magneting current 2 A and welding heat 75%, the joint strength is the highest. This is important for to study other properties of TiNi shape memory alloy further. The experimental results state that argon gas shield have different effects on different welding parameters, less on welding press, but great on welding heat. But excessive welding press and welding heat have great effects on joint tensile strength. Too high welding heat can produce the new intermetallic compound, this intermetallic compound lead to dislocation density to increase and form the potential crack initiation, which can easily make the joint fracture under stress effect and decrease the shape memory ratio of joint for high density dislocation groups existing in the twinned martensite.

  3. Effect of Nd:YAG laser beam welding on weld morphology and mechanical properties of Ti-6Al-4V butt joints and T-joints

    Science.gov (United States)

    Kashaev, Nikolai; Ventzke, Volker; Fomichev, Vadim; Fomin, Fedor; Riekehr, Stefan

    2016-11-01

    A Nd:YAG single-sided laser beam welding process study for Ti-6Al-4V butt joints and T-joints was performed to investigate joining techniques with regard to the process-weld morphology relationship. An alloy compatible filler wire was used to avoid underfills and undercuts. The quality of the butt joints and T-joints was characterized in terms of weld morphology, microstructure and mechanical properties. Joints with regular shapes, without visible cracks, pores, and geometrical defects were achieved. Tensile tests revealed high joint integrity in terms of strength and ductility for both the butt joint and T-joint geometries. Both the butt joints and T-joints showed base material levels of strength. The mechanical performance of T-joints was also investigated using pull-out tests. The performance of the T-joints in such tests was sensitive to the shape and morphology of the welds. Fracture always occurred in the weld without any plastic deformation in the base material outside the weld.

  4. Special metallurgy - the electrical butt-welding by flashing of sintered magnesium-magnesium oxide composites (1963)

    International Nuclear Information System (INIS)

    Electrical resistance welding has become quite important since World War II because of the need of a high yield in aeronautical production. Progress has been due in particular to the improvements made in electronically controlled apparatus making possible the automatic control of welding. For the butt-welding of sections requiring either a high production rate or a high quality weld, the flash butt-welding system has been very much developed these last few years. The use of this welding method is of great importance in the field of the bonding of oxidisable metals such as magnesium or aluminium and its alloys, because the welded joint is free from oxides. This study consists of general considerations on the flash-welding process with regard to temperature distribution in the parts during welding, and to electrical phenomena connected with flashing. Besides this general or theoretical section, we have applied the welding process to the bonding of sintered magnesium, a magnesium-magnesium oxide composite, whose use as a structural element in nuclear reactors is considered. (author)

  5. On detection and automatic tracking of butt weld line in thin wall pipe welding by a mobile robot with visual sensor

    International Nuclear Information System (INIS)

    An automatic pipe welding mobile robot system with visual sensor was constructed. The robot can move along a pipe, and detect the weld line to be welded by visual sensor. Moreover, in order to make an automatic welding, the welding torch can track the butt weld line of the pipes at a constant speed by rotating the robot head. Main results obtained are summarized as follows: 1) Using a proper lighting fixed in front of the CCD camera, the butt weld line of thin wall pipes can be recongnized stably. In this case, the root gap should be approximately 0.5 mm. 2) In order to detect the weld line stably during moving along the pipe, a brightness distribution measured by the CCD camera should be subjected to smoothing and differentiating and then the weld line is judged by the maximum and minimum values of the differentials. 3) By means of the basic robot system with a visual sensor controlled by a personal computer, the detection and in-process automatic tracking of a weld line are possible. The average tracking error was approximately 0.2 mm and maximum error 0.5 mm and the welding speed was held at a constant value with error of about 0.1 cm/min. (author)

  6. Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding

    Science.gov (United States)

    Grujicic, M.; Ramaswami, S.; Snipes, J. S.; Yavari, R.; Arakere, A.; Yen, C.-F.; Cheeseman, B. A.

    2013-05-01

    A fully coupled (two-way), transient, thermal-mechanical finite-element procedure is developed to model conventional gas metal arc welding (GMAW) butt-joining process. Two-way thermal-mechanical coupling is achieved by making the mechanical material model of the workpiece and the weld temperature-dependent and by allowing the potential work of plastic deformation resulting from large thermal gradients to be dissipated in the form of heat. To account for the heat losses from the weld into the surroundings, heat transfer effects associated with natural convection and radiation to the environment and thermal-heat conduction to the adjacent workpiece material are considered. The procedure is next combined with the basic physical-metallurgy concepts and principles and applied to a prototypical (plain) low-carbon steel (AISI 1005) to predict the distribution of various crystalline phases within the as-welded material microstructure in different fusion zone and heat-affected zone locations, under given GMAW-process parameters. The results obtained are compared with available open-literature experimental data to provide validation/verification for the proposed GMAW modeling effort.

  7. Finite Element Simulation of Residual Stresses in Butt Welding of Two AISI 304 Stainless Steel Plates

    Directory of Open Access Journals (Sweden)

    Gurinder Singh Brar

    2013-06-01

    Full Text Available Welding is one of the most reliable and efficient permanent metal joining processes in the industry. When two plates are joined by welding, a very complex thermal cycle is applied to the weldment. Thermal energy applied results in irreversible elastic-plastic deformation and consequently gives rise to the residual stresses in and around fusion zone and heat affected zone (HAZ. It is well established fact that structural integrity of components is substantially affected by the residual stresses when subjected to thermal and structural loads. Presence of residual stresses may be beneficial or harmful for the structural components depending on the nature and magnitude of residual stresses. Using finite element based commercially available software, coupled thermal-mechanical three dimensional finite element model was developed by making an approximate geometry of the butt welded joint. Finite element analysis was performed to understand the complete nature of residual stresses in manual metal arc welded joint of AISI 304 stainless steel plate. Variation of residual stress in the plates in the heat affected zone was also being studied. The results obtained by finite element method agree well with those from X-ray diffraction method as published in literature for the prediction of residual stresses.

  8. Microstructure feature of friction stir butt-welded ferritic ductile iron

    International Nuclear Information System (INIS)

    Highlights: • Defect-free ferritic ductile iron joints is fabricated by FSW. • The welding nugget is composed of graphite, martensite, and recrystallized ferrite. • The graphite displays a striped pattern in the surface and advancing side. • The ferritic matrix transforms into martensite structure during welding. • High degree of plastic deformation is found on the advancing side. - Abstract: This study conducted friction stir welding (FSW) by using the butt welding process to join ferritic ductile iron plates and investigated the variations of microsturcture in the joined region formed after welding. No defects appeared in the resulting experimental weld, which was formed using a 3-mm thick ductile iron plate and tungsten carbide alloy stir rod to conduct FSW at a rotational speed of 982 rpm and traveling speed of 72 mm/min. The welding region was composed of deformed graphite, martensite phase, and dynamically recrystallized ferrite structures. In the surface region and on the advancing side (AS), the graphite displayed a striped configuration and the ferritic matrix transformed into martensite. On the retreating side (RS), the graphite surrounded by martensite remained as individual granules and the matrix primarily comprised dynamically recrystallized ferrite. After welding, diffusion increased the carbon content of the austenite around the deformed graphite nodules, which transformed into martensite during the subsequent cooling process. A micro Vickers hardness test showed that the maximum hardness value of the martensite structures in the weld was approximately 800 HV. An analysis using an electron probe X-ray microanalyzer (EPMA) indicated that its carbon content was approximately 0.7–1.4%. The peak temperature on the RS, 8 mm from the center of the weld, measured 630 °C by the thermocouple. Overall, increased severity of plastic deformation and process temperature near the upper stir zone (SZ) resulted in distinct phase transformation

  9. Monitoring of the process of Flash-Butt Welding Monitoramento do processo de soldagem de topo por faiscamento

    OpenAIRE

    Yevgenia Chvertko; Mykola Shevchenko; Andriy Pirumov

    2013-01-01

    Statistical methods of analysis are currently widely used to develop control and monitoring systems for different welding processes. These methods allow to obtain information about the process including effect of all factors on its results, which is often difficult to evaluate due to the complexity of the process. The authors made efforts to apply these methods to develop the system for monitoring the parameters of flash-butt welding in real-time mode. The paper gives brief information about ...

  10. 77 FR 10773 - Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines; Scheduling of...

    Science.gov (United States)

    2012-02-23

    ... to its notice of institution (76 FR 67473, November 1, 2011) of the subject five-year reviews was.... See 76 FR 61937 (Oct. 6, 2011) and the newly revised Commission's Handbook on E-Filing, available on... COMMISSION Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines; Scheduling...

  11. 77 FR 18266 - Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines; Revised...

    Science.gov (United States)

    2012-03-27

    ... the conduct of the expedited subject five- year reviews (77 FR 10773, February 23, 2012). The... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines;...

  12. 76 FR 19788 - Carbon Steel Butt-Weld Pipe Fittings From Brazil, China, Japan, Taiwan, and Thailand

    Science.gov (United States)

    2011-04-08

    ... determined on January 4, 2011 that it would conduct expedited reviews (76 FR 5205). The Commission... COMMISSION Carbon Steel Butt-Weld Pipe Fittings From Brazil, China, Japan, Taiwan, and Thailand... fittings from Brazil, China, Japan, Taiwan, and Thailand would be likely to lead to continuation...

  13. Material flow analysis in dissimilar friction stir welding of AA2024 and Ti6Al4V butt joints

    Directory of Open Access Journals (Sweden)

    BuffaGianluca

    2016-01-01

    Full Text Available The complex material flow occurring during the weld of dissimilar AA2024 to Ti6Al4V butt and lap joints was highlighted through a dedicated numerical model able to take into account the effects of the different materials as well as the phase transformation of the used titanium alloy.

  14. Numerical and experimental evaluation of Nd:YAG laser welding efficiency in AZ31 magnesium alloy butt joints

    Science.gov (United States)

    Scintilla, Leonardo Daniele; Tricarico, Luigi

    2013-02-01

    In this paper, energy aspects related to the efficiency of laser welding process using a 2 kW Nd:YAG laser were investigated and reported. AZ31B magnesium alloy sheets 3.3 mm thick were butt-welded without filler using Helium and Argon as shielding gases. A three-dimensional and semi-stationary finite element model was developed to evaluate the effect of laser power and welding speed on the absorption coefficient, the melting and welding efficiencies. The modeled volumetric heat source took into account a scale factor, and the shape factors given by the attenuation of the beam within the workpiece and the beam intensity distribution. The numerical model was calibrated using experimental data on the basis of morphological parameters of the weld bead. Results revealed a good correspondence between experiment and simulation analysis of the energy aspects of welding. Considering results of mechanical characterization of butt joints previously obtained, the optimization of welding condition in terms of mechanical properties and energy parameters was performed. The best condition is represented by the lower laser power and higher welding speed that corresponds to the lower heat input given to the joint.

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

    Science.gov (United States)

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

    2015-09-01

    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.

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

    Science.gov (United States)

    Kawahito, Yousuke; Kito, Masayuki; Katayama, Seiji

    2007-05-01

    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.

  17. Influence of the phase morphology on the weldability of PLA/PBAT-blends by using butt-welding

    Science.gov (United States)

    Goebel, L.; Bonten, C.

    2014-05-01

    The material development in the field of bioplastics is steadily increasing. It is important to examine the processability but the Investigation of further process steps is also very important. In this paper the weldability of bioplastics is discussed. Compounds of Polylactide (PLA) and Polybutyleneadipate-terephthalate (PBAT) are produced by a twin screw extruder with different mixing ratios. Tensile specimens are produced by injection moulding and the tensile tests are carried out. In order to verify the weldability, some tensile specimens are cut in halfes and butt welded. Afterwards a tensile test is performed with the welded samples and the results are compared with the values of the unwelded samples. For understanding the results, the morphology of the welds were examined and correlated. It has been found that blends with a mixing ratio of 50:50 have the lowest welding factor, because of the immiscibility of PLA and PBAT. Weld images show segregated areas that reduce the force transmission.

  18. Effect of Friction Stir Welding Parameters on the Mechanical and Microstructure Properties of the Al-Cu Butt Joint

    Directory of Open Access Journals (Sweden)

    Sare Celik

    2016-05-01

    Full Text Available Friction Stir Welding (FSW is a solid-state welding process used for welding similar and dissimilar materials. FSW is especially suitable to join sheet Al alloys, and this technique allows different material couples to be welded continuously. In this study, 1050 Al alloys and commercially pure Cu were produced at three different tool rotation speeds (630, 1330, 2440 rpm and three different tool traverse speeds (20, 30, 50 mm/min with four different tool position (0, 1, 1.5, 2 mm by friction stir welding. The influence of the welding parameters on the microstructure and mechanical properties of the joints was investigated. Tensile and bending tests and microhardness measurements were used to determine the mechanical properties. The microstructures of the weld zone were investigated by optical microscope and scanning electron microscope (SEM and were analyzed in an energy dispersed spectrometer (EDS. Intermetallic phases were detected based on the X-ray diffraction (XRD analysis results that evaluated the formation of phases in the weld zone. When the welding performance of the friction stir welded butt joints was evaluated, the maximum value obtained was 89.55% with a 1330 rpm tool rotational speed, 20 mm/min traverse speed and a 1 mm tool position configuration. The higher tensile strength is attributed to the dispersion strengthening of the fine Cu particles distributed over the Al material in the stir zone region.

  19. The study on defects in aluminum 2219-T6 thick butt friction stir welds with the application of multiple non-destructive testing methods

    International Nuclear Information System (INIS)

    Research highlights: → Friction stir weld-defect forming mechanisms of thick butt-joints. → Relationship between weld-defects and friction stir welding process parameters. → Multiple non-destructive testing methods applied to friction stir welds. → Empirical criterion basing on mass-conservation for inner material-loss defects. → Nonlinear correlation between weld strengths and root-flaw lengths. -- Abstract: The present study focused on the relationship between primary friction stir welding process parameters and varied types of weld-defect discovered in aluminum 2219-T6 friction stir butt-welds of thick plates, meanwhile, the weld-defect forming mechanisms were investigated. Besides a series of optical metallographic examinations for friction stir butt welds, multiple non-destructive testing methods including X-ray detection, ultrasonic C-scan testing, ultrasonic phased array inspection and fluorescent penetrating fluid inspection were successfully used aiming to examine the shapes and existence locations of different weld-defects. In addition, precipitated Al2Cu phase coarsening particles were found around a 'kissing-bond' defect within the weld stirred nugget zone by means of scanning electron microscope and energy dispersive X-ray analysis. On the basis of volume conservation law in material plastic deformation, a simple empirical criterion for estimating the existence of inner material-loss defects was proposed. Defect-free butt joints were obtained after process optimization of friction stir welding for aluminum 2219-T6 plates in 17-20 mm thickness. Process experiments proved that besides of tool rotation speed and travel speed, more other appropriate process parameter variables played important roles at the formation of high-quality friction stir welds, such as tool-shoulder target depth, spindle tilt angle, and fixture clamping conditions on the work-pieces. Furthermore, the nonlinear correlation between weld tensile strengths and weld crack

  20. Study of Simulated Temperature of Butt Joint during Friction Stir Welding Of Aluminium Alloy by Using Hyperworks

    Directory of Open Access Journals (Sweden)

    Mohd Anees Siddiqui

    2015-01-01

    Full Text Available Friction stir welding (FSW is one of the latest welding technology that utilizes a special tool for generation of frictional heat in the work piece by its rotation due to which joining occurs without melting of metal. For this reason friction stir welding lies under the category of solid state joining. A part from experimental work, there is large space to work on simulation of FSW by using simulation tools. In the present paper, simulation of friction stir welding of aluminium alloy AA-6061 is done by using HyperWeld module of Altair HyperWorks. The virtual experiment of friction stir welding is conducted for variable tool rotational speeds with constant travelling speed and study of simulation results of variation in temperature distribution along the weld line of butt joint is done. The results of simulation shows that the temperature is symmetrically distributed along the weld line. It is observed that the maximum temperature along the weld line increases with the increase in rotational speed. It is also observed that the temperature at advancing side is greater that retreating side.

  1. Fabrication of single V-butt welded test specimens with artificial defects for Non Destructive Testing training and research purposes

    International Nuclear Information System (INIS)

    Non Destructive Testing (NDT) test specimens are very important in training of NDT personnel and are useful in evaluation of defects in actual NDT inspections. These test specimens must contain defects, which have known dimensions simulating the real defects that can occur in fabricated or in - service industrial components. Non-Destructive Testing personnel involved in the inspection of weldments must have a basic understanding of standard welding processes and the types of flaws common to such welding processes. Proper knowledge on types of flaws and welding precesses enables the manufacture of test specimens with artificial defects. Wrong manipulation of the electrode, incorrect welding current/speed, welding on dirty surfaces, welding with damp elecrodes, rapid colling of the weld metal, high strength quenching are some sources of defect formation. Conventional methods in use to create artificial defects in weldments are, restraining the weld from contract to create cracks, leaving arc air gauging in places where lack of penetration is required, welding to form blow holes at a crater etc. These may cause the manufacturer fatigue and may be time consuming and costly. In this work the authors have introduced relatively a simple and less expensive way to prepare single V-butt welded steel plates and pipes with artificial defects using shielded metal arc welding process. The flaws prepared in the weldments were incomplete penetration, slag, porosity, lack of fusion and crack. From the observations it is concluded that Low-welding current (64-68 Amp) can be efectively used to create incomplete penetration, porosity and lack of fusion in the weldments. Cracks can be originated at rigid joints, high strength quenching and if the parent metal cannot contract freely during welding. Using low electrode angle (48-52 degrees) non-metallic inclusions can be created. The results of the findings were confirmed using conventional NDT techniques such as Radiographic Testing and

  2. Numerical Simulation and Artificial Neural Network Modeling for Predicting Welding-Induced Distortion in Butt-Welded 304L Stainless Steel Plates

    Science.gov (United States)

    Narayanareddy, V. V.; Chandrasekhar, N.; Vasudevan, M.; Muthukumaran, S.; Vasantharaja, P.

    2016-02-01

    In the present study, artificial neural network modeling has been employed for predicting welding-induced angular distortions in autogenous butt-welded 304L stainless steel plates. The input data for the neural network have been obtained from a series of three-dimensional finite element simulations of TIG welding for a wide range of plate dimensions. Thermo-elasto-plastic analysis was carried out for 304L stainless steel plates during autogenous TIG welding employing double ellipsoidal heat source. The simulated thermal cycles were validated by measuring thermal cycles using thermocouples at predetermined positions, and the simulated distortion values were validated by measuring distortion using vertical height gauge for three cases. There was a good agreement between the model predictions and the measured values. Then, a multilayer feed-forward back propagation neural network has been developed using the numerically simulated data. Artificial neural network model developed in the present study predicted the angular distortion accurately.

  3. Research on the welding properties of typical butt joints with laser-welding%激光焊典型对接接头焊接性能研究

    Institute of Scientific and Technical Information of China (English)

    高瑞全; 韩晓辉; 何智勇; 赵延强

    2013-01-01

    通过研究奥氏体不锈钢材料2-SUS301 L-ST对接接头的外观形貌、力学性能、显微硬度、金相组织等,考察激光焊接典型对接接头焊接性能.试验研究表明:激光焊接间隙小于等于0.2 mm时,激光焊接过程稳定,焊缝成形均匀美观,未发现外观缺陷和内部缺欠;激光焊接接头具有较好的塑韧性,其平均拉伸强度为786 MPa,激光焊对接接头显微硬度约250 HV;激光焊缝的微观组织均为柱状晶奥氏体组织,热影响区显微组织致密、晶粒细小.%The welding properties of typical butt joints with laser welding were investigated,by researching on coating appearance, mechanical properties, micro-hardness, metallographic structure of butt joints with austenitic stainless steel (2-SUS301L-ST).The experiment results showed that,the laser welding process steadied,appearances of weld were uniformity and artistic and any external or internal defects were not found,when the welding clearance was not more than 0.2 mm;the plasticity and the toughness of welding joints were good, their average tensile strength was 786 MPa,and the micro-hardness of the welding joints was 250 HV;the micro-structures of laser welding lines were columnar austenitic texture, and the micro-structures of heat affected zone were compact and the crystalline grains were tiny.

  4. Residual stress distribution in austenitic stainless steel pipe butt-welded joint measured by neutron diffraction technique

    International Nuclear Information System (INIS)

    Residual stress is inevitable consequence of welding or manufacturing process, which might greatly affect propagation of high-cycle fatigue or SCC crack. In order to evaluate damages due to the crack, it is required to estimate residual stress and to reflect them to the evaluation process as well. The magnitude and distribution of residual stress greatly depend on the individual process of welding or manufacturing, while the accuracy of prediction or measurement is still insufficient. This paper reports the result of residual stress measurement of butt-welded pipe made of austenitic stainless steel. It also intended to improve prediction and measurement techniques concerning to residual stress. The measurement was conducted by neutron diffraction technique employing the diffractometer for residual stress analysis developed by Japan Atomic Energy Agency. The measured results showed typical characteristics of butt-welded pipe both in decline of stress along axial direction and in radial distribution of bending due to axial stress. The measured result agreed qualitatively with the result predicted by the finite element analysis. A quantitative comparison between measured result and analysis showed a shift of the measured stress toward higher tensile. The measured result was also compared with the results by X-ray diffraction and strain-gauge methods to grasp the distinctive results of the methods. (author)

  5. Effect of Included Angle in V-Groove Butt Joints on Shrinkages in Submerged Arc Welding Process

    Directory of Open Access Journals (Sweden)

    N. LAKSHMANA SWAMY

    2012-04-01

    Full Text Available The problems of distortion, residual stresses and reduced strength of structure in and around a welded joint are of major concern in the shipbuilding industry and in other similar manufacturing industries. The predictions of the degree of shrinkages in ship panels due to welding are of great importance from the point of view of dimensional control and it is important to analyze transverse and longitudinal shrinkage. This paper deals with the experimental analysis of transverse and longitudinal shrinkage in single and double V-groove butt joints in submerged arc welding by varying included angle and keeping process parameters constant. It is found that, the maximum shrinkage was at the centre of the plate and minimum at the ends. It is also found that, the transverse and longitudinal shrinkage increase with increase in the included angle. There is a significant increase in the transverse shrinkage and small variation in longitudinal shrinkage.

  6. Feasibility evaluations for the integration of laser butt welding of tubes in industrial pipe coil production lines

    Science.gov (United States)

    Penasa, Mauro; Colombo, Enrico; Giolfo, Mauro

    1994-09-01

    Due to the good performance shown by laser welded joints, to the quality and repeatability achievable by this welding technique and to its high process productivity, a feature inherent to the laser technology which, together with its high flexibility, allows different operations to be performed by a single source, consistent savings in a production line may be obtained. Therefore laser welding techniques may be of high relevance for industrial applications, provided that a sufficient attention is paid to avoiding a low utilization time to the operating laser source. The paper describes a feasibility study for the integration of a laser source as an automatic unit for circumferential butt welding of tubes in production lines of pipe coils, just before the cold bending station. Using a 6 kW CO2 source, thickness ranging from 3.5 to 11.2 mm in carbon, low alloyed Cr-Mo and austenitic stainless steels, have been successfully welded. Cr-Mo steels require on line preheating treatment, which however can be achieved by laser defocused passes just before welding. The results of the preliminary qualification performed on laser welded joints of the involved topologies of product (materials, diameters and thicknesses) are described together with technological tests required for approval: laser circumferential butt welding of tubes has proven to be effective, with satisfactory and repeatable results and good joint performances. An exhaustive comparison with current welding techniques (TIG, MIG) is then carried out, along with a detailed analysis of the potential advantages and benefits which may be expected by using the laser welding technique, as well as with a first estimation of the investments and running costs. Since laser productivity is saturated only at a rough 35% during the year, an accurate analysis of other possible applications and of a possible lay out of a laser working cell integrated in the factory production lines is performed. Usually little attention is

  7. Creep-fatigue evaluation on butt welded joints of type 304 SS

    International Nuclear Information System (INIS)

    In high temperature plant systems such as thermal power generation and petro-chemical complexes, various weldments are used for pressure vessels and piping. Usually in structural design methods for weldment of conventional pressure vessels and piping systems, load controlled stresses are dominant, and to protect early failure in weldments tensile and creep strengths of each welded joint have not to be lower than the standard values of base metal. While under cyclic deformation controlled stress such as thermal loading in LMFBR, creep-fatigue phenomenon caused by reversal loading and residual stress relaxation is dominant. Therefore, a creep-fatigue evaluation method of Type 304 ss butt welded joints has to be investigated under cyclic thermal loading. For a study of this effect, the strain concentration factor Kε; Kε = Max[1+(qwq-1)(1-2 γyσy/E εn), Kε0], which is derived from the generalized elastic follow-up concept as the plastic strain redistribution, was applied, and in the Kε factor the metallurgical discontinuity effects; qw and γy were considered. The elastic follow-up increment factor for weldment; qw is equal to 2 under uni-axial mechanical loading. And under bi-axial thermal loading in shell-type structures, it is clarified that 1.5 as the qw value can be applied. As the yield ration γy, the value of 0.8 is the best for Type 304 ss weldment. As for the creep damage estimation, the simplified procedure based on the time fraction rule is discussed, and it is investigated how the creep damage of weldment can be evaluated by using mechanical properties of base metal (design standard values). The initial value of stress relaxation is determined by the cyclic stress-strain relation of base metal and the above Kε value. Stress relaxation during strain hold can be analyzed by using creep strain behaviour of base metal. Finally the allowable creep-fatigue life can be estimated by using the design curves. (author). 8 refs, 14 figs

  8. Study on pulsed flashing butt welding equipment%脉冲闪光对焊设备的研究

    Institute of Scientific and Technical Information of China (English)

    池强; 王士元; 张建勋

    2001-01-01

    在对脉冲闪光对焊(pulsed flashing butt welding)的振动过程进行深入分析的基础上,提出并研制了直流电动机带动凸轮产生振动的闪光对焊装置,并设计了振动机构及其控制电路.工艺试验表明,该设备能实现脉冲闪光对焊的要求,焊接接头能够满足使用要求.

  9. Basic numerical study on gap influence of residual stress and distortion during high-brightness laser butt welding

    International Nuclear Information System (INIS)

    High-brightness laser such as fiber laser or disk laser is expected to minimize the total heat input energy in welding due to its high beam quality, and the welding residual stress and distortion also seem to be reduced as a result. However, the diameter of high-brightness laser beam is less than 0.6 mm and it is difficult to set the beam position to contact face between two parts because in general there would be a gap due to quality of parts. In this study, in order to reveal the effect of gap on the residual stress and the welding distortion during fiber laser welding, the butt welding of two plates were examined through the thermal elastic-plastic analysis with a new gap element. From the result of thermal analyses, it was found that the homogeneous ellipsoid body could be applicable to model the shape of heat source for the fiber laser and the gap width would not influence the penetration shape when the gap width was changed from 0.1 to 0.25 mm. In addition, the elastic-plastic analyses indicated that the transverse shrinkage slightly increased with increasing the gap width, while this shrinkage without gap was much smaller than that with gap. Also, it was revealed that the welding speed largely affects both the welding residual stress and distortion. Moreover, it was found that the residual stress was almost independent of the jig position, while the position of fixtures slightly affected the transverse shrinkage. (author)

  10. Busted Butte report on laboratory radionuclide migration experiments in non-welded tuff under unsaturated conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vandergraaf, T.T.; Drew, D.J.; Ticknor, K.V

    2002-11-01

    Three blocks of non-welded tuff, one nominally one cubic foot (trial block) and the other two, nominally one cubic metre (1 m{sup 3}), were excavated from the Busted Butte Test Facility on the Nevada Test Site and transported to the Atomic Energy of Canada Limited Whiteshell Laboratories in Pinawa, Manitoba. The trial block and one of the 1-m{sup 3} blocks were used for unsaturated flow experiments. The remaining 1-m{sup 3} block is being used for saturated flow experiments and will be reported on separately. After a vertical flow of synthetic transport solution was set up under unsaturated conditions, a suite of conservative and chemically reactive radionuclide tracers was injected at volumetric flow rates of 20 mL/hr in the trial block, and 10 mL/hr in the 1-m{sup 3} block. The duration of the migration experiment in the trial block was 87 days, while the migration experiment in the 1-m{sup 3} block was continuing after 600 days. Results obtained from the migration experiment in the trial block showed that transport of {sup 95m+99}Tc, injected as the pertechnetate (an)ion, was slightly faster than that of the transport solution, using tritiated water ({sup 3}H{sub 2}O) as a flow indicator. Retardation of {sup 237}Np was consistent with that predicted from results obtained in supporting static batch sorption studies. Post-migration analysis of the flow field in the trial block showed that the front of the {sup 22}Na had migrated about half the distance through the block, and that {sup 60}Co and {sup 137}Cs had been retained near the inlet. This observation agrees qualitatively with that predicted from the results from static batch sorption studies. In the larger scale experiment, the transport behavior of Tc is very similar to that of the transport solution at this point in time. None of the other radionuclide tracers have been detected in water collected from this block. This observation is consistent with the observations for the smaller block. (author)

  11. Research on Coiled Tubing (CT) Butt Welding Process and Properties of Welded Joint%连续管焊接工艺及接头性能研究

    Institute of Scientific and Technical Information of China (English)

    李霄; 石凯; 刘彦明; 王洪铎

    2012-01-01

    根据连续管结构特点开发了专用工装及优化的焊接工艺,并对焊接接头的强度、塑性、硬度、耐腐蚀性能进行了研究.结果表明,连续管对接接头的热影响区中总存在不同程度的软化,该软化区的存在使得接头断裂于焊缝附近,同时接头的强度降低.采用专门开发的水冷焊接工艺可以明显改善软化程度,接头强度下降幅度降低.接头的弯曲、压扁试验结果表明焊接接头具有良好的变形能力.在28%HCl模拟溶液中焊接接头的腐蚀速度很快,由于材质的不同及结构特点的影响,焊缝的腐蚀速度明显高于母材及热影响区.%According to structure characteristics of CT, the special welding fixture and optimized welding process were developed, and the properties of welded joint, such as strength, plasticity, hardness and corrosion resistance were researched. The results indicated that different degree softening always exist in HAZ of CT butt welded joints, the softening area make welded joint fracture appear nearby weld, and strength drop down. Adopting specially developed water cooling welding process can improve softening degree obviously, and decreasing range of welded joint strength is reduced. Welded joint bend and the flattening test results showed that welded joint is with perfect deformability. The corrosion rate of welded joint is very quick in 28%HC1 simulated solution. The corrosion rate of weld is higher than that of base metal and HAZ according to different material and characteristics.

  12. Influences of post weld heat treatment on tensile strength and microstructure characteristics of friction stir welded butt joints of AA2014-T6 aluminum alloy

    Science.gov (United States)

    Rajendran, C.; Srinivasan, K.; Balasubramanian, V.; Balaji, H.; Selvaraj, P.

    2016-08-01

    Friction stir welded (FSWed) joints of aluminum alloys exhibited a hardness drop in both the advancing side (AS) and retreating side (RS) of the thermo-mechanically affected zone (TMAZ) due to the thermal cycle involved in the FSW process. In this investigation, an attempt has been made to overcome this problem by post weld heat treatment (PWHT) methods. FSW butt (FSWB) joints of Al-Cu (AA2014-T6) alloy were PWHT by two methods such as simple artificial aging (AA) and solution treatment followed by artificial aging (STA). Of these two treatments, STA was found to be more beneficial than the simple aging treatment to improve the tensile properties of the FSW joints of AA2014 aluminum alloy.

  13. Monitoring of the process of Flash-Butt Welding Monitoramento do processo de soldagem de topo por faiscamento

    Directory of Open Access Journals (Sweden)

    Yevgenia Chvertko

    2013-03-01

    Full Text Available Statistical methods of analysis are currently widely used to develop control and monitoring systems for different welding processes. These methods allow to obtain information about the process including effect of all factors on its results, which is often difficult to evaluate due to the complexity of the process. The authors made efforts to apply these methods to develop the system for monitoring the parameters of flash-butt welding in real-time mode. The paper gives brief information about the features of flash-butt welding of reinforcement bars and some basic limitation of this process application. The main reasons of formation of defects in welded joints are given as well as analysis of possibility of application of monitoring systems for their determination. The on-line monitoring system based on neural networks was developed for evaluation of process deviations. This system is believed to be adequate for determination of process violations resulting in disturbances of welding parameter and can be used for prediction of possible defects in the welded joints.Análises estatísticas são normalmente utilizadas para desenvolver sistemas de controle e monitoramento de diferentes processos de soldagem. Estes métodos permitem obter informação sobre o processo, incluindo o efeito de todos os fatores sobre o resultado, os quais são difíceis de avaliar devido a complexidade do processo. Os autores do presente trabalho tentaram aplicar estes métodos para desenvolver um sistema de monitoração dos parâmetros da soldagem de topo por faiscamento em tempo real. O artigo dá uma ideia resumida sobre as características do processo de soldagem por faiscamento de vergalhões, assim como some limitações básicas da aplicação do processo. As razões principais para formação de defeitos na junta soldada são apresentadas, assim como a análise da possibilidade da aplicação de um sistema de monitoração para suas determinações. Um sistema em

  14. Laser-based welding of 17-4 PH martensitic stainless steel in a tubular butt joint configuration with a built-in backing bar

    Science.gov (United States)

    Ma, Junjie; Atabaki, Mehdi Mazar; Liu, Wei; Pillai, Raju; Kumar, Biju; Vasudevan, Unnikrishnan; Kovacevic, Radovan

    2016-08-01

    Laser-based welding of thick 17-4 precipitation hardening (PH) martensitic stainless steel (SS) plates in a tubular butt joint configuration with a built-in backing bar is very challenging because the porosity and cracks are easily generated in the welds. The backing bar blocked the keyhole opening at the bottom surface through which the entrapped gas could escape, and the keyhole was unstable and collapsed overtime in a deep partially penetrated welding conditions resulting in the formation of pores easily. Moreover, the fast cooling rate prompted the ferrite transform to austenite which induced cracking. Two-pass welding procedure was developed to join 17-4 PH martensitic SS. The laser welding assisted by a filler wire, as the first pass, was used to weld the groove shoulder. The added filler wire could absorb a part of the laser beam energy; resulting in the decreased weld depth-to-width ratio and relieved intensive restraint at the weld root. A hybrid laser-arc welding or a gas metal arc welding (GMAW) was used to fill the groove as the second pass. Nitrogen was introduced to stabilize the keyhole and mitigate the porosity. Preheating was used to decrease the cooling rate and mitigate the cracking during laser-based welding of 17-4 PH martensitic SS plates.

  15. Laser beam welding of dissimilar ferritic/martensitic stainless steels in a butt joint configuration

    Science.gov (United States)

    Khan, M. M. A.; Romoli, L.; Dini, G.

    2013-07-01

    This paper investigates laser beam welding of dissimilar AISI430F and AISI440C stainless steels. A combined welding and pre-and-postweld treatment technique was developed and used successfully to avoid micro-crack formation. This paper also examined the effects of laser welding parameters and line energy on weld bead geometry and tried to obtain an optimized laser-welded joint using a full factorial design of experiment technique. The models developed were used to find optimal parameters for the desired geometric criteria. All the bead characteristics varied positively as laser power increased or welding speed decreased. Penetration size factor decreased rapidly due to keyhole formation for line energy input in the range of 15-20 kJ/m. Laser power of 790-810 W and welding speed of 3.6-4.0 m/min were the optimal parameters providing an excellent welded component. Whatever the optimization criteria, beam incident angle was around its limiting value of 15° to achieve optimal geometrical features of the weld.

  16. F52法兰/X52接管环焊接头开裂原因浅析%Cracking Reason Analysis on Circumferential Welding Joints of F52 Flange and X52 Welded Pipe Butt Welding

    Institute of Scientific and Technical Information of China (English)

    牛靖; 刘迎来; 王鹏; 齐丽华; 冯耀荣; 吉玲康; 张建勋

    2011-01-01

    通过化学成分、微观组织、断口形貌分析等方法对某管线场站建设中F52法兰/X52接管环焊接头裂纹产生的原因进行了研究.结果表明,裂纹出现于打底焊缝F52法兰侧的近缝区,呈现出沿晶+穿晶的开裂形貌,属于焊接冷裂纹.打底焊法兰侧近缝区的粗大马氏体是裂纹产生的主要原因,焊接工艺不当是裂纹产生的直接诱因,控制F52法兰的化学成分和适当的打底焊前预热是防止该裂纹产生的主要途径.%The circumferential welding joints cracking reason of F52 flange and XS2 welded pipe butt welding in some pipeline station was analyzed by chemical composition analysis, microstructure observation and fracture appearance analysis. The results showed that the crack which appeared near weld zone of F52 flange side belongs to welding cold cracking during backing welding, because its fracture appearance presents intergranular and transgranular fracture. The coarse martensite near weld zone of flange side is main reason which leads to crack; the improper welding process is direct inducement for crack. Controlling chemical composition of F52 flange and preheating before backing welding are the principal methods to prevent cracks.

  17. 380CL车轮钢闪光对接焊组织与性能%Microstructure and Properties of 380CL Wheel Steel After Electric Flash Butt Welding

    Institute of Scientific and Technical Information of China (English)

    张桂芹; 董建君; 王燕; 赵文成

    2012-01-01

    380CL wheel steel after electric flash butt weld was analyzed by bend property, microstructure and mechanical property. The results show that the microstructure of weld bead obtained by electric flash butt weld is F+W+granular bainitic and the microstructure of HAZ is F+W+lath bainitic. The hardness of the weld bead and HAZ is higher than that of matrix metal. And the tensile and bending property of the welded plate are qualified.%对闪光对接焊后的380CL车轮钢进行了弯曲、金相及力学性能分析.结果表明:380CL车轮钢焊缝处金相组织为铁素体+魏氏组织+粒状贝氏体,热影响区金相组织为铁素体+魏氏组织+条状贝氏体,焊缝及热影响区硬度值均超过母材,焊接钢板拉伸、弯曲性能合格.

  18. Application of Flash Butt Welding Technology of Stirrups for Tall Building%高层建筑中箍筋闪光对焊技术的应用

    Institute of Scientific and Technical Information of China (English)

    骆发江; 徐长锋; 李鹏; 杨雪萍; 孟召虎; 耿欣宗

    2012-01-01

    针对常规开口箍筋浪费钢材、施工难度大等诸多缺点,提出了在建筑工程施工中使用封闭式箍筋闪光对焊施工工艺.详细分析了工艺优点、施工流程、操作要点、资源配备、质量控制和社会经济效益.结果表明将箍筋用闪光对焊焊成封闭环式不但可以避免常规箍筋安装中的弊端,提高工程质量,还可以节省钢材、提高工效,具有良好的社会效益和经济效益.%Based on the disadvantages of open stirrups such as wasting material and construction difficulty, closed stirrup with flash butt welding method is proposed in construction engineering. The technological advantages, construction process, operation points, resource arrangement, quality control, social and economic benefits are introduced for the closed stirrup with flash butt welding method. The results show that the closed stirrup with flash butt welding method can not only avoid disadvantages in normal closed stirrup construction, but also improve construction quality and work efficiency with fewer steel materials.

  19. Neuro-Fuzzy Model for the Prediction and Classification of the Fused Zone Levels of Imperfections in Ti6Al4V Alloy Butt Weld

    Directory of Open Access Journals (Sweden)

    Giuseppe Casalino

    2013-01-01

    Full Text Available Weld imperfections are tolerable defects as stated from the international standard. Nevertheless they can produce a set of drawbacks like difficulty to assembly, reworking, limited fatigue life, and surface imperfections. In this paper Ti6Al4V titanium butt welds were produced by CO2 laser welding. The following tolerable defects were analysed: weld undercut, excess weld metal, excessive penetration, incomplete filled groove, root concavity, and lack of penetration. A neuro-fuzzy model for the prediction and classification of the defects in the fused zone was built up using the experimental data. Weld imperfections were connected to the welding parameters by feed forward neural networks. Then the imperfections were clustered using the C-means fuzzy clustering algorithm. The clusters were named after the ISO standard classification of the levels of imperfection for electron and laser beam welding of aluminium alloys and steels. Finally, a single-value metric was proposed for the assessment of the overall bead geometry quality. It combined an index for each defect and functioned according to the criterion “the-smallest-the-best.”

  20. The fatigue strength of base material and butt welds made of S690 and S1100

    NARCIS (Netherlands)

    Pijpers, R.J.M.; Kolstein, M.H.; Romeijn, A.; Bijlaard, F.S.K.

    2007-01-01

    Modern steel manufacturing techniques make it possible to produce steel with nominal strengths up to 1100 MPa (very high strength steels, VHSS). For the design of cyclic loaded slender VHSS structures, the fatigue strength of both base material and welded components should be known. In a VHSS fatigu

  1. Cr20Ni80合金棒材闪光对焊特性%Specialities of flash butt welding of Cr20Ni80 alloy bars

    Institute of Scientific and Technical Information of China (English)

    王希靖; 蒋文学; 张昌青

    2011-01-01

    Flash butt welding of electrical heating alloy Cr20Ni80 was investigated and the mechanical properties, microstructure and hardness of the welded joints were discussed. The results showed that, on condition of selected process parameters, welding seam was good, the average joint tensile strength a-chieved 555 Mpa, elongation rate-18. 7%, cross-section reduction-20. 8%, and with no noticeable welding defects. Minimum hardness took place in the weld seams, the hardness in the heat-affected zone increased greatly. Compared with its parent material, there was no softening phenomenon. Flash butt welding of Cr20Ni80 alloy exhibited good adaptability and a welding joint with fine performance could be obtained.%对电热合金Cr20Ni80进行连续闪光对焊研究,讨论其焊接接头的力学性能、微观组织和接头硬度.结果表明:在选定的工艺参数条件下,焊缝结合良好,接头平均抗拉强度达到555 MPa,延伸率为18.7%,断面收缩率为20.8%;接头结合致密,无明显焊接缺陷;在焊缝处硬度最低,两侧的热影响区硬度明显增大,与母材相比没有出现软化现象.闪光对焊对Cr20Ni80合金的焊接具有良好的适应性,可得到性能优良的焊接接头.

  2. Numerical study of electron beam welded butt joints with the GTN model

    Science.gov (United States)

    Tu, Haoyun; Schmauder, Siegfried; Weber, Ulrich

    2012-08-01

    The fracture behavior of S355NL electron beam welded steel joints is investigated experimentally and numerically. The simulation of crack propagation in an electron beam welded steel joint was performed with the Gurson-Tvergaard-Needleman (GTN) damage model. A parameter study of the GTN model was adopted which reveals the influence of parameters on the material behavior of notched round and compact tension specimens. Based on the combined method of metallographic investigations and numerical calibration, the GTN parameters were fixed. The same parameters were used to predict the ductile fracture of compact tension specimens with the initial crack located at different locations. Good match can be found between the numerical and experimental results in the form of force versus Crack Opening Displacement as well as fracture resistance curves.

  3. Optimal design for laser beam butt welding process parameter using artificial neural networks and genetic algorithm for super austenitic stainless steel

    Science.gov (United States)

    Sathiya, P.; Panneerselvam, K.; Soundararajan, R.

    2012-09-01

    Laser welding input parameters play a very significant role in determining the quality of a weld joint. The joint quality can be defined in terms of properties such as weld bead geometry, mechanical properties and distortion. Therefore, mechanical properties should be controlled to obtain good welded joints. In this study, the weld bead geometry such as depth of penetration (DP), bead width (BW) and tensile strength (TS) of the laser welded butt joints made of AISI 904L super austenitic stainless steel were investigated. Full factorial design was used to carry out the experimental design. Artificial Neural networks (ANN) program was developed in MatLab software to establish the relationships between the laser welding input parameters like beam power, travel speed and focal position and the three responses DP, BW and TS in three different shielding gases (Argon, Helium and Nitrogen). The established models were used for optimizing the process parameters using Genetic Algorithm (GA). Optimum solutions for the three different gases and their respective responses were obtained. Confirmation experiment has also been conducted to validate the optimized parameters obtained from GA.

  4. Influence of arc pressure on the forming of molten pool in tungsten inert gas arc butt welding with micro gap for tantalum sheet

    Institute of Scientific and Technical Information of China (English)

    Zhou Fangming; Qian Yiyu

    2006-01-01

    Arc pressure is the key influencing factor to forming of molten pool.Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a distribution model of arc pressure and forming mechanism of molten pool with micro butt gap are proposed, and the influences of arc pressure on forming of molten pool are discussed.Experimental researches for the dynamic formation process of weld molten pool by using high-speed vidicon camera show that when buttgap is appropriate, that is from 0.1 to 0.15 mm, molten metals formed on two workpiece uplift and growup first, then are fused and form uniform molten pool finally.

  5. Effect of laser beam position on mechanical properties of F82H/SUS316L butt-joint welded by fiber laser

    International Nuclear Information System (INIS)

    Highlights: • The micro hardness of weld metal in F82H/SUS316L joint partially decreases after PWHT by shifting beam position to SUS316L. • Charpy impact energy of F82H/SUS316L joint obviously increases after PWHT due to the release of residual stress. • The tensile strength of weld metal in F82H/SUS316L joint is higher than that of SUS316L. • The fiber laser welding seems to be one of the most candidate methods to join between F82H and SUS316L pipes practically. - Abstract: A dissimilar butt-joint between reduced activation ferritic/martensitic steel F82H and SUS316L austenitic stainless steel was made by 4 kW fiber laser and the influence of laser beam position on its mechanical properties before and after post-weld heat treatment (PWHT) was examined at room temperature. From the nano-indentation measurements and the microstructural observations, it is found that the micro hardness of weld metal partially decreases after PWHT by shifting beam position to SUS316L because its phase seems to move from only the martensitic phase to the mixture of austenitic and martensitic phases. In addition, Charpy impact test suggests that the impact energy slightly increases by shifting beam position before PWHT and obviously increases after PWHT due to the release of residual stress. Moreover, the tensile test indicates that the tensile strength of weld metal is higher than that of SUS316L and the fracture occurs at the base metal of SUS316L regardless of laser beam position

  6. Effect of laser beam position on mechanical properties of F82H/SUS316L butt-joint welded by fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, Hisashi, E-mail: serizawa@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Mori, Daiki; Ogiwara, Hiroyuki; Mori, Hiroaki [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2014-10-15

    Highlights: • The micro hardness of weld metal in F82H/SUS316L joint partially decreases after PWHT by shifting beam position to SUS316L. • Charpy impact energy of F82H/SUS316L joint obviously increases after PWHT due to the release of residual stress. • The tensile strength of weld metal in F82H/SUS316L joint is higher than that of SUS316L. • The fiber laser welding seems to be one of the most candidate methods to join between F82H and SUS316L pipes practically. - Abstract: A dissimilar butt-joint between reduced activation ferritic/martensitic steel F82H and SUS316L austenitic stainless steel was made by 4 kW fiber laser and the influence of laser beam position on its mechanical properties before and after post-weld heat treatment (PWHT) was examined at room temperature. From the nano-indentation measurements and the microstructural observations, it is found that the micro hardness of weld metal partially decreases after PWHT by shifting beam position to SUS316L because its phase seems to move from only the martensitic phase to the mixture of austenitic and martensitic phases. In addition, Charpy impact test suggests that the impact energy slightly increases by shifting beam position before PWHT and obviously increases after PWHT due to the release of residual stress. Moreover, the tensile test indicates that the tensile strength of weld metal is higher than that of SUS316L and the fracture occurs at the base metal of SUS316L regardless of laser beam position.

  7. Project of integrity assessment of flawed components with structural discontinuity (IAF). Data book for residual stress analysis in weld joint. Butt weld joint of small diameter cylinder (4B Sch40)

    International Nuclear Information System (INIS)

    The project of Integrity Assessment of Flawed Components with Structural Discontinuity (IAF) was entrusted to Japan Power Engineering and Inspection Corporation (JAPEIC) from Nuclear and Industrial Safety Agency (NISA) and started from FY 2001. And then, it was taken over to Japan Nuclear Energy Safety Organization (JNES) which was established in October 2003 and carried out until FY 2007. In the IAF project, weld joints between nickel based alloys and low alloy steels around penetrations in reactor vessel, safe-end of nozzles and shroud supports were selected from among components and pipe arrangements in nuclear power plants, where high residual stresses were generated due to welding and complex structure. Residual stresses around of the weld joints were estimated by finite element analysis method (FEM) with a general modeling method, then the reasonability and the conservativeness was evaluated. In addition, for postulated surface crack of stress corrosion cracking (SCC), a simple calculation method of stress intensity factor (K) required to estimate the crack growth was proposed and the effectiveness was confirmed. JNES compiled results of the IAF project into Data Books of Residual Stress Analysis of Weld Joint, and Data Book of Simplified Stress Intensity Factor Calculation for Penetration of Reactor as typical Structure Discontinuity, respectively. Data Books of Residual Stress Analysis in Weld Joint. 1. Butt Weld joint of Small Diameter Cylinder (4B Sch40) (JNES-RE-2012-0005), 2, Dissimilar Metal Weld Joint in Safe End (One-Side Groove Joint (JNES-RE-2012-0006), 3. Dissimilar Metal Weld Joint in Safe End (Large Diameter Both-Side Groove Joint) (JNES-RE-2012-0007), 4. Weld Joint around Penetrations in Reactor Vessel (Insert Joint) (JNES-RE-2012-0008), 5. Weld Joint in Shroud Support (H8, H9, H10 and H11 Welds) (JNES-RE-2012-0009), 6. Analysis Model of Dissimilar Metal Weld Joint Applied Post Weld Heat Treatment (PWHT) (JNES-RE-2012-0010). Data Book of

  8. 大板梁翼板对接焊缝的超声波检测%Ultrasonic Testing on Butt Weld of Wing Plate of Main Girder

    Institute of Scientific and Technical Information of China (English)

    唐垚; 喻星星

    2015-01-01

    The ultrasonic testing method of the butt weld of the wing plate with a thickness of 140 mm of the main girder in the utility boiler is introduced. The selection of the probe, the determination of the scanning method in the detection process and the method for depicting the DAC curve using the CSK-Ⅳ test block are mainly discussed.%介绍了电站锅炉大板梁140 mm厚翼板对接焊缝的超声波检测方法. 主要论述了检测过程中探头的选取、 扫查方式的确定以及利用CSK-Ⅳ试块制作DAC曲线的方法.

  9. Technology and Equipment of Development in Flashing Butt Welding%闪光焊工艺与设备的发展

    Institute of Scientific and Technical Information of China (English)

    王治平; 王克争; 何方殿

    2000-01-01

    闪光焊(Flash butt welding:FBW)作为一种有效的焊接方法得到了广泛的应用,近些年来有了很大的发展,新的工艺和控制方法也不断地出现.本文具体介绍了闪光焊在焊接工艺、送进方式、控制方法等方面的发展情况.还介绍了一些比较典型的焊机,包括GAas80钢轨闪光对焊机、K-355钢轨闪光焊机和K-700-1型管道闪光对焊机等.

  10. The Effect of Ultrasonic Peening on Service Life of the Butt-Welded High-Temperature Steel Pipes

    Science.gov (United States)

    Daavari, Morteza; Vanini, Seyed Ali Sadough

    2015-09-01

    Residual stresses introduced by manufacturing processes such as casting, forming, machining, and welding have harmful effects on the mechanical behavior of the structures. In addition to the residual stresses, weld toe stress concentration can play a determining effect. There are several methods to improve the mechanical properties such as fatigue behavior of the welded structures. In this paper, the effects of ultrasonic peening on the fatigue life of the high-temperature seamless steel pipes, used in the petrochemical environment, have been investigated. These welded pipes are fatigued due to thermal and mechanical loads caused by the cycle of cooling, heating, and internal pressure fluctuations. Residual stress measurements, weld geometry estimation, electrochemical evaluations, and metallography investigations were done as supplementary examinations. Results showed that application of ultrasonic impact treatment has led to increased fatigue life, fatigue strength, and corrosion resistance of A106-B welded steel pipes in petrochemical corrosive environment.

  11. Parameters optimization of hybrid fiber laser-arc butt welding on 316L stainless steel using Kriging model and GA

    Science.gov (United States)

    Gao, Zhongmei; Shao, Xinyu; Jiang, Ping; Cao, Longchao; Zhou, Qi; Yue, Chen; Liu, Yang; Wang, Chunming

    2016-09-01

    It is of great significance to select appropriate welding process parameters for obtaining optimal weld geometry in hybrid laser-arc welding. An integrated optimization approach by combining Kriging model and GA is proposed to optimize process parameters. A four-factor, five-level experiment using Taguchi L25 is conducted considering laser power (P), welding current (A), distance between laser and arc (D) and traveling speed (V). Kriging model is adopted to approximate the relationship between process parameters and weld geometry, namely depth of penetration (DP), bead width (BW) and bead reinforcement (BR). The constructed Kriging model was used for parameters optimization by GA to maximize DP, minimize BW and ensure BR at a desired value. The effects of process parameters on weld geometry are analyzed. Microstructure and micro-hardness are also discussed. Verification experiments demonstrate that the obtained optimum values are in good agreement with experimental results.

  12. A Combined Experimental/Computational Analysis of the Butt-Friction-Stir-Welded AA2139-T8 Joints

    Science.gov (United States)

    Grujicic, M.; Snipes, J. S.; Ramaswami, S.; Yen, C.-F.

    2016-07-01

    Combined experimental and computational investigations are carried out of the mechanical properties of materials residing in different weld zones of friction stir-welded (FSW) joints of thick plates of AA2139-T8. The experimental portion of the work comprised (a) identification of the weld zones within the FSW joints, through the use of optical-microscopy characterization of a transverse section; (b) validation of the weld zones identified in (a) via the generation of a micro-hardness field over the same transverse section; (c) extracting and subsequently testing miniature tensile specimens from different weld zones; and (d) extracting and testing a larger-size tensile specimen spanning transversely the FSW weld. The computational portion of the work comprised (i) validation of the mechanical properties, as determined experimentally using the miniature tensile specimens, of the material residing within different zones of the FSW joint; and (ii) clarification of the benefits yielded by the knowledge of the local material properties within the FSW joint. These benefits arise from the fact that (a) joint mechanical properties are generally inferior to those of the base metal; (b) the width of the weld in thick metallic-armor is often comparable to the armor thickness, and therefore may represent a significant portion of the armor exposed-surface area; and (c) modeling of the weld-material structural response under loading requires the availability of high-fidelity/validated material constitutive models, and the development of such models requires knowledge of the local weld-material mechanical properties.

  13. CT80连续油管TIG焊对接接头热循环过程研究%Welding Thermal Cycle of CT 80 Coiled Tube Butt Joint by TIG Welding

    Institute of Scientific and Technical Information of China (English)

    李霄; 石凯; 王洪铎; 李洁

    2011-01-01

    采用热电偶多点同步测量的方法研究r CT80连续油管对接接头的焊接热循环过程结果表明,由于CT80连续油管管径小,焊接热累积效应明显,热影响区中总是存在不问程度的软化区,为获得良好的焊接接头性能,在制定焊接工艺时,应避免热量的过分集中,从而减小软化的幅度及范围.%The thermal cycle during butt welding was studied by thermocouple and multi-point synchronized measuring technique. The results show that CT80 is very sensitive to welding heat, and the heat accumulation is obvious for mini-dimension coiled tubing, different degree of softening always exist in HAZ. In order to get good properties, the strength matching should be pay more attention during welding process setting, to avoid welding heat assembly for reducing the softening scale and degree.

  14. Influence of pin geometry on mechanical and structural properties of butt friction stir welded 2024-T351 aluminum alloy

    Directory of Open Access Journals (Sweden)

    Radisavljević Igor Z.

    2015-01-01

    Full Text Available The aim of this work was to investigate the combined effect of small difference in pin geometry, together with rotation and welding speed on the weldability, mechanical and structural properties of FSW 2024-T351 Al plates. The only difference in tool pin design was the shape of thread: regular and rounded. Specimens were welded using rotation rate of 750 rev/min and welding speeds of 73 and 93 mm/min. In all four cases, specimens were defect free, with good or acceptable weld surface. Modification in pin design showed strong influence on macro structure and hardness distribution. Weak places are identified as low hardness zone, close to the nugget zone and are in good agreement with fracture location in tensile testing. Weld efficiency, as a measure of weld quality, are better in case of 310 tool, while UTS values can differ up to 13% for the equal welding parameters. Therefore, it can be assumed that small modification in tool design, particularly in pin geometry, can have great influence on weld formation and mechanical properties.

  15. How to choose diesel power unit in mobile railway flash-butt-welding system%移动式钢轨闪光焊机系统中柴油发电机组的选择

    Institute of Scientific and Technical Information of China (English)

    王志伟; 戴虹; 易琼

    2012-01-01

    在目前移动式钢轨闪光焊机系统中,均采用柴油发电机组作为焊机系统的供电电源.列举了现有移动式交流钢轨闪光焊机系统中柴油发电机组的功率选配现状,分析了移动式钢轨闪光焊机实际用电功率需求,指出现有柴油发电机组选配功率不足的普遍问题,提出初步改进意见.%In current mobile railway flash-butt-welding system,all welding machine supply power is diesel power unil.Enumerate current diesel power unit selections in mobile railway flash-butt-welding system and analyze power consumption in mobile railway flash-butt-welding machine,figure out under-power in current diesel power unit,propose preliminary improvement suggestion.

  16. Study on Flash Butt Welding Parameters of Extra-high-tensile R5 Mooring Chain%超高强度R5系泊链焊接参数的研究

    Institute of Scientific and Technical Information of China (English)

    李剑; 张卫新; 朱桥良; 张明

    2011-01-01

    R5级系泊链钢是一种对焊接工艺要求较高的材料,为保证系泊链产品力学性能合格,通过大量试验对其闪光焊接参数进行了研究.结果表明,烧化量、顶锻量、焊接速度和二次空载电压是影响焊接接头质量的重要参数;要保证产品性能,必须将闪光焊接参数控制在一个非常窄的范围内,并获得了其最优化的焊接工艺.%The effects of flash butt welding parameters on properties of products were explored for Grade R5 mooring chain. It is shown that the change of the flashing length, upsetting length, flashing speed and no-load secondary voltage which are the parameters of the flash butt welding have a significant influence on quality of weld joint. Through this work, flash butt welding condition of the Φ84 mm R5 mooring chain for the offshore structure was presented.

  17. Application of new GMAW welding methods used in prefabrication of P92 (X10CrWMoVNb9-2) pipe butt welds

    Energy Technology Data Exchange (ETDEWEB)

    Urzynicok, Michal [Boiler Elements Factory ' ZELKOT' , Koszecin (Poland); Kwiecinski, Krzysztof; Slania, Jacek [Instytut Spawalnictwa, Gliwice (Poland); Szubryt, Marian [TUEV Nord, Katowice (Poland)

    2010-07-01

    Welding of collector pipes, flat heads, dished ends and connector pipes performed with high temperature and creep-resistant steels most often has been performed using TIG process combined with MMA processes. Progress in MAG process and availability of high quality filler materials (solid wires) enables welding of the above connections also using this method. In order to prove its efficiency, this article presents the results of related tests. The range of tests was similar to that applied during the qualification of welding technology. The investigation also involved microscopic and fractographic examinations. The results reveal that welding with new methods such as GMAW is by no means inferior to a currently applied MMA method yet the time of the process is shorter by 50%. The article present the world's first known positive results in welding of P92 grade steel using GMAW welding method. (orig.)

  18. High-temperature creep rupture of low alloy ferritic steel butt-welded pipes subjected to combined internal pressure and end loadings.

    Science.gov (United States)

    Vakili-Tahami, F; Hayhurst, D R; Wong, M T

    2005-11-15

    Constitutive equations are reviewed and presented for low alloy ferritic steels which undergo creep deformation and damage at high temperatures; and, a thermodynamic framework is provided for the deformation rate potentials used in the equations. Finite element continuum damage mechanics studies have been carried out using these constitutive equations on butt-welded low alloy ferritic steel pipes subjected to combined internal pressure and axial loads at 590 and 620 degrees C. Two dominant modes of failure have been identified: firstly, fusion boundary failure at high stresses; and, secondly, Type IV failure at low stresses. The stress level at which the switch in failure mechanism takes place has been found to be associated with the relative creep resistance and lifetimes, over a wide range of uniaxial stresses, for parent, heat affected zone, Type IV and weld materials. The equi-biaxial stress loading condition (mean diameter stress equal to the axial stress) has been confirmed to be the worst loading condition. For this condition, simple design formulae are proposed for both 590 and 620 degrees C. PMID:16243708

  19. Effects of filling material and laser power on the formation of intermetallic compounds during laser-assisted friction stir butt welding of steel and aluminum alloys

    Science.gov (United States)

    Fei, Xinjiang; Jin, Xiangzhong; Peng, Nanxiang; Ye, Ying; Wu, Sigen; Dai, Houfu

    2016-11-01

    In this paper, two kinds of materials, Ni and Zn, are selected as filling material during laser-assisted friction stir butt welding of Q235 steel and 6061-T6 aluminum alloy, and their influences on the formation of intermetallic compounds on the steel/aluminum interface of the joints were first studied. SEM was used to analyze the profile of the intermetallic compound layer and the fractography of tensile fracture surfaces. In addition, EDS was applied to investigate the types of the intermetallic compounds. The results indicate that a thin iron-abundant intermetallic compound layer forms and ductile fracture mode occurs when Ni is added, but a thick aluminum-abundant intermetallic compound layer generates and brittle fracture mode occurs when Zn is added. So the tensile strength of the welds with Ni as filling material is greater than that with Zn as filling material. Besides, the effect of laser power on the formation of intermetallic compound layer when Ni is added was investigated. The preheated temperature field produced by laser beam in the cross section of workpiece was calculated, and the tensile strength of the joints at different laser powers was tested. Results show that only when suitable laser power is adopted, can suitable preheating temperature of the steel reach, then can thin intermetallic compound layer form and high tensile strength of the joints reach. Either excessive or insufficient laser power will reduce the tensile strength of the joints.

  20. Method and equipment for measurement of residual stresses in erection welded butts of pipelines made of clad steel

    International Nuclear Information System (INIS)

    Investigations into determination of residual stresses on welded joints of pipelines of 34 mm thick 22 K pearlitic steel cladded with a 4 mm thick layer of chromium-nickel steel are conducted under mounting at the Kursk NPP. Mounting welded joints of the pipelines of clad steel are under the effect of residual stresses, particularly, joints of tube-knee type, where the level of residual stresses reaches 450-550 MPa. Repair of mounting welded joints of pipeles of clad steel is stated to result in increase of residual stresses on the surface of the joints

  1. Effect of Included Angle in V-Groove Butt Joints on Shrinkages in Submerged Arc Welding Process

    OpenAIRE

    N. Lakshmana Swamy; G. MAHENDRAMANI

    2012-01-01

    The problems of distortion, residual stresses and reduced strength of structure in and around a welded joint are of major concern in the shipbuilding industry and in other similar manufacturing industries. The predictions of the degree of shrinkages in ship panels due to welding are of great importance from the point of view of dimensional control and it is important to analyze transverse and longitudinal shrinkage. This paper deals with the experimental analysis of transverse and longitudina...

  2. Study on weld bead surface profile and angular distortion in 6 mm thick butt weld joints of SS304 using fiber laser

    Science.gov (United States)

    Bhargava, P.; Paul, C. P.; Mundra, G.; Premsingh, C. H.; Mishra, S. K.; Nagpure, D.; Kumar, Atul; Kukreja, L. M.

    2014-02-01

    We deployed a 2 kW continuous wave fiber laser integrated with the 5-axis workstation to understand the effect of various processing parameters (laser power, welding speed, beam spot size and chamfer at welded edges) on depth of penetration, angular distortion and welded bead surface profile during autogenous laser welding of 6 mm thick austenitic stainless steel type 304 plates. Full penetration with reduced weld bead surface undulation (fusion zone with a few porosities at isolated locations. The microstructure at the fusion zone was largely austenitic with few ferrites and the direction of growth was epitaxial towards the fusion line. The measured values of microhardness at base material and fusion zone were 208±4 HV0.1 and 235±10 HV0.1 respectively. The tensile testing of laser welded samples indicated the ultimate strength >605 MPa and these samples could be bent for an angle >170° without noticeable crack during bend test. The study opened the avenues for the deployment of fiber laser welding technology for applications demanding critical values of surface weld bead profile and distortion.

  3. X80长输油气管道闪光对接焊技术研究%Research on Flash Butt Welding Process of X80 Long-distance Oil and Gas Pipeline

    Institute of Scientific and Technical Information of China (English)

    高建文; 胡建春; 宋晞明; 李洁; 傅建楠

    2015-01-01

    According to the welding quality requirements of long-distance oil and gas pipeline construction, the flash butt welding process of X80 pipeline steel was studied. Through analyzing the chemical composition and mechanical properties, combined with the selected welding process and welding method, the welding was carried out for X80 pipeline steel, and the mechanical properties of its welded joints were tested. The results showed that the flash butt welding performance of X80 steel is very good, and the strength, hardness and low temperature toughness can meet the safety requirement of X80 grade pipeline steel. The welding method and the technological parameters can be used for site welding.%针对长输油气管道建设对焊接质量的要求,对X80管线钢的闪光对接焊工艺进行了研究。通过对长输管道用X80管线钢化学成分及力学性能进行分析,结合选定的焊接方法和焊接工艺,对该管线钢进行了焊接,并对其焊接接头的力学性能进行了测试。结果表明,闪光对接焊得到的焊接接头性能良好,接头的强度、硬度、韧性等性能均满足X80管线钢管的安全要求。所选用的焊接方法和工艺参数可用于该管材的现场焊接。

  4. X80长输油气管道闪光对接焊技术研究%Research on Flash Butt Welding Process of X80 Long-distance Oil and Gas Pipeline

    Institute of Scientific and Technical Information of China (English)

    高建文; 胡建春; 宋晞明; 李洁; 傅建楠

    2015-01-01

    针对长输油气管道建设对焊接质量的要求,对X80管线钢的闪光对接焊工艺进行了研究。通过对长输管道用X80管线钢化学成分及力学性能进行分析,结合选定的焊接方法和焊接工艺,对该管线钢进行了焊接,并对其焊接接头的力学性能进行了测试。结果表明,闪光对接焊得到的焊接接头性能良好,接头的强度、硬度、韧性等性能均满足X80管线钢管的安全要求。所选用的焊接方法和工艺参数可用于该管材的现场焊接。%According to the welding quality requirements of long-distance oil and gas pipeline construction, the flash butt welding process of X80 pipeline steel was studied. Through analyzing the chemical composition and mechanical properties, combined with the selected welding process and welding method, the welding was carried out for X80 pipeline steel, and the mechanical properties of its welded joints were tested. The results showed that the flash butt welding performance of X80 steel is very good, and the strength, hardness and low temperature toughness can meet the safety requirement of X80 grade pipeline steel. The welding method and the technological parameters can be used for site welding.

  5. Analysis of optical and acoustic signals in CO_2 laser butt welding%CO_2激光拼焊的光与声信号分析

    Institute of Scientific and Technical Information of China (English)

    盂宣宣; 王春明; 胡席远

    2011-01-01

    The blueviolet radiation(400-440 nm),infrared radiation(1 200-1 700 nm) and audio sound(20-20 kHz) are used as signals detected by a multi-sensor real-time monitoring system in the process of CO2 laser butt welding.The signals can be collected and recorded online.The valuable information in the signals was found out by time-domain,frequency domain and time-frequency analysis.According to the signal features,it can be concluded that the high frequency part(higher than 7 000 Hz) of the optical and acoustic signals,especially the blueviolet optical radiation signal can reflect the stability of welding pool and keyhole well,and can be used to identify the weld seam defects caused by large gap joint.%采用自行研制的多传感器激光焊接实时监测系统,以CO2激光拼焊过程中的蓝紫光辐射(400~440 nm)、红外辐射(1 200~1 700 nm)以及可听声(20~20 kHz)等三种信号作为被检测参量,进行了信号的在线采集与记录,通过时域、频域以及时频分析,实现信号中有效信息的挖掘.结果表明,7 000 Hz以上的高频段光声信号成分,尤其是蓝紫光信号,较好地反映了熔池与小孔的稳定性,可以用于识别间隙过大造成的焊缝质量问题.

  6. 预拉伸法降低异种钢焊接残余应力的作用研究%Effect of pre-tensile stress on welding residual stress filed in butt-welded dissimilar flat plates

    Institute of Scientific and Technical Information of China (English)

    赵东升; 吴国强; 刘玉君; 孙敏科; 纪卓尚

    2013-01-01

      采用热弹塑性有限元法计算了Q235钢与304不锈钢平板对接焊在不同预拉伸应力作用下的焊接残余应力场,计算结果表明,焊接残余应力呈现非对称式分布,纵向残余应力的峰值均出现在304不锈钢一侧且高于其屈服强度。预置纵向拉伸应力能显著降低纵向焊接残余应力,而且当预置拉伸应力越大时(低于屈服强度),降低焊接残余应力的效果越明显。采用红外热像仪测量了焊接过程中焊接材料表面的温度变化情况,有限元计算的结果与其符合较好。%Thermal Elasto-plastic finite element method was used to simulate the welding residual stresses in butt-welded Q235 and 304 Stainless Steel plates with different pre-tensile stresses. The simulation re-sults indicate that the welding residual stresses present asymmetric distribution, peak of longitudinal resid-ual stress tends to be in 304 stainless steel side. Pre-tensile stress can decrease the longitudinal residual stress significantly, and the more the pre-loads, the lower the longitudinal residual stresses. An infrared thermal imager was also applied to measure surface temperature changing of welding materials in welding process, the results are accordant with that drawn from elasto-plastic finite element measurement.

  7. 加热均匀度对焊接质量的影响%Influence of flash-butt welded joint quality based the degree of heat input

    Institute of Scientific and Technical Information of China (English)

    张小路; 邹良甫

    2013-01-01

    在焊轨生产中,为了稳定焊接质量,从焊接设备角度分析如何保证焊接工艺稳定状态,对于进一步减少或消除焊接缺陷十分重要.以K1000型固定式闪光焊机的电极与钢轨底板接触的契合程度,通过调整电极与钢轨接触面的契合程度,达到标准焊接状态,研究了由此所引发的轨底脚灰斑、轨脚过烧、三角区细小灰斑和未焊合等缺陷数量分布特征,以及对焊接质量的危害规律.结果表明:电极与钢轨的接触状态不良,会导致工艺参数的调整难以获得稳定质量的预期效果,在很大程度上会影响钢轨接头落锤稳定性,应在生产中给予重视.%In order to maintain the quality of welded joint during the manufacture.analyzing how to keep the welding procedure steady from the perspective of the equipment is so important to eliminate the welded defects.This article elaborates the influence of K1000 stationary bash-butt welded joint quality based the degree of the electrode accord with the rail surface from below grade up to the standard.The flat spot in the bottom of the joint,overburn and lack of bond will be easily raised and each has its own rule of harm.The test results indicate that it is difficult to achieve the process parameter test expected effect if the degree of the electrode accord with the rail surface in a bad situation.and the stability of drop-weighttest of welded joint will be greatly affected.More attention should be paid on this factor durin manufacturing.

  8. Numerical Modelling Of Thermal And Structural Phenomena In Yb:YAG Laser Butt-Welded Steel Elements

    Directory of Open Access Journals (Sweden)

    Kubiak M.

    2015-06-01

    Full Text Available The numerical model of thermal and structural phenomena is developed for the analysis of Yb:YAG laser welding process with the motion of the liquid material in the welding pool taken into account. Temperature field and melted material velocity field in the fusion zone are obtained from the numerical solution of continuum mechanics equations using Chorin projection method and finite volume method. Phase transformations in solid state are analyzed during heating and cooling using classical models of the kinetics of phase transformations as well as CTA and CCT diagrams for welded steel. The interpolated heat source model is developed in order to reliably reflect the real distribution of Yb:YAG laser power obtained by experimental research on the laser beam profile.

  9. 单晶铜/多晶铜闪光对焊接头组织的演变%Microstructure Evolution of Flash Butt Welding Joint Between Single Crystal Copper and Poly-crystal Copper

    Institute of Scientific and Technical Information of China (English)

    李炳; 范新会; 王鑫; 陈建; 严文

    2013-01-01

    电阻焊在焊接单晶铜/多晶铜时,可使焊接热过程对单晶组织影响最小化。采用不同焊接电流,对单晶铜/多晶铜进行闪光对焊,对焊接接头的热影响区宽度和显微组织进行了分析。结果表明:闪光对焊对多晶铜组织的影响极为显著,随着离焊缝距离的增加,依次呈现出粗晶区、细晶区、超细晶区、超细晶与母材混合区。单晶铜一端仅在近缝处的极小范围内发生了再结晶行为。%When single crystal copper and poly-crystal copper (PCC ) were welded by resistance welding ,the effect on single crystal copper(SCC) is very small .For SCC and PCC by flash butt welding with different welding currents ,the width of heat affected zone and microstructures of welded joint were investigated .The results showed that flash butt welding made significant changes in the microstructure of PCC .Coarse grain area ,fine grain area ,super fine grain area ,super fine crystal mixed with the base metal zone can be observed with increase of the distance from the welding seam .However , recrystallization happened just in tiny range nearby the welding seam for single crystal copper .

  10. Assessment of Weld Overlays for Mitigating Primary Water Stress Corrosion Cracking at Nickel Alloy Butt Welds in Piping Systems Approved for Leak-Before-Break

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Edward J.; Anderson, Michael T.

    2012-08-01

    This TLR provides an assessment of weld overlays as a mitigation strategy for PWSCC, and includes an assessment of the WOL-related inspection requirements of Code Case N-770-1, as conditioned in §50.55a.

  11. 76 FR 67473 - Stainless Steel Butt-Weld Pipe Fittings from Italy, Malaysia, and The Philippines; Institution of...

    Science.gov (United States)

    2011-11-01

    ...-weld pipe fittings from Italy, Malaysia, and the Philippines (71 FR 71530). The Commission is now...), and part 207, subparts A, D, E, and F (19 CFR part 207), as most recently amended at 74 FR 2847... Philippines (66 FR 11257). Following five-year reviews by Commerce and the Commission, effective December...

  12. 对接焊缝缺陷漏磁场特征分析及识别研究%Characteristic Analysis and Recognition of Magnetic Flux Leakage Field of Butt Weld Defects

    Institute of Scientific and Technical Information of China (English)

    戴光; 崔巍; 杨志军; 陈志华; 孙立强

    2011-01-01

    为实现钢板对接焊缝存在不同类型缺陷的识别研究,针对铁磁性焊缝的特点,探讨应用漏磁法检测钢板对接焊缝不同类型缺陷.根据漏磁检测(MFL)原理,采用有限元方法(FEM),分别建立钢板对接焊缝中可能存在的裂纹、气孔、未熔合和未焊透等缺陷的三维FEM模型.研究钢板对接焊缝包含以上不同类型缺陷时所产生的漏磁场分布特征,得到漏磁场磁感应强度水平分量和垂直分量相关对比分析曲线.仿真结果表明:漏磁法适用于钢板对接焊缝缺陷的识别研究;根据漏磁场磁感应强度分量的曲线特征,能够实现对焊缝缺陷的分类.%In order to realize the recognition of different types of defects existing in butt welds in steel plates, magnetic flux leakage ( MFL) method was used to detect different types of butt weld defects in steel plates with consideration on the characteristics of ferromagnetic weld. According to the principle of MFL testing, 3D finite element method (FEM) models were established by using FEM numerical simulation for such defects as crack, stoma, incomplete fusion and incomplete penetration, respectively. Meanwhile, the distributing characteristics of magnetic flux leakage field for the above different types of butt weld defects in steel plate were studied, and the contrastive curves of horizontal component and vertical component of the magnetic induction density of magnetic flux leakage field were obtained. The results indicate that MFL method is suitable for the recognition study of butt weld defects of steel plates; also the classification of weld defects can be realized according to the curves of characteristics of component of the magnetic induction density of magnetic flux leakage field. This study provides theoretical basis for follow-up quantitative evaluation of weld defects.

  13. Butt joining of Al-Cu bilayer sheet through friction stir welding%搅拌摩擦焊接Al-Cu双层复合板

    Institute of Scientific and Technical Information of China (English)

    R. BEYGI; M. KAZEMINEZHAD; A. H. KOKABI

    2012-01-01

    Butt joining of Al-Cu bilayer sheet produced by cold roll bonding was studied through friction stir welding(FSW).A defect free joint was obtained.Flow patterns and mixing of two layers during FSW were investigated.Microstructural investigations and hardness profile measurements were carried out.It is shown that material flow in stir zone leads to the formation of banding structure in Cu layer at advancing side.Traces of Al particles along with Al-Cu intermetallic compounds exist in the fined grain region of this banding structure which leads to higher hardness values.%对冷轧Al-Cu双层复合板进行搅拌摩擦焊接,获得了无缺陷的焊接接头.对搅拌摩擦焊过程中的金属流动行为和两层之间的混合进行了研究,考察了显微组织和硬度的变化.结果表明,在搅拌区的金属流动导致了在Cu层中前进侧生成条带状结构,在这些条带状结构中的细晶区域中,存在微量的Al颗粒和Al-Cu金属间化合物,这导致了其硬度的增加.

  14. The non-destructive examination of butt-fillet tube-to-tubeplate welds for sodium-heated steam generators

    International Nuclear Information System (INIS)

    The paper describes the inspection techniques which have been developed at Risley Nuclear Laboratories over the last decade for the tube-to-tubeplate welds in the sodium heated evaporator units of the Prototype Fast Reactor at Dounreay, Caithness, Scotland. These techniques include radiography for the fabrication inspection, magnetic crack detection for failure investigations and ultrasonic inservice inspection techniques. A computerised data recording system is also described for the inservice inspection techniques. (author)

  15. 耐蚀钢轨U68CuCr闪光焊工艺研究%Study on flash butt welding process of corrosion resistance rail U68CuCr

    Institute of Scientific and Technical Information of China (English)

    朱敏; 任安超; 费俊杰; 吉玉; 郑建国

    2014-01-01

    Corrosion resistance rail U68CuCr is a new product of rail.The flash butt welding process of 100 m corrosion resistance rail was confirmed via study on the process of preheat flash butt welding.It could be drawn a conclusion that when the heat input of welding was 6 600-6 700 kJ,the number of preheat was 10,the peak of preheat short-circuit current 7 1 .3 kA,the time of short circuit 3-4 s,the rapid flash time 1 .2-1.5 s,the force of forge up to 420 kN,the distance of forge 11-12 mm,and total time of welding 130 s.The performance index of welding joint was satisfied with TB/T 1632-2005"welding of rail".The rail welded by this flash butt welding process has been used in j ing-guang railway.%耐蚀钢轨U68CuCr是新研发的钢轨品种,通过对预热闪光焊接工艺研究,制定出100 m耐蚀钢轨闪光焊接工艺。根据试验结果可以得出,当焊接热输入量在6600~6700 kJ,预热达到10次,预热峰值短路电流71.3 kA,短路时间3~4 s,快闪时间1.2~1.5 s,顶锻力达到420 kN,顶锻量为11~12 mm,焊接总耗时130 s,焊接后的钢轨焊头各项性能满足 TB/T 1632-2005《钢轨焊接》的要求。按照该闪光焊工艺焊接的钢轨,已在京广铁路上使用。

  16. Multi-objective optimization of weld geometry in hybrid fiber laser-arc butt welding using Kriging model and NSGA-II

    Science.gov (United States)

    Gao, Zhongmei; Shao, Xinyu; Jiang, Ping; Wang, Chunming; Zhou, Qi; Cao, Longchao; Wang, Yilin

    2016-06-01

    An integrated multi-objective optimization approach combining Kriging model and non-dominated sorting genetic algorithm-II (NSGA-II) is proposed to predict and optimize weld geometry in hybrid fiber laser-arc welding on 316L stainless steel in this paper. A four-factor, five-level experiment using Taguchi L25 orthogonal array is conducted considering laser power ( P), welding current ( I), distance between laser and arc ( D) and traveling speed ( V). Kriging models are adopted to approximate the relationship between process parameters and weld geometry, namely depth of penetration (DP), bead width (BW) and bead reinforcement (BR). NSGA-II is used for multi-objective optimization taking the constructed Kriging models as objective functions and generates a set of optimal solutions with pareto-optimal front for outputs. Meanwhile, the main effects and the first-order interactions between process parameters are analyzed. Microstructure is also discussed. Verification experiments demonstrate that the optimum values obtained by the proposed integrated Kriging model and NSGA-II approach are in good agreement with experimental results.

  17. 海洋隔水管对接环焊缝接头高周疲劳性能研究%Research on High Cycle Fatigue Property for Butt Circumferential Weld of Marine Riser

    Institute of Scientific and Technical Information of China (English)

    余钊辉; 党恩; 朱安达; 杨龙; 张建勋

    2013-01-01

    The four-point bend fatigue test method was used to measure the high cycle fatigue property of marine riser X80/X80J butt circumferential weld. The influence on crack initiation location of stress concentration,microstructure and hardness was analyzed comprehensively. The results showed that the fatigue crack of welded joint with weld reinforcement initiates from toes, and then extends to the heat affected zone from the weld reinforcement,while the crack initiates from weld and propagates along the weld without reinforcement. The stress concentration caused by the weld reinforcement is the main factor to reduce the welded joint fatigue performance. The fatigue limit of welded joint is 216 MPa for with reinforcement and 400 MPa for without the weld reinforcement.%采用四点弯曲疲劳试验法,测试了海洋隔水管道X80/X80J对接环焊缝高周疲劳性能。综合分析了应力集中、显微组织和硬度对裂纹萌生位置的影响。结果表明,有余高焊接接头疲劳裂纹在焊趾处萌生并向热影响区扩展,去除余高的焊接接头疲劳裂纹从焊缝处萌生并沿焊缝扩展;焊缝余高引起的应力集中是降低焊接接头疲劳性能的主要因素,有余高焊接接头的疲劳极限为216 MPa,去除余高的焊接接头疲劳极限为400 MPa。

  18. U71Mn钢轨闪光焊焊接接头落锤试验时断裂原因分析%Fracture analysis of flash butt welding of U71Mn rail in drop weight test

    Institute of Scientific and Technical Information of China (English)

    王林; 陈亮; 刘艳; 苟国庆; 李达; 陈辉; 涂铭旌

    2012-01-01

    The fracture reasons of flash butt welding of U71 Mn rail in drop weight test were analyzed in both macro and micro aspects. The results showed that the rail fractured in weld, which belongs to transverse brittle fracture. Sulfide inclusions existed in the welded joints is the main reason caused the rail fracture.%针对某闪光焊U71Mn钢轨在落锤试验时发生断裂的原因,从宏观和微观二个方面进行了分析.结果表明:该钢轨断裂于焊缝,属于横向脆性断裂.钢轨焊接接头中存在的硫化物夹杂是造成钢轨断裂的主要原因.

  19. 深海脐带缆内套钢管全位置脉冲TIG对接焊研究%Research on Full Position Pulse TIG Butt Welding of Steel Pipes in Deep-sea Umbilical Cable

    Institute of Scientific and Technical Information of China (English)

    杜兴吉; 夏正文; 王坤

    2014-01-01

    深海脐带缆是连接上部控制装置和海底生产系统的生命线,其内每根由数十至数百根钢管对接焊成的内套钢管质量必须是无懈可击的。由于管-管对接焊接时存在特殊性,在焊接过程中较容易出现焊接缺陷,严重影响到整个脐带缆的工作性能。通过大量试验,对每根长12~40 m的钢管进行精密组对,并采用全位置脉冲TIG焊技术对无法转动的小直径钢管环缝进行焊接,焊接采用TIG焊一次焊接成形,确定了最佳的焊接工艺规范参数,获得了焊缝表面成形美观、根部焊透性好、接头质量可靠等性能优良的焊接接头。%The deep sea umbilical cable is the lifeline for connecting the topside control facilities and the undersea production system;the quality of each steel pipe in umbilical cable which consists of tens to hundreds of steel pipe butt welding must be impeccable. Because the particularity exists in tube-tube butt welding, the welding defects occur easily in welding course, which seriously affects the working performance of umbilical cable. Through a large number of tests, during precision group for each 12 m to 40 m steel pipe, the circumferential weld of small diameter steel pipe of unable to rotate was welded by full position pulse TIG welding process. It determined the best welding procedure specification parameters, and obtained perfect welded joints with good weld profile, good penetrability and excellent quality.

  20. SiCp/3003Al复合材料与3003Al的闪光对焊研究%Flash Butt Welding of Silicon Carbide Particulate-reinforced 3003 Aluminum Composite with 3003 Aluminum

    Institute of Scientific and Technical Information of China (English)

    李杏瑞; 杨涤心; 肖宏滨

    2001-01-01

    The joining performance of SiCp partic ulate reinforced aluminummetal matrix composite (Al/SiCp) with 3003Al was stu died by continuous flash butt welding.The results of the test have shown that un der the certain welding parameter,the joints of SiCp/300Al with 3003Al are sou nd without any porosities and crack,and the strength of bounded joints increase with increasing SiCp volume percentage.Therefore,Continuous flash butt welding is fit for bonding SiCp/Al composite.%采用连续闪光对焊的焊接方法,对SiCp/3003Al复合材料与3003Al合金的焊接性进行研究。试验结果表明:在合适的工艺参数下,SiCp/3003Al与3003Al合金闪光对焊焊缝区结合致密、无气孔及裂纹等缺陷;接头强度高且随增强相(SiC颗粒)体积分数的增加而增加。因此,采用闪光对焊方法焊接颗粒增强型Al基复合材料是可行的。

  1. Whole Quenching in Solution of Tri-nitrate in Water for Butt Welded High Speed Steel Tap%对焊高速钢丝锥的三硝水溶液整体淬火

    Institute of Scientific and Technical Information of China (English)

    付桂琴; 夏俊生

    2009-01-01

    由HSP15超硬高速钢刃部和45钢柄部堆焊的手工丝锥可在硬度高达48~52 HRC的超高强度钢零件上攻螺纹.这种对焊丝锥的传统热处理工艺是刃部、柄部分别处理.后采用在三硝水溶液中整体淬火的工艺处理,从而简化了工艺过程,节省了能耗,消除了淬火油烟,而且丝锥的硬度和耐磨性比按传统工艺热处理的丝锥更好.改进后的热处理工艺已成功地应用于对焊丝锥的生产.%A kind of manual taps,butt welded by edge of HSP15 superhard high speed steel with handle of 45 steel, can tap in ultra-high strength steel parts with the hardness as high as 48~52 HRC. For such butt welded taps, their edges and handles were respectively heat treated in conventional practice. Afterwards, the taps were integrally quenched into a solution of tri-nitrate in water, in this way simplifying the heat treatment process, decreasing the energy consumption and eliminating the mist during oil-quenching, with the taps providing higher hardness and wea-rability compared with the conventional heat treatment process. The improved heat treatment process has now been successfully adopted in the production of butt welded taps.

  2. KAS260闪光对焊机控制组件分析研究%Analysis and study of controlling module of KAS260 flashing butt welding machine

    Institute of Scientific and Technical Information of China (English)

    冯锦国; 郝迎吉; 赵英

    2011-01-01

    简述闪光对焊基本工作原理和基本分类.介绍了从德国MRP公司引进的KAS260闪光对焊机的基本组成、控制原理和控制组件的组成及其主要功能.分析研究控制组件中焊接电压真有效值模拟电路的计算方法和焊接电压稳压控制的除法原理,比较除法原理和减法原理;控制组件中焊接电流的真有效值计算方法;比例换向阀是如何利用焊接电流进行控制的控制原理;通过模拟电路产生锯齿波的原理;触发矩形波的产生原理;以及最终晶闸管触发脉冲的产生原理.为正确使用和充分发挥设备的性能提供帮助.%Briefly introduce the sorts and fundamental principle of flashing butt. Introduce the fundamental constitutes,controlling principle of KAS260 flashing butt welding machine imported from MRP company in Germany,and introduce the constitutes of the controlling module of KAS260 Flashing butt welding machine and their function. Mainly analyze and study the welding voltage RMS calculation method that utilizes simulation circuit and division principle of welding voltage controlling method, and compare division principle and subtraction principle. Mainly analyze and study the welding current RMS calculation method of controlling module,the proportional reversing valve controlling principle that utilizes welding current,the tooth toothed wave generation principle that utilizes simulation circuit,the activating rectangle wave generation principle,and the last activating pulse generation principle of thyristors in the controlling module. Strongly provide aid for right using the machine and extremely exerting machine performance.

  3. Effect of flash butt welding process parameters on structure and property of tantalum strip%钽条闪光对焊工艺参数对其组织性能的影响

    Institute of Scientific and Technical Information of China (English)

    张晓; 万庆峰; 解永旭; 杨文明; 刘云峰; 郭林波

    2015-01-01

    为解决连续化生产中钽条焊接的技术难题,在惰性气体的保护下采用电容储能式预热闪光对焊,对轧制后的4 mm×4 mm钽条进行焊接试验研究。利用金相显微镜、扫描电镜和力学性能检测设备等分析检测手段,对不同焊接顶锻力作用下的焊接区(包括热影响区)的显微组织、晶粒和晶界微区成分、硬度以及焊接区拉伸强度等进行了测试。研究表明,采用合适的闪光对焊工艺可以实现大尺寸钽条的对接,焊缝组织致密,接头具有较高的结合强度,对于大尺寸钽条无头轧制与连续拉拔技术的发展具有一定的使用价值。%To solve the technical problems of tantalum strip welding during continuous production,the welding experiments of rolled 4 mm × 4 mm tantalum strips were conducted using capacitor discharge preheating flash butt welding under inert gas protection. Using optical microscopy,scanning electron microscope and mechanical properties testing equipment, the microstructure, grains and grain boundary compositions, hardness and tensile strength of the welding zones( including heat⁃affected zone) under different forging forces were tested. The bonding of large⁃sized tantalum butts can be achieved using appropriate flash butt welding process, with dense welding microstructure and high bonding strength. It helps tothe development ofendless rolling and continuous drawing of large⁃sized tantalum strips.

  4. Quality Control of the Flame Normalizing in Rail Flash-butt Welded Joint%钢轨闪光焊接头火焰正火的质量控制

    Institute of Scientific and Technical Information of China (English)

    周涛

    2016-01-01

    Flame normalizing is one of the methods to improve the mechanical properties of the welded joint. This paper summarizes the construction experience, on the basis of tests by means of theoretical analysis, obtains a specific set of quality control measures of flame normalizing in rail flash-butt welded joint.%正火是继钢轨焊接结束后一种重要的提高其机械性能的方法,本文总结以往的施工经验,在试验的基础上通过理论分析,得出一套具体的钢轨焊接火焰正火的质量控制措施。

  5. Analysis of fracture of U71Mn rail welded butt jioints on flash welding%U71Mn钢轨闪光焊对接接头断裂原因分析

    Institute of Scientific and Technical Information of China (English)

    钟英华

    2011-01-01

    随着列车行车速度的提高,钢轨的损坏由过去的磨损转变为各种形式的疲劳损坏,而夹杂物往往被视为显微裂纹的发源地,疲劳裂纹与夹杂物的存在关系密切.非金属夹杂物降低了钢轨的塑性、韧性和疲劳寿命.夹杂物对钢轨疲劳性能影响的具体程度取决于一系列因素,如夹杂物的数量、颗粒大小、形态及分布等.应用肉眼观察、光镜、电镜和能谱分析等方法从宏观和微观两个方面分析成昆线闪光对焊U71Mn钢轨断件的断裂原因.结果表明,本钢轨断件的破坏是由于疲劳裂纹扩展引起的横向断裂,即钢轨核伤;而疲劳裂纹是由闪光焊后残留在焊缝中的硅酸盐非金属夹杂物引起的.%As the train speed increased,damage to rail is changed from wear to various forms of fatigue.Inclusions are often seen as the birthplace of micro cracks, fatigue cracks and inclusions have a close relationship.The inclusions can reduce the plasticity, toughness and fatigue life of the rail.The concrete influence intensity that the performance of the inclusion to rail are decided by a series of factors,such as quantity,particle magnitude,shape and distribution and so on.The fracture of U71Mn rail welded butt jioints was analyzed by visual observation,metallographic microscope,SEM and EDS from macro and micro.The results show that:the cracking of the rail is fatigue-crack propagation,fatigue cracking is caused by silicate-non-metallic inclusions which are residues in the weld after flash welding.

  6. 20钢玻璃内衬防腐管与304不锈钢管对接工艺分析%Study on Butt Welding Process of 20 Steel Glass Lining Anticorrosion Tube and 304 Stainless Steel Pipe

    Institute of Scientific and Technical Information of China (English)

    赵泽敬; 赵志彬; 毛习飞; 王志文

    2015-01-01

    对于20钢玻璃内衬防腐管与304不锈钢钢管对接选用和耐蚀堆焊层相同的材料AT-ERNi625焊丝进行打底,填充盖面分别选择了AT-ERNi625焊丝和304焊丝,采用拉伸、弯曲试验、显微硬度试验测试焊接接头力学性能;通过扫描电镜、光学显微镜对焊缝断口及显微组织进行分析。结果表明,焊缝抗拉强度大于20钢抗拉强度,其显微硬度从母材到焊缝,从盖面层到打底层都呈现下降趋势,其力学性能满足使用要求;在母材20钢一侧出现了脱碳层,焊缝一侧出现增碳层,焊缝中的组织主要是少量的针状铁素体和奥氏体。%For 20 steel glass lining anticorrosion tube and 304 stainless steel pipe butt welding, it selected AT-ERNi625 welding wire to conduct backing, which is the same material as corrosion resistant surfacing layer. Filling and covering respectively chose ERNi625 welding wire and 304 welding wire. The mechanical properties of welded joints were tested by tensile test and microhardness test, and the weld fracture and microstructure were analyzed by scanning electron microscope, optical microscope. The results indicated that the tensile strength of weld is higher than that of 20 steel, and the microhardness present a downward trend from base metal to weld, from covering welding layer to backing layer. The mechanical properties can meet application requirements. The decarburization layer appeared at the side of the parent metal 20 steel, and recarburization layer appeared at the side of weld. The organization in weld mainly consist of a small amount of acicular ferrite and austenite.

  7. 搭接焊铝塑管与对接焊铝塑管的长期静液压强度计算%Calculation of Long-term Hydrostatic Pressure Strength of Overlap-welding and Butt-welding Aluminum-plastic Pipes

    Institute of Scientific and Technical Information of China (English)

    李明轩

    2011-01-01

    将16~32规格的搭接焊铝塑管的长期静液压试验曲线外推至50年,通过考虑与对接焊铝塑管相同的总体设计系数(C=1.25),证明在T0=95℃的长期工作温度下,16~32规格的搭接焊铝塑管与对接焊铝塑管的允许工作压力(P0)相当.搭接焊铝塑管也能满足95℃、1.25 MPa下使用寿命为50年的要求.根据国家标准对搭接焊铝塑管与对接焊铝塑管的铝管层最小壁厚和最小拉伸强度的要求,计算出16~50规格的搭接焊铝塑管与对接焊铝塑管的P0.结果表明,小规格二者的P0相当,大规格对接焊铝塑管的P0优势明显.%The long-term hydrostatic pressure test curves of overlap-welding aluminum-plastic pipes with diameters of 16 mm to 32 mm were extrapolated to 50 years by considering the same overall design factor as 1.25 with butt-welding aluminum-plastic pipes. It showed that at 95 ℃ long-term operating temperature, overlap-welding aluminum-plastic pipes with diameters of 16 mm to 32 mm had a comparative allowable working pressure ( P0 ) compared with butt-welding aluminum-plastic pipes, and could meet the requirements of the 50-year service life under 95 ℃ and 1. 25 MPa. According to the requirements of minimum thickness and minimum tensile strength of aluminum layer in national standards,P0 of the overlap-welding aluminum-plastic pipes and butt-welding aluminum-plastic pipes with diameters of 16 mm to 50 mm was calculated. The results showed that both had the same P0 for the small size, but butt-welding aluminum-plastic pipes had the obvious advantage for the large size.

  8. FEM Analysis of Stress Concentration Coefficient of SMA490 BW Steel Welded Butt Joint for Bogie%转向架用SMA490 BW钢对接接头应力集中系数有限元分析

    Institute of Scientific and Technical Information of China (English)

    何柏林; 魏康

    2015-01-01

    Objective To analyze the stress concentration coefficient of SMA490BW steel butt joint for bogie, which has an im-portant significance for improving VHCF properties of bogie welded structure and ensuring the safe, reliable operation of high-speed train. Methods Finite element model of very high cycle fatigue sample of SMA490BW steel butt joint for bogie was built. The in-fluences of joint geometric parameters ( weld edge transition arc radius r,weld toe inclination angleθ) on stress concentration coeffi-cient Kt of weld toe were studied based on the finite element software ABAQUS, and the relationship between the stress concentra-tion coefficient and the geometric parameters was analyzed and established based on regression analysis of Origin software. Results When the weld edge transition arc radius r was 0. 2 mm, the stress concentration coefficient Kt was 1. 391, 1. 747, 1. 976, 2. 263, 2. 425, 2. 525 respectively at weld toe inclination angle θ of 10°, 20°, 30°, 40°, 50°, 60°;when the weld toe inclination angleθwas 30°, the stress concentration coefficient Kt was 1. 976, 1. 763, 1. 535, 1. 419, 1. 345, 1. 306, 1. 257, 1. 201 respectively at weld edge transition arc radius r of 0. 2, 0. 5, 1, 1. 5, 2, 2. 5, 3, 4 mm. Conclusion Stress concentration at weld toe of butt welded joint was relatively large, and weld edge transition arc radius r and weld toe inclination angle θ played important roles in stress concentration coefficient Kt . For the same weld edge transition arc radius r, the stress concentration coefficient Kt at weld toe increased with increasing inclination angle θ. While in the case of the same weld toe inclination angle θ, the stress concentration coefficient Kt at weld toe decreased with increasing transition arc radius r. The stress concentration coefficient equation has a gui-ding significance to the improvement of stress concentration at weld toe and the design of ultrasonic fatigue sample of butt joint for bogie.%

  9. YHG-1200 TH闪光焊机在兰新高铁钢轨焊接中的应用研究%Application of YHG-1200 TH Flash-butt Welding Machine on Lanzhou-Urimqi High-speed Railway

    Institute of Scientific and Technical Information of China (English)

    公彦良

    2016-01-01

    兰新铁路第二双线新疆段LXTJ6标负责铺设长钢轨约650单线km,无缝线路采用60 kg/ m、U71Mn(G)钢轨。为了保证钢轨焊接接头的质量,提高焊接效率,兰新铁路长钢轨接头焊接采用YHG鄄1200TH 型移动式闪光焊机进行施焊。介绍该焊机的性能、焊接工艺参数选定方法和钢轨闪光焊焊接接头的型式检验方法,通过试验和实践验证所选工艺参数的合理性。%The sixth section of Lanzhou ~ Urimqi second double track railway line in Xinjiang covers some 650 km track-laying in terms of single track. 60 kg/m U71Mn (G) rail is used for CWR. In order to guarantee the quality and improve the efficiency of rail welding, YHG-1200TH flash-butt welding machine is employed. The paper introduces the functions and performances of the machine, the methods for selecting welding parameters and quality examination. The rationality and validity of the selected welding parameters are proved experimentally.

  10. 特高压钢管塔对接环焊缝超声波检测影响因素分析%Influence Factors Analysis on Ultrasonic Testing of Ultra High Voltage(UHV) Steel Pipe Tower Butt Circumferential Weld

    Institute of Scientific and Technical Information of China (English)

    王国俊; 武英利; 韩晋锋

    2015-01-01

    特高压钢管塔对接环焊缝的超声波检测,依据 GB/T 11345和Q/GDW 707进行检测。由于钢管塔构件和焊缝的错边、余高和焊缝宽度等情况,易导致检测误判。对钢管塔法兰-钢管对接环焊缝超声波检测若干影响因素进行了分析,提出了识别和判定方法,可以实现对钢管塔对接环焊缝焊接质量的有效控制。%According to the criteria of GB/T 11345 and Q/GDW 707, ultrasonic testing was applied into butt circumferential weld of UHV steel tower. Weld offset,reinforcement,weld width of steel tower may lead to misjudgments of ultrasonic testing. In this paper, aiming to the analysis on the influence factors of steel tower flange and butt circumferential weld on exact implementation of ultrasonic testing, the methods of distinguish and judgment of ultrasonic testing were put forward. It can realize efficient controlling of welding quality for steel tower butt circumferential weld.

  11. Research on Stress Intensity Factors for Weld Root Crack of T-butt Joints%T形焊接接头根部裂纹应力强度因子研究

    Institute of Scientific and Technical Information of China (English)

    宋占勋; 方少轩; 谢基龙

    2013-01-01

    Stress intensity factors (SIFs) for weld root crack of T-butt joints are researched. Semi-ellipse crack models for weld root of T-butt joints are built with finite model. Geometric parameters and boundary conditions are established according to finite model. Singular element method is used to simulate stress singularity of crack tip with finite element calculation. Element size of crack tip is obtained by convergence experiment. Calculation results show that, SIFs of crack tip have regularity for different initial crack size under same load, and the importance of different geometric parameters affect SIF is different. Therefore, some geometric parameters must be focused on fatigue research for weld root of T-butt joint. The simulation results are fitted by multiple linear regression method. These results could provide a valuable reference for further research of crack propagation and fatigue life prediction.%建立T形焊接接头根部裂纹的半椭圆裂纹模型,定义裂纹模型的构形参数以及边界条件,分析裂纹尖端的应力强度因子.采用奇异单元法,通过有限元计算,模拟裂纹尖端的应力奇异性.并通过收敛性检验确定裂纹尖端的单元尺寸.在此基础上,计算裂纹尖端量纲一应力强度因子,并分析其受几何参数影响的变化规律.计算结果表明,对于给定的载荷条件下,不同初始裂纹尺寸时,裂纹尖端的应力强度因子存在一定的规律性,且不同几何参数对应力强度因子的影响程度存在一定差异,因此,对焊接结构疲劳强度研究时需要有一定的侧重点.采用多重线性回归方法拟合仿真计算结果,这些结果为进一步研究T形焊接接头根部裂纹扩展和疲劳寿命预测提供参考.

  12. Analysis of SCR square wave inverter main circuit in flash-butt-welding system for mobile railway%移动式钢轨交流闪光焊专用晶闸管方波逆变器主电路分析

    Institute of Scientific and Technical Information of China (English)

    王志伟; 易琼

    2012-01-01

    针对现有移动式钢轨交流闪光焊机系统三相负载不平衡和焊接波形不良的现状,研制一种新型的交流闪光焊专用晶闸管方波逆变器.通过主电路分析和样机试验证明,这种晶闸管方波逆变器能有效改善焊接波形,相比现有的钢轨交流闪光焊机晶闸管调压系统,可以节能30%以上.%Aim to current unbalanced three-phase loads and poor welding quality of flash-butt-welding system for mobile railway, this paper developed a new type square wave inverter dedicated to AC flash butt welding,the analysis and practice can prove that the SCR square wave inverter can improve welding waveform,and may save energy 30% or more compare traditional AC flash butt welding.

  13. Comparative study of MF inverter resistance welding and flash butt welding of major diameter and high-level round-link chain%采用中频逆变电阻焊和闪光对焊焊接圆环链的对比研究

    Institute of Scientific and Technical Information of China (English)

    许祥平; 李恒; 王锡岭; 陈恒强

    2015-01-01

    We apply the technology of MF inverter resistance welding and flash butt welding to the welding of major diameter and high-level round-link chain , compare the producing process , realize reliable connection and match the specification requirements of joints′properties .The results show that the MF inverter resistance welding tech-nology has higher automation in chain and welding process , higher production efficiency , better production envi-ronment without the need to remove burrs after welding ,better welding joint performance , higher rate of qualified products .In the case of optimal process parameters , MF inverter′s properties of welded joint is better than the flash butt′s.%文中采用中频逆变电阻焊技术和闪光对焊技术分别焊接大直径高等级圆环链。对比研究了两种焊接工艺过程特点,分析了接头微观组织形貌、断口形貌和接头性能之间的相互关系。结果表明:中频逆变电阻焊技术的编链和焊接工艺过程比闪光对焊生产自动化程度高、生产效率高、生产环境好、焊后无需清除毛刺。在各自最优工艺参数条件下,中频逆变电阻焊对焊圆环链所得接头性能比闪光对焊所得性能好,产品合格率高。

  14. Evaluación del comportamiento a fatiga de una unión soldada a tope de acero AISI 1015//Evaluation of the fatigue behaviour of a butt welded joint of AISI 1015 steel

    Directory of Open Access Journals (Sweden)

    Pavel Michel Almaguer‐Zaldivar

    2015-01-01

    Full Text Available Las uniones soldadas son un componente importante de una estructura, por lo que siempre es necesario conocer la respuesta de las mismas sometidas a cargas cíclicas. El objetivo de este trabajo es obtener la curva S-N de una unión soldada a tope de acero AISI 1015 y electrodo E6013 como material de aporte. Los ensayos a fatiga se realizaron de acuerdo a la norma ASTM en una máquina universal MTS810. Se utilizaron probetas de sección rectangular. El ciclo de carga fueasimétrico a tracción, con un coeficiente de asimetría de 0,1. Se obtuvo que la unión estudiada tiene un límite de resistencia a la fatiga de 178 MPa, a un punto de corte de 2 039 093 ciclos.Palabras claves: unión soldada, fatiga, curva S-N, AISI 1015, electrodo E6013._______________________________________________________________________________AbstractWelded joints are an important component in structures, by this reason is necessary to know the behaviour of these elements under cyclic loads. The objective of this work is to obtain the S-N curve of the butt welded joint of AISI 1015 steel and electrode E6013 as the contribution material. Fatiguetest was realized within the ASTM standard in the MTS810 testing machine. Rectangular cross section specimens was used. Cyclic loads was asymmetric tensile and the asymmetry ratio used was 0,1. In this study was obtained the fatigue limit equal to 178 MPa, at the cut point of 2 039 093 cycles.Key words: welded joint, fatigue, S-N curve, AISI 1015 steel, electrode E6013.

  15. TC4钛合金闪光对焊接头不同焊后热处理的组织与性能%Effect of PWHTs on the Microstructure and Mechanical Properties of Flash Butt Welded TC4 Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    王金雪; 袁鸿; 张国栋; 余槐; 肖志翔; 江飞龙; 刘忠

    2013-01-01

    针对TC4钛合金开展了闪光对焊试验,分析研究了接头在不同焊后热处理工艺下的组织和力学性能。结果表明:采用闪光对焊方法焊接TC4钛合金,能够获得优质的焊接接头。焊后固溶+时效状态下,接头的强度达到1104MPa,与同状态下母材等强;焊后普通退火状态下,接头强度低于固溶时效状态,但塑性和韧性高于固溶时效状态,且随着焊后退火温度的升高,接头的强度降低,塑性和韧性升高。%Flash butt welding experiments of TC4 Titanium Alloy were carried out, then the microstructure and properties of the joints under the different post weld heat treatment procedures were studied. Results indicate that flash butt welding is suitable to weld the TC4 titanium alloy, and can gain the high quality joint. Under solution and aging condition, the tensile strength of the welded joints achieve 1104MPa, which is equal to the basic metal at the same condition. While ordinary annealing after welding,the tensile strength of the welded joints is lower than that under the condition of solution and aging, and the elongation and impact toughness are higher than that under the condition of solution and aging. Along with the increased annealing temperature,the tensile strength of the welded joints is reduced and the elongation and impact toughness is increased.

  16. Direct measurement of the residual stresses near a 'boat-shaped' repair in a 20 mm thick stainless steel tube butt weld

    International Nuclear Information System (INIS)

    Neutron diffraction measurements have been performed to quantify directly the three-dimensional residual stress field in a stainless steel pipe girth weld containing a part-circumference weld repair. Adjacent to the repair, the measured through-wall axial stress profile was found to be membrane in character and of tensile magnitude equal to about 60% of the base metal 1% proof stress. The measurements show that the repair procedure substantially increased axial and hydrostatic components of residual stress in the neighbouring heat-affected zone

  17. Simulación numérica del coeficiente de concentración de tensiones en grietas de uniones soldadas a tope//Numerical simulation of the stresses concentration coefficient in cracks butt welded joints

    Directory of Open Access Journals (Sweden)

    Pavel Almaguer-Zaldivar

    2012-09-01

    Full Text Available La fatiga es uno de los más complejos fenómenos en el estudio de falla en piezas sometidas a la acción de cargas dinámicas. El objetivo de este trabajo es exponer una metodología basada en el método de los elementos finitos para la evaluación del coeficiente de concentración de tensiones en grietas longitudinales y transversales de uniones soldadas a tope. El material utilizado es el acero AISI 1015 y el electrodo E6013 de fabricación cubana. Se caracterizan los defectos mencionados y posteriormente se varían sus dimensiones para obtener relaciones entre ellas y el coeficiente de concentración de tensiones. Las simulaciones se realizaron con el software CosmosWork 2008. Con esta metodología se obtuvieron nomogramas y ecuaciones que describen el comportamiento del coeficiente de concentración de tensiones en diferentes nodos de la grieta. Los valores del coeficiente de concentración de tensiones obtenidos muestran una correspondencia con la variación de la severidad del defecto.Palabras claves: coeficiente de concentración de tensiones, simulación, uniones soldadas a tope, grietas, fatiga.______________________________________________________________________________AbstractFatigue is one of the more complex phenomenons in the failure of parts under dynamic loads. In this work is pursued as main objective to expose a methodology based on the finite elements method for the evaluation of the stress concentration coefficient in longitudinal and traverse cracks of butt welded joints. The material bases selected to carry out the study it is the steel AISI 1015 and the electrode E6013 Cuban manufacturing. It is carried out a characterization of the mentioned defects and later the dimensions of each defect are varied to obtain relationships between them and the stress concentration coefficient. The simulations were carried out with the software CosmosWork 2008. With the proposed methodology were obtained graphs and equations that

  18. Application of ADRC in position servo system for billet flash butt welding%自抗扰控制技术在钢坯闪光对焊位置伺服系统的应用

    Institute of Scientific and Technical Information of China (English)

    郭栋; 付永领; 龙满林

    2013-01-01

    为提高钢坯闪光对焊液压位置伺服系统的品质,采用自抗扰控制技术进行了控制器的设计,并基于物理模型进行仿真验证.针对系统中存在难以准确数学建模的非线性环节、参数时变的特性以及执行机构存在耦合和干涉的特点,利用AMESim平台构建了系统模型.依据系统的主要影响因素以及在响应速度高、抗干扰能力强、稳定性好的特性要求下,设计了3阶非线性自抗扰控制器.AMESim与Matlab联合仿真结果表明,基于自抗扰控制技术的控制策略不仅具有很好的抗扰动能力,而且取得了较好的位置伺服效果.虚拟仿真试验结果表明,在无头轧制闪光对焊位置伺服中引入自抗扰控制技术是可行性的,并具有其优势性.%To improve the performance of the hydraulic position servo system of billet flash butt welding, which is a key technology for endless rolling system, the active disturbance rejection control ( ADRC ) technique was proposed in controller design and followed by verifying simulations. Considering the challenges, such as the difficulty in establishing precise mathematical modeling of nonlinear parts for the system, time-varying characteristics of the system parameters, and coupling and interference existing in the actuator, an AMESim platform was adopted to build models. Based on main influencing factors of the system, the third-order nonlinear discrete ADRC was designed to meet the requirements of high speed response, strong anti-interference ability and good stability for the position servo. Simulation of the position servo was carried out through the joint platform integrated AMESim and Matlab to test the validity of the proposed method. The simulated results show that the system had good anti-disturbance ability and better effect of position servo was achieved through the control strategy based on ADRC technique , which verified the feasibility and advantages of using ADRC technology in

  19. A final report on the performance achieved by non-destructive testing of defective butt welds in 50mm thick Type 316 stainless steel

    International Nuclear Information System (INIS)

    This report concludes a programme of work started approximately eight years ago to fabricate deliberately defective austenitic downhand welds in 50 mm thick Type 316 plate and then to examine them non-destructively under ideal laboratory conditions. After completing and reporting the Non-Destructive Testing (NDT), the specimens were subjected to detailed metallography to locate, identify and size all the planned and unplanned flaws in the welds. The report gives the final analysis of this exercise on the relative merits of X-radiography, pulse echo ultrasonics and the time-of-flight technique for the detection, location and sizing of weld flaws. It was found that X-radiography and pulse echo ultrasonics were the best techniques for flaw detection but neither technique was reliable for flaw sizing. The time-of-flight technique provided accurate sizing data but the location of the flaws had to be known to identify the diffracted signals from the extremities of the flaws due to the poor signal to noise ratio. Observations are also reported on the fabrication of deliberately defective austenitic welds for use as reference specimens in the FR programme. (author)

  20. Ultrasonic systems for examining butt-fillet tube to tube plate welds in the evaporators of the Dounreay Prototype Fast Reactor

    International Nuclear Information System (INIS)

    Ultrasonic techniques and comprehensive data recording systems are described which have been developed for the in-service inspection of the tube to tube plate welds in the evaporator steam generator units of the Prototype Fast Reactor at Dounreay, Caithness, Scotland

  1. 压力容器对接焊接接头衍射时差法超声检测工艺要点%Key Points of the TOFD Procedure for Butt Welded Joints of Pressure Vessel

    Institute of Scientific and Technical Information of China (English)

    姚志华

    2015-01-01

    传统的超声检测容易产生缺陷漏检和误判。射线检测步骤繁多,耗时耗材,且需进行严格的辐射防护。相对而言,衍射时差法(TOFD)超声检测具有可靠性高、缺陷定位精度高、检测操作简便快捷、 TOFD图像更有利于缺陷的识别和分析等优点。具体地阐述了对接焊接接头衍射时差法超声检测的工艺要点。%It is possible that some flaws may be undetected and misjudged for traditional ultrasonic testing ( UT) . For radiographic testing ( RT) , the operation is complicated and relatively time-consuming, it also need strict personal protection for radiation hazard compared with UT. In contrast, ultrasonic time of flight diffraction technique (TOFD) has some advantages such as good reliability, high accuracy for flaws location, easy operation, easy identification and interpretation of the TOFD image. This paper describes the key points of the TOFD procedure for butt welded joints to normalize the testing requirements.

  2. 基于金属磁记忆方法的压力容器对接焊缝应力检测%Stress Inspection of Pressure Vessel Butt Weld Based on Metal Magnetic Memory Technique

    Institute of Scientific and Technical Information of China (English)

    章彬斌; 梁斌

    2011-01-01

    It is probable to occur many kinds of damage in the area of stress concentration zone when the pressure vessel is in operation, so finding those injury and eliminate the stress concentration is very useful to stable pressure vessel for improving its usage life. This paper is mainly to summarize the basic principle and parameter set of the diagnose equipment of the metal magnetic memory. And it calculated the residual stress distribution of 09MnNiDR butt-welded(WM) and heat affected zone( HAZ) according to the relevant standards with the data being analyzed with one software. The result of the analysis showed that the residual stress of heat affected zone was higher than welding and it was also similar with the result of experimentation and numerical analysis based on the same welding procedure. It revealed that magnetic memory test could find the stress concentration zone of pressure vessels, and could be used for the early diagnosis of pressure vessels.%压力容器运行中易在应力集中区出现各种损伤,因此找出并消除应力集中区对稳定压力容器的使用寿命非常有益.阐述了金属磁记忆方法的基本原理、诊断设备的参数设置,并通过分析软件得到的数据,根据相关标准计算09MnNiDR对接焊缝和热影响区的残余应力分布情况.分析结果表明,热影响区残余应力高于焊缝,数据结果与同类焊接工艺下的试验和数值分析基本吻合.说明磁记忆检测可发现压力容器的应力集中区,实现压力容器的早期诊断.

  3. HOT SPOT STRESS ANALYSIS OF DIFFERENT GIRTH BUTT WELD DETAILS OF CAST STEEL JOINT%不同焊接构造的铸钢节点环形对接焊缝的热点应力分析

    Institute of Scientific and Technical Information of China (English)

    韩庆华; 郭琪; 林允昶; 邢颖

    2014-01-01

    铸钢节点与主体构件的环形对接焊缝处存在材料差异、几何差异和焊接残余应力,因此环形对接焊缝是铸钢节点疲劳破坏的重要研究对象。目前,国内对铸钢节点焊缝疲劳问题的研究比较缺乏,传统名义应力方法并不适用于铸钢节点。采用热点应力方法对铸钢节点环形对接焊缝的疲劳问题进行探究,比较4种热点应力外推方法的计算结果。为减小铸钢节点与主体构件不等壁厚对接焊缝产生的应力集中对疲劳性能的影响,分析对比了3种不同的焊接构造,并分别研究在壁厚t、径厚比d/t、壁厚比T/t三种参数影响下的热点应力变化规律。%The girth butt weld attaching to the cast steel joint and the hot-rolled tube are the important object of the fatigue study of the cast steel joint due to the material nonlinearity and geometric nonlinearity across the weld . However , the research on this issue rarely saw in China and the nominal stress method was not applicable to it .In the paper, the hot spot stress method was used while the results of hot spot stress extrapolations were compared .To reduce the impact of the stress concentration , different weld details were designed .The hot spot stress curve was drawn under consideration of the tube ’ s thickness and the other two parameters .

  4. Joint Performance for Laser Cutting-welding of Zinc-coated Tailored Blanks

    Institute of Scientific and Technical Information of China (English)

    WANG Chunming; HU Lunji; LIU Jianhua; HU Xiyuan; DU Hanbin

    2005-01-01

    The process of laser butt welding of zinc-coated steel ( SGCD3 and WLZn ) blanks was presented, whose edges were prepared by laser cutting. The properties of the butt joints, such as tensile strength, bending, stamping, weld shape, and corrosion- resistant were tested. The experiments of laser cutting and welding were carried out on a custom-made system designed, which is a set of equipment for wide sheet butt welding based on a laser cutting-welding combination process. The experiments proved the technological feasibility of laser butt welding for thin zinc coated steel sheets whose edges were prepared by laser cutting on the same equipment.

  5. The effect of thermal properties and weld efficiency on residual stresses in welding

    OpenAIRE

    E. Armentani; Esposito, R.; R. Sepe

    2007-01-01

    Purpose: A parametric model is adopted and the technique of element “birth and death” is used to estimate theeffect of thermal properties and weld efficiency on residual stresses in butt weld joints.Design/methodology/approach: Residual stresses and distortions on butt welded joints are numericallyevaluated by means of finite element method. The FE analysis allows to highlight and evaluate the stress fieldand its gradient around the fusion zone of welded joints, higher than any other located ...

  6. 直流电阻对焊接口张开及纵向裂纹的形成机制%The Mechanism of the Interface Split in the Flash and the Longitudinal Crack on the Joint Surface in DC Upset Butt Welding

    Institute of Scientific and Technical Information of China (English)

    吴丰顺; 张尧; 刘志福; 谢明立

    2001-01-01

    采用有限元方法对板料直流电阻对焊过程中的接口张开、接头表面纵向裂纹问题进行了研究.分析表明,焊接过程中金属的塑性流动导致界面质点力学状态发生动态变化,包括应力大小和拉压应力状态的变化.变形过程中,界面质点在x轴方向所受的拉应力是接头内部产生层状撕裂的力学原因,在y轴方向和z轴方向所受拉应力是产生接口张开和形成飞边纵向裂纹的力学原因.%The butt joint interface split in the flash and longitudinal crack on the joint surface appeared in the process of D.C. upset butt welding have been studied by using the element method. The results show that the metal' s plastic flow causes the variance of the stress status, including the value of the stress and the variance of the stress status from the stretch stress to the compress stress. In the process of D.C. upset butt welding, the stretch stress in x direction causes the layer avulsion, the stretch stress in y direction causes the butt joint interface split in the flash and the stretch stress in z direction causes longitudinal cracks on the joint surface.

  7. Coyote Buttes Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is the result of a study commencing July 3, 1970 and ending August 20 1970. The study area was the Coyote Buttes Field just east of refuge headquarters....

  8. Welding.

    Science.gov (United States)

    Cowan, Earl; And Others

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

  9. 基于总线的移动式钢轨闪光焊机控制系统%Research on control system of mobile rail flash butt welding machine on the basis of bus

    Institute of Scientific and Technical Information of China (English)

    吕其兵; 贺颂; 戴晓纲

    2012-01-01

    The operation,sensor,and control information between the machine and controller is transferred through the cable when the mobile rail flash butt welding machine is used in continuous line construction, because the cable is long and multi-core,the control system is of low reliability,and is difficult to be maintained.According to the problem mentioned above,a new project based on CC-link was put forward to solve this problem/Hie control system was designed on the basis of the host module FX2N-16CCL-M,the PLC FX2N-64MR and the digital module AJ65SBTB1-160/1',so the core of the cable,through which the information between the machine and controller was transferred, was reduced, the reliability was improved, and the maintenance was become easy .The control system's response rate and information's transmission rate was analyzed,and the new control system can demand the real-time requestThe experiment indicated that the new control system could finish the welding process.%移动式钢轨闪光焊杌现场施工时,焊杌机头与控制柜之间操作、检测和控制信息的传递通过电缆进行,该连接电缆芯数多且距离长,从而导致控制系统故障率高,且检修难度大.针对上述问题,提出了基于CC-link总线设计系统的软硬件解决方案.采用FX2N-16CCL-M主站模块、FX2N-64MR三菱PLC、AJ65SBTB1-16D和AJ65SBTB1-16T数字量模块重新设计了基于总线的移动式钢轨闪光焊机控制系统,从而使机头和控制柜之间的信息通过总线进行传输,大大减少了焊机机头和控制柜之间连接电缆的芯数,提高了可靠性,降低了检修难度;分析新系统通过总线进行信息传输的速度和控制速度,采用总线方式完全能满足控制系统实时性的要求.通过现场试焊表明,新系统能完成钢轨的焊接.

  10. 闪光对焊接头金相组织、性能和工艺关系的研究%A STUDY ON THE RELATIONSHIP BETWEEN METALLOGRAPHY STRUCTURE,JOINT PERFORMANCE AND WELDING PROCESS OF FLASH BUTT WELDING

    Institute of Scientific and Technical Information of China (English)

    黄华刚; 王克争; 何方殿; 吴建新; 刘文铎

    2000-01-01

    The quality of the FBW joint is mainly decided by temperature field distribution, process parameters during upsetting and the structure defects. Structure defects are the result of integration of the two factors mentioned above. The performance of the weld would be improved with the regulation of the temperature field distribution and the upsetting parameters.%影响闪光焊接头性能的最主要因素包括焊缝区域的温度场分布、闪光顶锻的工艺参数和焊缝区域出现的缺陷组织。焊缝区域的组织缺陷是前两者综合作用的结果。提高焊缝性能应当从温度场分布和顶锻工艺着手。

  11. 46 CFR 154.660 - Pipe welding.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt...

  12. 坡口形式对Q345/SUS304异种钢对接接头残余应力和变形的影响%Study on Influences of Groove Type on Welding Residual Stress and Deformation in Q345/SUS304 Dissimilar Steel Butt-welded Joints

    Institute of Scientific and Technical Information of China (English)

    蔡建鹏; 叶延洪; 张彦杰; 邓德安

    2015-01-01

    residual stress and deformation in a Q345/SUS304 dissimilar steel butt welded joint whose thick plate is 10 mm is investigated by means of both numerical simulation and experiment. Based on ABAQUS software, a thermal elastic plastic finite element method is developed to simulate welding temperature field, residual stress and deformation of multi-pass joint. By using the developed computational approach, the temperature fields, residual stress distributions and deformations in V-groove and X-groove Q345/SSU304 joints are calculated. The welding residual stress distribution on the surface of a joint with X-groove are obtained by hole drilling strain gauge method, while the shrinkages and angular distortions in V-groove and X-groove joints are measured by using vernier caliper and 3D coordinate measuring system, respectively. The comparison between numerical model and experimental mock-up shows that the welding residual stresses and the deformations of the V-groove joint predicted by the finite element model are in good agreement with those measured by experiment. This information suggests that the computational approach developed by this work is effective. Both the experimental and simulation results show that the longitudinal residual stress distribution is discontinuous near the fusion line between Q345 and weld metal. Besides, the region with high tensile residual stress in SUS304 side is wider than that in Q345 side. It seems that groove type has a limited influence on the peak value of longitudinal residual stress, while it has certain influence on the peak value of transverse residual stress. Both the simulated results and the measured data indicate that the transverse shrinkage and the angular distortion of V-groove joint are significantly larger than those of X-groove joint.

  13. Hot spot stress analysis of girth butt weld in cast steel joint%铸钢节点环形对接焊缝热点应力分析

    Institute of Scientific and Technical Information of China (English)

    韩庆华; 陈志钢; 芦燕

    2011-01-01

    铸钢节点的壁厚大于连接杆件,两者连接时壁厚方向存在几何形状的突变,引起焊缝附近的应力集中,降低其疲劳性能。目前现行规程或标准针对铸钢节点与主体结构连接处焊缝的疲劳问题没有明确的设计规定。本文选取两种焊接构造,采用热点应力的表面线性外推法对环形对接焊缝进行轴力作用下的疲劳性能有限元分析。同时选取结构杆件的壁厚t、径厚比d/t以及铸钢与普通杆件的壁厚比T/t作为热点应力的影响因素进行参数分析。分析结果表明:热点应力与厚度t关系不大,随着ln(d/t)的增大热点应力呈线性增加;随着T/t的增加,热点应力先增大后减小;ln(σ/(T/t))随着T/t的增加呈线性减小。%As cast steel joints are thicker than the hot-rolled tubes attached,sharp transition in the direction of thickness would cause stress concentration and weaken its fatigue performance.At present,there are no regulations or standards to guide the design of girth butt weld's fatigue behavior of cast steel joints.A hot-spot stress FEM analysis of weld's fatigue behavior was conducted based on the surface extrapolation method in this paper,considering two kinds of welding details under axial loads.Parametric analysis were carried out on the thickness(t) of hot-rolled tube,the ratio of tube's diameter to its thickness(d/t) and the ratio of cast steel joint's thickness to tube's(T/t).The results show that although the hot-spot stress is independent of the thickness of tubes(t),it will increase linearly with the increment of ln(d/t) and increase firstly then decrease with the increment of T/t.In addition,ln(σ/(T/t))(σ means the hot-spot stress) decreases linearly with the increment of T/t.

  14. Application of analog opo-electrical insolation circuit HCPL-7840 in inventerflash-butt-welding power source%模拟光电隔离电路HCPL-7840在闪光焊逆变电源中的应用

    Institute of Scientific and Technical Information of China (English)

    王志伟; 易琼

    2012-01-01

    This article introduction a analog Opto-Isolate circuit HCPL-7840,from analyze flash butt welding inverter model machine, figure out the effect of HCPL-7840 in sample-circuit,and get good result in precision sample,simple system structure,low price.%介绍了模拟光电隔离电路HCPL-7840,并结合闪光焊专用逆变电源样机设计实例,说明HCPL-7840在采样电路中的作用,实验证明,该电路采样精度高、系统结构简单、价格低.

  15. Thermal Stresses in Welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær

    1998-01-01

    Studies of the transient temperature fields and the hereby induced deformations and stressses in a butt-welded mild steel plate modelledrespectively in 2D plane stress state (as well as plane strain state) and in full 3D have been done. The model has been implemented in the generalpurpose FE...

  16. A study of processes for welding pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Weston, J. (ed.)

    1991-07-01

    A review was made of exisiting and potential processes for welding pipelines: fusion welding (arc, electron beam, laser, thermit) and forge welding (friction, flash, magnetically impelled arc butt, upset butt, explosive, shielded active gas, gas pressure). Consideration of J-lay operations gave indications that were reflections of the status of the processes in terms of normal land and offshore S-lay operation: forge welding processes, although having promise require considerable development; fusion welding processes offer several possibilities (mechanized GMA welding likely to be used in 1991-2); laser welding requires development in all pipeline areas: a production machine for electron beam welding will involve high costs. Nondestructive testing techniques are also reviewed. Demand for faster quality assessment is being addressed by speeding radiographic film processing and through the development of real time radiography and automatic ultrasonic testing. Conclusions on most likely future process developments are: SMAW with cellulosic electrodes is best for tie-ins, short pip runs; SMAW continues to be important for small-diameter lines, although mechanized GMA could be used, along with mechanical joining, MIAB, radial fraction, and flash butt; mechanized GMA welding is likely to predominate for large diameter lines and probably will be used for the first J-lay line (other techniques could be used too); and welding of piping for station facilities involves both shop welding of sub-assemblies and on-site welding of pipe and sub-assemblies to each other (site welding uses both SMAW and GMAW). Figs, tabs.

  17. 带电顶锻时间对高强钢闪光对焊接头组织及性能影响研究%Effects of upset current time on microstructures and mechanical properties of flash butt welded joints

    Institute of Scientific and Technical Information of China (English)

    郗晨瑶; 宣兆志; 孙大千; 王杰功; 宋国山; 郭冉

    2015-01-01

    T he effects of upset current time (St ) on microstructures and mechanical properties of flash butt welded joints are studied .The results show that both the interface and overheated zone can be defined as bainite and ferrite structure with coarse grain and high density dislocations . When St increases ,the holding time at high temperature increases and the cooling speed decreases ,w hich leads to the joint microstructure coarsening ,the amount of ferrite increasing and hardness decreasing at the interface zone . T he joint bending cracks mainly occur at interface zone . St strongly influence the bending crack length .Under the experimental conditions ,the optimal upset time St is 0 .3 s or 0 .7 s for improving bending property of flash butt welded joints .%研究了带电顶锻时间(St )对高强钢闪光对焊接头组织及性能的影响规律.结果表明 ,接头界面区和过热区主要为贝氏体+铁素体组织 ,其突出特点是晶粒明显粗化并存在高密度的位错.随着 St增加 ,焊接热循环高温停留时间增加 ,冷却速度降低 ,这导致接头组织粗化 ,界面区铁素体量增加 ,接头硬度有降低的趋势.接头弯曲裂纹主要出现在界面区,带电顶锻时间(St )对弯曲裂纹长度具有较明显的影响.在本试验条件下 ,选择 St=0 .3 s、0 .7 s有利于明显改善闪光对焊接头的弯曲性能.

  18. Thermal treatment of dissimilar steels' welded joints

    Science.gov (United States)

    Nikulina, A. A.; Denisova, A. S.; Gradusov, I. N.; Ryabinkina, P. A.; Rushkovets, M. V.

    2016-04-01

    In this paper combinations of chrome-nickel steel and high-carbon steel, produced by flash butt welding after heat treatment, are investigated. Light and electron microscopic studies show that the welded joints after heat treatment have a complex structure consisting of several phases as initial welded joints. A martensite structure in welded joints after thermal treatment at 300... 800 °C has been found.

  19. Laser welding of advanced high strength steels

    OpenAIRE

    Ahmed, Essam Ahmed Ali

    2011-01-01

    This research work focuses on characterization of CO2 laser beam welding (LBW) of dual phase (DP) and transformation induced plasticity (TRIP) steel sheets based on experimental, numerical simulation and statistical modeling approaches. The experimental work aimed to investigate the welding induced-microstructures, hardness, tensile properties and formability limit of laser welding butt joints of DP/DP, TRIP/TRIP and DP/TRIP steel sheets under different welding speeds. The effects of shieldin...

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

    International Nuclear Information System (INIS)

    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

  1. Welding technology for rails. Rail no setsugo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, M.; Karimine, K. (Nippon Steel Corp., Tokyo (Japan)); Uchino, K.; Sugino, K. (Nippon Steel Corp., Kitakyushu, Fukuoka (Japan). Technical Research Inst. of Yawata Works); Ueyama, K. (JR Railway Technical Research Inst., Tokyo (Japan))

    1993-08-01

    The rail joining technology is indispensable for making long welded rails. Flush butt welding, gas welding, enclosed arc welding, and thermit welding are used properly as the welding methods. A method for improving the joint reliability by controlling the residual stress distribution of welded joint is investigated to prepare high carbon component weld metal similar to the rail. Problems with each of the welding methods and the newly developed technology to solve the problems are outlined. Composition of the coating is improved also, and a high C system welding rod is developed which has satisfactory weldability. High performance and high efficient new enclosed arc welding technology not available by now is developed which utilizes high carbon welding metal as a new EA welding work technology, and put to practical use. As a result of this study, useful guides are obtained for the establishment of satisfactory thermit welding technology. 17 refs., 16 figs., 1 tab.

  2. EMAT weld inspection and weld machine diagnostic system for continuous coil processing lines

    Science.gov (United States)

    Latham, Wayne M.; MacLauchlan, Daniel T.; Geier, Dan P.; Lang, Dennis D.

    1996-11-01

    Weld breaks of steel coil during cold rolling and continuous pickling operations are a significant source of lost productivity and product yield. Babcock and Wilcox Innerspec Technologies has developed a weld process control system which monitors the key variables of the welding process and determines the quality of the welds generated by flash butt welding equipment. This system is known as the Temate 2000 Automated Flash Butt Weld Inspection and Weld Machine Diagnostic System. The Temate 2000 system utilizes electro- magnetic acoustic transducer (EMAT) technology as the basis for performing on-line, real-time, nondestructive weld quality evaluation. This technique accurately detects voids, laps, misalignment and over/under trim conditions in the weld. Results of the EMAT weld inspection are immediately presented to the weld machine operator for disposition. Welding process variables such as voltage, current, platen movements and upset pressures are monitored and collected with the high speed data acquisition system. This data is processed and presented in real-time display to indicate useful welding process information such as platen crabbing, upset force, peak upset current, and many others. Alarming for each variable is provided and allows detailed maintenance reports and summary information to be generated. All weld quality and process parameter data are stored, traceable to each unique weld, and available for post process evaluation. Installation of the Temate 2000 system in a major flat rolled steel mill has contributed to near elimination of weld breakage and increased productivity at this facility.

  3. Residual stresses in welded structures

    International Nuclear Information System (INIS)

    The nature of residual stresses in welded structures is discussed in terms of their magnitude, directionality, spatial distribution, range and variability. The effects of the following factors on the residual stresses are considered: material properties, material manufacture, structural geometry, fabrication procedure, welding procedure, post-weld treatments and service conditions. Examples are given of residual stress distributions in plate butt welds, circumferential butt welds and weld cladding. These illustrate the different magnitudes and distributions of residual stress that can be found in different joint geometries, and demonstrate the effects of the mechanical, thermal and metallurgical properties of the constituent materials and the sensitivity of residual stresses to pass sequence and to the restraints applied during welding. Further examples for the common case of circumferential butt welds in pipes and pressure vessels are used to illustrate the extent of residual stresses as a function of distance from the weld and the effects of post-weld heat treatment. Measurements or analytical predictions of residual stresses are often subject to significant scatter or variability. This scatter may be due to systematic factors such as variability in measurement location or material properties, or to experimental error in measured data, erroneous assumptions in analytical modelling or unknown factors such as pre-existing residual stresses, inadequately documented welding or fabrication procedures or unrecorded local repairs. Improved prediction and reduction of uncertainty of residual stresses will require better recording of the whole manufacturing and service history of the welded structure and its component materials and better understanding and analysis of the many processes that may affect the residual stresses

  4. Effect of Welding Parameters on the Weldability of Material

    OpenAIRE

    S. P. Tewari,; Ankur Gupta; Jyoti Prakash

    2010-01-01

    In this study, the effect of various welding parameters on the weldability of Mild Steel specimens having dimensions 50mm× 40mm× 6 mm welded by metal arc welding were investigated. The welding current, arc voltage, welding speed, heat input rate are chosen as welding parameters. The depth of penetrations were measured for each specimen after the welding operation on closed butt joint and the effects of welding speed and heat input rate parameters on depth of penetration were investigated.

  5. Welding procedure of pipes of thermoplastic

    International Nuclear Information System (INIS)

    Consideration is given to the sequence and peculiarities of production operations of butt hot-tope welding of polyethylene and polypropylene tubes. Methods of destructive testing of weld are correlated. Data on the developed standard-process documentation are presented. 12 refs.; 1 fig.; 1 tab

  6. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...... in the weld causing expulsion of the melt pool. Trailing beams were applied to melt additional material and ensure a melt pool. The method showed good results for increasing tolerances to impurities and reduction of scrapped parts from blowouts during laser welding....

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

    Energy Technology Data Exchange (ETDEWEB)

    Egland, Keith; Ludewig, Howard

    2006-05-25

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

  8. Mobile flash butt welding construction method and technology of new 75 N rail%新型75N 钢轨移动闪光焊接施工工艺

    Institute of Scientific and Technical Information of China (English)

    宋宏图; 程星璠

    2016-01-01

    Taking an overloaded railway 75N new rail welding construction as an example,this paper introduced the characteristics,application scope and process principle of mobile flash welding construction methods,elaborated the construction process and quality control key points of the method,illustrated the used main machine,and put forward the welding construction safety and environmental protection measures,pointed out that using mobile flash welding could improve the welding quality and efficiency,could obtain good social and economic benefits.%以某重载铁路75N新型钢轨焊接施工为例,介绍了移动闪光焊接施工工法的特点、适用范围及工艺原理,阐述了该工法的施工流程及质量控制要点,列举了所使用的主要机具,并提出了焊接施工的安全和环保措施,指出采用移动闪光焊接提高了焊接的质量和效率,可获得良好的社会及经济效益。

  9. Embrittlement of welds produced by pulsed laser welding

    International Nuclear Information System (INIS)

    Welding through radiation of Nd:Yag laser is characterized by hard thermal deformation cycle under action of which the microstructure changes are obtained. These changes exert considerable influence on the mechanical properties. Experimentally investigated the influence of multipulse action on the butt weld strength at static tension. It was found that by increasing multiplicity equalled to increasing of overlapping factor the destroying stresses are decreased up to some

  10. Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints

    OpenAIRE

    J. Łabanowski

    2007-01-01

    Purpose: The aim of the current study is to reveal the influence of welding conditions on structure and stresscorrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Butt joints between duplex 2205 and austenitic 316L steels were performedwith the use of submerged arc welding (SAW) method. The plates 15 mm in thickness were welded with heatinput in the range of 1.15 – 3.2 kJ/mm using duplex steel filler metal. Microstructure examinations an...

  11. Welding of titanium alloy by different types of lasers

    OpenAIRE

    A. Lisiecki

    2012-01-01

    Purpose: of this paper was focused on comparing the welding modes during laser welding of butt joints of titanium alloy Ti6Al4V sheets 1.5 and 2.0 mm thick with direct diode laser and Disk solid state laser.Design/methodology/approach: Bead-on-plate welds were produced at different parameters of laser welding, different welding speed, different output laser power resulted in different heat input of laser welding process. The test welds were investigated by visual test, metallographic observat...

  12. 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.

  13. AECL devises new nuclear welding system

    International Nuclear Information System (INIS)

    Automatic autogenous TIG pipe butt welding equipment has been developed for producing joints in reactor coolant monitoring systems for tubes of between 6 and 25 mm diameter and up to 3 mm wall thickness in stainless steel. The equipment is designed to work on site with power requirements of up to 2.2 KW maximum. A major feature of the design, therefore, was a welding system of sufficiently small size, portability and ruggedness to be able to withstand on-site conditions. Quality control is carried out automatically by a comparison of welding parameters with those of a standard acceptable weld. Details of power source characteristics and welding procedure are given. (author)

  14. Numerical simulation and experimental investigation of temperature distribution in the circumferentially butt GTAW of Incoloy 800H pipes

    International Nuclear Information System (INIS)

    The multi-pass circumferential butt GTAW process of Incoloy 800H pipes was modelled with the FEM in 3D. The element birth and death technique was used for the addition of filler material. Goldak model was used to simulate the distribution of arc heat source. The validation of the simulation model was carried out based on the precise temperature measurements within the HAZ of the welds by thermocouples as well as metallographic characterisation of the cross section of the welds. A good agreement was found between the simulation and experimental results for both thermal field and weld zone shape. The present model showed that increasing the heat input resulted in a wider weld zone as well as a higher HAZ peak temperature. These effects were related to the net heat input and not to either welding current or welding speed, individually. The developed simulation model is a useful tool to investigate the welding thermal regime and the weld pool profile.

  15. Neural network modeling for weld shape process of P-GMAW

    Institute of Scientific and Technical Information of China (English)

    Yan Zhihong; Wu Lin; Zhang Guangjun; Gao Hongming

    2007-01-01

    Weld shape control is a fundamental issue in automatic welding. In this paper, a double side visual system is established for pulsed gas metal arc welding (P-GMAW), and both topside and backside weld pool images can be captured and stored continuously in real time. By analyzing the weld shape regulation with the molten metal volume, some topside weld pool characterized parameters (WPCPs) are proposed for determining penetration in butt welding of thin mild steel. Moreover, some BP network models are established to predict backside weld pool width with welding parameters and WPCPs as inputs.

  16. Monitoring of Welding Processes with Application of Artificial Neural Networks

    OpenAIRE

    Чвертко, Євгенія Петрівна; Пірумов, Андрій Євгенович; Шевченко, Микола Віталійович

    2014-01-01

    The paper presents a summary of methods of monitoring systems’ development for the processes involving heating of filler material and/ or base metal by the electric current and with periodical shortages of the welding circuit. The processes investigated were MAG welding, underwater flux-cored welding and flash-butt welding. Details of experiments, primary data processing procedures based on statistical analysis methods are described, the aim of primary processing being obtaining of informativ...

  17. Friction stir welding (FSW) of aluminium foam sandwich panels

    OpenAIRE

    M. Bušić; Kožuh, Z.; D. Klobčar; Samardžić, I.

    2016-01-01

    The article focuses on the influence of welding speed and tool tilt angle upon the mechanical properties at the friction stir welding of aluminium foam sandwich panels. Double side welding was used for producing butt welds of aluminium sandwich panels applying insertion of extruded aluminium profile. Such insertion provided lower pressure of the tool upon the aluminium panels, providing also sufficient volume of the material required for the weldment formation. Ultimate tensile strength and f...

  18. Influencia de la cantidad de O2 adicionado al CO2 en el gas de protección sobre la microestructura del metal depositado en uniones soldadas de bordes rectos en aceros de bajo contenido de carbono con el proceso GMAW Influence of O2 content, added to CO2 in the shielding gas, on the microstructure of deposited metal in butt welded joint with straight edges, in low carbon steels using GMAW process

    Directory of Open Access Journals (Sweden)

    Eduardo Díaz-Cedré

    2010-12-01

    Full Text Available La presencia de ferrita acicular (FA en la microestructura del cordón de soldadura, dentro de determinado rango de valores, eleva considerablemente la tenacidad de las uniones soldadas. Es por ello, que el presente trabajo trata sobre un estudio que relaciona la cantidad de ferrita acicular en el cordón en función del contenido de oxígeno presente en la mezcla activa CO2+O2, durante la realización de uniones soldadas de bordes rectos en aceros de bajo carbono con el proceso con electrodo fusible y protección gaseosa (GMAW en condiciones invariables de parámetros de proceso (corriente de soldadura, voltaje de arco, velocidad de soldadura, longitud libre y flujo de gas protector. Como resultado del trabajo se estableció la relación gráfica existente entre la ferrita acicular y el contenido de oxígeno en la mezcla.The presence of acicular ferrite (AF in the microstructure of weld bead, in a specified range of values, increase considerably the toughness of welded joints. The present paper, for that reason, study the relationship between the acicular ferrite quantity in the deposited metal and the oxygen present in the active gas mixture of CO2+O2, during the execution of butt welded joints with straight edges, in low carbon steels with consumable electrode and gas protection (GMAW in invariable conditions of process parameters (welding current, arc voltage, welding speed, electrode extension, and gas flow. The graphic relation between the acicular ferrite and the oxygen content was established, as result of the research work.

  19. Q345qD 桥梁钢对接焊缝疲劳裂纹扩展性能试验研究%Experimental study on fatigue crack behavior of Q345qD bridge steel butt welds

    Institute of Scientific and Technical Information of China (English)

    宗亮; 施刚; 王元清; 廖小伟

    2015-01-01

    The experimental study on fatigue crack growth rate and threshold of butt welds for Q345qD plates of 6.1,10.0 and 23.5 mm thickness was performed,aiming to implement fatigue assessment of welded structural details of existing steel bridges based on fracture mechanics.Two data processing methods were employed to de-rive fatigue crack growth parameters with 95% guarantee.It turns out that the fatigue crack growth rate based on data of each specimen is larger than that based on group method of data handling in terms of normal stress inten-sity range (10 ~70 MPa·m0.5 ).The fatigue crack growth rate will increase as the stress ratio increases.For Q345qD butt welds of this batch,the fatigue crack growth rate is slower than the universal steel performance pro-vided by BS7910.The fatigue crack growth threshold will decrease with the increase of the stress ratio,and the quantitative relationship is also developed in this paper.%为采用断裂力学方法对既有钢桥焊接细节进行疲劳评估,对6.1,10.0和23.5 mm 的 Q345qD 桥梁钢对接焊缝进行疲劳裂纹扩展速率试验和疲劳裂纹扩展门槛值测定试验,基于两种数据处理方法得到了不同厚度、不同应力比下的疲劳裂纹扩展速率参数。试验结果表明:在通常的应力强度因子幅值范围(10~70 MPa·m0.5)内,基于单试件数据点的处理结果对应的裂纹扩展速率明显高于基于成组数据点的处理结果;Q345qD 对接焊缝的疲劳裂纹扩展速率随应力比增加而增加;本批次的 Q345qD 对接焊缝的疲劳裂纹扩展性能优于 BS7910中给出的通用钢材疲劳裂纹扩展性能;Q345qD 对接焊缝疲劳扩展门槛值随应力比增加而降低,并给出了门槛值随应力比变化的公式。

  20. Butt and butt assembly in aluminium alloy: what are the effects of the welding or manufacturing defects on their fatigue resistance? Experimental results - part 2; Assemblage bout-a-bout en alliage d'aluminium: quels sont les effets des defauts de soudage ou de fabrication sur leur tenue a la fatique? Resultats experimentaux - 2. partie

    Energy Technology Data Exchange (ETDEWEB)

    Colchen, D. [Institut de Soudure, Serv. Fatigue et Mecanique de la Rupture, 57 - Yutz (France)

    2005-02-01

    In order to better know the fatigue resistance of aluminium alloys assemblies having welding or manufacturing defects, tensile tests on test-pieces reproducing methodically these defects have been carried out. Then, with the number of tests carried out, we have been able to establish with a numerical model Wohler curves in extent stresses. The influence that quantitatively exerts the dis-alignments, the deflections, the porosities, the geometry of under-cuts...has been deduced. These works lead on recommendations joining the fatigue resistance and critical size of one or several defects, and allow then to evaluate a specific resistance to wear and tear of an assembly in terms of its manufacturing quality. (O.M.)

  1. Alloy 800 welding experience at UKAEA Springfields

    International Nuclear Information System (INIS)

    Investigatins into the welding of alloy 800 at the Reactor Fuel Element Laboratories, Springfields, commenced about three years ago following an extended development programme on tube to tube plate welding of low alloy and stainless steels for the Prototype Fast Reactor. The techniques and approach developed for critical fuel element welding applications had proved equally suitable for the precision welding requirements on the much heavier sections of heat exchangers. It had been demonstrated that the same control of weld quality and profile could be achieved with consistency and the permissible range of critical parameters could be readily defined. Because of this, development work was continued to include other materials, such as alloy 800, which might be of potential use. The tungsten inert gas (T.I.G.) arc welding process is used, and the equipment, including the control system, is described. Tube to tube-plate welding, and tube to tube butt welding, are discussed. (author)

  2. Weld geometry strength effect in 2219-T87 aluminum

    Science.gov (United States)

    Nunes, A. C., Jr.; Novak, H. L.; Mcilwain, M. C.

    1981-01-01

    A theory of the effect of geometry on the mechanical properties of a butt weld joint is worked out based upon the soft interlayer weld model. Tensile tests of 45 TIG butt welds and 6 EB beads-on-plate in 1/4-in. 2219-T87 aluminum plate made under a wide range of heat sink and power input conditions are analyzed using this theory. The analysis indicates that purely geometrical effects dominate in determining variations in weld joint strength with heat sink and power input. Variations in weld dimensions with cooling rate are significant as well as with power input. Weld size is suggested as a better indicator of the condition of a weld joint than energy input.

  3. Microstructure and Mechanical Properties of the Butt Joint in High Density Polyethylene Pipe

    Directory of Open Access Journals (Sweden)

    Pashupati Pokharel

    2016-01-01

    Full Text Available The microstructure and mechanical properties of the butt joint in high density polyethylene (HDPE pipes were evaluated by preparing the joints with increasing the cooling time from 10 s to 70 s before pressure created for fusion of the pipes. Here, cold fusion flaws in HDPE butt joint were created with increasing the cooling time around 70 s caused by the close molecular contact followed by insufficient interdiffusion of chain segments back and forth across the wetted interface. The tensile failure mechanism of the welded pipes at different fusion time was projected based on the tensile test of dog-bone shaped, fully notched bar type as well as round U-notched specimens. The mechanical properties of the joints at different fusion time were correlated with the corresponding fracture surface morphology. The weld seam as well as tensile fracture surfaces were etched using strong oxidizing agents. The crystallinity of surface etched weld zone by potassium permanganate based etchant was found higher than unetched sample due to the higher susceptibility of amorphous phase of polyethylene with oxidizing agent. The U-notched tensile test of butt welded HDPE pipe and surface etching of the weldments provided clear delineation about the joint quality.

  4. Inspection of thick welded joints using laser-ultrasonic SAFT.

    Science.gov (United States)

    Lévesque, D; Asaumi, Y; Lord, M; Bescond, C; Hatanaka, H; Tagami, M; Monchalin, J-P

    2016-07-01

    The detection of defects in thick butt joints in the early phase of multi-pass arc welding would be very valuable to reduce cost and time in the necessity of reworking. As a non-contact method, the laser-ultrasonic technique (LUT) has the potential for the automated inspection of welds, ultimately online during manufacturing. In this study, testing has been carried out using LUT combined with the synthetic aperture focusing technique (SAFT) on 25 and 50mm thick butt welded joints of steel both completed and partially welded. EDM slits of 2 or 3mm height were inserted at different depths in the multi-pass welding process to simulate a lack of fusion. Line scans transverse to the weld are performed with the generation and detection laser spots superimposed directly on the surface of the weld bead. A CCD line camera is used to simultaneously acquire the surface profile for correction in the SAFT processing. All artificial defects but also real defects are visualized in the investigated thick butt weld specimens, either completed or partially welded after a given number of passes. The results obtained clearly show the potential of using the LUT with SAFT for the automated inspection of arc welds or hybrid laser-arc welds during manufacturing.

  5. Inspection of thick welded joints using laser-ultrasonic SAFT.

    Science.gov (United States)

    Lévesque, D; Asaumi, Y; Lord, M; Bescond, C; Hatanaka, H; Tagami, M; Monchalin, J-P

    2016-07-01

    The detection of defects in thick butt joints in the early phase of multi-pass arc welding would be very valuable to reduce cost and time in the necessity of reworking. As a non-contact method, the laser-ultrasonic technique (LUT) has the potential for the automated inspection of welds, ultimately online during manufacturing. In this study, testing has been carried out using LUT combined with the synthetic aperture focusing technique (SAFT) on 25 and 50mm thick butt welded joints of steel both completed and partially welded. EDM slits of 2 or 3mm height were inserted at different depths in the multi-pass welding process to simulate a lack of fusion. Line scans transverse to the weld are performed with the generation and detection laser spots superimposed directly on the surface of the weld bead. A CCD line camera is used to simultaneously acquire the surface profile for correction in the SAFT processing. All artificial defects but also real defects are visualized in the investigated thick butt weld specimens, either completed or partially welded after a given number of passes. The results obtained clearly show the potential of using the LUT with SAFT for the automated inspection of arc welds or hybrid laser-arc welds during manufacturing. PMID:27062646

  6. Numerical analysis of welded joint treated by explosion shock waves

    Institute of Scientific and Technical Information of China (English)

    GUAN Jianjun; CHEN Huaining

    2007-01-01

    This paper focuses on the simulation of welding residual stresses and the action of explosion shock waves on welding residual stresses. Firstly, the distributions of welding temperature field and residual stress on a butt joint were numerically simulated with the sequentially coupled method. Secondly, the effect of explosion shock waves, produced by plastic strip-like explosive, on welding residual stress distri-bution was predicted with coupled Lagrange-ALE algorithm.It was implicated that explosion treatment could effectively reduce welding residual stresses. The simulation work lays a foundation for the further research on the rule of explosion treatment's effect on welding residual stresses and the factors that may influence it.

  7. Microstructure of AA 2024 fixed joints formed by friction stir welding

    Science.gov (United States)

    Eliseev, A. A.; Kalashnikova, T. A.; Tarasov, S. Yu.; Rubtsov, V. E.; Fortuna, S. V.; Kolubaev, E. A.

    2015-10-01

    Friction stir welded butt joints on 2024T3 alloy have been obtained using different process parameters. The microstructures of all the weld joint zones have been examined and such structural parameters as grain size, particle size and volume content of particles have been determined in order to find correlations with the microhardness of the corresponding zones of the weld.

  8. Combination of laser keyhole and conduction welding: Dissimilar laser welding of niobium and Ti-6Al-4V

    Science.gov (United States)

    Torkamany, M. J.; Malek Ghaini, F.; Poursalehi, R.; Kaplan, A. F. H.

    2016-04-01

    Pulsed Nd:YAG laser welding of pure niobium plate to titanium alloy Ti-6Al-4V sheet in butt joint is studied regarding the laser/metal interaction modes. To obtain the optimized process parameters in dissimilar welding of Ti-6Al-4V/Nb, the melting ratio of laser beam energy for each weld counterpart is evaluated experimentally. Different laser welding modes of keyhole and conduction are predicted regarding the absorbed energy from the similar laser pulses on each weld counterpart. Laser keyhole and conduction welding were observed simultaneously through direct visualization of laser interaction with dissimilar metals using High Speed Imaging (HSI) system.

  9. Detection of micro-weld joint by magneto-optical imaging

    Science.gov (United States)

    Gao, Xiangdong; Liu, Yonghua; You, Deyong

    2014-10-01

    It is required that the laser beam focus should be controlled to accurately follow the weld joint center during laser butt joint welding; therefore, the weld joint position must be detected automatically in real-time. An approach for detecting the micro-weld joint (weld gap less than 0.1 mm) based on magneto-optical (MO) imaging is investigated during laser butt-joint welding of low carbon steel. Magneto-optical sensor was used to capture the dynamic images of weld joint. Weld MO image gray distribution features were analyzed to extract the transition zone of weld joint. The influences of a different magnetic field intensity and the welding speed on detecting the weld joint position were mainly studied. Under different welding conditions where welding path, weld gap or welding speed varies, it has been found that using magneto-optic imaging technology could effectively detect the position of the micro-weld joint. Different weld joint positions in MO images have been detected with various magnetic field intensities. Experimental results show that the welding speed has little influence on the detection of weld joint position.

  10. 钢轨闪光焊接头过热区缺陷的形成机理及预防方法%Formation mechanism and prevention methods of defects in overheat area at rail f lash-butt welding joint

    Institute of Scientific and Technical Information of China (English)

    丁韦; 张宪良; 赵国; 宋宏图

    2015-01-01

    T he formation and expansion mechanism of the micro cracks in overheat area at the rail flash-butt welding joint was analyzed. Combined with relevant fatigue tests and fracture scanning,it was proved that crack defects were related to M nS inclusions in rail base metal band structure. M nS inclusions showed layered distribution along the longitudinal direction of the band structureand,w eaken the strength of the band structure in the vertical direction. W elding heat caused its strength decreased further. Band structure in the vertical direction bore strong shear stress while upsetting and trimming at the last stage of welding. W hen the shear stress exceeded the band structure strength at vertical direction,a tiny crack was caused. T he fracture characteristic of drop-hammer test was that in macroscopic fracture of crack source area small cracks and voids should be observed. T he method of controlling such defect is by reducing the base metal segregation and increasing joint temperature during trimming.%对钢轨闪光焊接头轨底过热区出现的微裂纹缺陷的形成和扩展机理进行了分析,并结合相关疲劳试验及断口扫描,证明裂纹缺陷与钢轨母材带状组织中的 MnS夹杂物有关。MnS 夹杂物沿着带状组织纵向层状分布,弱化带状组织垂直方向的强度。焊接加热使得其强度进一步下降。焊接末期的顶锻和推凸使得带状组织沿垂直方向承受较强的剪切应力,当剪切应力值超过带状组织垂直方向的强度时就会出现微小裂纹。存在这类裂纹的落锤断口特征是在裂纹源区宏观断口可观察到微小裂纹及空洞。控制该缺陷产生的方法是减小母材成分偏析和提高推凸时的接头温度。

  11. Laser welding and post weld treatment of modified 9Cr-1MoVNb steel.

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z. (Nuclear Engineering Division)

    2012-04-03

    Laser welding and post weld laser treatment of modified 9Cr-1MoVNb steels (Grade P91) were performed in this preliminary study to investigate the feasibility of using laser welding process as a potential alternative to arc welding methods for solving the Type IV cracking problem in P91 steel welds. The mechanical and metallurgical testing of the pulsed Nd:YAG laser-welded samples shows the following conclusions: (1) both bead-on-plate and circumferential butt welds made by a pulsed Nd:YAG laser show good welds that are free of microcracks and porosity. The narrow heat affected zone has a homogeneous grain structure without conventional soft hardness zone where the Type IV cracking occurs in conventional arc welds. (2) The laser weld tests also show that the same laser welder has the potential to be used as a multi-function tool for weld surface remelting, glazing or post weld tempering to reduce the weld surface defects and to increase the cracking resistance and toughness of the welds. (3) The Vicker hardness of laser welds in the weld and heat affected zone was 420-500 HV with peak hardness in the HAZ compared to 240 HV of base metal. Post weld laser treatment was able to slightly reduce the peak hardness and smooth the hardness profile, but failed to bring the hardness down to below 300 HV due to insufficient time at temperature and too fast cooling rate after the time. Though optimal hardness of weld made by laser is to be determined for best weld strength, methods to achieve the post weld laser treatment temperature, time at the temperature and slow cooling rate need to be developed. (4) Mechanical testing of the laser weld and post weld laser treated samples need to be performed to evaluate the effects of laser post treatments such as surface remelting, glazing, re-hardening, or tempering on the strength of the welds.

  12. DNA typing from cigarette butts.

    Science.gov (United States)

    Watanabe, Yoshihisa; Takayama, Tomohiro; Hirata, Keiji; Yamada, Sadao; Nagai, Atsushi; Nakamura, Isao; Bunai, Yasuo; Ohya, Isao

    2003-03-01

    We performed DNA typing for D1S80, HLADQA1, TH01 and PM using the butts of 100 cigarettes that were smoked by ten different individuals (ten cigarettes per individual). The results obtained from DNA typing for D1S80 agreed with the results obtained using bloodstains in 76 cigarette butt samples. Sixteen samples produced false results, showing the loss of the longer allelic hetero-band. When examined using agarose gel electrophoresis, high-molecular weight DNA was not observed in these samples. The same results were also observed for buccal swab samples and saliva stains obtained from the same individuals. In the remaining eight cigarette butt samples, PCR products were not detected. The results obtained from DNA typing for TH01, HLADQA1 and PM agreed with the results obtained using bloodstains in 90 samples. In the remaining ten samples of a specific kind of cigarette (Marlboro), the PCR products were not detected. The extracts from the ends of the Marlboro cigarettes were stained yellow. When the DNA extracted from Marlboro cigarette butts was treated with Microcon-100 (amicon) or SizeSep 400 Span Columns (Amersham Pharmacia Biotech), PCR products could be detected. When PCR amplification was performed after adding extracts from the ends of unsmoked Marlboro cigarettes to DNA extracted from bloodstains, PCR products could not be detected. The present data indicate that the degradation of high-molecular weight DNA and the inhibition of PCR by dyes of the cigarette end should be kept in mind when performing DNA typing using cigarette ends.

  13. Weld repair method for aluminum lithium seam

    Science.gov (United States)

    McGee, William Floyd (Inventor); Rybicki, Daniel John (Inventor)

    1998-01-01

    Aluminum-lithium plates are butt-welded by juxtaposing the plates and making a preliminary weld from the rear or root side of the seam. An initial weld is then made from the face side of the seam, which may cause a defect in the root portion. A full-size X-ray is made and overlain over the seam to identify the defects. The defect is removed from the root side, and rewelded. Material is then removed from the face side, and the cavity is rewelded. The procedure repeats, alternating from the root side to the face side, until the weld is sound.

  14. Visual Tracking System for Welding Seams

    Institute of Scientific and Technical Information of China (English)

    Zeng-shun ZHAO; Ji-zhen WANG; Xue-Zhen CHENG

    2010-01-01

    To track the narrow butt welding seams in container manufacture, a visual tracking system based on smart camera is proposed in this paper. A smart camera is used as the sensor to detect the welding seam. The feature extraction algorithm is designed with the consideration of the characteristics of the smart camera, which is used to compute the error between the welding torch and the welding seam. Visual control system based on image is presented, which employs a programmable controller to control a stepper motor to eliminate the tracking error detected by the smart camera. Experiments are conducted to demonstrate the effectiveness of the vision system.

  15. Mechanical properties and corrosion resistance of dissimilar stainless steel welds

    OpenAIRE

    J. Łabanowski

    2007-01-01

    Purpose: The purpose of this paper is to determine the influence of welding on microstructure, mechanical properties, and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Duplex 2205 and austenitic 316L steels were used. Butt joints of plates 15 mm in thickness were performed with the use of submerged arc welding (SAW) method. The heat input was in the range of 1.15 – 3.2 kJ/mm. Various plates’ edge preparation...

  16. 铝和不锈钢FSW对搭接接头界面结构及性能研究%Interface Structure and Properties on Friction Stir Welding Dissimilar Alloys Lap-Butt Joint of Aluminum and Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    徐海升; 沈以赴; 冯晓梅; 陈文华

    2015-01-01

    采用搅拌摩擦焊接方法,设计了基于“差高-偏置”的对搭接接头,对厚度为4 mm的5A06铝合金和厚度为2 mm的316L不锈钢进行了搅拌摩擦焊接(Friction stir welding,FSW)焊接试验.通过观察焊缝金相形貌发现,焊接界面光滑平整,没有形成Hook钩,在焊缝靠近界面位置形成了钢颗粒增强铝基复合组织和河流状花样组织结构.通过SEM观察,铝-钢之间形成了一层厚度约为3μm的中间过渡层.显微硬度及拉伸测试结果表明,过渡层的显微硬度较高,接头的拉伸强度达到了铝合金母材强度的89.7%.

  17. Monitoring of solidification crack propagation mechanism in pulsed laser welding of 6082 aluminum

    Science.gov (United States)

    von Witzendorff, P.; Kaierle, S.; Suttmann, O.; Overmeyer, L.

    2016-03-01

    Pulsed laser sources with pulse durations in the millisecond regime can be used for spot welding and seam welding of aluminum. Seam welds are generally produced with several overlapping spot welds. Hot cracking has its origin in the solidification process of individual spot welds which determines the cracking morphology along the seam welding. This study used a monitoring unit to capture the crack geometry within individual spot welds during seam welding to investigate the conditions for initiation, propagation and healing (re-melting) of solidification cracking within overlapping pulsed laser welds. The results suggest that small crack radii and high crack angles with respect to welding direction are favorable conditions for crack healing which leads to crack-free seam welds. Optimized pulse shapes were used to produce butt welds of 0.5 mm thick 6082 aluminum alloys. Tensile tests were performed to investigate the mechanical strength in the as-welded condition.

  18. Comparative Analysis of X-ray Detection Standard of Pipe Butt Welding Joint%管道对接焊接接头射线检测标准比较分析

    Institute of Scientific and Technical Information of China (English)

    王印宇

    2014-01-01

    JB辕T 4730-2005《承压设备无损检测》和SY辕T 4109-2005《石油天然气钢质管道无损检测》在无损检测行业中都有着广泛的应用,但两个标准有一定的差别,在具体应用中,应根据两个标准的各自特点进行综合考虑。文章对两个标准射线部分的不同之处进行比较,目的是便于无损检测人员能更好地理解标准,更加准确地使用标准,从而保证无损检测工作质量和工程焊接质量。%JB/ T 4730-2005 "Pressure Equipment Nondestructive Testing" and SY / T 4109-2005 "Petroleum and Natural Gas Steel Pipeline Nondestructive Testing" are widely used in the NDT industry, but there are some differences between the two standards. In the specific application, the characteristics of the two standards should be considered. The paper compared the differences of the two standards in X-ray part, in order to facilitate the NDT personnel to better understand the standard, use the standard more accurately, so as to ensure the NDT work quality and quality of engineering welding.

  19. A Study on the Welding Characteristics of Tailor Welded Blank Metal Sheets Using GTAW and Laser Welding

    Science.gov (United States)

    Thasanaraphan, Pornsak

    In this study, a computational and experimental effort was carried out to qualitatively understand the weld pool shape, distortion and residual stress for continuous laser welding and manual pulsed gas metal arc welding. For all the welding simulations given in this dissertation, a welding specific finite element package, SYSWELD, is used. This research focuses on the welding behavior observed in light-weight metal structures known as the tailor-welded blanks, TWBs. They are a combination of two or more metal sheets with different thickness and/or different materials that are welded together in a single plane prior to forming, e.g., stamping. They made from the low carbon steel. As laser welding experiment results show, the weld pool shape at the top and bottom surface, is strongly influenced by surface tension, giving it a characteristic hourglass shape. In order to simulate the hourglass shape, a new volumetric heat source model was developed to predict the transient temperature profile and weld pool shape, including the effect of surface tension. Tailor welded blanks with different thicknesses were examined in the laser welding process. All major physical phenomena such as thermal conduction, heat radiation and convection heat losses are taken into account in the model development as well as temperature-dependant thermal and mechanical material properties. The model is validated for the case of butt joint welding of cold rolled steel sheets. The results of the numerical simulations provide temperature distributions representing the shape of the molten pool, distortion and residual stress with varying laser beam power and welding speed. It is demonstrated that the finite element simulation results are in good agreement with the experiment results. This includes the weld pool shape and sheet metal distortion. While there is no experimental data to compare directly with residual stress results, the distorted shape provides an indirect measure of the welding

  20. Application of pulsed tandem gas metal arc welding for fabrication of high strength steel panels in naval surface vessels

    International Nuclear Information System (INIS)

    Pulsed tandem gas metal arc welding (PT-GMAW) has been identified as a process that is potentially capable of increasing productivity and minimising distortion in the fabrication of surface ship panels. For this study, the PT-GMAW process was used in pulse pulse mode to butt-weld 8 MM HSLA65 steel plate in order to determine its suitability as a replacement for standard gas-metal-arc welding (GMAW) and submerged-arc welding (SAW) in naval shipbuilding. In the pulse-pulse mode, the leading and trailing welding wires alternately transfer metal into a single molten weld pool at deposition rates or travel speeds greater than those used in conventional single-wire arc welding processes. The results showed that the lowest level of distortion occurred in a single-bead butt weld using PT-GMAW. Higher levels of distortion were measured after square-butt welding using double-bead PT-GMAW, with one bead per side; and applying standard GMAW multiple-bead butt welding with a single-V preparation. Although the magnitude of the maximum tensile residual stresses was similar for all welds, the single-bead weld rising PT-GMAW resulted in the largest region of high tensile residual stresses (>500 MPa) in the longitudinal direction. Nevertheless, it showed the lowest distortion and the strength, hardness and impact toughness were similar to those of the double-bead PT-GMAW weldment and the standard GMAW weldment.

  1. Improvement of Fatigue Life of Welded Structural Components of a Large Two-Stroke Diesel Engine by Grinding

    DEFF Research Database (Denmark)

    Agerskov, Henning; Hansen, Anders V.; Bjørnbak-Hansen, Jørgen;

    2004-01-01

    The crankshaft housings of large two-stroke diesel engines are welded structures subjected to constant amplitude loading and designed for infinite life at full design load. A new design of the so-called frame box has been introduced in the engine using butt weld joints of thick plates, welded from...

  2. Welding Process Feedback and Inspection Optimization Using Ultrasonic Phased Arrays

    Science.gov (United States)

    Hopkins, D. L.; Neau, G. N.; Davis, W. B.

    2009-03-01

    Measurements performed on friction-stir butt welds in aluminum and resistance spot welds in galvanized steel are used to illustrate how ultrasonic phased arrays can be used to provide high-resolution images of welds. Examples are presented that demonstrate how information extracted from the ultrasonic signals can be used to provide reliable feedback to welding processes. Modeling results are used to demonstrate how weld inspections can be optimized using beam-forming strategies that help overcome the influence of surface conditions and part distortion.

  3. Friction stir welding (FSW of aluminium foam sandwich panels

    Directory of Open Access Journals (Sweden)

    M. Bušić

    2016-07-01

    Full Text Available The article focuses on the influence of welding speed and tool tilt angle upon the mechanical properties at the friction stir welding of aluminium foam sandwich panels. Double side welding was used for producing butt welds of aluminium sandwich panels applying insertion of extruded aluminium profile. Such insertion provided lower pressure of the tool upon the aluminium panels, providing also sufficient volume of the material required for the weldment formation. Ultimate tensile strength and flexural strength for three-point bending test have been determined for samples taken from the welded joints. Results have confirmed anticipated effects of independent variables.

  4. Investigation of flux-powder wire’s components-stabilizers on welding and technological properties in underwater welding

    OpenAIRE

    КАХОВСЬКИЙ М.Ю.; Максимов, С. Ю.

    2015-01-01

    Based on long-term experience of welding by mechanized flux-cored wires, the E.O. Paton Electric Welding Institute investigated a self-protecting flux-cored wire for wet underwater welding of stainless steels type 18-10. It allows to perform welding of butt, fillet and overlapped joints in flat and vertical positions of high-alloy corrosion-resistant steels type of 18-10 (AISI 304L, 308L, 347 and 321). The article presents results of development of welding-repair technology using self-shielde...

  5. Welding in space and the construction of space vehicles by welding; Proceedings of the Conference, New Carrollton, MD, Sept. 24-26, 1991

    Science.gov (United States)

    The present conference discusses such topics in spacecraft welding as the NASA Long Duration Exposure Facility's evidence on material properties degradation, EVA/telerobotic construction techniques, welding of the superfluid helium on-orbit transfer flight demonstration tanks and hardware, electron-beam welding of aerospace vehicles, variable-polarity plasma arc keyhole welding of Al, aircraft experiments of low-gravity fusion welding, flash-butt welding of Al alloys, and a computer-aided handbook for space welding fabrication. Also discussed are the welded nozzle extension for Ariane launch vehicles, the existence of on-orbit cold-welding, structural materials performance in long-term space service, high-strength lightweight alloys, steels, and heat-resistant alloys for aerospace welded structures, the NASA-Goddard satellite repair program, and the uses of explosion welding and cutting in aerospace engineering.

  6. Multi-response optimization of CO2 laser welding process of austenitic stainless steel

    OpenAIRE

    Benyounis, Khaled; Olabi, Abdul-Ghani; Hashmi, Saleem

    2008-01-01

    Recently, laser welding of austenitic stainless steel has received great attention in industry, due to its wide spread application in petroleum refinement stations, power plant, pharmaceutical industry and households. Therefore, mechanical properties should be controlled to obtain good welded joints. The welding process should be optimized by the proper mathematical models. In this research, the tensile strength and impact strength along with the joint operating cost of laser welded butt join...

  7. Residual Stress Evaluation of Weld Inlay Process on Reactor Vessel Nozzles

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Kihyun; Cho, Hong Seok [KEPCO KPS, Naju (Korea, Republic of)

    2015-10-15

    Weld overlay, weld inlay and stress improvement are mitigation technologies for butt joints. Weld overlay is done on pressurizer nozzles which are the highest potential locations occurring PWSCC due to high temperature in Korea. Reactor vessel nozzles are other big safety concerns for butt joints. Weld overlay and stress improvement should be so difficult to apply to those locations because space is too limited. Weld inlay should be one of the solutions. KEPCO KPS has developed laser welding system and process for reactor nozzles. Welding residual stress analysis is necessary for flaw evaluation. United States nuclear regulatory commission has calculated GTAW(Gas Tungsten Arc Welding) residual stress using ABAQUS. To confirm effectiveness of weld inlay process, welding residual stress analysis was performed. and difference between GTAW and LASER welding process was compared. Evaluation of weld inlay process using ANSYS and ABAQUS is performed. All of the both results are similar. The residual stress generated after weld inlay was on range of 450-500 MPa. Welding residual stresses are differently generated by GTAW and LASER welding. But regardless of welding process type, residual tensile stress is generated on inside surface.

  8. Development of Simplified Finite Element Models for Welded Joints

    Energy Technology Data Exchange (ETDEWEB)

    Song, Seong Il; Ahn, Sung Wook; Kim, Young Geul; Kim, Hyun Gyu [Seoul National Univ. of Sci. and Tech., Seoul (Korea, Republic of)

    2015-11-15

    In this paper, we develop simplified finite element (FE) models for butt-, lap- and T-welded joints by performing numerical and experimental experiments. Three-point bending tests of butt- and lap-welded specimens are performed to obtain the stiffness of the specimens and the strains at points near the welding beads. Similarly the stiffness and strains of T-welded specimen are measured by applying a point load at the end of the specimen. To develop simplified FE models, we consider the shape parameters of width, thickness and the angle of weld elements in the numerical simulations. The shape parameters of the simplified FE models are determined by building linear regression models for the experimental data sets.

  9. FIRE HAZARDS ANALYSIS - BUSTED BUTTE

    Energy Technology Data Exchange (ETDEWEB)

    R. Longwell; J. Keifer; S. Goodin

    2001-01-22

    The purpose of this fire hazards analysis (FHA) is to assess the risk from fire within individual fire areas at the Busted Butte Test Facility and to ascertain whether the DOE fire safety objectives are met. The objective, identified in DOE Order 420.1, Section 4.2, is to establish requirements for a comprehensive fire and related hazards protection program for facilities sufficient to minimize the potential for: (1) The occurrence of a fire related event. (2) A fire that causes an unacceptable on-site or off-site release of hazardous or radiological material that will threaten the health and safety of employees. (3) Vital DOE programs suffering unacceptable interruptions as a result of fire and related hazards. (4) Property losses from a fire and related events exceeding limits established by DOE. Critical process controls and safety class systems being damaged as a result of a fire and related events.

  10. FIRE HAZARDS ANALYSIS - BUSTED BUTTE

    International Nuclear Information System (INIS)

    The purpose of this fire hazards analysis (FHA) is to assess the risk from fire within individual fire areas at the Busted Butte Test Facility and to ascertain whether the DOE fire safety objectives are met. The objective, identified in DOE Order 420.1, Section 4.2, is to establish requirements for a comprehensive fire and related hazards protection program for facilities sufficient to minimize the potential for: (1) The occurrence of a fire related event. (2) A fire that causes an unacceptable on-site or off-site release of hazardous or radiological material that will threaten the health and safety of employees. (3) Vital DOE programs suffering unacceptable interruptions as a result of fire and related hazards. (4) Property losses from a fire and related events exceeding limits established by DOE. Critical process controls and safety class systems being damaged as a result of a fire and related events

  11. R. Freeman Butts: Educational Foundations and Educational Diplomacy

    Science.gov (United States)

    Allison, John

    2014-01-01

    R. Freeman Butts was an American historian and philosopher of education who died in March 2010. This paper will investigate Butts' various roles and writings and ask the question: why is Butts important to the contemporary generation of teacher educators and teachers? This paper will argue that the breadth of Butts' work builds…

  12. A study of structure and mechanical properties of welded joints in polyethylene pipes

    International Nuclear Information System (INIS)

    The structure and the mechanical properties of a butt weld in a polyethylene pipe were examined and contrasted to non-welded PE pipe. X-ray diffraction, differential scanning calorimeter and fourier transform infra red spectrometer measurements revealed details of axial amorphous and crystal orientation in the original pipe. Contrary to expectations considering the squeeze flow nature of butt-welding, formation of randomly oriented crystal structure was determined in the weld region. Tensile and notched impact tests at ambient and sub-ambient temperatures and varying rates of impact showed that welding consistently reduced resistance to failure. Microscopic evaluation of the brittle fracture surfaces revealed the surface morphology of the welded zone to be coarser than the non-welded PE material

  13. PENGARUH BESAR ARUS LISTRIK DENGAN MENGGUNAKAN ELEKTRODA SMAW TERHADAP KEKUATAN SAMBUNGAN LAS BUTT JOINT PADA PLAT MILD STEEL

    Directory of Open Access Journals (Sweden)

    Sarjito Jokosisworo

    2012-03-01

    Full Text Available The influence of mechanic disposition, is one of the factor influence ship strength. This influence can be test by mechanical test in welding butt joint. The result test database analysis can be conclude that very helpful to increase safety and quality butt joint. With steel specification C= 0,15%, Si= 0,24%, Mn= 0,88%,P= 0,018%, S= 0,034%. This material give a 90, 110, 125 ampere with SMAW AC electrode diameter 3,2 mm x 350 mm with V root and 600 angle In the fabrication of mild steel products, components or equipment, manufacturers employ welding as the principal joining method. Mild steel are weldable materials, and a welded joint can provide optimum corrosion resistance, strength, and fabrication economy. However, designers should recognize that any metal, including stainless steels, may undergo certain changes during welding. It is necessary, therefore, to exercise a reasonable degree of care during welding to minimize or prevent any deleterious effects that may occur, and to preserve the same degree of corrosion resistance and strength in weld zone that is an intheren part of the base metal

  14. Welding of Thermomechanically Rolled Steel by Yb:YAG Disk Laser / Spawanie Stali Walcowanej Termomechanicznie Laserem Dyskowym Yb:YAG

    Directory of Open Access Journals (Sweden)

    Lisiecki A.

    2015-12-01

    Full Text Available Autogenous laser welding of 5.0 mm thick butt joints of thermomechanically rolled steel S700MC was investigated. The Yb:YAG disk laser TruDisk 3302 emitted at 1.03 μm was used for the trials of autogenous welding. The effect of laser welding parameters and thus thermal conditions of welding on weld shape, microstructure of weld metal and heat affected zone (HAZ, tensile strength, bending angle, impact toughness and microhardness profile was determined. Studies have shown that it is advantageous to provide a high welding speed and low heat input. High cooling rate of weld metal and HAZ leads to the formation of a favorable structure characterized by a large proportion of fine-grained acicular ferrite and provides high mechanical properties of butt joints.

  15. A Neural Network Approach for GMA Butt Joint Welding

    DEFF Research Database (Denmark)

    Christensen, Kim Hardam; Sørensen, Torben

    2003-01-01

    squares has been used with the back-propagation algorithm for training the network, while a Bayesian regularization technique has been successfully applied for minimizing the risk of inexpedient over-training. Finally, a predictive closed-loop control strategy based on a so-called single-neuron self...

  16. Stress indices for girth welded joints, including radial weld shrinkage, mismatch and tapered-wall transitions

    International Nuclear Information System (INIS)

    A review is presented of B, C and K stress indices used in the ASME Nuclear Power Plant Code for girth butt welds and girth fillet welds. Theoretical stresses are presented to aid in evaluating C-indices. Fatigue test data are presented to aid in evaluating K-indices and CK-products. A limit load theory is presented to aid in evaluating B-indices. As a result of this review, recommendations are made for changes in the ASME Code. A major part of this consists of presenting definitions for girth welded joints and transitions and appropriate stress indices for those joints

  17. Welding of titanium alloy by different types of lasers

    Directory of Open Access Journals (Sweden)

    A. Lisiecki

    2012-12-01

    Full Text Available Purpose: of this paper was focused on comparing the welding modes during laser welding of butt joints of titanium alloy Ti6Al4V sheets 1.5 and 2.0 mm thick with direct diode laser and Disk solid state laser.Design/methodology/approach: Bead-on-plate welds were produced at different parameters of laser welding, different welding speed, different output laser power resulted in different heat input of laser welding process. The test welds were investigated by visual test, metallographic observations including macro and microstructure analysis. Additionally mechanical test were carried out such as tensile tests and technological bending test of the joints. The influence of basic laser welding parameters on the penetration depth, shape of fusion zone, width of welds and width of heat affected zones were studied. Additionally the phenomena of laser heating and melting of the welded sheets were analyzed.Findings: It was found that the mechanism of HPDL laser welding of titanium alloy differs distinctly from the mechanism of Disk laser welding. The test welds produced by HPDL laser were high quality. Welds produced by the Disk laser are characterized by a columnar shape of fusion zones, very narrow with narrow and fine structure heat affected zone.Research limitations/implications: In further investigations of laser welding of titanium alloys applying the key-hole welding mode a special care must be taken to the shielding of the weld zone and protection the weld pool and weld metal against the harmful gases from air atmosphere.Practical implications: Results of investigations presented in this paper may be applied directly for welding high quality butt joints of titanium alloy with the HPDL laser. In a case of laser welding with the Disk laser practical application requires further study, especially concentrated on the effectiveness of gas protection of the welding area including the key-hole, weld pool and surrounding regions of metal

  18. Structural integrity and fatigue crack propagation life assessment of welded and weld-repaired structures

    Science.gov (United States)

    Alam, Mohammad Shah

    2005-11-01

    Structural integrity is the science and technology of the margin between safety and disaster. Proper evaluation of the structural integrity and fatigue life of any structure (aircraft, ship, railways, bridges, gas and oil transmission pipelines, etc.) is important to ensure the public safety, environmental protection, and economical consideration. Catastrophic failure of any structure can be avoided if structural integrity is assessed and necessary precaution is taken appropriately. Structural integrity includes tasks in many areas, such as structural analysis, failure analysis, nondestructive testing, corrosion, fatigue and creep analysis, metallurgy and materials, fracture mechanics, fatigue life assessment, welding metallurgy, development of repairing technologies, structural monitoring and instrumentation etc. In this research fatigue life assessment of welded and weld-repaired joints is studied both in numerically and experimentally. A new approach for the simulation of fatigue crack growth in two elastic materials has been developed and specifically, the concept has been applied to butt-welded joint in a straight plate and in tubular joints. In the proposed method, the formation of new surface is represented by an interface element based on the interface potential energy. This method overcomes the limitation of crack growth at an artificial rate of one element length per cycle. In this method the crack propagates only when the applied load reaches the critical bonding strength. The predicted results compares well with experimental results. The Gas Metal Arc welding processes has been simulated to predict post-weld distortion, residual stresses and development of restraining forces in a butt-welded joint. The effect of welding defects and bi-axial interaction of a circular porosity and a solidification crack on fatigue crack propagation life of butt-welded joints has also been investigated. After a weld has been repaired, the specimen was tested in a universal

  19. Laser welding of the 12Kh18N10T steel

    International Nuclear Information System (INIS)

    A possibility of laser welding of 5 and 6 mm thick butt joints of the 12Kh18N10T stainless steel has been studied. The laser beam power constituted 5 and 23 kW and rates-75 and 250 m/h, respectively. Both two-sided air blasting of the molten pool by helium and the AN-60 flux were used for the weld metal protection from oxidation. The quality of welding was assessed on the basis of the results metallographic and X-ray structural analyses of welds and mechanical tests. The effect of welding parameters and weld metal protection technique on the quality of welded joints has been shown. The mechanical properties of welded joints are satisfactory. It has been made the conclusion on the possibility of laser welding of the above steel for the weld metal protection from oxidation using fluxes and inert gases

  20. Tube welding of heat exchange surfaces

    International Nuclear Information System (INIS)

    Many years experience of exploitation of a great number of butts of similar steels, made by partial fusion and with heating by high-frequency current is analysed. Their high reliability and capability of operation are observed. Taking into account the requirements of ducers of power-generating equipment, it is concluded, that subsequent development of tube butt welding by pressure must follow the way: increase of welded tube nomenclature (by diameter and thickness of the wall); improvement of methods of removing internal fin or the introduction of finless welding methods; wide use of instruments of the process parameters control and application of nondestructive control methods. It is shown, that the increase of reliability of the welded joints of tubes of similar steels (austenitic and perlitic) may be achieved by the change of the joint construction, using special spaciers and tubes of perlitic steel, containing carbide-forming elements, which exclude the softening of perlitic steel near the butt in the process of the steel operation

  1. CO2 laser welding of AISI 321stainless steel

    International Nuclear Information System (INIS)

    CO2 laser welding of AISI 321austenitic stainless steel has been carried out. Bead on plate welds on 2 mm thick steel were performed with 450W CO2 laser at speeds ranging from 200 to 900 mm/min. It was observed that weld depth and width was decreased with increasing the speed at constant laser power. Butt welds on different sheet thickness of 1, 2 and 2.5 mm were performed with laser power of 450 W and at speed 750, 275 and 175 mm/min, respectively. The microstructures of the welded joints and the heat affected zones (HAZ) were examined by optical microscopy and SEM. The austenite/delta ferrite microstructure was reported in the welded zone. The microhardness and tensile strength of the welded joints were measured and found almost similar to base metal due to austenitic nature of steel

  2. Disk Laser Welding of Car Body Zinc Coated Steel Sheets / Spawanie Laserem Dyskowym Blach Ze Stali Karoseryjnej Ocynkowanej

    Directory of Open Access Journals (Sweden)

    Lisiecki A.

    2015-12-01

    Full Text Available Autogenous laser welding of 0.8 mm thick butt joints of car body electro-galvanized steel sheet DC04 was investigated. The Yb:YAG disk laser TruDisk 3302 with the beam spot diameter of 200 μm was used. The effect of laser welding parameters and technological conditions on weld shape, penetration depth, process stability, microstructure and mechanical performance was determined. It was found that the laser beam spot focused on the top surface of a butt joint tends to pass through the gap, especially in the low range of heat input and high welding speed. All test welds were welded at a keyhole mode, and the weld metal was free of porosity. Thus, the keyhole laser welding of zinc coated steel sheets in butt configuration provides excellent conditions to escape for zinc vapours, with no risk of porosity. Microstructure, microhardness and mechanical performance of the butt joints depend on laser welding conditions thus cooling rate and cooling times. The shortest cooling time t8/5 was calculated for 0.29 s.

  3. Development of inspection technology for laser welding section

    International Nuclear Information System (INIS)

    We are developing the inspection technology for laser micro spot welding. Butt welding for the inner wall of heat exchanger tubes were successfully carried out by a composite-type optical fiber scope. The related technologies are the following: 1. Rapid inspection by Eddy Current Testing, 2. Fiber endoscope observation, 3. Synchrotron X-ray absorption contrast method. These technologies are versatile to be applied in maintenance for industrial production plants. (author)

  4. Pulsed TIG welding in the fabrication of nuclear components and structures

    International Nuclear Information System (INIS)

    TIG welding is an important welding technique in nuclear plant fabrication for the welding of critical components and structures where a high level of weld integrity is demanded. Whilst the process is ideally suited to precision welding, since the arc is a small intense heat source, it has proved to be somewhat intolerant to production variations in 'difficult' applications, such as tube to tube plate welding and orbital tube welding with tube in the fixed position. Whilst the problems directly associated with this intolerance (of the welding process) are less frequently observed when used manually, difficulties are experienced in fully mechanised welding operations particularly when welding to a relatively rigid approved procedure. Pulsing of the welding current was developed as a technique to achieve greater control of the behaviour of the weld pool. Instead of moving the weld pool in a continuous motion around the joint, welding was conducted intermittently in the form of overlapping spots. This technique, which offers significant advantages over continuous current welding has been exploited in nuclear fabrication for welding those components which demand a high level of weld quality. In this paper, the essential features of this technique are described and, in indicating its advantages, examples have been drawn from recent experiences on the welding of two types of joint for the Advanced Gas Cooled Reactor, a tube sheet and a butt joint in the G Position. (author)

  5. Tobacco and cigarette butt consumption in humans and animals

    OpenAIRE

    Novotny, Thomas E.; Hardin, Sarah N; Hovda, Lynn R; Novotny, Dale J; McLean, Mary Kay; Khan, Safdar

    2011-01-01

    Discarded cigarette butts may present health risks to human infants and animals because of indiscriminate eating behaviours. Nicotine found in cigarette butts may cause vomiting and neurological toxicity; leachates of cigarette butts in aquatic environments may cause exposure to additional toxic chemicals including heavy metals, ethyl phenol and pesticide residues. This report reviews published and grey literature regarding cigarette butt waste consumption by children, pets and wildlife. Alth...

  6. 77 FR 12106 - Kapka Butte Sno-Park Construction

    Science.gov (United States)

    2012-02-28

    ... Federal Highway Administration Kapka Butte Sno-Park Construction AGENCY: Western Federal Lands Highway... designation as Joint-Lead Agency for the Kapka Butte Sno-Park Construction project. SUMMARY: The FHWA is... pursuant to 23 U.S.C. 139(c)(1) for the Kapka Butte Sno-Park Construction project which is being studied...

  7. Uncoupled Thermo - Mechanical for the Determination of Welding Deformations

    Directory of Open Access Journals (Sweden)

    Lenuta Suciu

    2006-10-01

    Full Text Available Simulation of the welding process for butt and tee joints using finite element analyses are presented. The simulation are performed with the commercial software Ansys, which includes mathematical model, temperature dependent material properties, transfer and mechanical analyses. One way thermo – mechanical coupling is assumed.

  8. Welding of Thermomechanically Rolled Steel by Yb:YAG Disk Laser / Spawanie Stali Walcowanej Termomechanicznie Laserem Dyskowym Yb:YAG

    OpenAIRE

    Lisiecki A.

    2015-01-01

    Autogenous laser welding of 5.0 mm thick butt joints of thermomechanically rolled steel S700MC was investigated. The Yb:YAG disk laser TruDisk 3302 emitted at 1.03 μm was used for the trials of autogenous welding. The effect of laser welding parameters and thus thermal conditions of welding on weld shape, microstructure of weld metal and heat affected zone (HAZ), tensile strength, bending angle, impact toughness and microhardness profile was determined. Studies have shown that it is advantage...

  9. Weldability of dissimilar joint between PNC-FMS and Type 316 steel under electron beam welding

    International Nuclear Information System (INIS)

    The dissimilar butt welding joint of 11Cr-ferritic/martensitic steel (PNC-FMS) and Type 316 austenitic stainless steel (SUS316) produced by electron beam (EB) welding was studied. This study was carried out to investigate optimization of EB welding and postweld heat treatment (PWHT) for the wrapper tube materials. Optimum EB welding conditions were a focus position of 30–40 mm and a welding speed of 1750–2000 mm/min, and optimum PWHT was performed after welding at 690°C for 60 min. As a result, no formation of δ-ferrite was observed adjacent to the fusion zone, and the mechanical properties of the welds were similar to those of the base material. In this regard, EB welding is a proper fusion welding process for dissimilar PNC-FMS and SUS316. (author)

  10. Active flux tungsten inert gas welding of austenitic stainless steel AISI 304

    Directory of Open Access Journals (Sweden)

    D. Klobčar

    2016-10-01

    Full Text Available The paper presents the effects of flux assisted tungsten inert gas (A-TIG welding of 4 (10 mm thick austenitic stainless steel EN X5CrNi1810 (AISI 304 in the butt joint. The sample dimensions were 300 ´ 50 mm, and commercially available active flux QuickTIG was used for testing. In the planned study the influence of welding position and weld groove shape was analysed based on the penetration depth. A comparison of microstructure formation, grain size and ferrit number between TIG welding and A-TIG welding was done. The A-TIG welds were subjected to bending test. A comparative study of TIG and A-TIG welding shows that A-TIG welding increases the weld penetration depth.

  11. Application of Taguchi approach to optimize friction stir welding parameters of polyethylene

    Directory of Open Access Journals (Sweden)

    Bejaoui S.

    2010-06-01

    Full Text Available This paper presents experimental and numerical results of butt friction stir welding of high density polyethylene. The FSW designed tool insulates the welded samples and preserves the heat gained from friction thus avoiding the appearance of blisters and splits after welding. The experimental tests, conducted according to combinations of process factors such as rotation speed, welding speed, pin diameter and hold time at beginning welding, were carried out according the Taguchi orthogonal table L27 in randomized way. Temperatures in the joint during the welding operation and flow stresses from the tensile tests of welded samples were measured and variances were analyzed. Identified models were used to simulate, by finite elements, the tensile tests performed on specimens having a weld cordon in their active area. The results show coherence between the numerical predictions and experimental observations in different cases of weld cordon mechanical behaviour.

  12. Ultrasonic examination of stainless steel EB welds by an immersion technique

    International Nuclear Information System (INIS)

    The authors report the development of an ultrasonic examination method of austenitic stainless steel electron beam (EB) welds. This method is based on an automatic immersion technique employing focused transducers and is aimed at detecting both the weld soundness and penetration. The authors describe the examination procedure with a calibration of the ultrasonic equipment, a complete weld scanning, and a repetition of the calibration for matters of verification. They also describe how results are interpreted in terms of wave soundness (attenuation) and weld penetration. They discuss the reliability of the examination procedure. They comment results obtained for EB butt welds in a AISI 304 pipe

  13. Vision of the Arc for Quality Documentation and for Closed Loop Control of the Welding Process

    DEFF Research Database (Denmark)

    Kristiansen, Morten; Kristiansen, Ewa; Jensen, Casper Houmann;

    2014-01-01

    For gas metal arc welding a vision system was developed, which was robust to monitor the position of the arc. The monitoring documents the welding quality indirectly and a closed loop fuzzy control was implemented to control an even excess penetration. For welding experiments on a butt......-joint with a V-groove with varying root gapthe system demonstrated increased welding quality compared to the system with no control. The system was implemented with a low cost vision system, which makes the system interesting to apply in industrial welding automation systems....

  14. The effect of thermal properties and weld efficiency on residual stresses in welding

    Directory of Open Access Journals (Sweden)

    E. Armentani

    2007-01-01

    Full Text Available Purpose: A parametric model is adopted and the technique of element “birth and death” is used to estimate theeffect of thermal properties and weld efficiency on residual stresses in butt weld joints.Design/methodology/approach: Residual stresses and distortions on butt welded joints are numericallyevaluated by means of finite element method. The FE analysis allows to highlight and evaluate the stress fieldand its gradient around the fusion zone of welded joints, higher than any other located in the surrounding area.Findings: The main conclusion is the significant effect of varying the value of the conductivity on residualstresses.Practical implications: Several experimental destructive and non destructive techniques for directly measuringresidual stress have been developed. However, the application of these methods in practice is usually limitedby either cost or accuracy. Numerical simulation based on finite element techniques, therefore, offers acomprehensive solution for the prediction of residual stress and strain as well as welding distortion in complexwelded structures.Originality/value: In this study it is shown that the technique of element “birth and death” can be usefullyapplied to welding process in order to take in account the effect of the thermal properties of materials.

  15. Effect of welding process, type of electrode and electrode core diameter on the tensile property of 304L austenitic stainless steel

    OpenAIRE

    Akinlabi OYETUNJI; Nwafagu NWIGBOJI

    2014-01-01

    The effect of welding process, type of electrode and electrode core diameter on the tensile property of AISI 304L Austenitic Stainless Steel (ASS) was studied. The tensile strength property of ASS welded samples was evaluated. Prepared samples of the ASS were welded under these three various variables. Tensile test was then carried out on the welded samples. It was found that the reduction in ultimate tensile strength (UTS) of the butt joint samples increases with increase in core diameter of...

  16. Resistance welding of tubes at low regidual pressure jn tube cavity

    International Nuclear Information System (INIS)

    The procedure of butt resistance welding of boilers in diameter of 32 mm at low residual pressure in tube cavities has been studied. It is shown that the creation of low residual pressure in tube cavity makes it possible to produce qualitative joints of tubes of the 20, 12Kh1MF, 12Kh18N12T steels. The maximum relative deformation in the butt zone should be in the range of 0.5...0.6

  17. Disk Laser Welding of Car Body Zinc Coated Steel Sheets / Spawanie Laserem Dyskowym Blach Ze Stali Karoseryjnej Ocynkowanej

    OpenAIRE

    Lisiecki A.; Burdzik R.; Siwiec G.; Konieczny Ł.; Warczek J.; Folęga P.; Oleksiak B.

    2015-01-01

    Autogenous laser welding of 0.8 mm thick butt joints of car body electro-galvanized steel sheet DC04 was investigated. The Yb:YAG disk laser TruDisk 3302 with the beam spot diameter of 200 μm was used. The effect of laser welding parameters and technological conditions on weld shape, penetration depth, process stability, microstructure and mechanical performance was determined. It was found that the laser beam spot focused on the top surface of a butt joint tends to pass through the gap, espe...

  18. The non-destructive testing of transition welds

    International Nuclear Information System (INIS)

    This paper reviews C.E.G.B. experience of the NDT of transition butt welds joining tubes, pipes and thick plates. Pre-service inspection has been predominantly by radiography, while dye penetrants have been most frequently used for the in-service inspection of pipe to pipe welds. Some ultrasonic inspection has been performed with conventional techniques but its value was uncertain because of high attenuation and scatter in the weld metal. Nevertheless, ultrasonics is potentially the most useful technique, particularly for in-service inspection. Recent laboratory work is described which shows that the ultrasonic inspection of transition welds presents essentially the same problems as for austenitic welds of similar geometry, and that a limited sensitivity inspection is usually possible. The welding process used and the thickness of the weldment are identified as the most important factors governing the inspection capability. (author)

  19. 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.…

  20. Welding IV.

    Science.gov (United States)

    Allegheny County Community Coll., Pittsburgh, PA.

    Instructional objectives and performance requirements are outlined in this course guide for Welding IV, a competency-based course in advanced arc welding offered at the Community College of Allegheny County to provide students with proficiency in: (1) single vee groove welding using code specifications established by the American Welding Society…

  1. Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints

    Directory of Open Access Journals (Sweden)

    J. Łabanowski

    2007-01-01

    Full Text Available Purpose: The aim of the current study is to reveal the influence of welding conditions on structure and stresscorrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Butt joints between duplex 2205 and austenitic 316L steels were performedwith the use of submerged arc welding (SAW method. The plates 15 mm in thickness were welded with heatinput in the range of 1.15 – 3.2 kJ/mm using duplex steel filler metal. Microstructure examinations and corrosiontests were carried out. Slow strain rate tests (SSRT were performed in inert (glycerin and aggressive (boiling35% MgCl2 solution environments.Findings: It was shown that place of the lowest resistance to stress corrosion cracking is heat affected zone atduplex steel side of dissimilar joins. That phenomenon was connected with undesirable structure of that zoneconsisted of great amount of coarse ferrite grains and acicular austenite precipitates. High welding inputs do notdeteriorate stress corrosion cracking resistance of welds.Research limitations/implications: High welding heat inputs should enhance the precipitation process ofintermetallic phases in the HAZ. It is necessary to continue the research to determine the relationship betweenwelding parameters, obtained structures, and corrosion resistance of dissimilar stainless steels welded joints.Practical implications: Application of more productive joining process for dissimilar welds like submerged arcwelding instead of currently employed gas metal arc welding (GMAW method will be profitable in terms ofreduction the welding costs.Originality/value: The stress corrosion cracking resistance of dissimilar stainless steel welded joints wasdetermined. The zone of the weaker resistance to stress corrosion cracking was pointed out.

  2. Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Sabina Luisa Campanelli

    2013-12-01

    Full Text Available Friction Stir Welding (FSW is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force.

  3. Fiber-laser welding for ultra-high tensile strength steel and stainless steel

    International Nuclear Information System (INIS)

    Ultra-high tensile strength steel of 980 or 1150 MPa class has been often used for a large scale construction machine with lightweight parts because of transport weight limit. This steel needs its pre-processing before welding and has a tendency of delayed cracking, that requests a high welding technique with qualified welders. Austenitic stainless steel frequency used for nuclear energy related equipments has much strains caused by welding because of a large coefficient of thermal expansion. As a welding with small amount of its heat input and without a large size facility like a vacuum chamber, a fiber-laser welding was chosen to apply to equipments made of ultra-high tensile strength steel and stainless steel. Tensile and bending tests for I-butt and around 2mm root gap welded joints of high strength steel of 980 MPa showed their mechanical properties were similar to those of base metal. I-butt welded joints of high strength steel of 1150 MPa showed similar mechanical properties of base metal but as for root gap welded joint, a filler metal was not available. With filler metal of 980 MPa instead, the welded joints showed similar tensile strength of base metal but a crack occurred at the bending test according to the JIS welding procedure qualification specification. Application of fiber laser welding to stainless steel had been conducted successfully for I-butt welded joints of good penetration up to the plate thickness of 8mm. As an example, T-joint of mercury target vessel for J-PARC was produced by fiber laser welding, that became to apply to other nuclear equipments. (T. Tanaka)

  4. Measurement of throughwall residual stresses in large-diameter piping butt weldments using strain-gauge techniques

    International Nuclear Information System (INIS)

    Measurements of throughwall distributions of the residual stresses in five large-diameter Type 304 stainless steel Schedule 80 butt weldments are presented. Three weldments were fabricated using conventional welding procedure; one weldment was fabricated by a heat sink welding procedure in which water spray cooling was applied to the inner surface after the initial closure pass; and one weldment was fabricated using a last-pass heat sink welding procedure. Four of the weldments were fabricated strictly for stress measurements; however, one of the weldments is from an operating reactor which was in service for approximately twelve years. Numerical simulations of the analytical procedures used to derive the throughwall stress distributions are presented and used to assess the adequacy of the procedures. Possible effects of these stress distributions on the nature of crack growth in large-diameter weldments are discussed briefly

  5. Integrated FEM-DBEM simulation of crack propagation in AA2024-T3 FSW butt joints considering manufacturing effects

    DEFF Research Database (Denmark)

    Sonne, Mads Rostgaard; Carlone, P.; Citarella, R.;

    2015-01-01

    This paper deals with a numerical and experimental investigation on the influence of residual stresses on fatigue crack growth in AA2024-T3 friction stir welded butt joints. An integrated FEM-DBEM procedure for the simulation of crack propagation is proposed and discussed. A numerical FEM model...... of the contour method. The computed stress field is transferred to a DBEM environment and superimposed to the stress field produced by a remote fatigue traction load applied on a friction stir welded cracked specimen. Numerical results are compared with experimental data showing good agreement and highlighting...... of the welding process of precipitation hardenable AA2024-T3 aluminum alloy is employed to infer the process induced residual stress field. The reliability of the FEM simulations with respect to the induced residual stresses is assessed comparing numerical outcomes with experimental data obtained by means...

  6. Cyclically controlled welding purge chamber

    Science.gov (United States)

    Gallagher, Robert L. (Inventor)

    1996-01-01

    An arrangement for butt-welding cylindrical sections of large, thin-wall tanks includes a rotatable mandrel with side-by-side sets of radial position adjusters. Each set of adjusters bears on one of the tank sections adjacent the seam, to prevent the sections from sagging out-of-round. The mandrel rotates relative to the welder, so that a continuous seam is formed. A purge chamber is fixed in position behind the seam at the weld head, and is flushed with inert gas. The purge chamber includes a two-sided structure which is contiguous with the cylindrical sections and a circumferential vane to form an open-ended tube-like structure, through which the radial position adjusters pass as the mandrel and cylindrical workpiece sections rotate. The tube-like structure is formed into a chamber by a plurality of movable gates which are controlled to maintain a seal while allowing adjusters to progress through the purge chamber.

  7. A study on the CO2 laser welding characteristics of high strength steel up to 1500 MPa for automotive application

    OpenAIRE

    C.-H. Kim; J.-K. Choi; M.-J. Kang; Y.-D. Park

    2010-01-01

    Purpose: This paper presents the mechanical and metallurgical characteristics of laser weldments for automotive steels with high strength ranging from 370 MPa to 1500 MPa.Design/methodology/approach: Butt joint welding was conducted on high strength steel sheets by using a CO2 laser with 6 kW output power. For sound welds with full penetration, the proper welding conditions were chosen and the cross-sectional bead shape, tensile strength, hardness profile and micro-structure were evaluated ...

  8. Welding process

    International Nuclear Information System (INIS)

    This invention relates to a process for making a large number of weld beads as separate contours, spaced out from each other, by means of an automatic welding head. Under this invention, after striking the arc in the prescribed manner and positioning the torch on the first contour to be welded and having made the first weld bead, the torch current is reduced to bring about a part fade out of the arc. The torch is then moved to the starting position on a second contour to be welded where a static timed pre-fusion is effected by resumption of the welding current to carry out the second weld bead by following the second welding contour in the same manner and so forth. The invention particularly applies to the welding of tube ends to a tube plate

  9. 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.

  10. Simultaneous control of weld pool size and position for precision TIG welding

    International Nuclear Information System (INIS)

    This paper describes the application of novel feedback control techniques to the welding of the thermal sleeve joint for fast reactor heat exchangers. It is required to produce a full penetration Tee-butt weld between a tube and flange, without fusion into the tube bore. Two complementary feedback control systems are therefore employed: (a) the penetration of the Tee-butt weld is ensured by viewing the back of the weld with photodiodes, the signals from which control the current and travel speed; and (b) protrusion into the bore is prevented by measuring the radiation from the bore surface by means of photodiodes: the signal from these is applied to a magnetic arc deflector, which controls the position of the arc with respect to the tube to maintain the required bore temperature. The system has been demonstrated experimentally, and it is shown that the feedback control system enables consistently good quality welds to be made in a situation where quality control is notoriously difficult. (author)

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

    International Nuclear Information System (INIS)

    Butt welds of 1.6 mm thick 6013-T6 sheet were produced using laser beam welding and friction stir welding processes. Employing the former joining technique, filler powders of the alloys Al-5%Mg and Al-12%Si were used. Microstructure, hardness profiles, tensile properties and the corrosion behaviour of the welds in the as-welded condition were investigated. The hardness in the weld zone was lower compared to that of the base material in the peak-aged temper. Hardness minima were measured in the fusion zone and in the thermomechanically affected zone for laser beam welded and friction stir welded joints, respectively. Metallographic and fractographic examinations revealed pores in the fusion zone of the laser beam welds. Porosity was higher in welds made using the filler alloy Al-5%Mg than using the filler metal Al-12%Si. Transmission electron microscopy indicated that the β'' (Mg2Si) hardening precipitates were dissolved in the weld zone due to the heat input of the joining processes. Joint efficiencies achieved for laser beam welds depended upon the filler powders, being about 60 and 80% using the alloys Al-5%Mg and Al-12%Si, respectively. Strength of the friction stir weld approached over 80% of the ultimate tensile strength of the 6013-T6 base material. Fracture occurred in the region of hardness minima unless defects in the weld zone led to premature failure. The heat input during welding did not cause a degradation of the corrosion behaviour of the welds, as found in continuous immersion tests in an aqueous chloride-peroxide solution. In contrast to the 6013-T6 parent material, the weld zone was not sensitive to intergranular corrosion. Alternate immersion tests in 3.5% NaCl solution indicated high stress corrosion cracking resistance of the joints. For laser beam welded sheet, the weld zone of alternately immersed specimens suffered severe degradation by pitting and intergranular corrosion, which may be associated with galvanic coupling of filler metal and

  12. Tobacco and cigarette butt consumption in humans and animals.

    Science.gov (United States)

    Novotny, Thomas E; Hardin, Sarah N; Hovda, Lynn R; Novotny, Dale J; McLean, Mary Kay; Khan, Safdar

    2011-05-01

    Discarded cigarette butts may present health risks to human infants and animals because of indiscriminate eating behaviours. Nicotine found in cigarette butts may cause vomiting and neurological toxicity; leachates of cigarette butts in aquatic environments may cause exposure to additional toxic chemicals including heavy metals, ethyl phenol and pesticide residues. This report reviews published and grey literature regarding cigarette butt waste consumption by children, pets and wildlife. Although reports of human and animal exposures number in the tens of thousands, severe toxic outcomes due to butt consumption are rare. Nonetheless, the ubiquity of cigarette butt waste and its potential for adverse effects on human and animal health warrants additional research and policy interventions to reduce the stream of these pollutants in the environment.

  13. A repair process for an heterogenous welded joint between a nuclear reactor component tube and a pipe

    International Nuclear Information System (INIS)

    The repairing process involves cutting a tubular section of the tube (made of low alloy steel) and the pipe (made of austenitic stainless steel), which includes the welded joint, and preparing an heterogenous tubular section for substitution (a first section, made of ferritic steel, is butt welded to a second section, made of austenitic stainless steel); the tubular section is then narrow-joint welded with the low-alloy steel tube, and finally welded to the austenitic stainless steel pipe. Application to repairing a welded joint between a pressurizer tube and an expansion pipe connected to the primary circuit. (author). 5 refs., 4 figs

  14. Ultrasonic defects measurements of fuel welded joints

    International Nuclear Information System (INIS)

    Fuel elements welding joints of atomic power station should provide hermetic state of sheath in the course of exploitation period. The quality of welded joints is determined by non-destructive methods of control. Weld width and defects' evidence are determined by ultrasonic means in butt resistance welding joints of fuel elements. The boundary of a weld line is not structurally heterogeneous, so the reflection of waves with the frequency up to 50 MHz is not observed, that allows to obtain high sensitivity to small defects with opening of ∼ 0.4 x 10-3 mm. The best results could be achieved by means of supervision of two-dimensional images of defects. The program of data processing makes it possible to measure the width of the weld with the accuracy of ± 0.1 mm and sizes of defects. Fast generation (∼ 25 sec.) of weld images at C and B - scanning could be obtained as well. High sensitivity to small defects occurs through utilization of diffraction of spherical ultrasonic wave's effect. The proposed method of defects' measurements could be applied to different technical problems of atomic industry and mechanical engineering. (author)

  15. Effects of flashing and upset sequences on microstructure, hardness, and tensile properties of welded structural steel joints

    International Nuclear Information System (INIS)

    Highlights: → Flash butt welding ASTM A529 steel specimens with varied process settings. → Tensile, hardness, and nondestructive evaluation of welds and HAZs. → Acicular ferrite in weld zone provides necessary strength and ductility. → Maximum hardness achieved within the weld zone. → Quantity of interfacial inclusions depends on upset dimension and flashing time. -- Abstract: In this study, ASTM A529 carbon-manganese steel angle specimens were joined by flash butt welding and the effects of varying process parameter settings were investigated. The resulting weld metal and heat affected zones were examined and further processed using tensile testing, Rockwell hardness testing, ultrasonic scanning, optical microscopy, and scanning electron microscopy with energy dispersive spectroscopy. Test results showed that hardness was increased in the weld zone for all specimens, which can be attributed to the extensive deformation of the upset operation. Statistical analysis of experimental data highlighted the sensitivity of weld strength and the presence of weld zone inclusions and interfacial defects to the process factors of upset current, flashing time duration, and upset dimension. Microstructural analysis revealed various phases within the weld and heat affected zone, including acicular ferrite, Widmanstatten or side-plate ferrite, and grain boundary ferrite. Fractography of tensile specimens indicated brittle cleavage fracture within the weld zone for certain factor combinations. The significance of process factor levels on microstructure, fracture characteristics, and weld zone strength, inclusions, and embrittlement was analyzed.

  16. Socket welding method

    International Nuclear Information System (INIS)

    Upon joining of metal tubes having a same composition, a metal having a corrosion potential higher by from 50 to 300mV than that of the metal which constitutes the metal tube is disposed at the periphery of the joint portion of the metal tubes in order to improve corrosion resistance of the joint portion of pipelines in a plant such as a nuclear reactor. In a socket joint in which metal tubes having a greater outer diameter than the inner diameter of the other are fitted to each other at the joint portion, more remarkable effect can be obtained. This is because the area of the gap portion is greater than in the case of butt welding. Further, it is preferred that a metal having a corrosion potential greater by from 50 to 300mV than that of the metal tube is interposed at least to a portion of the overlapped portion of the tubes in order to prevent corrosion of the gap portion. Then, a carbon steel pipe weld-joint having sufficiently high resistance to temperature and pressure water SCC can be attained in a BWR reactor water circumstance, and the safety of the BWR can be ensured, as well as the working life of the reactor plant can be attained. (N.H.)

  17. Ultrasonic-assisted friction stir welding on V95AT1 (7075) aluminum alloy

    Science.gov (United States)

    Tarasov, S. Yu.; Rubtsov, V. Ye.; Kolubaev, E. A.; Ivanov, A. N.; Fortuna, S. V.; Eliseev, A. A.

    2015-10-01

    Ultrasonic-assisted friction stir butt welding on aluminum alloy V95AT1 (7075) has been carried out. Samples have been characterized using metallography, microhardness and XRD. As shown, ultrasonic treatment during welding provides extra plasticizing of metal and better stirring efficiency. The latter serves for elimination of defects, such as root flaw and grain refining in the stir zone. The stress state in the welded joint is characterized by tensile stress in the direction of the weld seam centerline and compression in the transversal direction. The ultrasonic treatment was shown to increase the compression stress and relieve the tensile one.

  18. Multiple Crack Growth Prediction in AA2024-T3 Friction Stir Welded Joints, Including Manufacturing Effects

    DEFF Research Database (Denmark)

    Carlone, Pierpaolo; Citarella, Roberto; Sonne, Mads Rostgaard;

    2016-01-01

    A great deal of attention is currently paid by several industries toward the friction stir welding process to realize lightweight structures. Within this aim, the realistic prediction of fatigue behavior of welded assemblies is a key factor. In this work an integrated finite element method - dual...... boundary element method (FEM-DBEM) procedure, coupling the welding process simulation to the subsequent crack growth assessment, is proposed and applied to simulate multiple crack propagation, with allowance for manufacturing effects. The friction stir butt welding process of the precipitation hardened AA...

  19. Corrosion Resistance of Synergistic Welding Process of Aluminium Alloy 6061 T6 in Sea Water

    Directory of Open Access Journals (Sweden)

    Kharia Salman Hassan

    2014-12-01

    Full Text Available This work involves studying corrosion resistance of AA 6061T6 butt welded joints using Two different welding processes, tungsten inert gas (TIG and a solid state welding process known as friction stir welding, TIG welding process carried out by using Rolled sheet of thickness6mm to obtain a weld joint with dimension of (100, 50, 5 mm using ER4043 DE (Al Si5 as filler metal and argon as shielding gas, while Friction stir welding process carried out using CNC milling machine with a tool of rotational speed 1000 rpm and welding speed of 50mm/min to obtain the same butt joint dimensions. Also one of weld joint in the same dimensions subjected to synergistic weld process TIG and FSW weld process at the same previous weld conditions. All welded joints were tested by X-ray radiography and Faulty pieces were excluded. The joints without defects used to prepare many specimens for Corrosion test by the dimensions of (15*15*3 mm according to ASTM G71-31. Specimens subjected to micro hardness and microstructure test. Corrosion test was achieved by potential at scan rate( +1000 ,-1000mv/sec to estimate corrosion parameters by extrapolator Tafle method after polarized ±100 mv around open circuit potential,in seawater (3.5%NaCl at a temperature of 25°C. From result which obtained by Tafel equation. It was found that corrosion rate for TIG weld joint was higher than the others but synergistic weld process contributed in improving TIG corrosion resistance by a percentage of 14.3%. and FSW give the lest corrosion rate comparing with base metal.

  20. Development of laser welding techniques for vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Strain, R.V.; Leong, K.H.; Smith, D.L. [Argonne National Laboratory, IL (United States)

    1996-10-01

    Laser welding is potentially advantageous because of its flexibility and the reduced amount of material affected by the weld. Bead-on-plate and butt welds were previously performed to depths of about 4 mm with a 6-kW CO{sub 2} laser on V-4%Cr-4%Ti and V-5%Cr-5%Ti alloys. These welds were made at a speed of 0.042 m/s using argon purging at a flow rate of 2.8 m{sup 3}/s. The purge was distributed with a diffuser nozzle aimed just behind the laser beam during the welding operation. The fusion zones of welds made under these conditions consisted of very fine, needle-shaped grains and were also harder than the bulk metal (230-270 dph, compared to {approx}180 dph for the bulk metal). A limited number of impact tests showed that the as-welded ductile-brittle transition temperatures (DBTT) was above room temperature, but heat treatment at 1000{degrees}C for 1 h in vacuum reduced the DBTT to <{minus}25{degrees}C. Activities during this reporting period focused on improvements in the purging system and determination of the effect of welding speed on welds. A 2-kW continuous YAG laser at Lumonics Corp. in Livonia, MI, was used to make 34 test welds for this study.

  1. Steel welding.

    OpenAIRE

    Kučera, Marek

    2011-01-01

    Topic of the thesis concerns the problem of steel welding. The aim was to give acomprehensive overview on the topic, describe the known methods, advantages and disadvantages of welding technology. The introductory part is focused on introducing the basics of the process required to produce high-quality connections. Chapter three offers an overview of known and used welding methods with thein brief description of the method. The next chapter describes steel as material suitable for welding....

  2. Optimization of GMAW process of AA 6063-T5 aluminum alloy butt joints based on the response surface methodology and on the bead geometry

    International Nuclear Information System (INIS)

    The geometry of the weld beads is characterized by the overhead, the width and the penetration. These values are indices of the behavior of the welded joint and therefore, they can be considered as factors that control the process. This work is performed to optimize the GMAW process of the aluminum alloy AA 6063-T5 by means of the response surface methodology (RSM). The variables herein considered are the arc voltage, the welding speed, the wire feed speed and the separation between surfaces in butt joints. The response functions that are herein studied are the overhead, the width, the penetration and the angle of the bead. The obtained results by RSM show high grade of agreement with the experimental values. The procedure is experimentally validated by welding for the theoretically obtained optimized technological conditions and a wide agreement between theoretical and experimental values is found. (Author) 16 refs.

  3. 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…

  4. Friction Stir Welding in HSLA-65 Steel: Part I. Influence of Weld Speed and Tool Material on Microstructural Development

    Science.gov (United States)

    Barnes, S. J.; Bhatti, A. R.; Steuwer, A.; Johnson, R.; Altenkirch, J.; Withers, P. J.

    2012-07-01

    A systematic set of single-pass full penetration friction stir bead-on-plate and butt-welds in HSLA-65 steel were produced using a range of different traverse speeds (50 to 500 mm/min) and two tool materials (W-Re and PCBN). Microstructural analysis of the welds was carried out using optical microscopy, and hardness variations were also mapped across the weld-plate cross sections. The maximum and minimum hardnesses were found to be dependent upon both welding traverse speed and tool material. A maximum hardness of 323 Hv(10) was observed in the mixed martensite/bainite/ferrite microstructure of the weld nugget for a welding traverse speed of 200 mm/min using a PCBN tool. A minimum hardness of 179 Hv(10) was found in the outer heat-affected zone (OHAZ) for welding traverse speed of 50 mm/min using a PCBN tool. The distance from the weld centerline to the OHAZ increased with decreasing weld speed due to the greater heat input into the weld. Likewise for similar energy inputs, the size of the transformed zone and the OHAZ increased on moving from a W-Re tool to a PCBN tool probably due to the poorer thermal conductivity of the PCBN tool. The associated residual stresses are reported in Part II of this series of articles.

  5. Weldability of A7075-T651 and AZ31B dissimilar alloys by MIG welding method based on welding appearances

    International Nuclear Information System (INIS)

    It is not recommended to weld aluminium and magnesium dissimilar alloys using fusion welding method because of the formation of AlmMgn type intermetallic brittle compounds like Mg2Al3, Mg17Al12 etc. in the welding joint. These brittle compounds deteriorate the mechanical properties of the joint. But so far, insufficient researches have been attempted to stop the formation of AlmMgn type intermetallic brittle compounds in fusion welding method. The aim of this research work was to investigate on the weldability between A7075-T651 and AZ31B dissimilar alloys based on welding appearances and study the formation of intermetallic brittle compounds at the joint. In this research, A7075-T651 and AZ31B alloys were welded using ER5356 filler wire in MIG welding method in butt configuration. 100% argon was used as shielding gas. The results showed that, most of the welding appearances were moderate. The macroscopic investigation at all welding cross section showed that a lot of AlmMgn intermetallic brittle compounds were formed at the interface between weld seam and AZ31B parent metal side which caused macro cracks. A good number of macro pores were also observed at AZ31B parent metal side. These cracks and pores could easily cause the failure of the joint at very low stress.

  6. Numerical and experiment study of residual stress and strain in multi-pass GMA welding

    Directory of Open Access Journals (Sweden)

    R.R. Chand

    2013-03-01

    Full Text Available Purpose: Recently, manufacturing industries have been concentrated on selection an optimal of welding parameter and condition that reduces the risk of mechanical failures on weld structures should be required in manufactory industry. In robotic GMA (Gas Metal Arc welding process, heat and mass inputs are coupled and transferred by the weld arc to the molten weld pool and by the molten metal that is being transferred to the weld pool. The amount and distribution of the input energy are basically controlled by the obvious and careful choices of welding process parameters in order to accomplish the optimal bead geometry and the desired mechanical properties of the quality weldment. The residual stress and welding deformation have the large impact on the failure of welded structures.Design/methodology/approach: To achieve the required precision for welded structures, it is required to predict the welding distortions at the early stages. Therefore, this study represented 2D Finite Element Method (FEM to predict residual stress and strain on thick SS400 steel metal plate.Findings: The experiment for Gas Metal Arc (GMA welding process is also performed with similar welding condition to validate the FE results. The simulated and experiment results provide good evidence that heat input is main dependent on the welding parameter and residual stress and distortions are mainly affected by amount on heat input during each weld-pass.Practical implications: This present study on based on the numerical analysis using ansys software, for a thick multi-pass GMA welding. A birth and death technique is employed to control the each weld pass welding.Originality/value: The developed 2D multi-pass model employs Goldak’s heat distribution, to simulate welding on SS400 steel butt-weld joint with a thickness of 16mm. moreover the numerical results are validated with experiment results.

  7. Study of issues in difficult-to-weld thick materials by hybrid laser arc welding

    Science.gov (United States)

    Mazar Atabaki, Mehdi

    . The heat and mass transfer and the issues in joining of dissimilar alloys by the hybrid laser/arc welding process (HLAW) were explicitly explained in details. A finite element model was developed to simulate the heat transfer in HLAW of the aluminum alloys. Two double-ellipsoidal heat source models were considered to describe the heat input of the gas metal arc welding and laser welding processes. An experimental procedure was also developed for joining thick advanced high strength steel plates by using the HLAW, by taking into consideration different butt joint configurations. The geometry of the weld groove was optimized according to the requirements of ballistic test, where the length of the softened heat affected zone should be less than 15.9 mm measured from the weld centerline. Since the main issue in HLAW of the AHSS was the formation of the pores, the possible mechanisms of the pores formation and their mitigation methods during the welding process were investigated. Mitigation methods were proposed to reduce the pores inside in the weld area and the influence of each method on the process stability was investigated by an on-line monitoring system of the HLAW process. The groove angle was optimized for the welding process based on the allowed amount of heat input along the TRICLADRTM interface generated by an explosive welding. The weld was fractured in the heat affected zone of the aluminum side in the tensile test. The microharness was shown that the temperature variation caused minor softening in the heat affected zone satisfying the requirement that the width of the softened heat affected zone in the steel side falls within 15.9 mm far away from the weld centerline. The microstructure analysis showed the presence of tempered martensite at the vicinity of the weld area, which it was a cause of softening in the heat affected zone.

  8. Laser welding of Ti-Ni type shape memory alloy

    International Nuclear Information System (INIS)

    The present study was undertaken to apply the laser welding to the joining of a shape memory alloy. Butt welding of a Ti-Ni type shape memory alloy was performed using 10 kW CO2 laser. The laser welded specimens showed successfully the shape memory effect and super elasticity. These properties were approximately identical with those of the base metal. The change in super elasticity of the welded specimen during tension cycling was investigated. Significant changes in stress-strain curves and residual strain were not observed in the laser welded specimen after the 50-time cyclic test. The weld metal exhibited the celler dendrite. It was revealed by electron diffraction analysis that the phase of the weld metal was the TiNi phase of B2 structure which is the same as the parent phase of base metal and oxide inclusions crystallized at the dendrite boundary. However, oxygen contamination in the weld metal by laser welding did not occur because there was almost no difference in oxygen content between the base metal and the weld metal. The transformation temperatures of the weld metal were almost the same as those of the base metal. From these results, laser welding is applicable to the joining of the Ti-Ni type shape memory alloy. As the application of laser welding to new shape memory devices, the multiplex shape memory device of welded Ti-50.5 at % Ni and Ti-51.0 at % Ni was produced. The device showed two-stage shape memory effects due to the difference in transformation temperature between the two shape memory alloys. (author)

  9. 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...

  10. Composite Aluminum-Copper Sheet Material by Friction Stir Welding and Cold Rolling

    OpenAIRE

    Kahl, S.; Osikowicz, W.

    2013-01-01

    An aluminum alloy and a pure copper material were butt-joined by friction stir welding and subsequently cold rolled. The cold-rolling operation proved to be very advantageous because small voids present after friction stir welding were closed, the interface area per material thickness was enlarged, a thin intermetallic layer was partitioned, and the joint was strengthened by strain hardening. Tensile test specimens fractured in the heat-affected zone in the aluminum material; tensile strength...

  11. Influence of heat input on corrosion resistance of SAW welded duplex joints

    Directory of Open Access Journals (Sweden)

    J. Nowacki

    2006-04-01

    Full Text Available Purpose: Purpose of this paper is description of influence of the heat input of submerged arc welding (SAW of duplex steel UNS S31803 on welded butt joints corrosion resistance.Design/methodology/approach: Butt joints on plates of 9 – 30 mm thickness were executed where the applied heat input of welding exceeded the 2.5 kJ/mm value. Maximum heat input level was HI ≤ 3.0; HI ≤ 3.5; HI ≤ 4.0; HI ≤ 4.5; HI ≤ 5.0. Analysis of welding heat input influence on mechanical properties, value of ferrite share, and corrosion of test joints has been done. Non-destructive and destructive testing, e. g. visual examinations, microstructure examination, corrosion resistance tests according to ASTM G48 Method A, HV5 hardness tests, impact and tensile test were carried out. For analysis of welding heat input influence on creation of welding imperfections, there were executed welding of sheet of thickness 9, 14, 28 mm.Findings: It was shown that submerged arc welding of duplex steel with the heat input from 2.5 kJ/mm up to 5.0 kJ/mm has no negative influence on properties of the joints. Based on the performed tests the conclusion is that according to DNV Rules the welding heat input exceeding the recommended values has no negative impact on strength properties and corrosion resistance of the executed welded joints.Research limitations/implications: Research implications the welding heat input exceeding the recommended values should influenced the precipitation processes in the HAZ, what need further experiments.Practical implications: Application of high value of the welding heat input will be profitable in terms of the welding costs.Originality/value: An original value of the paper is to prove that a usage of high value welding heat input provides the best joints quality.

  12. Effect of Weld Tool Geometry on Friction Stir Welded Ti-6Al-4V

    Science.gov (United States)

    Querin, Joseph A.; Schneider, Judy A.

    2008-01-01

    In this study, flat 0.250" thick Ti-6Al-4V panels were friction stir welded (FSWed) using weld tools with tapered pins. The five different pin geometries of the weld tools included: 0 degree (straight cylinder), 15 degree, 30 degree, 45 degree, and 60 degree angles on the frustum. All weld tools had a smooth 7 degree concave shoulder and were made from microwave sintered tungsten carbide. For each weld tool geometry, the FSW process parameters were optimized to eliminate internal defects. All the welds were produced in position control with a 2.5 degree lead angle using a butt joint configuration for the panels. The process parameters of spindle rpm and travel speed were varied, altering the hot working conditions imparted to the workpiece. Load cells on the FSWing machine allowed for the torque, the plunge force, and the plow force to be recorded during welding. Resulting mechanical properties were evaluated from tensile tests results of the FSWjoints. Variations in the material flow were investigated by use of microstructural analysis including optical microscopy (OM), scanning electron microscopy (SEM), and orientation image mapping (aIM).

  13. Welding of Mo-Based Alloy Using Electron Beam and Laser-GTAW Hybrid Welding Techniques

    Science.gov (United States)

    Chatterjee, Anjan; Kumar, Santosh; Tewari, Raghvendra; Dey, Gautam Kumar

    2016-03-01

    In the current study, welding of TZM (molybdenum-based alloy) plates in square-butt configuration was carried out using electron beam and laser-GTAW hybrid power sources. Microstructures of weld joint containing three zones—parent metal, heat-affected zone, and fusion zone—were clearly identified when examined through optical and scanning electron microscopy. The weld joints were found to be sound with very wide fusion and heat-affected zones. The microstructure of the fusion zone was coarse-grained. as-solidified microstructure, while the microstructure of heat-affected zone was the recrystallized microstructure with reduction in grain size as distance from the fusion line increased. Microhardness profile using Vickers hardness tester was obtained across the weld region, and the tensile properties of the weld joints were evaluated by performing room temperature tensile test and fracture was examined using scanning electron microscope. Joint coefficient of the weld joints were ~40 to 45 pct of that of the parent metals with nonmeasurable tensile ductility with predominantly transgranular mode of fracture indicating weakness along the grain boundary. Detailed orientation imaging and transmission electron microscopy were carried out to understand the most dominating factor in introducing weld joint brittleness.

  14. X-Ray diffraction technique applied to study of residual stresses after welding of duplex stainless steel plates

    Energy Technology Data Exchange (ETDEWEB)

    Monin, Vladimir Ivanovitch; Assis, Joaquim Teixeira de [Instituto Politecnico do Rio e Janeiro (IPRJ), Nova Friburgo, RJ (Brazil); Lopes, Ricardo Tadeu; Turibus, Sergio Noleto; Payao Filho, Joao C., E-mail: sturibus@nuclear.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2014-08-15

    Duplex stainless steel is an example of composite material with approximately equal amounts of austenite and ferrite phases. Difference of physical and mechanical properties of component is additional factor that contributes appearance of residual stresses after welding of duplex steel plates. Measurements of stress distributions in weld region were made by X-ray diffraction method both in ferrite and austenite phases. Duplex Steel plates were joined by GTAW (Gas Tungsten Arc Welding) technology. There were studied longitudinal and transverse stress components in welded butt joint, in heat affected zone (HAZ) and in points of base metal 10 mm from the weld. Residual stresses measured in duplex steel plates jointed by welding are caused by temperature gradients between weld zone and base metal and by difference of thermal expansion coefficients of ferrite and austenite phases. Proposed analytical model allows evaluating of residual stress distribution over the cross section in the weld region. (author)

  15. Friction stir welding of dissimilar joint between semi-solid metal 356 and AA 6061-T651 by computerized numerical control machine

    OpenAIRE

    Muhamad Tehyo; Prapas Muangjunburee; Somchai Chuchom

    2011-01-01

    The objective of this research is to investigate the effect of welding parameters on the microstructure and mechanicalproperties of friction stir welded butt joints of dissimilar aluminum alloy sheets between Semi-Solid Metal (SSM) 356 and AA6061-T651 by a Computerized Numerical Control (CNC) machine. The base materials of SSM 356 and AA 6061-T651 werelocated on the advancing side (AS) and on the retreating side (RS), respectively. Friction Stir Welding (FSW) parameterssuch as tool pin profil...

  16. Torque strength of an endplate welding due to process parameters using a fuel assembling welder

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae-Seo; Kim, Soo-Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-05-15

    As fuel bundles in a PHWR core irradiated, inner pressure in the claddings of the fuel rods increases owing to the outer pressure and fission products of the nuclear fissions. Because of a leak possibility from a welding between a cladding and end plug, this welding part is connected with the safety of nuclear fuel rods. Endplug-cladding welding of nuclear fuel rods in a PHWR takes advantage of a resistance upset butt welding. The weldment between a cladding and endplug is to be sound to prevent a leakage of fission products from a cladding as a UO{sub 2} pellet is irradiated. Weld flash was made from a deformation due to a welding heat and increasing the pressure of the resistivity and resistance from a cladding and endplug. Weld line of a welding interface, microstructure of a weldment and a crystallographic structure change were sources of an iodine induced SCC in a reactor. The soundness of a weldment is important because a weld line connects the leakage of fission products from an operational reactor. In this study, welding specimens were fabricated by a resistance welding method using a bundle fuel welder to measure and analyze the torque of an endplug-endplate welding. The torque of a weldment between an endplug and endplate was measured and analyzed with the welding time. The weldability of a weldment between an endplug and endplate was investigated by a metallographic examination.

  17. Investigation into the Influence of Post-Weld Heat Treatment on the Friction Stir Welded AA6061 Al-Alloy Plates with Different Temper Conditions

    Science.gov (United States)

    İpekoğlu, Güven; Erim, Seçil; Çam, Gürel

    2014-02-01

    In this study, the effect of post-weld heat treatment (PWHT) on the microstructure and mechanical properties of friction stir butt-joined AA6061 Al-alloy plates both in O and T6-temper conditions was investigated by detailed microstructural investigations and microhardness measurements, in combination with transverse tensile testing. It was determined that the PWHT might result in abnormal grain growth (AGG) in the weld zone particularly in the joints produced in O-temper condition depending on the weld parameters used during friction stir welding. The PWHT generally led to an improvement in the mechanical properties even if AGG took place. Thus, the post-weld heat-treated joints exhibited mechanical properties much higher than those of respective as-welded plates and comparable to those of the respective base plates.

  18. A study of laser and electron beam welding of Nb-1Zr-0.1C alloy

    International Nuclear Information System (INIS)

    The Nb-1Zr-0.1C alloy is one of the most promising refractory metal alloys, having an excellent combination of high temperature properties and is suitable for several structural applications in the proposed Compact High Temperature Reactor (CHTR). The application calls for the welding of this alloy to itself in different shapes and sizes. Due to reactive nature of this alloy proper precautions are necessary during its welding. In comparison to the conventional welding processes, the high energy density sources like, laser and electron beam which can produce deep penetrations with narrow heat affected zones are more suitable techniques to weld the components of this Nb-alloy. A systematic study was conducted for the development of laser and electron beam welding of the Nb-1Zr-0.1C alloy. The specimens of this alloy were welded using both processes in bead on plate and butt joint configuration by systematically varying the process parameters like power, travel speed and welding atmosphere and their effects on the weld quality, such as visual appearance of weld, depth and width of the weld, weld defects like crack, porosity, etc. were studied. The metallurgical characterization (optical and electron microscopic examination) of the weld joints produced by both techniques and the microhardness profile across the width of welds was also studied. The detailed results of the optimization of welding parameters and the characterization of the weld joints are discussed in this paper. (author)

  19. 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…

  20. Numerical estimation of temperature distribution in laser welded elements

    OpenAIRE

    W. Piekarska; Kubiak, M.

    2008-01-01

    This paper presents a nurncrical modcl of tcmpcraturc fictd in lascr butt welded plate. Thc tcmpcraturc ficld in thc wcldcd joint wasobtained using the finitc difrcrcncc mcthod to solve thc hcat transfer cqualion with a convection unit in EuIcrian coordinatcs. Larcnt hcat,hcat of phasc rransforrna!ion in solid statc and evaporation hcat wcrc considcrcd in thc nurncrical algorithtn. Thc thcrmo-physicalparameters in hcat transfcr cquation wcrc assumcd as dcpcnding on tcrnpcraturc. The Goldak's ...

  1. Influence of argon pollution on the weld surface morphology

    OpenAIRE

    Krolczyk, G.M.; Nieslony, P.; Krolczyk, J.B.; I. Samardzic; Legutko, S.; S. Hloch; Barrans, Simon; Maruda, R.W.

    2015-01-01

    In this paper the surfaces of butt welded joints in steel tubes were analyzed using an optical 3D measurement system to determine the morphology and topographic parameters. It was established that pollution of the argon shield gas with oxygen did not influence the width of the heat-affected zone. However, the composition of the shield gas significantly influenced the surface asymmetry, Ssk, and its inclination Sku. The measurement of these parameters enabled the selection of a ...

  2. WELDING TORCH

    Science.gov (United States)

    Correy, T.B.

    1961-10-01

    A welding torch into which water and inert gas are piped separately for cooling and for providing a suitable gaseous atmosphere is described. A welding electrode is clamped in the torch by a removable collet sleeve and a removable collet head. Replacement of the sleeve and head with larger or smaller sleeve and head permits a larger or smaller welding electrode to be substituted on the torch. (AEC)

  3. A study on the CO2 laser welding characteristics of high strength steel up to 1500 MPa for automotive application

    Directory of Open Access Journals (Sweden)

    C.-H. Kim

    2010-03-01

    Full Text Available Purpose: This paper presents the mechanical and metallurgical characteristics of laser weldments for automotive steels with high strength ranging from 370 MPa to 1500 MPa.Design/methodology/approach: Butt joint welding was conducted on high strength steel sheets by using a CO2 laser with 6 kW output power. For sound welds with full penetration, the proper welding conditions were chosen and the cross-sectional bead shape, tensile strength, hardness profile and micro-structure were evaluated for each case.Findings: Laser welding is known to be a low heat input process because of its high heat density and welding speed. But for laser welding of ultra high strength steel with strength over 780 MPa, micro-structural softening was observed in the HAZ (heat affected zone, resulting from dissolved martensite.Practical implications: The tensile strength reduction in laser welding of ultra high strength steed should be considered in the design of car body structures. The HAZ softening that occurs in butt joint welding can reduce the tensile shear strength for overlap joint welds, which are predominantly mostly used in the BIW (body-in-white structure.Originality/value: This paper quantitatively demonstrates the occurrence of HAZ softening and a tensile strength reduction in laser welding of automotive steel with 780 MPa strength and more.

  4. PRESS FORMABILITY OF YAG LASER WELDED TRIP STEEL SHEETS

    Institute of Scientific and Technical Information of China (English)

    A.Nagasaka

    2002-01-01

    The effects of YAG laser welding conditions on mechanical properties and pressformability (bendability, stretch-formability and deep drawability) of high-strengthtransformation-induced plasticity-aided dual-phase (TDP) steel were investigated.Tensile tests and press forming tests have been conducted for laser butt welded jointsbetween two pieces of the same steel. The tensile property and press formability wereaffected by the welding speed of 100 to 1100mm/min and the energy of 6 to 9J/pulse.Excellent press formability was obtained with the energy of 6J/pulse and the weldingspeed of 300mm/min. It was concluded that the excellent weldability of the TDP steelcan be ascribed to the weld joint formation.

  5. Micro friction stir welding of copper electrical contacts

    Directory of Open Access Journals (Sweden)

    D. Klobčar

    2014-10-01

    Full Text Available The paper presents an analysis of micro friction stir welding (μFSW of electrolytic tough pitch copper (CuETP in a lap and butt joint. Experimental plan was done in order to investigate the influence of tool design and welding parameters on the formation of defect free joints. The experiments were done using universal milling machine where the tool rotation speed varied between 600 and 1 900 rpm, welding speed between 14 and 93 mm/min and tilt angle between 3° and 5°. From the welds samples for analysis of microstructure and samples for tensile tests were prepared. The grain size in the nugget zone was greatly reduced compared to the base metal and the joint tensile strength exceeded the strength of the base metal.

  6. Comparison of the material modelling performing characterization of weld microstructure of S355N steel and defining of residual stresses

    OpenAIRE

    Kuitunen, Mikko

    2016-01-01

    The objective of this Master thesis was to answer the following questions. Do the characterized microstructures of VTT S355N samples with their mechanical properties and the experimental results of TIG welds of the Voss‘s doctoral thesis correspond to the modelled material results? Is the mixing of the investigated weld samples of LAHW and MAG welds even? Do X-ray diffraction measured residual stresses of S355N butt weld samples correspond with the measured residual stresses of Contour method...

  7. Plasma arc welding weld imaging

    Science.gov (United States)

    Rybicki, Daniel J. (Inventor); Mcgee, William F. (Inventor)

    1994-01-01

    A welding torch for plasma arc welding apparatus has a transparent shield cup disposed about the constricting nozzle, the cup including a small outwardly extending polished lip. A guide tube extends externally of the torch and has a free end adjacent to the lip. First and second optical fiber bundle assemblies are supported within the guide tube. Light from a strobe light is transmitted along one of the assemblies to the free end and through the lip onto the weld site. A lens is positioned in the guide tube adjacent to the second assembly and focuses images of the weld site onto the end of the fiber bundle of the second assembly and these images are transmitted along the second assembly to a video camera so that the weld site may be viewed continuously for monitoring the welding process.

  8. Measurement of micro weld joint position based on magneto-optical imaging

    International Nuclear Information System (INIS)

    In a laser butt joint welding process, it is required that the laser beam focus should be controlled to follow the weld joint path accurately. Small focus wandering off the weld joint may result in insufficient penetration or unacceptable welds. Recognition of joint position offset, which describes the deviation between the laser beam focus and the weld joint, is important for adjusting the laser beam focus and obtaining high quality welds. A new method based on the magneto-optical (MO) imaging is applied to measure the micro weld joint whose gap is less than 0.2 mm. The weldments are excited by an external magnetic field, and an MO sensor based on principle of Faraday magneto effect is used to capture the weld joint images. A sequence of MO images which are tested under different magnetic field intensities and different weld joint widths are acquired. By analyzing the MO image characteristics and extracting the weld joint features, the influence of magnetic field intensity and weld joint width on the MO images and detection of weld joint position is observed and summarized. (paper)

  9. Measurement of micro weld joint position based on magneto-optical imaging

    Science.gov (United States)

    Gao, Xiang-Dong; Chen, Zi-Qin

    2015-01-01

    In a laser butt joint welding process, it is required that the laser beam focus should be controlled to follow the weld joint path accurately. Small focus wandering off the weld joint may result in insufficient penetration or unacceptable welds. Recognition of joint position offset, which describes the deviation between the laser beam focus and the weld joint, is important for adjusting the laser beam focus and obtaining high quality welds. A new method based on the magneto-optical (MO) imaging is applied to measure the micro weld joint whose gap is less than 0.2 mm. The weldments are excited by an external magnetic field, and an MO sensor based on principle of Faraday magneto effect is used to capture the weld joint images. A sequence of MO images which are tested under different magnetic field intensities and different weld joint widths are acquired. By analyzing the MO image characteristics and extracting the weld joint features, the influence of magnetic field intensity and weld joint width on the MO images and detection of weld joint position is observed and summarized. Project supported by the National Natural Science Foundation of China (Grant No. 51175095), the Natural Science Foundation of Guangdong Province, China (Grant No. 10251009001000001), the Guangdong Provincial Project of Science and Technology Innovation of Discipline Construction, China (Grant No. 2013KJCX0063), and the Science and Technology Plan Project of Guangzhou City, China (Grant No. 1563000554).

  10. Residual stress measurements in a P92 steel-In625 superalloy metal weldment in the as-welded and after post weld heat treated conditions

    International Nuclear Information System (INIS)

    Residual stress measurements have been undertaken in a multi-pass circumferential double J butt-weld made from a P92 martensitic steel pipe using an In625 superalloy weld metal. Stresses were evaluated in the as welded condition and after post weld heat treatment. The deep hole drilling and neutron diffraction techniques were used to provide through thickness measurements for the parent, weld metal and heat affected region for the as-welded and the post weld heat treated conditions. The use of multiple residual stress measurement techniques provides an understanding of the stress distributions as well as increasing confidence in the reliability of the measurements. The results presented are discussed with respect to the residual stress magnitude and location as well as with respect to the effectiveness of the post weld heat treatment procedure. - Highlights: • Work on dissimilar weldment of a P92 steel pipe using an In625 weld filler. • Residual stress measurements using DHD and ND techniques in dissimilar metal welds. • DHD-ND residual stress measurements and R6 assessment profiles comparison. • High residual stresses found in the AW condition of the welded pipe. • Relatively high residual stresses remain after PWHT

  11. Effect of Multipass TIG and Activated TIG Welding Process on the Thermo-Mechanical Behavior of 316LN Stainless Steel Weld Joints

    Science.gov (United States)

    Ganesh, K. C.; Balasubramanian, K. R.; Vasudevan, M.; Vasantharaja, P.; Chandrasekhar, N.

    2016-04-01

    The primary objective of this work was to develop a finite element model to predict the thermo-mechanical behavior of an activated tungsten inert gas (ATIG)-welded joint. The ATIG-welded joint was fabricated using 10 mm thickness of 316LN stainless steel plates in a single pass. To distinguish the merits of ATIG welding process, it was compared with manual multipass tungsten inert gas (MPTIG)-welded joint. The ATIG-welded joint was fabricated with square butt edge configuration using an activating flux developed in-house. The MPTIG-welded joint was fabricated in thirteen passes with V-groove edge configuration. The finite element model was developed to predict the transient temperature, residual stress, and distortion of the welded joints. Also, microhardness, impact toughness, tensile strength, ferrite measurement, and microstructure were characterized. Since most of the recent publications of ATIG-welded joint was focused on the molten weld pool dynamics, this research work gives an insight on the thermo-mechanical behavior of ATIG-welded joint over MPTIG-welded joint.

  12. Effect of power distribution on the weld quality during hybrid laser welding of an Al-Mg alloy

    Science.gov (United States)

    Leo, P.; Renna, G.; Casalino, G.; Olabi, A. G.

    2015-10-01

    This paper treats of the analysis of the effect of arc and laser powers on the quality of the arc assisted fiber laser welding of an Al-Mg alloy in the butt configuration. Grain size, weld geometry defects, porosity, and magnesium loss were measured. Magnesium content of the fused zone decreased as the laser power increased while the porosity increased with laser power. Microhardness profiles and tensile properties were explained on the basis of the joint microstructure and defects and related to the power distribution. The porosity level and Mg content in the fused zone affected both tensile strength and ductility. The power distribution that stabilized the welding process and minimize the weld porosity was defined.

  13. On-line quality inspection in laser blank welding using ART2 neural network

    Institute of Scientific and Technical Information of China (English)

    Zou Yuanyuan; Zhao Mingyang; Zhang Lei

    2006-01-01

    Laser blank welding is becoming more and more important in the automotive industry and the quality of the weld is critical for a successful application. A fully automated solution is required to inspect the quality of the blanks. This paper presents a vision inspection system with a CMOS camera which uses ART2 network to inspect the defects on-line to obtain the geometry and the quality of the weld seam. The neural network ART2 has the capability of self-learning from the environment.It can distinguish the defects that have been learned before and give new outputs for new defects. So ART2 network is suitable for weld quality inspection in laser blank welding. Additionally, a CO2 laser is used for the blank butt-welding.

  14. Mechanism of laser welding on dissimilar metals between stainless steel and W-Cu alloy

    Institute of Scientific and Technical Information of China (English)

    Kai Chen; Zhiyong Wang; Rongshi Xiao; Tiechuan Zuo

    2006-01-01

    @@ CO2 laser is employed to join a piece of powder metallurgical material (PMM) to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of stainless steel, powder Ni35, and Cu in W-Cu PMM. It is indicated that some parts of the W-Cu base metal are heated by laser and the metal Cu at the width of 0.06-0.12 mm from the edge is melted into the melting pool in the laser welding process. The formation of firm weld joint is just because that the melting liquid metal could fill the position occupied by metal Cu and surround the metal W granules fully. The analysis results indicate that the mechanism of the laser welding for stainless steel and W-Cu alloy is a special mode of fusion-brazing welding.

  15. Microstructures and properties of tungsten inert gas welding joint of super-eutectic ZA alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The microstructure of butt-welding joint of supper-eutectic ZA alloy in TIG welding was analyzed through optical microscope and transmission electronic microscope. The results show that the weld seam microstructure is fine and mainly composed of columnar crystals and minor equiaxed crystals, the microstructure in the zone near the weld seam is coarse columnar crystals, and the grain in heat-affected zone does not grow markedly. The joint microstructure at room temperature is consisted of β phase (rich Al), η-Zn, ε phase (CuZn compound), Al4Cu9 and other compounds. The hardness of the weld bond area and the tensile strength of the joint are a little higher than that of base materials. The specific elongation of the weld and bond area is a little lower than those of base materials.

  16. Influence of Surface Pre-treatments on Laser Welding of Ti6Al4V Alloy

    Science.gov (United States)

    Sánchez-Amaya, J. M.; Amaya-Vázquez, M. R.; González-Rovira, L.; Botana-Galvin, M.; Botana, F. J.

    2014-05-01

    In the present study, Ti6Al4V samples have been welded under conduction regime by means of a high power diode laser. The main objective of the work has been to determine the actual influence of the surface pre-treatments on the laser welding process. Thus, six different pre-treatments were applied to Ti6Al4V samples before performing bead-on-plate and butt welding treatments. The depth, width, microstructure, and microhardness of the different weld zones were deeply analyzed. Grinding, sandblasting, and chemical cleaning pre-treatments lead to welds with the highest depth values, presenting high joint strengths. Treatments based on the application of dark coatings generate welds with lower penetration and worse mechanical properties, specially the graphite-based coating.

  17. Life time assessment and repair of dissimilar metal welds. Part 1; Livslaengdsbedoemning och reparation av blandsvetsskarvar. Etapp 1

    Energy Technology Data Exchange (ETDEWEB)

    Storesund, Jan; Borggreen, Kjeld

    2005-04-01

    Research on the performance of dissimilar metal welds in high temperature plant has been performed for many years. Nevertheless damages are frequent in such welds. In order to decrease the damage problems and make it possible to estimate residual lifetimes of dissimilar metal welds in our Nordic countries it is first essential to i) collect the knowledge in the literature and ii) map current dissimilar metal welds and their condition in Swedish and Danish plants. The present report describes this first part of the work. There is a comprehensive literature of she subject. Most work has been performed on ferritic/austenitic dissimilar welds. In Swedish and Danish plants the dominating type is ferritic/martensitic dissimilar welds. The damage mechanisms are about the same in the two types, creep is the dominating mechanism, but plant experience indicates that the ferritic/austenitic combination is more prone to damage than the ferritic/martensitic one. An important difference between the two types is that Ni-base weld metal generally prolongs the lifetime for ferritic/austenitic dissimilar welds whereas it shows an opposite effect in ferritic/martensitic ones. In the latter case use of a 5 % Cr weld metal seems to be the best choice but the experiences of such welds are limited. The mapping of dissimilar welds indicates that there are predominantly special kinds of welds which fail whereas ordinary butt welds and branch welds are relatively free from damage.

  18. Weld overlay cladding with iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.M. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    The author has established a range of compositions for these alloys within which hot cracking resistance is very good, and within which cold cracking can be avoided in many instances by careful control of welding conditions, particularly preheat and postweld heat treatment. For example, crack-free butt welds have been produced for the first time in 12-mm thick wrought Fe{sub 3}Al plate. Cold cracking, however, still remains an issue in many cases. The author has developed a commercial source for composite weld filler metals spanning a wide range of achievable aluminum levels, and are pursuing the application of these filler metals in a variety of industrial environments. Welding techniques have been developed for both the gas tungsten arc and gas metal arc processes, and preliminary work has been done to utilize the wire arc process for coating of boiler tubes. Clad specimens have been prepared for environmental testing in-house, and a number of components have been modified and placed in service in operating kraft recovery boilers. In collaboration with a commercial producer of spiral weld overlay tubing, the author is attempting to utilize the new filler metals for this novel application.

  19. Development of Multi-Purpose Jig for Laser Welding

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Sung-Ho; Hong, Jintae; Joung, Chang-Young; Kim, Ka-Hye [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    A Nuclear Fuel Test Rig, which is designed to investigate nuclear fuel, need hundreds of detailed component assembly or welding processes. To weld small and complicate components, the laser welding process is one of the most important processes in fabricating a Nuclear Fuel Test Rig. Joung developed an automatic Laser Welding System. Hong analyzed the welding properties of Zircaloy-4 and STS 316L of the rig's material. Kim used a Dual Cooled Fuel Test Rig. In this study, a Multi-Purpose Jig, which is able to change the angle and fix the center of the Mother material to help the Laser welding system, is described. In this study, a Multi-Purpose Jig available in fabricating a nuclear fuel test rig was developed. Using the developed Multi-Purpose Jig, butt and lap welding experiments are currently in progress. As a result, it was confirmed that precise fixing and support are possible. Using the developed jig, the workability and accuracy of the laser welding for small components were dramatically improved.

  20. Development of Multi-Purpose Jig for Laser Welding

    International Nuclear Information System (INIS)

    A Nuclear Fuel Test Rig, which is designed to investigate nuclear fuel, need hundreds of detailed component assembly or welding processes. To weld small and complicate components, the laser welding process is one of the most important processes in fabricating a Nuclear Fuel Test Rig. Joung developed an automatic Laser Welding System. Hong analyzed the welding properties of Zircaloy-4 and STS 316L of the rig's material. Kim used a Dual Cooled Fuel Test Rig. In this study, a Multi-Purpose Jig, which is able to change the angle and fix the center of the Mother material to help the Laser welding system, is described. In this study, a Multi-Purpose Jig available in fabricating a nuclear fuel test rig was developed. Using the developed Multi-Purpose Jig, butt and lap welding experiments are currently in progress. As a result, it was confirmed that precise fixing and support are possible. Using the developed jig, the workability and accuracy of the laser welding for small components were dramatically improved

  1. A Recent Welding Technique: Laser Welding

    OpenAIRE

    ATİK, Dt.Ezgi; CİĞER, Prof. Dr. Semra

    2013-01-01

    Welding is a process that joins two adjacent metal surfaces with or without using filling material. The latest laser welding technique is a technology based on using infrared light spectrum. Laser welding has numerous advantages considering other conventional welding options used in dentistry and because of these reasons laser welding is used widely. When searching the literature in concern with laser welding, it is observed that this technique is compared with other conventional welding meth...

  2. Sutter Buttes-the lone volcano in California's Great Valley

    Science.gov (United States)

    Hausback, Brain P.; Muffler, L.J. Patrick; Clynne, Michael A.

    2011-01-01

    The volcanic spires of the Sutter Buttes tower 2,000 feet above the farms and fields of California's Great Valley, just 50 miles north-northwest of Sacramento and 11 miles northwest of Yuba City. The only volcano within the valley, the Buttes consist of a central core of volcanic domes surrounded by a large apron of fragmental volcanic debris. Eruptions at the Sutter Buttes occurred in early Pleistocene time, 1.6 to 1.4 million years ago. The Sutter Buttes are not part of the Cascade Range of volcanoes to the north, but instead are related to the volcanoes in the Coast Ranges to the west in the vicinity of Clear Lake, Napa Valley, and Sonoma Valley.

  3. 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.

  4. Growth of lamellar pearlite in the weld zone between dissimilar steels

    Science.gov (United States)

    Nikulina, A. A.; Smirnov, A. I.; Bataev, I. A.; Bataev, A. A.; Popelyukh, A. I.

    2016-01-01

    Transmission electron microscopy is used to study the welds between high-carbon pearlitic and chromium-nickel austenitic steel workpieces performed by flash butt welding. It has been established that lamellar pearlite colonies alloyed with chromium and nickel are formed in the weld zones between dissimilar steels. Thin austenite interlayers have been detected in the center of ferrite plates. The structure formed presents the C-F-A-F-C-F-A-F (and so on) sequence of three plate-shaped phases. The ferrite-cementite structure in alloyed-pearlite colonies is finer than that in unalloyed pearlite.

  5. Effect of Welding Processes on Tensile and Impact Properties, Hardness and Microstructure of AISI 409M Ferritic Stainless Joints Fabricated by Duplex Stainless Steel Filler Metal

    Institute of Scientific and Technical Information of China (English)

    A K Lakshminarayanan; K Shanmugam; V Balasubramanian

    2009-01-01

    The effect of welding processes such as shielded metal arc welding, gas metal arc welding and gas tungsten arc welding on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade is studied. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the welded joints have been evaluated and the results are compared. From this investigatio.n, it is found that gas tungsten arc welded joints of ferritic stainless steel have superior tensile and impact properties compared with shielded metal are and gas metal arc welded joints and this is mainly due to the presence of finer grains in fusion zone and heat affected zone.

  6. Optimization of welding variables for duplex stainless steel by GTAW and SMAW

    International Nuclear Information System (INIS)

    The main problems faced during the welding of duplex stainless steels are cleanliness and slag inclusions. In the present work the methods to eliminate these problems were studied during the welding of duplex stainless steel by Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW). Since the duplex stainless steel is an expensive material, the initial experiments for optimization of welding variables were. carried out on low carbon steel (CS) plates with duplex consumables. Welding of butt groove joints on CS plates was carried with various sets of welding variables i.e. current, voltage and arc energy using duplex consumables. The. radiographic inspection, micro-structural observations and hardness testing of the welds suggested the welding variables that will produce a sound weld on CS plate. These optimized variables were then used for the welding of edge groove joint and T -joint on duplex stainless steel by GTAW and SMAW processes. The hardness and micro-structural study of the joints produced on duplex stainless steel by GTAW and SMAW with duplex consumables were also studied. No slag inclusions and porosity were observed in the microstructure of these weldments and their properties were found similar to the parent metal. (author)

  7. Development of a process envelope for friction stir welding of DH36 steel – A step change

    International Nuclear Information System (INIS)

    Highlights: • The friction stir welding speed on DH36 steel has been substantially increased. • Excellent quality welds offering potential economic advantages are obtained. • Friction stir welding of steel generates a very complex metallurgical system. • Slow and intermediate welding speed tensile samples fractured in the parent material. • Increasing traverse speed is seen to improve the impact toughness of the weld. - Abstract: Friction stir welding of steel presents an array of advantages across many industrial sectors compared to conventional fusion welding techniques. However, the fundamental knowledge of the friction stir welding process in relation to steel remains relatively limited. A microstructure and property evaluation of friction stir welded low alloy steel grade DH36 plate, commonly used in ship and marine applications has been undertaken. In this comprehensive study, plates of 2000 × 200 × 6 mm were butt welded together at varying rotational and traverse speeds. Samples were examined microscopically and by transverse tensile tests. In addition, the work was complemented by Charpy impact testing and micro-hardness testing in various regions of the weld. The study examined a wide range of process parameters; from this, a preliminary process parameter envelope has been developed and initial process parameter sets established that produce commercially attractive excellent quality welds through a substantial increase in the conventionally recognised weld traverse speed

  8. Optimization of Gas Metal Arc Welding (GMAW) Process for Maximum Ballistic Limit in MIL A46100 Steel Welded All-Metal Armor

    Science.gov (United States)

    Grujicic, M.; Ramaswami, S.; Snipes, J. S.; Yavari, R.; Yen, C.-F.; Cheeseman, B. A.

    2015-01-01

    Our recently developed multi-physics computational model for the conventional gas metal arc welding (GMAW) joining process has been upgraded with respect to its predictive capabilities regarding the process optimization for the attainment of maximum ballistic limit within the weld. The original model consists of six modules, each dedicated to handling a specific aspect of the GMAW process, i.e., (a) electro-dynamics of the welding gun; (b) radiation-/convection-controlled heat transfer from the electric arc to the workpiece and mass transfer from the filler metal consumable electrode to the weld; (c) prediction of the temporal evolution and the spatial distribution of thermal and mechanical fields within the weld region during the GMAW joining process; (d) the resulting temporal evolution and spatial distribution of the material microstructure throughout the weld region; (e) spatial distribution of the as-welded material mechanical properties; and (f) spatial distribution of the material ballistic limit. In the present work, the model is upgraded through the introduction of the seventh module in recognition of the fact that identification of the optimum GMAW process parameters relative to the attainment of the maximum ballistic limit within the weld region entails the use of advanced optimization and statistical sensitivity analysis methods and tools. The upgraded GMAW process model is next applied to the case of butt welding of MIL A46100 (a prototypical high-hardness armor-grade martensitic steel) workpieces using filler metal electrodes made of the same material. The predictions of the upgraded GMAW process model pertaining to the spatial distribution of the material microstructure and ballistic limit-controlling mechanical properties within the MIL A46100 butt weld are found to be consistent with general expectations and prior observations.

  9. 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…

  10. Thermographic Analysis of Stress Distribution in Welded Joints

    Directory of Open Access Journals (Sweden)

    Domazet Ž.

    2010-06-01

    Full Text Available The fatigue life prediction of welded joints based on S-N curves in conjunction with nominal stresses generally is not reliable. Stress distribution in welded area affected by geometrical inhomogeneity, irregular welded surface and weld toe radius is quite complex, so the local (structural stress concept is accepted in recent papers. The aim of this paper is to determine the stress distribution in plate type aluminum welded joints, to analyze the reliability of TSA (Thermal Stress Analysis in this kind of investigations, and to obtain numerical values for stress concentration factors for practical use. Stress distribution in aluminum butt and fillet welded joints is determined by using the three different methods: strain gauges measurement, thermal stress analysis and FEM. Obtained results show good agreement - the TSA mutually confirmed the FEM model and stresses measured by strain gauges. According to obtained results, it may be stated that TSA, as a relatively new measurement technique may in the future become a standard tool for the experimental investigation of stress concentration and fatigue in welded joints that can help to develop more accurate numerical tools for fatigue life prediction.

  11. Welding robots

    OpenAIRE

    Pires, J. Norberto; Loureiro, Altino; Godinho, T.; Ferreira, P; Fernando, B; Morgado, J

    2003-01-01

    Using robots in industrial welding operations is common but far from being a streamlined technological process. The problems are with the robots, still in their early design stages and difficult to use and program by regular operators; the welding process, which is complex and not really well known and the human-machine interfaces, which are unnatural and not really working. In this article, these problems are discussed, and a system designed with the double objective of serving R&D efforts o...

  12. [Even cigarette butts can impact environment and health: preliminary considerations].

    Science.gov (United States)

    Martino, Gianrocco; Gorini, Giuseppe; Chellini, Elisabetta

    2013-01-01

    In Italy, every year about 72 billion of cigarette butts are thrown away in the environment. Cigarette butts represent 50% of the wastes of urban areas (parks, roads) in the world, and 40% of Mediterranean Sea wastes. In particular, total polluting load is constituted of 1,872 Bq millions of Polonium-210, assuming 75 mBq per cigarette butt, and 1,800 tons of volatile organic compounds. As a matter of fact, according to several surveys, cigarette butts are considered by smokers and non-smokers as a common and acceptable waste in the environment. In 2008, European Union issued a Directive on wastes considering the «extended producer responsibility» (i.e., every industry is liable for costs of collection, transport and disposal of its own products). In October 2012, the Italian Parliament proposed a bill that classifies cigarette butts as special wastes in the frame of this responsibility. It could be interesting in the future to follow the legislative process of that bill in the Italian Parliament in order to show how strong it will be supported.

  13. 焊接技术在金属切削刀具中的应用%Welding technique application in metal machining tool

    Institute of Scientific and Technical Information of China (English)

    马庆文

    2012-01-01

      目前我国刀具焊接基本上分为两种:摩擦焊和闪光对焊。本文主要介绍了焊接技术在金属切削刀具中的应用及其在生产加工中相关的知识。%  At present,domestic machining tool welding is basically divided into friction stir welding and flashing butt welding. This paper mainly describes welding technique application in metal machining tool and relevant knowledge for processing.

  14. Welding Distortion Prediction in 5A06 Aluminum Alloy Complex Structure via Inherent Strain Method

    Directory of Open Access Journals (Sweden)

    Zhi Zeng

    2016-09-01

    Full Text Available Finite element (FE simulation with inherent deformation is an ideal and practical computational approach for predicting welding stress and distortion in the production of complex aluminum alloy structures. In this study, based on the thermal elasto-plastic analysis, FE models of multi-pass butt welds and T-type fillet welds were investigated to obtain the inherent strain distribution in a 5A06 aluminum alloy cylindrical structure. The angular distortion of the T-type joint was used to investigate the corresponding inherent strain mechanism. Moreover, a custom-designed experimental system was applied to clarify the magnitude of inherent deformation. With the mechanism investigation of welding-induced buckling by FE analysis using inherent deformation, an application for predicting and mitigating the welding buckling in fabrication of complex aluminum alloy structure was developed.

  15. Analysis of pulsed Nd:YAG laser welding of AISI 304 steel

    International Nuclear Information System (INIS)

    Pulsed laser welding of AISI 304 stainless steel plate was simulated using commercial finite element software to determine the optimal welding conditions. Due to geometric symmetry, only one plate was modeled to reduce the simulation computation time. User subroutines were created to account for a moving three-dimensional heat source and to apply boundary conditions. The material properties such as conductivity, specific heat, and mass density were determined as functions of temperature. The latent heat was considered within the given temperature range. The three-dimensional heat source model for pulsed laser beam butt welding was designed by comparing the finite element analysis results and experimental data. This successful simulation of pulsed Nd:YAG laser welding for AISI 304 stainless steel will prove useful for determining optimal welding conditions

  16. Effect of Autogenous Arc Welding Processes on Tensile and Impact Properties of Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

    A K Lakshminarayanan; K Shanmugam; V Balasubramanian

    2009-01-01

    The effect of autogeneous arc welding processes on tensile and impact properties of ferritic stainless steel conformed to AISI 409M grade is studied.Rolled plates of 4 mm thickness have been used as the base material for preparing single pass butt welded jointa.Tensile and impact properties,microhardness,microstructure,and fracture surface morphology of continuous current gas tungsten arc welding (CCGTAW),pulsed current gas tungsten arc welding (PCGTAW),and plasma arc welding (PAW) joints are evaluated and the results are compared.It is found that the PAW joints of ferritic stainless steel show superior tensile and impact properties when compared with CCGTAW and PCGTAW joints,and this is mainly due to lower heat input,finer fusion zone grain diameter,and higher fusion zone hardness.

  17. The influence of heat treatment on the properties of laser welded Al-Li alloy

    International Nuclear Information System (INIS)

    An Al-Li-Cu-Mg-Zr alloy was welded with CO2 laser to produce full-penetration, single pass butt welds. Initial YS of 487 MPa for unwelded material decreased to 268 MPa after laser welding as well as the measured elongation decreased from 17.48% to 3.7% respectively. The postweld heat treatment consisting of solutionizing at 550 oC for 2 h and/or artificial aging at 150, 175, 200 and 225oC for 2, 4, 8, 16 and 32 h were performed to improve the properties of welded material. Studies by optical, scanning and transmission electron microscopes were provided in: as-welded, as-heat-treated and as-deformed states to show the microstructural changes with postweld heat treatment. (author)

  18. Process modeling and parameter optimization using radial basis function neural network and genetic algorithm for laser welding of dissimilar materials

    Science.gov (United States)

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

    2015-11-01

    The welded joints of dissimilar materials have been widely used in automotive, ship and space industries. The joint quality is often evaluated by weld seam geometry, microstructures and mechanical properties. To obtain the desired weld seam geometry and improve the quality of welded joints, this paper proposes a process modeling and parameter optimization method to obtain the weld seam with minimum width and desired depth of penetration for laser butt welding of dissimilar materials. During the process, Taguchi experiments are conducted on the laser welding of the low carbon steel (Q235) and stainless steel (SUS301L-HT). The experimental results are used to develop the radial basis function neural network model, and the process parameters are optimized by genetic algorithm. The proposed method is validated by a confirmation experiment. Simultaneously, the microstructures and mechanical properties of the weld seam generated from optimal process parameters are further studied by optical microscopy and tensile strength test. Compared with the unoptimized weld seam, the welding defects are eliminated in the optimized weld seam and the mechanical properties are improved. The results show that the proposed method is effective and reliable for improving the quality of welded joints in practical production.

  19. Nd:YAG laser welding of aerospace grade ZE41A magnesium alloy: Modeling and experimental investigations

    International Nuclear Information System (INIS)

    Keyhole formation as well as the geometry of weld profiles during Nd:YAG laser welding of ZE41A-T5 were studied through combining various models and concepts. The results indicated that weld width and fusion area decrease with increasing welding speed. In the case of partially penetrated welding, penetration depth decreases with increasing welding speed. Also, the model predicted that excessive decrease in laser power or increase in defocusing distance decreases surface power density, thereby changing the welding mode from fully penetrated keyhole, to partially penetrated keyhole, and then to the conduction mode. The predicted conditions for keyhole stability and welding modes as well as the weld profiles for various processing conditions were validated by some selected welding experiments. These experiments included studying the effects of welding speed, laser power, joint gap and laser defocusing on the weld geometry of 2- and 6-mm butt joints or bead-on-plates of ZE41A-T5 sand castings using a continuous wave 4 kW Nd:YAG laser system and 1.6-mm EZ33A-T5 filler wire. Good agreements were found between the model predictions and experimental results indicating the validity of the assumptions made for the development of the model

  20. Non vacuum electron beam welding of zinc coated high-strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Bach, F.W.; Beniyash, A.; Lau, K.; Versemann, R. [Hannover Univ. (Germany). Inst. of Materials Science

    2005-07-01

    Due to the requirement of conservation of nature and natural resources, today more and more high-strength steels are applied for modern concepts of lightweight construction in auto body manufacturing. For a better corrosion protection mainly hot-dip galvanized sheets or electrolytically coated sheets are used. Non Vacuum Electron Beam Welding (NVEBW) offers several technological and economical advantages for joining zinc coated sheets, which are presented in this paper. The results are based on extensive welding investigations that were performed with the 175 kV-NVEBW machine at Institute of Materials Science, University of Hanover. Different zinc coated steels (microalloyed steel, dualphase steel, residualaustenite steel, complexphase steel, martensitic steel) with sheet thicknesses between 0.8-2.0 mm were welded. A main focus of the work is to investigate the influence of the zinc coating on the welding behaviour at different seam geometries (butt joint, edge-raised seam, lap joint, fillet weld, tailored blank). Up to welding speeds of 10 m/min welds with good properties were obtained. In some cases (lap joints, edge raised seams) it is necessary to weld with a weld gap for zinc evaporation. But it turned out that NVEBW has a wide tolerance concerning the gap width. Furthermore, the presentation shows the results of extensive mechanical tests to NVEBW-welded high-strength steels, especially to hardness tests, tensile tests and forming investigations. (orig.)

  1. Dissimilar pulsed Nd:YAG laser welding of pure niobium to Ti–6Al–4V

    International Nuclear Information System (INIS)

    Highlights: • Pulsed Nd:YAG laser welding of Ti–6Al–4V/Nb sheets was carried out successfully. • Laser beam alignment relative to dissimilar joint interface has crucial role. • In tensile testing of as welded sample failure occurred outside the weld in Nb side. - Abstract: Dissimilar butt welding of pure niobium plate to the titanium alloy Ti–6Al–4V sheet using a pulsed Nd:YAG laser is performed. Effects of laser pulse energy, duration and repetition rates on the melt profile on both sides of the weld line were investigated. Considering the thermo-physical properties of the two base metals, variation of the weld profiles on different sides of the weld line is discussed. Through optimization of the process parameters a sound weld with full penetration along the dissimilar interface was obtained. However, islands of Ti rich and Nb rich phases were identified in the weld metal. Tensile strength of the welded joints matched that of the weaker base metal i.e. niobium and the specimens broke outside the fusion line

  2. On the Microstructural and Mechanical Characterization of Hybrid Laser-Welded Al-Zn-Mg-Cu Alloys

    Science.gov (United States)

    Wu, S. C.; Hu, Y. N.; Song, X. P.; Xue, Y. L.; Peng, J. F.

    2015-04-01

    Butt-welded 2-mm-thick high-strength aluminum alloys have been welded using a hybrid fiber laser and pulsed arc heat source system with the ER5356 filler. The microstructure, size of precipitates, texture, grain size and shape, change of strengthening elements, mechanical properties, and surface-based fatigue fracture characteristics of hybrid-welded joints were investigated in detail. The results indicate that the hybrid welds and the unaffected base materials have the lowest and largest hardness values, respectively, compared with the heat-affected zone. It is resonably believed that the elemental loss, coarse grains, and changed precipitates synthetically produce the low hardness and tensile strengths of hybrid welds. Meanwhile, the weaker grain boundary inside welds appears to initiate a microcrack. Besides, there exists an interaction of fatigue cracks and gas pores and microstructures.

  3. Surface Residual Stresses in Ti-6Al-4V Friction Stir Welds: Pre- and Post-Thermal Stress Relief

    Science.gov (United States)

    Edwards, P.; Ramulu, M.

    2015-09-01

    The purpose of this study was to determine the residual stresses present in titanium friction stir welds and if a post-weld thermal stress relief cycle would be effective in minimizing those weld-induced residual stresses. Surface residual stresses in titanium 6Al-4V alloy friction stir welds were measured in butt joint thicknesses ranging from 3 to 12 mm. The residual stress states were also evaluated after the welds were subjected to a post-weld thermal stress relief cycle of 760 °C for 45 min. High (300-400 MPa) tensile residual stresses were observed in the longitudinal direction prior to stress relief and compressive residual stresses were measured in the transverse direction. After stress relief, the residual stresses were decreased by an order of magnitude to negligible levels.

  4. A J estimation scheme for surface cracks in piping welds

    International Nuclear Information System (INIS)

    A cooperative program between EDF, CEA and AREVA NP was launched in 2004 to develop a J estimation scheme which takes into account the strength mis-match effects. The scheme relies on the definition of an 'equivalent' stressplastic strain curve, as proposed in the R6 rule. This curve is then used with the analytical methods for homogeneous cracked components. In a first step, the method is developed for circumferential surface cracks in straight butt-welded pipes submitted to mechanical loading. It takes into account the geometry of the weld joint (V-shaped), as well as the location of the crack within the weld. This paper recalls the background of the method, provides the detailed formulae needed to apply the J-estimation scheme and finally presents thevalidation work, based on a large finite element database

  5. Butt Joint Tool Status: ITER-US-LLNL-NMARTOVETSKY-01312007

    Energy Technology Data Exchange (ETDEWEB)

    Martovetsky, N N

    2007-02-01

    Butt joint tool vacuum vessel has been built at C&H Enterprise, Inc. Leak checking and loading tests were taken place at the factory. The conductor could not be pumped down better than to 500 mtorr and therefore we could not check the sealing mechanism of the seal around conductor. But the rest of the vessel, including the flat gasket, one of the difficult seals worked well, no indication of leak at sensitivity 1e-7 l*torr/sec. The load test showed fully functional system of the load mechanism. The conductors were loaded up to 2200 kgf (21560 N) and the pressure between the butts was uniform with 100% of the contact proved by pressure sensitive film. The status of the butt joint tool development is reported.

  6. Geology of Gable Mountain-Gable Butte Area

    Energy Technology Data Exchange (ETDEWEB)

    Fecht, K.R.

    1978-09-01

    Gable Mountain and Gable Butte are two ridges which form the only extensive outcrops of the Columbia River Basalt Group in the central portion of the Pasco Basin. The Saddle Mountains Basalt and two interbedded sedimentary units of the Ellensburg Formation crop out on the ridges. These include, from oldest to youngest, the Asotin Member (oldest), Esquatzel Member, Selah Interbed, Pomona Member, Rattlesnake Ridge Interbed, and Elephant Mountain Member (youngest). A fluvial plain composed of sediments from the Ringold and Hanford (informal) formations surrounds these ridges. The structure of Gable Mountain and Gable Butte is dominated by an east-west-trending major fold and northwest-southeast-trending parasitic folds. Two faults associated with the uplift of these structures were mapped on Gable Mountain. The geomorphic expression of the Gable Mountain-Gable Butte area resulted from the comlex folding and subsequent scouring by post-basalt fluvial systems.

  7. Boundary for the Deadman coal zone in the Black Butte area (bbbndg.shp)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This ArcView shapefile contains a polygon representation of the Deadman coal zone in the Black Butte area of the Point of Rocks-Black Butte coalfield, Wyoming. This...

  8. Effects of Gap Width and Groove on the Mechanical Properties of Butt Joint Between Aluminum Alloy and Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    Honggang DONG; Chuanqing LIAO

    2013-01-01

    Butt joining of 5A02 aluminum alloy to 304 stainless steel sheets was conducted using gas tungsten arc welding process with Al-12%Si (wt.%,the same below) and Zn-15%Al flux-cored filler wires.The effects of gap width and groove in steel side on the microstructure and tensile strength of the resultant joints were investigated.For the joint made with 0 mm-wide gap and without groove in steel side,severe incomplete brazing zone occurred along the steel side and bottom surfaces,and consequently seriously deteriorated the joint strength.However,presetting 1.5 mm-wide gap or with groove in steel side could promote the wetting of molten filler metal on the faying surfaces,and then significantly enhance the resultant joint strength.Moreover,post-weld heat treatment could further improve the tensile strength of the joints.During tensile testing,the specimens from the joints made with Al-12%Si flux-cored filler wire fractured through the weld or interfacial layer,but those from the heat-treated joints made with Zn-15%Al flux-cored filler wire fractured in the aluminum base metal.

  9. Thermal and mechanical properties of e-beam irradiated butt-fusion joint in high-density polyethylene pipes

    Science.gov (United States)

    Vijayan, Vipin; Pokharel, Pashupati; Kang, Min Kwan; Choi, Sunwoong

    2016-05-01

    The effects of electron beam irradiation on the thermal and mechanical properties of a butt-fusion joint in high density polyethylene (HDPE) pipes were investigated. Differential scanning calorimetry, X-ray diffraction, and Fourier transform infra-red spectroscopy of welded samples revealed the changes of crystallinity due to the cross linking effect of electron beam irradiation. The suppression of the degree of crystallinity with increasing the irradiation dose from 0 kGy to 500 kGy indicated that the e-beam radiation induced cross-links among the polymer chains at the weld zone. The cross-link junction at the joint of HDPE pipe prevented chain folding and reorganization leading to the formation of imperfect crystallites with smaller size and also less in content. Tensile test of the welded samples with different dose of e-beam irradiation showed the increased values of the yield stress and Young's modulus as a function of irradiation dose. On the other hand, the elongation at break diminished clearly with increasing the irradiation doses.

  10. CHARACTERIZATION OF DEFECTS IN ALLOY 152, 52 AND 52M WELDS

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, Stephen M.; Toloczko, Mychailo B.; Olszta, Matthew J.; Seffens, Rob J.; Efsing, Pal G.

    2009-08-27

    , defect characteristics and weld residual strains were examined by optical metallography, scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. Industry-supplied mock-up welds were characterized including alloy 52 and 152 weldments, alloy 52M overlay and inlay welds, and an alloy 52 overlay. II. WELDMENTS II.A. Alloy 52 and 152 Weld Mockups The alloy 52 and 152 weld mockups were fabricated by MHI for the Kewaunee reactor and were obtained from the EPRI NDE Center. The mockups were U-groove welds joining two plates of 304SS as shown in Figure 1. Alloy 152 butter (heat 307380) was placed on the U-groove surface for both mockups by shielded metal arc welding (SMAW). For the alloy 152 weld mockup, the alloy 152 fill (heat 307380) was also applied using SMAW while for the alloy 52 weld mockup, the alloy 52 fill (heat NX2686JK) was applied using gas tungsten arc welding (GTAW). Welding parameters for the fill materials were substantially different with the alloy 152 SMAW having a deposition speed of 4-25 cm/min with a current of 95-145 A and the alloy 52 GTAW having a deposition speed of 4-10 cm/min with a current of 150-300 A. One prominent feature in these mockup welds is the presence of a crack starting at the 304SS butt joint at the bottom of the U-groove and extending up into the weld. It appears that the 304SS plate on either side of the butt joint acted as an anchor for the weld resulting in a stress rise across the slit that drove crack formation and extension up into the fill weld. As will be shown in the next section, the extent of the cracking around this stress riser was much greater in the MHI 52 weld mockup.

  11. Lightweight design potential of cyclically loaded laser hybrid welds of HSLA steel S1100QL; Leichtbaupotenzial zyklisch belasteter Laserstrahl-Hybridschweissverbindungen aus S1100QL

    Energy Technology Data Exchange (ETDEWEB)

    Winderlich, Bernd; Jahn, Axel; Brenner, Berndt [Fraunhofer-Institut fuer Werkstoff- und Strahltechnik (IWS), Dresden (Germany)

    2011-07-01

    Laser hybrid welded joints of HSLA steel S1100QL are well suited for industrial use in cyclically highly loaded structures. In comparison to conventional MAG welding, laser hybrid welding enables shorter process time, lower heat input and reduced weldment distorsion. Hybrid butt welds ground flush to plate reach the same fatigue strength level as the blast cleaned base material. Pores in the weld metal are the fatigue limiting factor. Application of these welded joints is useful at high mean stress and low number of cycles. In this case it gives an advantage of grinding over generation of residual compressive stresses at the weld toe by the UIT method. Design and manufacturing issues and testing requirements are discussed. (orig.)

  12. Low Cycle Fatigue Behavior of Alloy 617 Base Metal and Welded Joints at Room Temperature and 850 .deg. C for VHTR Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Jin; Dew, Rando T. [Pukyong National Univ., Busan (Korea, Republic of); Kim, Woo Gon; Kim, Min Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Low cycle fatigue (LCF) is an important design consideration for high temperature IHX components. Moreover, some of the components are joined by welding techniques and therefore the welded joints are unavoidable in the construction of mechanical structures. Since Alloy 617 was introduced in early 1970s, many attempts have been made in the past two decades to evaluate the LCF and creep-fatigue behavior in Alloy 617 base metal at room temperature and high temperature. However, little research has focused on the evaluation and characterization of the Alloy 617 welded joints. butt-welded joint specimens was performed at room temperature and 850 .deg. C. Fatigue lives of GTAW welded joint specimens were lower than those of base metal specimens. LCF cracking and failure in welded specimens initiated in the weld metal zone and followed transgranluar dendritic paths for both at RT and 850 .deg. C.

  13. Dissimilar Arc Welding of Advanced High-Strength Car-Body Steel Sheets

    Science.gov (United States)

    Russo Spena, P.; D'Aiuto, F.; Matteis, P.; Scavino, G.

    2014-11-01

    A widespread usage of new advanced TWIP steel grades for the fabrication of car-body parts is conditional on the employment of appropriate welding methods, especially if dissimilar welding must be performed with other automotive steel grades. Therefore, the microstructural features and the mechanical response of dissimilar butt weld seams of TWIP and 22MnB5 steel sheets after metal-active-gas arc welding are examined. The microstructural and mechanical characterization of the welded joints was carried out by optical metallography, microhardness and tensile testing, and fractographic examination. The heat-affected zone on the TWIP side was fully austenitic and the only detectable effect was grain coarsening, while on the 22MnB5 side it exhibited newly formed martensite and tempered martensite. The welded tensile specimens exhibited a much larger deformation on the TWIP steel side than on the 22MnB5. The fracture generally occurred at the interface between the fusion zone and the heat-affected zones, with the fractures surfaces being predominantly ductile. The ultimate tensile strength of the butt joints was about 25% lower than that of the TWIP steel.

  14. Welding Curtains

    Science.gov (United States)

    1984-01-01

    Concept of transparent welding curtains made of heavy duty vinyl originated with David F. Wilson, President of Wilson Sales Company. In 1968, Wilson's curtains reduced glare of welding arc and blocked ultraviolet radiation. When later research uncovered blue light hazards, Wilson sought improvement of his products. He contracted Dr. Charles G. Miller and James B. Stephens, both of Jet Propulsion Laboratory (JPL), and they agreed to undertake development of a curtain capable of filtering out harmful irradiance, including ultraviolet and blue light and provide protection over a broad range of welding operation. Working on their own time, the JPL pair spent 3 years developing a patented formula that includes light filtering dyes and small particles of zinc oxide. The result was the Wilson Spectra Curtain.

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

    OpenAIRE

    Quoc Manh Nguyen; Shyh-Chour Huang

    2015-01-01

    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 la...

  16. A Relationship of the Torque Strength between Endplates and Endcaps due to the Welding Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae Seo; Kim, Soo Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-10-15

    As fuel bundles in a PHWR core irradiated, inner pressure in the claddings of the fuel rods increases owing to the outer pressure and fission products of the nuclear fissions. Because of a leak possibility from a welding between a cladding and an endcap, this welding part is connected with the safety of nuclear fuel rods. Endcap-cladding welding of nuclear fuel rods in a PHWR takes advantage of a resistance upset butt welding. The weldment between a cladding and an endcap is to be sound to prevent a leakage of fission products from a cladding as a UO{sub 2} pellet is irradiated. Weld flash was made from a deformation due to a welding heat and increasing the pressure of the resistivity and resistance from a cladding and an endcap. Weld line of a welding interface, microstructure of a weldment and a crystallographic structure change were sources of an iodine induced SCC in a reactor. The soundness of a weldment is important because a weld line connects the leakage of fission products from an operational reactor. In this study, welding specimens were fabricated by a resistance welding method using a fuel bundle welder to measure and analyze the torque strength of an endplate-endcap welding. The torque strength between endplates and endcaps was measured and analyzed with the welding current and the welding time. The torque strength between endplates and endcaps was, on the whole, within 6.9-12.7 N{center_dot}m in the range of fabrication specification of the fuel bundles. The weldability of between an endplate and an endcap was investigated by a metallographic examination.

  17. Modelling and Analysis of Phase Transformations and Stresses in Laser Welding Process / Modelowanie I Analiza Przemian Fazowych I Naprężeń W Procesie Spawania Laserowego

    OpenAIRE

    Piekarska W.

    2015-01-01

    The work concerns the numerical modelling of structural composition and stress state in steel elements welded by a laser beam. The temperature field in butt welded joint is obtained from the solution of heat transfer equation with convective term. The heat source model is developed. Latent heat of solid-liquid and liquid-gas transformations as well as latent heats of phase transformations in solid state are taken into account in the algorithm of thermal phenomena. The kinetics of phase transf...

  18. Development of weld plugging for steam generator tubes of FBR

    International Nuclear Information System (INIS)

    This study was undertaken to develop a method of weld plugging of the heat-exchanger tubes of steam generator of Prototype FBR 'MONJU' in case these tubes are damaged for some reason. We studied mainly the shape of plug, welding procedure and effect of postweld heat treatment (PWHT). Evaporator tube sheet, tube and plug are made of 2-1/4Cr-1Mo steel and usually preheating and PWHT will be required for welding of this steel. The results of this study is as follows. 1) Plug was designed to make butt joint welding with grooved tube sheet around the tube hole to satisfy the requirements of plug designing, stress analysis, and good weldability. 2) TIG welding process was selected and certified its good weldability and good performance. 3) PWHT can be done by using high frequency induction heating method locally and also designing the plug to weld joint with tube sheet which was grooved around the tube hole. 4) Mock up test was done and it was certified that this plugging procedure has good weldability and good performance ability for Non Destructive Inspection. (author)

  19. Monitoring of high-power fiber laser welding based on principal component analysis of a molten pool configuration

    International Nuclear Information System (INIS)

    There exists plenty of welding quality information on a molten pool during high-power fiber laser welding. An approach for monitoring the high-power fiber laser welding status based on the principal component analysis (PCA) of a molten pool configuration is investigated. An infrared-sensitive high-speed camera was used to capture the molten pool images during laser butt-joint welding of Type 304 austenitic stainless steel plates with a high-power (10 kW) continuous wave fiber laser. In order to study the relationship between the molten pool configuration and the welding status, a new method based on PCA is proposed to analyze the welding stability by comparing the situation when the laser beam spot moves along, and when it deviates from the weld seam. Image processing techniques were applied to process the molten pool images and extract five characteristic parameters. Moreover, the PCA method was used to extract a composite indicator which is the linear combination of the five original characteristics to analyze the different status during welding. Experimental results showed that the extracted composite indicator had a close relationship with the actual welding results and it could be used to evaluate the status of the high-power fiber laser welding, providing a theoretical basis for the monitoring of laser welding quality. (paper)

  20. PCR-based typing of DNA extracted from cigarette butts.

    Science.gov (United States)

    Hochmeister, M N; Budowle, B; Jung, J; Borer, U V; Comey, C T; Dirnhofer, R

    1991-01-01

    Limited genetic marker information can be obtained from saliva by typing by conventional serological means. Thus, the application of PCR-based DNA typing methods was investigated as a potential approach for typing genetic markers in saliva. DNA was isolated from 200 cigarettes smoked by 10 different individuals (20 cigarettes per individual) and from 3 cigarette butts recovered from 2 crime scenes (adjudicated cases) using a Chelex 100 extraction procedure. The amount of recovered human DNA was quantified by slot-blot analysis and ranged from approximately less than 2-160 ng DNA per cigarette butt for the 200 samples, and 8 ng, 50 ng, and 100 ng for the cigarette butts from the adjudicated cases. The DNA was successfully amplified by the polymerase chain reaction (PCR) for the HLA-DQ alpha locus (99 out of 100 samples) as well as for the variable number of tandem repeat (VNTR) locus D1S80 (99 out of 100 samples). Amplification and typing of DNA was successful on all samples recovered from the crime scenes. The results suggest that PCR-based typing of DNA offers a potential method for genetically characterizing traces of saliva on cigarette butts.

  1. Impact of cigarette butt leachate on tidepool snails.

    Science.gov (United States)

    Booth, David J; Gribben, Paul; Parkinson, Kerryn

    2015-06-15

    In urban areas, cigarette butts are the most common discarded refuse articles. In marine intertidal zones, they often fall into tidepools. We tested how common intertidal molluscs were affected by butt leachate in a laboratory experiment, where snails were exposed to various leachate concentrations. Mortality was very high, with all species showing 100% mortality at the full leachate concentration (5 butts per litre and 2h soak time) after 8days. However, Austrocochlea porcata showed higher mortality than the other 2 species at lower concentrations (10%, 25%) which may affect the relative abundance of the 3 snails under different concentrations of leachate pollution. Also, sublethal effects of leachate on snail activity were observed, with greater activity of Nerita atramentosa than the other 2 species at higher concentrations, suggesting it is more resilient than the other 2 species. While human health concerns predominate with respect to smoking, we show strong lethal and sublethal (via behavioural modifications) impacts of discarded butts on intertidal organisms, with even closely-related taxa responding differently.

  2. Development of science imperative for progress: Pervez Butt

    CERN Multimedia

    2002-01-01

    Mr. Parvez Butt, chairman of the Pakistan Atomic Energy Commission, has said that development of science and technology is imperative for progress and prosperity of any country. He was addressing a meeting on "CERN Data Grid and its Application" an opportunity for learning for scientists of developing countries (1/2 page).

  3. Willamette Valley - Baskett Butte Oak Savannah Restoration-Phase 2

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This project is a follow-up to the 2010 project that removed three invasive tree species across 85 acres on Baskett Butte at Baskett Slough NWR. Lack of fire in the...

  4. Simulation of power system of large energy flash butt welder based on Simulink%基于Simulink的大功率闪光焊机的电源仿真

    Institute of Scientific and Technical Information of China (English)

    王睿; 孙立雄; 张军伟; 高忠林

    2013-01-01

    针对大截面钢坯闪光焊接的特点,分析了大功率闪光焊机电源的工作原理,其主电路采用变压器初级调压、次级整流的拓扑结构.建立了基于Simulink功率模块的具有非线性特征的主电路模型和动态电阻负载模型.动态电阻主要由焊件的电阻和焊件端面之间的接触电阻组成.仿真结果表明,建立的主电路模型和动态电阻负载模型能够较为真实地模拟闪光对焊的动态过程,推动了大功率闪光焊机电源系统的数字化建模和仿真的研究水平.%According to characteristic of flash butt welding of large cross billets,this article presents the main circuit configuration of flash butt welding power system. The main circuit adopts three-phase voltage controller with secondary rectification. Based on the Simulink environment,the main circuit model and dynamic model of resistance load with non-linear features are built. Research shows that the simulation model can really simulate the dynamic process of flash butt welding,the digital model and simulation of power system of flash butt welder are improved.

  5. Analysing the Effect of Parameters in Multipass Submerged arc Welding Process

    Directory of Open Access Journals (Sweden)

    Deepti Jaiswal

    2013-08-01

    Full Text Available Submerged arc welding (SAW is a high quality, high deposition rate welding process commonly used to join plates of higher thickness in load bearing components. This process provide a purer and cleaner high volume weldment that has a relatively a higher material deposition rate compared to the traditional welding welding methods. The effect of controllable process variables on the heat input and the microhardness of weld metal and heat affected zone (HAZ for bead on joint welding were calculated and analysed using design of experiment software and fractional factorial technique developed for the multipass SAW of boiler and pressure vessel plates. The main purpose of present work is to investigate and correlated the relationship between various parameters and microhardness and microhardness of single “V” butt joint and predicting weld bead qualities before applying to the actual joining of metal by welding. It is found that the microhardness of weld metal and heat affected zone decreased when the number of passes increases that is total heat input increased.

  6. Welding of thin sheets of high strength zinc alloy coated steels

    International Nuclear Information System (INIS)

    Zinc alloy coated, high strength (G550) sheet steels are important materials in automobile manufacture, building and construction. Spot or arc welding is typically required in the component manufacturing process, but these processes result in localised softening because of the weld thermal cycle. As a consequence, the strength is normally downgraded significantly for design purposes to values typical of the annealed Zn or Zn alloy grades (G250 or G300). The investigation described in this paper involved the examination of the effect of the welding process and welding variables on butt welding on 1mm thick Zn-coated and Zn-Al-coated sheet steels. It has been demonstrated that these sheet steels can be successfully welded by both FCAW and GMAW methods using appropriately low welding heat inputs. However, strength loss below the minimum specified 5.50 MPa tensile strength did occur because of transformation and recrystallisation of the recovery annealed base metal structure as a result of the heat input of the welding process. The extent of the strength loss increased with increasing nominal weld heat input due to an increased width of the softened heat affected zone (HAZ) regions and grain growth in the grain refined and recrystallised regions. The maximum loss in yield strength at the highest heat input of 130 J/mm was about 150 MPa, suggesting that a minimum yield stress of 400 MPa can be safely used for structural design calculations.

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

    International Nuclear Information System (INIS)

    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

  8. Microstructure and Mechanical Properties of Laser Beam Welds of 15CDV6 Steel

    Directory of Open Access Journals (Sweden)

    M.V.L Ramesh

    2015-07-01

    Full Text Available The present study is concerned with laser beam welding of 15CDV6 steel, that is in the hardened (quenched and tempered condition before welding. Autogenously butt-welded joints are made using carbon dioxide laser with a maximum output of 3.5 kw in the continuous wave mode. Weld microstructure, microhardness measurement across the weldment, transverse tensile properties, and room temperature impact properties of the weldment have been evaluated. The fusion zone exhibits a epitaxial grain growth. The microstrutural features of heat-affected zone and fusion zone vary, due to different thermal cycles for which these were subjected during welding. The average weld metal hardness was 480 Hv. The observed hardness distribution across the welds were correlated with the microstructures. The welds exhibited lower toughness of 50 joules as compared to parent metal of 55 joules and the tensile strength values of the welded specimens are close to that obtained for sheet specimens.Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 339-342, DOI: http://dx.doi.org/10.14429/dsj.65.8749

  9. Friction Stir-Welded Titanium Alloy Ti-6Al-4V: Microstructure, Mechanical and Fracture Properties

    Science.gov (United States)

    Sanders, D. G.; Edwards, P.; Cantrell, A. M.; Gangwar, K.; Ramulu, M.

    2015-05-01

    Friction stir welding (FSW) has been refined to create butt welds from two sheets of Ti-6Al-4V alloy to have an ultra-fine grain size. Weld specimen testing was completed for three different FSW process conditions: As welded, stress relieved, stress relieved and machined, and for the un-welded base material. The investigation includes macrostructure, microstructure, microhardness, tensile property testing, notched bar impact testing, and fracture toughness evaluations. All experiments were conducted in accordance with industry standard testing specifications. The microstructure in the weld nugget was found to consist of refined and distorted grains of alpha in a matrix of transformed beta containing acicular alpha. The enhanced fracture toughness of the welds is a result of increased hardness, which is attributed to an increase in alpha phase, increase in transformed beta in acicular alpha, and grain refinement during the weld process. The noted general trend in mechanical properties from as welded, to stress relieved, to stress relieved and machined conditions exhibited a decrease in ultimate tensile strength, and yield strength with a small increase in ductility and a significant increase in fracture toughness.

  10. Regulating the disposal of cigarette butts as toxic hazardous waste.

    Science.gov (United States)

    Barnes, Richard L

    2011-05-01

    The trillions of cigarette butts generated each year throughout the world pose a significant challenge for disposal regulations, primarily because there are millions of points of disposal, along with the necessity to segregate, collect and dispose of the butts in a safe manner, and cigarette butts are toxic, hazardous waste. There are some hazardous waste laws, such as those covering used tyres and automobile batteries, in which the retailer is responsible for the proper disposal of the waste, but most post-consumer waste disposal is the responsibility of the consumer. Concepts such as extended producer responsibility (EPR) are being used for some post-consumer waste to pass the responsibility and cost for recycling or disposal to the manufacturer of the product. In total, 32 states in the US have passed EPR laws covering auto switches, batteries, carpet, cell phones, electronics, fluorescent lighting, mercury thermostats, paint and pesticide containers, and these could be models for cigarette waste legislation. A broader concept of producer stewardship includes EPR, but adds the consumer and the retailer into the regulation. The State of Maine considered a comprehensive product stewardship law in 2010 that is a much better model than EPR. By using either EPR or the Maine model, the tobacco industry will be required to cover the cost of collecting and disposing of cigarette butt waste. Additional requirements included in the Maine model are needed for consumers and businesses to complete the network that will be necessary to maximise the segregation and collection of cigarette butts to protect the environment.

  11. Microstructure and pitting corrosion of armor grade AA7075 aluminum alloy friction stir weld nugget zone – Effect of post weld heat treatment and addition of boron carbide

    Directory of Open Access Journals (Sweden)

    P. Vijaya Kumar

    2015-06-01

    Full Text Available Friction stir welding (FSW of high strength aluminum alloys has been emerged as an alternative joining technique to avoid the problems during fusion welding. In recent times FSW is being used for armor grade AA7075 aluminum alloy in defense, aerospace and marine applications where it has to serve in non uniform loading and corrosive environments. Even though friction stir welds of AA7075 alloy possess better mechanical properties but suffer from poor corrosion resistance. The present work involves use of retrogression and reaging (RRA post weld heat treatment to improve the corrosion resistance of welded joints of aluminum alloys. An attempt also has been made to change the chemical composition of the weld nugget by adding B4C nano particles with the aid of the FSW on a specially prepared base metal plate in butt position. The effects of peak aged condition (T6, RRA and addition of B4C nano particles on microstructure, hardness and pitting corrosion of nugget zone of the friction stir welds of AA7075 alloy have been studied. Even though RRA improved the pitting corrosion resistance, its hardness was slightly lost. Significant improvement in pitting corrosion resistance was achieved with addition of boron carbide powder and post weld heat treatment of RRA.

  12. Distortion Control during Welding

    OpenAIRE

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ methods to control welding distortion. In these methods local heating and/or cooling strategies are applied during welding. Additional heating and/or cooling sources can be implemented either stationa...

  13. Optimization of deep penetration laser welding of thick stainless steel with a 10 kW fiber laser

    International Nuclear Information System (INIS)

    Highlights: • The focal position is a key parameter for high-power fiber laser welding of thick plate. • Good full penetration weld cannot be obtained just via varying the welding speed without a proper focal position. • The bottom shielding gas improves the stability of the total welding process. • The cross section of the optimal butt joint appears “I” shape. • The joint is ductile fractured far from the weld seam with the tensile strength of 809 MPa. - Abstract: Deep penetration laser welding of 12 mm thick stainless steel plates was conducted using a 10 kW high-power fiber laser. The effect of the processing parameters on the weld bead geometry was examined, and the microstructure and mechanical properties of the optimal joint were investigated. The results show that the focal position is a key parameter in high-power fiber laser welding of thick plates. There is a critical range of welding speed for achieving good full penetration joint. The type of top shielding gas influences the weld depth. The application of a bottom shielding gas improves the stability of the entire welding process and yields good weld appearances at both the top and bottom surfaces. The maximum tensile stress of the joint is 809 MPa. The joint fails at the base metal far from the weld seam with a typical cup–cone-shaped fracture surface. The excellent welding appearance and mechanical properties indicate that high-power fiber laser welding of a 304 stainless steel thick plate is feasible

  14. Modelling of laser welding of flat parts using the modifying nanopowders

    Science.gov (United States)

    Cherepanov, A. N.; Shapeev, V. P.

    2013-06-01

    A mathematical model is formulated to describe thermophysical processes at laser welding of metal plates for the case when the modifying nanoparticles of refractory compounds have been introduced in the weld pool (the nanopowder seed cultrure fermenters — NSCF). Specially prepared nanoparticles of refractory compounds serve the crystallization centers that is they are in fact the exogenous primers, on the surface of which the individual clusters are grouped. Owing to this, one can control the process of the crystallization of the alloy and the formation of its structure and, consequently, the joint weld properties. As an example, we present the results of computing the butt welding of two plates of aluminum alloy and steel. Computed and experimental data are compared.

  15. Study on fracture characteristic of welded high-density polyethylene pipe

    Institute of Scientific and Technical Information of China (English)

    齐芳娟; 霍立兴; 张玉凤; 荆洪阳; 杨新岐

    2002-01-01

    Crack opening displacement(COD) was applied to characterize the fracture initiation of the tough high density polyethylene. Normal single side notched three-point bend specimens and silica rubber replica techniques were used to study the characteristic COD of high-density polyethylene pipe and its butt-fusion joints including the weld fusion zone and heat affected zone at different temperature from -78℃ to 20℃ . Testing results show that the characteristic COD appears to depend on the structural features that are determined by welding process and the testing temperature. As the temperature is lowered, the characteristic COD of all zones studied decreases. Because the welding process significantly changes some structural feature of the material, characteristic COD of the weld fusion zone is the smallest one among those of the three zones. The results can be used for the engineering design and failure analysis of HDPE pipe.

  16. Prediction of Welding Residual Stress in 2. 25Cr-1Mo Steel Pipe

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A numerical analysis method was proposed to predict the welding residual stress in 2.25Cr-1Mo steel pipe considering solid-state phase transformations. A thermal elastic plastic finite element (FE) model considering effects of martensite transformation was developed based on commercial ABAQUS software. Continuous cooling transformation (CCT) diagrams were employed to simulate the fraction of martensite in fusion zone, coarsegrained heat affected zone and fine-grained heat affected zone. The Koistinen-Marburger relationship was used to trace the formation of martensite. The effects of both volume change and yield strength change due to phase transformation on welding residual stress were considered using the proposed FE model. The result shows that the phase transformation has significant effects on the welding residual stress in multi-pass butt weld of pipe. The predicted simulation results by the proposed numerical method are generally in good agreement with experimental results.

  17. T.I.G. Welding of stainless steel. Numerical modelling for temperatures calculation in the Haz; Soldadura T.I.G. de acero inoxidable. Modelo numerico para el calculo de temperaturas en la ZAT

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Conesa, E. J.; Estrems-Amestoy, M.; Miguel-Eguia, V.; Garrido-Hernandez, A.; Guillen-Martinez, J. A.

    2010-07-01

    In this work, a numerical method for calculating the temperature field into the heat affected zone for butt welded joints is presented. The method has been developed for sheet welding and takes into account a bidimensional heat flow. It has built a computer program by MS-Excel books and Visual Basic for Applications (VBA). The model has been applied to the TIG process of AISI 304 stainless steel 2mm thickness sheet. The welding process has been considered without input materials. The numerical method may be used to help the designers to predict the temperature distribution in welded joints. (Author) 12 refs.

  18. Shear strength of fillet welds in aluminum alloy 2219. [for use on the solid rocket motor and external tank

    Science.gov (United States)

    Lovoy, C. V.

    1978-01-01

    Fillet size is discussed in terms of theoretical or design dimensions versus as-welded dimensions, drawing attention to the inherent conservatism in the design load sustaining capabilities of fillet welds. Emphasis is placed on components for the solid rocket motor, external tank, and other aerospace applications. Problems associated with inspection of fillet welds are addresses and a comparison is drawn between defect counts obtained by radiographic inspection and by visual examination of the fracture plane. Fillet weld quality is related linearly to ultimate shear strength. Correlation coefficients are obtained by simple straight line regression analysis between the variables of ultimate shear strength and accumulative discontinuity summation. Shear strength allowables are found to be equivalent to 57 percent of butt weld A allowables (F sub tu.)

  19. 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...

  20. 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.

  1. Highspeed laser welding of steel using a high-power single-mode continuous-wave fiber laser

    Science.gov (United States)

    Drechsel, J.; Loeschner, U.; Schwind, S.; Hartwig, L.; Schille, J.; Exner, H.; Huebner, P.; Eysert, A.

    2013-02-01

    Since a few years, high brilliance laser sources find their way into laser material processing. Laser micro processing by applying high brilliance laser radiation up to 3 kW of continuous wave laser power in combination with ultrafast beam deflection systems has been successfully demonstrated in 2008 for the first time. In the fields of laser welding, high brilliant laser radiation was mainly used for micro welding, but up to now the macro range is still insufficiently investigated. Hence, this study reports on detailed investigations of high speed laser welding of different steel grades, performed with a high power single mode fiber laser source. The laser beam was deflected relative to the sample by using both a fast galvanometer scanner system with f-theta focusing objective and a linear axis in combination with a welding optic, respectively. In the study, the mainly process influencing parameters such as laser power, welding speed, thickness of the metal sheets, angle of incidence and laser beam spot size were varied in a wide range. The weld seam quality was evaluated by structural analyses, static tensile tests and EDX measurements. Finally, the laser welding process has been optimized for different weld seam geometries, for example bead-on-plate welds and butt welds.

  2. OPTIMIZATION OF PROCESS PARAMETERS TO MINIMIZE ANGULAR DISTORTION IN GAS TUNGSTEN ARC WELDED STAINLESS STEEL 202 GRADE PLATES USING PARTICLE SWARM OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    R. SUDHAKARAN

    2012-04-01

    Full Text Available This paper presents a study on optimization of process parameters using particle swarm optimization to minimize angular distortion in 202 grade stainless steel gas tungsten arc welded plates. Angular distortion is a major problem and most pronounced among different types of distortion in butt welded plates. The process control parameters chosen for the study are welding gun angle, welding speed, plate length, welding current and gas flow rate. The experiments were conducted using design of experiments technique with five factor five level central composite rotatable design with full replication technique. A mathematical model was developed correlating the process parameters with angular distortion. A source code was developed in MATLAB 7.6 to do the optimization. The optimal process parameters gave a value of 0.0305° for angular distortion which demonstrates the accuracy of the model developed. The results indicate that the optimized values for the process parameters are capable of producing weld with minimum distortion.

  3. Investigation of Effect of Welding Current on Welding Penetration in Covered Electrode Arc Welding And MIG Welding

    OpenAIRE

    Bekir ÇEVİK

    2013-01-01

    In this study, the effect of welding current on penetration in covered electrode arc welding and MIG (Metal Inert Gas) welding was investigated. St 37 quality steel materials were used in the experiments. Three different welding current (60, 90 and 120 A with covered electrode arc welding, 100, 125 and 155 A with MIG welding) was selected for welding process and was made 200 mm long weld. The welded specimens were cut particular lengths, then metallographic tests were performed. As a result o...

  4. Ballistic-Failure Mechanisms in Gas Metal Arc Welds of Mil A46100 Armor-Grade Steel: A Computational Investigation

    Science.gov (United States)

    Grujicic, M.; Snipes, J. S.; Galgalikar, R.; Ramaswami, S.; Yavari, R.; Yen, C.-F.; Cheeseman, B. A.

    2014-09-01

    In our recent work, a multi-physics computational model for the conventional gas metal arc welding (GMAW) joining process was introduced. The model is of a modular type and comprises five modules, each designed to handle a specific aspect of the GMAW process, i.e.: (i) electro-dynamics of the welding-gun; (ii) radiation-/convection-controlled heat transfer from the electric-arc to the workpiece and mass transfer from the filler-metal consumable electrode to the weld; (iii) prediction of the temporal evolution and the spatial distribution of thermal and mechanical fields within the weld region during the GMAW joining process; (iv) the resulting temporal evolution and spatial distribution of the material microstructure throughout the weld region; and (v) spatial distribution of the as-welded material mechanical properties. In the present work, the GMAW process model has been upgraded with respect to its predictive capabilities regarding the spatial distribution of the mechanical properties controlling the ballistic-limit (i.e., penetration-resistance) of the weld. The model is upgraded through the introduction of the sixth module in the present work in recognition of the fact that in thick steel GMAW weldments, the overall ballistic performance of the armor may become controlled by the (often inferior) ballistic limits of its weld (fusion and heat-affected) zones. To demonstrate the utility of the upgraded GMAW process model, it is next applied to the case of butt-welding of a prototypical high-hardness armor-grade martensitic steel, MIL A46100. The model predictions concerning the spatial distribution of the material microstructure and ballistic-limit-controlling mechanical properties within the MIL A46100 butt-weld are found to be consistent with prior observations and general expectations.

  5. Development of phased array ultrasonic testing in lieu of radiography for testing complete joint penetration (CJP) welds

    Science.gov (United States)

    Haldipur, P.; Boone, Shane D.

    2014-04-01

    The past decade has seen new, emerging innovation of Ultrasonic Testing (UT). Specifically, multiple manufacturers have produced Phased Array Ultrasonic Testing (PAUT) systems. The PAUT systems embed a matrix of multiple (some up to 128) single transducers into one probe used for scanning elastic materials. Simultaneously exciting multiple transducers offers distinct advantages; depending on the sequencing of transducer excitation, the ultrasonic beam could be steered within the material and multiple beams help develop extra dimensional data to assist with visualization of possible flaws including the discontinuity size, shape and location. Unfortunately, there has not been broad acceptance of PAUT in the bridge fabrication industry because it is currently not a recognized inspection technology in AWS D1.5. One situation in which the technology would excel would be inspection of Complete Joint Penetration (CJP) butt welds. Currently, AWS D1.5 required CJP welds subjected to tensile or reversal stresses only be inspected by Radiographic Testing (RT). However, discontinuities normally seen by RT can also be seen with PAUT. Until specification language is adopted into D1.5, there will continue to be hesitancy to use PAUT for the inspection of CJP butt welds. Developmental work must first be performed to develop the acceptance criteria and the specification language. The developmental work from the inspections carried out on butt-weld specimens and transition butt-weld specimens are presented in this paper. Specific scan plans were developed using the ES-Beam simulation software for each of the test specimens. In depth analysis of PAUT data obtained to determine exact location and sizing information of the defects was performed. The results also present the comparison of results from PAUT to those obtained using conventional UT and radiography.

  6. Stress corrosion crack initiation of alloy 182 weld metal in primary coolant - Influence of chemical composition

    Energy Technology Data Exchange (ETDEWEB)

    Calonne, O.; Foucault, M.; Steltzlen, F. [AREVA (France); Amzallag, C. [EDF SEPTEN (France)

    2011-07-01

    Nickel-base alloys 182 and 82 have been used extensively for dissimilar metal welds. Typical applications are the J-groove welds of alloy 600 vessel head penetrations, pressurizer penetrations, heater sleeves and bottom mounted instrumented nozzles as well as some safe end butt welds. While the overall performance of these weld metals has been good, during the last decade, an increasing number of cases of stress corrosion cracking of Alloy 182 weld metal have been reported in PWRs. In this context, the role of weld defects has to be examined. Their contribution in the crack initiation mechanism requires laboratory investigations with small scale characterizations. In this study, the influence of both alloy composition and weld defects on PWSCC (Stress Corrosion Cracking in Primary Water) initiation was investigated using U-bend specimens in simulated primary water at 320 C. The main results are the following: -) the chemical compositions of the weld deposits leading to a large propensity to hot cracking are not the most susceptible to PWSCC initiation, -) macroscopically, superficial defects did not evolve during successive exposures. They can be included in large corrosion cracks but their role as 'precursors' is not yet established. (authors)

  7. Residual stress analysis of aluminium welds with high energy synchrotron radiation at the HARWI II beamline

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Torben; Martins, Rene V.; Schreyer, Andreas [GKSS Research Centre, Geesthacht (Germany)

    2008-07-01

    In civil aircraft production advanced welding techniques, like laser beam welding or friction stir welding, are used to reduce weight and production costs. By the welding process residual stresses are introduced in the weld zone and the surrounding area. These stresses may depend on diverse factors and can have disadvantageous influence on the service performance of the weld. For strain scanning GKSS research centre built up the high energy materials science beamline HARWI II at HASYLAB. The use of high energetic photons from about 80 keV-120 keV enables diffraction experiments in transmission geometry, which provides the information about the macroscopic stresses. A large sample-detector-distance ensures a high angular resolution for the peak position determination. The heavy load diffractometer allows making use of massive sample environments. For example laser beam welded t- and butt-joints were investigated with high spatial resolution. The large grain size of the specimen makes the measurements with high spatial resolution more difficult due to the poor grain statistics. The influences of the gauge volume size and grain statistics on the strain measurements were systematically investigated. For the t-joint configuration two dimensional stress maps were calculated from the data. For the near future an in-situ FSW experiment is planed to investigate the metallophysical processes during the welding.

  8. Improving the Fatigue Performance of the Welded Joints of Ultra-Fine Grain Steel by Ultrasonic Peening

    Institute of Scientific and Technical Information of China (English)

    王东坡; 王婷; 霍立兴; 张玉凤

    2004-01-01

    Contrast tests were carried out to study the fatigue performance of the butt joints treated by ultrasonic peening, aiming at the improvement of ultrasonic peening treatment(UPT) on welded joints of a new material.The material is a new generation of fine grain and high purity SS400 steel that has the same ingredients as the traditional low carbon steel. The specimens are in two different states:welded and ultrasonic peening conditions.The corresponding fatigue testing data were analyzed according to the regulation of the statistical method for fatigue life of the welded joints established by International Institute of Welding(IIW). Welding residual stress was considered in two different ways: the constant stress ratio R = 0. 5 and the Ohta method. The nominal stress-number (σ-N)curves were corrected because of the different plate thickness compared to the standard and because there was no mismatch or angular deformation. The results indicated that: 1 ) Compared with the welded specimens, when the stress range was 200 MPa, the fatigue life of the SS400 steel specimens treated by ultrasonic peening is prolonged by over 58 times, and the fatigue strength FAT corresponding to 106 cycles is increased by about 66%; 2) As for the SS400 butt joint ( single side welding double sides molding), after being treated by UPT, the nominal S-N curve (m = 10) of FAT 100 MPa(R =0.5) should be used for fatigue design. The standard S-N curves of FAT 100 MPa ( R = 0. 5, m = 10) could be used for fatigue design of the SS400 steel butt joints treated by ultrasonic peening.

  9. Greater Natural Buttes: One Model for Stakeholder Cooperation

    OpenAIRE

    Bell, Brooke

    2012-01-01

    The presentation will discuss the recently approved Greater Natural Buttes Environmental Impact Statement and the path of stakeholder involvement that brought the NEPA process to a successful conclusion. Brooke will briefly touch on the keys to project success and the “effective” management practices that allow Anadarko to minimize the development footprint and coexist with wildlife, threatened plants, recreationalists, and the community. Brooke Bell, Regulatory Affairs Manager, Anadarko P...

  10. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ met

  11. 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.…

  12. Mechanical properties and corrosion resistance of dissimilar stainless steel welds

    Directory of Open Access Journals (Sweden)

    J. Łabanowski

    2007-01-01

    Full Text Available Purpose: The purpose of this paper is to determine the influence of welding on microstructure, mechanical properties, and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Duplex 2205 and austenitic 316L steels were used. Butt joints of plates 15 mm in thickness were performed with the use of submerged arc welding (SAW method. The heat input was in the range of 1.15 – 3.2 kJ/mm. Various plates’ edge preparations were applied. Microstructure examinations were carried out. Mechanical properties were evaluated in tensile tests, bending tests and Charpy-V toughness tests. Susceptibility to stress corrosion cracking was determined with the use of slow strain rate tests (SSRT performed in inert (glycerin and aggressive (boiling 35% MgCl2 solution environments.Findings: All tested joints showed acceptable mechanical properties. Metallographic examinations did not indicate the excessive ferrite contents in heat affected zones (HAZ of the welds. It was shown that area of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon is connected with undesirable structure of that zone consisted of greater amounts of coarse ferrite grains and acicular austenite precipitates. High heat inputs do not deteriorate mechanical properties as well as stress corrosion cracking resistance of welds.Practical implications: All tested joints showed acceptable mechanical properties. Metallographic examinations did not indicate the excessive ferrite contents in heat affected zones (HAZ of the welds. It was shown that area of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon is connected with undesirable structure of that zone consisted of greater amounts of coarse ferrite grains and acicular austenite precipitates. High heat inputs do not deteriorate

  13. The Western Environmental Technology Office (WETO), Butte, Montana. Technology summary

    International Nuclear Information System (INIS)

    The Western Environmental Technology Office (WETO) is a multi-purpose engineering test facility located in Butte, Montana, and is managed by MSE, Inc. WETO seeks to contribute to environmental research by emphasizing projects to develop heavy metals removal and recovery processes, thermal vitrification systems, and waste minimization/pollution prevention technologies. WETO's environmental technology research and testing activities focus on the recovery of usable resources from waste. In one of WETO's areas of focus, groundwater contamination, water from the Berkeley Pit, located near the WETO site, is being used in demonstrations directed toward the recovery of potable water and metal from the heavy metal-bearing water. The Berkeley Pit is part of an inactive copper mine near Butte that was once part of the nation's largest open-pit mining operation. The Pit contains approximately 25 billion gallons of Berkeley Pit groundwater and surface water containing many dissolved minerals. As part of DOE/OST's Resource Recovery Project (RRP), technologies are being demonstrated to not only clean the contaminated water but to recover metal values such as copper, zinc, and iron with an estimated gross value of more than $100 million. When recovered, the Berkeley Pit waters could benefit the entire Butte valley with new water resources for fisheries, irrigation, municipal, and industrial use. At WETO, the emphasis is on environmental technology development and commercialization activities, which will focus on mine cleanup, waste treatment, resource recovery, and water resource management

  14. The Western Environmental Technology Office (WETO), Butte, Montana. Technology summary

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The Western Environmental Technology Office (WETO) is a multi-purpose engineering test facility located in Butte, Montana, and is managed by MSE, Inc. WETO seeks to contribute to environmental research by emphasizing projects to develop heavy metals removal and recovery processes, thermal vitrification systems, and waste minimization/pollution prevention technologies. WETO`s environmental technology research and testing activities focus on the recovery of usable resources from waste. In one of WETO`s areas of focus, groundwater contamination, water from the Berkeley Pit, located near the WETO site, is being used in demonstrations directed toward the recovery of potable water and metal from the heavy metal-bearing water. The Berkeley Pit is part of an inactive copper mine near Butte that was once part of the nation`s largest open-pit mining operation. The Pit contains approximately 25 billion gallons of Berkeley Pit groundwater and surface water containing many dissolved minerals. As part of DOE/OST`s Resource Recovery Project (RRP), technologies are being demonstrated to not only clean the contaminated water but to recover metal values such as copper, zinc, and iron with an estimated gross value of more than $100 million. When recovered, the Berkeley Pit waters could benefit the entire Butte valley with new water resources for fisheries, irrigation, municipal, and industrial use. At WETO, the emphasis is on environmental technology development and commercialization activities, which will focus on mine cleanup, waste treatment, resource recovery, and water resource management.

  15. Black Butte switches to laser for mapping open pit mines

    Energy Technology Data Exchange (ETDEWEB)

    Corbley, K.P. [Corbley Communications Inc., Littleton, CO (USA)

    2001-03-01

    The Black Butte Coal Co. has turned to a new laser-based mapping technology called Light Detection and Ranging, LIDAR, for mapping the topography of surface mines. The system, known as the Remote Airborne Mapping System (RAMS), is provided by EnerQuest Systems LLC of Denver. In four projects at the 63-square mile Black Butte operation, advanced airborne LIDAR has demonstrated advantage over aerial photography in terms of timeliness and convenience for mapping coal seams in an open-pit mine. LIDAR uses a scanning laser altimeter to directly measure the latitude, longitude and elevation coordinates of ground points by emitting light pulses towards the ground from the unit in the aircraft. Black Butte mine uses a dragline for overburden stripping. 3-D models of the pit and seams are created with Minescape software. The LIDAR system allows modeling of overburden to determine the position of the economic cutoff by mapping outside the pit: mapping inside the pit enables the 3-D model to be checked. 1 fig., 1 photo.

  16. Laser welding in space

    Science.gov (United States)

    Kaukler, W. F.; Workman, G. L.

    1991-01-01

    Autogenous welds in 304 stainless steel were performed by Nd-YAG laser heating in a simulated space environment. Simulation consists of welding on the NASA KC-135 aircraft to produce the microgravity and by containing the specimen in a vacuum chamber. Experimental results show that the microgravity welds are stronger, harder in the fusion zone, have deeper penetration and have a rougher surface rippling of the weld pool than one-g welds. To perform laser welding in space, a solar-pumped laser concept that significantly increases the laser conversion efficiency and makes welding viable despite the limited power availability of spacecraft is proposed.

  17. Research on Hot Melt (Welding) Bonding Defects of PE Pipe%PE 管热熔(焊接)粘接缺陷的研究

    Institute of Scientific and Technical Information of China (English)

    董守江; 邱建新; 温友林; 周裕昌; 冯志飞

    2015-01-01

    本文首先将PE管的热熔焊接与金属焊接进行了区别,并介绍了其工艺过程;其次对PE管热熔对接接头的断口特征进行了分类,并分析了PE管热熔对接接头中可能产生的缺陷,虚(焊)粘、假(焊)粘是PE管存在的主要缺陷,对对接接头的强度影响较大。可以采取超声波检测方法控制PE管热熔(焊接)粘接接头的内部质量,以保证工程应用安全。%In this article, the distinction between the fusion welding and melt welding of the PE pipe was given, whose process was also introduced. Then the fracture characteristics of PE pipe butt joints were classiifed, and it gave an analysis of the possible defects of PE pipe butt fusion joints, ifnding that, virtual (welding) stick and false (welding) of PE pipe sticking were major defects which had inlfuence on the impact of butt joints. Ultrasonic testing could be used to take control of PE pipe internal quality of fusion(welding) adhesive joints in order to ensure the safety of engineering application.

  18. 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.

  19. Effects of pulsed Nd:YAG laser welding parameters and subsequent post-weld heat treatment on microstructure and hardness of AISI 420 stainless steel

    International Nuclear Information System (INIS)

    Highlights: ► Weld depth and width increase with voltage and decrease with welding speed. ► The weld microstructure consists of martensite, delta ferrite, retained austenite. ► The high hardness was observed in HAZ due to precipitation of M23C6 carbide. ► Hardness of weld decreases with tempering temperature. ► Higher toughness for type 2 than 1; more martensite transforms to ferrite and M23C6. -- Abstract: Martensitic stainless steels are often used in cases where high strength and medium corrosion resistance are required. In this study, pulsed Nd:YAG laser welding of AISI 420 martensitic stainless steel is considered. Welding of samples were carried out autogenously. The spacing between samples was set to almost zero. All samples were butt welded. The effect of welding parameters such as voltage, laser beam diameter, frequency, pulse duration, and welding speed on the weld dimensions were investigated and the optimum values were obtained for the 450 V voltage, 0.6 mm focal diameter, 6 Hz frequency, 5 ms pulse duration and 1.5 mm/s welding speed. Microstructure of weld pool and heat affected zone (HAZ) were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). Micro-hardness studies were also carried out. The results showed the presence of some remaining delta-ferrite in the martensitic weld structure and coarsening of M23C6 carbides in HAZ. The magnitude of hardness in the HAZ was higher than that of the weld zone. To reduce the hardness of weld and HAZ and to increase the toughness in these regions, two types of post-weld heat treatments (PWHTs) were carried out. In type 1, samples tempered for 2 h. In type 2, samples austenitizied for 0.5 h at 1010 °C and then tempered for 2 h. In order to achieve high strength and toughness, optimum temper temperatures for type 1 and 2 heat treatments were obtained for 595 and 537 °C, respectively. The results showed higher toughness for type 2 than type 1.

  20. 77 FR 39735 - Stainless Steel Butt-Weld Pipe Fittings From Italy, Malaysia, and the Philippines

    Science.gov (United States)

    2012-07-05

    ... The Commission instituted these reviews on November 1, 2011 (76 FR 67473) and determined on February 6, 2012 that it would conduct expedited reviews (77 FR 10773, February 23, 2012). On March 21, 2012, the Commission revised its schedule in these expedited reviews (77 FR 18266, March 27, 2012). The...

  1. Gas metal arc welding of butt joint with varying gap width based on neural networks

    DEFF Research Database (Denmark)

    Christensen, Kim Hardam; Sørensen, Torben

    2005-01-01

    squares has been used with the back-propagation algorithm for training the network, while a Bayesian regularization technique has been successfully applied for minimizing the risk of inexpedient over-training. Finally, a predictive closed-loop control strategy based on a so-called single-neuron self...

  2. Flash-butt welding construction%钢筋闪光对焊施工

    Institute of Scientific and Technical Information of China (English)

    伍春生

    2008-01-01

    介绍了钢筋闪光对焊焊接工艺的优点,阐述了其焊接工艺流程及操作要点,对施工注意事项进行了总结,并对钢筋对焊的异常现象及缺陷种类作了概述,同时提出了相应的防止措施,从而确保钢筋的焊接质量.

  3. Repair welding of fusion reactor components. Final technical report

    International Nuclear Information System (INIS)

    The exposure of metallic materials, such as structural components of the first wall and blanket of a fusion reactor, to neutron irradiation will induce changes in both the material composition and microstructure. Along with these changes can come a corresponding deterioration in mechanical properties resulting in premature failure. It is, therefore, essential to expect that the repair and replacement of the degraded components will be necessary. Such repairs may require the joining of irradiated materials through the use of fusion welding processes. The present ITER (International Thermonuclear Experimental Reactor) conceptual design is anticipated to have about 5 km of longitudinal welds and ten thousand pipe butt welds in the blanket structure. A recent study by Buende et al. predict that a failure is most likely to occur in a weld. The study is based on data from other large structures, particularly nuclear reactors. The data used also appear to be consistent with the operating experience of the Fast Flux Test Facility (FFTF). This reactor has a fuel pin area comparable with the area of the ITER first wall and has experienced one unanticipated fuel pin failure after two years of operation. The repair of irradiated structures using fusion welding will be difficult due to the entrapped helium. Due to its extremely low solubility in metals, helium will diffuse and agglomerate to form helium bubbles after being trapped at point defects, dislocations, and grain boundaries. Welding of neutron-irradiated type 304 stainless steels has been reported with varying degree of heat-affected zone cracking (HAZ). The objectives of this study were to determine the threshold helium concentrations required to cause HAZ cracking and to investigate techniques that might be used to eliminate the HAZ cracking in welding of helium-containing materials

  4. Study of laser and electron beam welding of Nb-1Zr-0.1C and TZM alloys

    International Nuclear Information System (INIS)

    The refractory metal alloys Nb-1Zr-0.1C and TZM (0.5 Ti-0.08 Zr-0.04 C) having an excellent combination of high temperature properties; which makes them suitable for structural applications in advanced nuclear reactors operating at high temperature.The applications of these alloys call for their welding in different forms and shapes. Due to their high melting point, thermal conductivity and reactive nature; welding of these alloys is challenging and difficult task. The high energy density welding techniques like laser and electron beam (EB) capable of producing deep penetration welds with minimal heat affected zone (HAZ) are more suitable for welding of these alloys. Both the techniques had some advantages and limitations which need to be studied. The autogeneous laser (Nd:YAG) and EB welds in bead-on-plate (BOP) and butt joint configuration were produced on sheets of Nb-1Zr-0.1C and TZM alloy by systematically varying the process parameters. The laser and EB welds produced on sheets of Nb-1Zr-0.1C alloy were subjected to optical and electron microscopic examination and were characterized in detailed by studying their weld profiles, optical and SEM micrographs of the weld zone and HAZ

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

    International Nuclear Information System (INIS)

    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

  6. Gas tungsten arc and laser beam welding processes effects on duplex stainless steel 2205 properties

    Energy Technology Data Exchange (ETDEWEB)

    Mourad, A-H.I., E-mail: ahmourad@uaeu.ac.ae [Mechanical Engineering Department, Faculty of Engineering, United Arab Emirates University, Al-Ain, P.O. Box. 17555 (United Arab Emirates); Khourshid, A.; Sharef, T. [Mechanical Design and Production Department, Faculty of Engineering, Tanta University, Tanta (Egypt)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer LBW results in considerable variation in the ferrite-austenite balance of FZ. Black-Right-Pointing-Pointer LBW produces smaller FZ size than GTAW. Black-Right-Pointing-Pointer The effect of FZ size is more pronounced than that of ferrite-austenite balance. Black-Right-Pointing-Pointer Satisfactory mechanical properties were obtained using both GTAW and LBW. Black-Right-Pointing-Pointer LBW process has produced welded joint properties comparable to BM. - Abstract: A comparative study on the influence of gas tungsten arc welding (GTAW) and carbon dioxide laser beam welding (LBW) processes on the size and microstructure of fusion zone FZ then, on the mechanical and corrosion properties of duplex stainless steel DSS grade 2205 plates of 6.4 mm thickness was investigated. Autogenous butt welded joints were made using both GTAW and LBW. The GTA welded joint was made using well established welding parameters (i.e., current ampere of 110 A, voltage of 12 V, welding speed of 0.15 m/min and argon shielding rate of 15 l/min). While optimum LBW parameters were used (i.e., welding speed of 0.5 m/min, defocusing distance of 0.0 mm, argon shielding flow rate of 20 l/min and maximum output laser power of 8 kW). The results achieved in this investigation disclose that welding process play an important role in obtaining satisfactory weld properties. In comparison with GTAW, LBW has produced welded joint with a significant decrease in FZ size and acceptable weld profile. The ferrite-austenite balance of both weld metal WM and heat affected zone (HAZ) are influenced by heat input which is a function of welding process. In comparison with LBW, GTAW has resulted in ferrite-austenite balance close to that of base metal BM due to higher heat input in GTAW. However, properties of LB welded joint, particularly corrosion resistance are much better than that of GTA welded joint. The measured corrosion rates for LBW and GTAW joints are 0.05334 mm

  7. Gas tungsten arc and laser beam welding processes effects on duplex stainless steel 2205 properties

    International Nuclear Information System (INIS)

    Highlights: ► LBW results in considerable variation in the ferrite–austenite balance of FZ. ► LBW produces smaller FZ size than GTAW. ► The effect of FZ size is more pronounced than that of ferrite–austenite balance. ► Satisfactory mechanical properties were obtained using both GTAW and LBW. ► LBW process has produced welded joint properties comparable to BM. - Abstract: A comparative study on the influence of gas tungsten arc welding (GTAW) and carbon dioxide laser beam welding (LBW) processes on the size and microstructure of fusion zone FZ then, on the mechanical and corrosion properties of duplex stainless steel DSS grade 2205 plates of 6.4 mm thickness was investigated. Autogenous butt welded joints were made using both GTAW and LBW. The GTA welded joint was made using well established welding parameters (i.e., current ampere of 110 A, voltage of 12 V, welding speed of 0.15 m/min and argon shielding rate of 15 l/min). While optimum LBW parameters were used (i.e., welding speed of 0.5 m/min, defocusing distance of 0.0 mm, argon shielding flow rate of 20 l/min and maximum output laser power of 8 kW). The results achieved in this investigation disclose that welding process play an important role in obtaining satisfactory weld properties. In comparison with GTAW, LBW has produced welded joint with a significant decrease in FZ size and acceptable weld profile. The ferrite–austenite balance of both weld metal WM and heat affected zone (HAZ) are influenced by heat input which is a function of welding process. In comparison with LBW, GTAW has resulted in ferrite–austenite balance close to that of base metal BM due to higher heat input in GTAW. However, properties of LB welded joint, particularly corrosion resistance are much better than that of GTA welded joint. The measured corrosion rates for LBW and GTAW joints are 0.05334 mm/year and 0.2456 mm/year, respectively. This is related to the relatively small size of both WM and HAZ produced in the case

  8. Welded solar cell interconnection

    Science.gov (United States)

    Stofel, E. J.; Browne, E. R.; Meese, R. A.; Vendura, G. J.

    1982-01-01

    The efficiency of the welding of solar-cell interconnects is compared with the efficiency of soldering such interconnects, and the cases in which welding may be superior are examined. Emphasis is placed on ultrasonic welding; attention is given to the solar-cell welding machine, the application of the welding process to different solar-cell configurations, producibility, and long-life performance of welded interconnects. Much of the present work has been directed toward providing increased confidence in the reliability of welding using conditions approximating those that would occur with large-scale array production. It is concluded that there is as yet insufficient data to determine which of three methods (soldering, parallel gap welding, and ultrasonic welding) provides the longest-duration solar panel life.

  9. Laser-ultrasonic inspection of hybrid laser-arc welded HSLA-65 steel

    Science.gov (United States)

    Lévesque, D.; Rousseau, G.; Wanjara, P.; Cao, X.; Monchalin, J.-P.

    2014-02-01

    The hybrid laser-arc welding (HLAW) process is a relatively low heat input joining technology that combines the synergistic qualities of both the high energy density laser beam for deep penetration and the arc for wide fit-up gap tolerance. This process is especially suitable for the shipbuilding industry where thick-gauge section, long steel plates have been widely used in a butt joint configuration. In this study, preliminary exploration was carried out to detect and visualize the welding defects using laser ultrasonics combined with the synthetic aperture focusing technique (SAFT). Results obtained on 9.3 mm thick butt-welded HSLA-65 steel plates indicated that the laser-ultrasonic SAFT inspection technique can successfully detect and visualize the presence of porosity, lack of fusion and internal crack defects. This was further confirmed by X-ray digital radiography and metallography. The results obtained clearly show the potential of using the laser-ultrasonic technology for the automated inspection of hybrid laser-arc welds.

  10. Laser-ultrasonic inspection of hybrid laser-arc welded HSLA-65 steel

    International Nuclear Information System (INIS)

    The hybrid laser-arc welding (HLAW) process is a relatively low heat input joining technology that combines the synergistic qualities of both the high energy density laser beam for deep penetration and the arc for wide fit-up gap tolerance. This process is especially suitable for the shipbuilding industry where thick-gauge section, long steel plates have been widely used in a butt joint configuration. In this study, preliminary exploration was carried out to detect and visualize the welding defects using laser ultrasonics combined with the synthetic aperture focusing technique (SAFT). Results obtained on 9.3 mm thick butt-welded HSLA-65 steel plates indicated that the laser-ultrasonic SAFT inspection technique can successfully detect and visualize the presence of porosity, lack of fusion and internal crack defects. This was further confirmed by X-ray digital radiography and metallography. The results obtained clearly show the potential of using the laser-ultrasonic technology for the automated inspection of hybrid laser-arc welds

  11. Littered cigarette butts as a source of nicotine in urban waters

    Science.gov (United States)

    Roder Green, Amy L.; Putschew, Anke; Nehls, Thomas

    2014-11-01

    The effect of nicotine from littered cigarette butts on the quality of urban water resources has yet to be investigated. This two-part study addresses the spatial variation, seasonal dynamics and average residence time of littered cigarette butts in public space, as well as the release of nicotine from cigarette butts to run-off in urban areas during its residence time. Thereby, we tested two typical situations: release to standing water in a puddle and release during alternating rainfall and drying. The study took place in Berlin, Germany, a city which completely relies on its own water resources to meet its drinking water demand. Nine typical sites located in a central district, each divided into 20 plots were studied during five sampling periods between May 2012 and February 2013. The nicotine release from standardized cigarette butts prepared with a smoking machine was examined in batch and rainfall experiments. Littered cigarette butts are unevenly distributed among both sites and plots. The average butt concentration was 2.7 m-2 (SD = 0.6 m-2, N = 862); the maximum plot concentration was 48.8 butts m-2. This heterogeneity is caused by preferential littering (gastronomy, entrances, bus stops), redistribution processes such as litter removal (gastronomy, shop owners), and the increased accumulation in plots protected from mechanized street sweeping (tree pits, bicycle stands). No significant seasonal variation of cigarette butt accumulation was observed. On average, cigarette butt accumulation is characterized by a 6 days cadence due to the rhythm and effectiveness of street sweeping (mean weekly butt accumulation rate = 0.18 m-2 d-1; SD = 0.15 m-1). Once the butt is exposed to standing water, elution of nicotine occurs rapidly. Standardized butts released 7.3 mg g-1 nicotine in a batch experiment (equivalent to 2.5 mg L-1), 50% of which occurred within the first 27 min. In the rainfall experiment, the cumulative nicotine release from fifteen consecutive

  12. Creep properties of welded joints in OFHC copper for nuclear waste containment

    International Nuclear Information System (INIS)

    In Sweden it has been suggested that copper canisters are used for containment of spent nuclear fuel. These canisters will be subjected to temperatures up to 100 degrees C and external pressures up to 15 MPa. Since the material is pure (OFHC) copper, creep properties must be considered when the canisters are dimensioned. The canisters are sealed by electron beam welding which will affect the creep properties. Literature data for copper - especially welded joints - at the temperatures of interest is very scare. Therefore uniaxial creep tests of parent metal, weld metal, and simulated HAZ structures have been performed at 110 degrees C. These tests revealed considerable differences in creep deformation and rupture strength. The weld metal showed creep rates and rupture times ten times higher and ten times shorter, respectively, than those of the parent metal. The simulated HAZ was equally strongen than the parent metal. These differences were to some extent verified by results from creep tests of cross-welded specimens which, however, showed even shorter rupture times. Constitutive equations were derived from the uniaxial test results. To check the applicability of these equations to multiaxial conditions, a few internal pressure creep tests of butt-welded tubes were performed. Attemps were made to simulate their creep behaviour by constitutive equations were used. These calculations failed due to too great differences in creep deformation behaviour across the welded joint. (authors)

  13. A non-conventional technique for evaluating welded joints based on the electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Santos, T.G.; Sorger, G., E-mail: telmo.santos@fct.unl.pt, E-mail: lgs18243@campus.fct.unl.pt [Universidade Nova de Lisboa, UNIDEMI, Departamento de Engenharia Mecanica e Industrial, Faculdade de Ciencias e Tecnologia, Caparica (Portugal); Vilaca, P., E-mail: pedro.vilaca@aalto.fi [Aalto Univ., Dept. of Engineering Design and Production, School of Engineering, Aalto (Finland); Miranda, R., E-mail: rmiranda@fct.unl.pt [Universidade Nova de Lisboa, UNIDEMI, Departamento de Engenharia Mecanica e Industrial, Faculdade de Ciencias e Tecnologia, Caparica (Portugal)

    2015-01-15

    Recent studies showed that electrical conductivity is a valuable technique to identify the different zones of solid-state welded joints with a good correlation with the microstructure and hardness. This is a relevant result since this technique is fast and, in some cases, non destructive, The concept was applied to other welding processes such as the ones involving fusion to a wide range of materials, For this, a comprehensive study was performed using friction stir welding, tungsten inert gas (TlG) and gas metal arc (MAG) welding processes in either bead on plate or butt joints in: carbon steel, magnesium and titanium, Eddy current nondestructive testing (NDT) was used to measure the electrical conductivity at different depths in transverse sections of the processed materials. The profiles were compared to the hardness profiles in the same sections. As a result, a correlation was observed in most materials welded by solid state and by fusion processes. The variation of the electrical conductivity closely follows that measured in the hardness. Another interesting conclusion is that, even for fusion welding of carbon steels, the technique has potential to complement the hardness measurements and microstructural observations, allowing the identification of the distinct zones of welds in materials commonly used in industry. (author)

  14. Microstructure and Mechanical Properties of Hybrid Welded Joints with Laser and CO2-Shielded Arc

    Science.gov (United States)

    Wahba, M.; Mizutani, M.; Katayama, S.

    2016-06-01

    With the objective of reducing the operating costs, argon-rich shielding gas was replaced by 100% CO2 gas in hybrid laser-arc welding of shipbuilding steel. The welding parameters were optimized to obtain buried-arc transfer in order to mitigate spatter formation. Sound butt joints could be successfully produced for plates of 14 and 17 mm thickness in one welding pass. Subsequently, the welded joints were subjected to different tests to evaluate the influence of CO2 shielding gas on the mechanical properties of the welded joints. All tensile-tested specimens failed in the base material, indicating the higher strength of the welded joints. The impact toughness of the welded joints, measured at -20 °C, reached approximately 76% of that of the base material, which was well above the limit set by the relevant standard. The microstructure of the fusion zone consisted of grain boundary ferrite and acicular ferrite uniformly over the plate thickness except for the joint root where the microstructure was chiefly ferrite with an aligned second phase. This resulted in higher hardness in the root region compared with the top and middle parts of the fusion zone.

  15. Microstructure and Mechanical Properties of Hybrid Welded Joints with Laser and CO2-Shielded Arc

    Science.gov (United States)

    Wahba, M.; Mizutani, M.; Katayama, S.

    2016-07-01

    With the objective of reducing the operating costs, argon-rich shielding gas was replaced by 100% CO2 gas in hybrid laser-arc welding of shipbuilding steel. The welding parameters were optimized to obtain buried-arc transfer in order to mitigate spatter formation. Sound butt joints could be successfully produced for plates of 14 and 17 mm thickness in one welding pass. Subsequently, the welded joints were subjected to different tests to evaluate the influence of CO2 shielding gas on the mechanical properties of the welded joints. All tensile-tested specimens failed in the base material, indicating the higher strength of the welded joints. The impact toughness of the welded joints, measured at -20 °C, reached approximately 76% of that of the base material, which was well above the limit set by the relevant standard. The microstructure of the fusion zone consisted of grain boundary ferrite and acicular ferrite uniformly over the plate thickness except for the joint root where the microstructure was chiefly ferrite with an aligned second phase. This resulted in higher hardness in the root region compared with the top and middle parts of the fusion zone.

  16. Butt lengths differ by area deprivation level: a field study to explore intensive smoking.

    Science.gov (United States)

    Thomson, George; Wilson, Nick; Bushell, Lisa; Al Matar, Waseem; Ball, Bridget; Chiu, Jessie; Culliford, Nicola; Gately, Callum; Gibson, Kirsty; Hudson, Jennifer; Hunt, Paul; Rangamuwa, Kanishka; Tapp, Dylan; Wickramaratne, Hasith; Young, Vanessa

    2008-05-01

    We collected cigarette butts in a range of residential areas, to assess differences in the length of unburnt tobacco in the butts, and in proportions of roll-your-own (RYO) cigarettes. Two high, two medium, and two low deprivation areas, as classified by deciles of the New Zealand Deprivation Index, were selected for the Wellington region. Collected butts were systematically classified and measured. A mixed model of analysis, treating location clusters nested within deprivation level areas as a random effect, was used to assess differences in mean length of unburnt tobacco in the butts. A total of 6,262 cigarette butts and separate filters were collected, of which 3,509 (56.0%) were measurable manufactured cigarette butts, 1,069 were unmeasurable manufactured butts, 1,450 were RYO butts, and 236 were RYO filters. The RYO butts were not measured because of the extent of their degradation. The unburnt tobacco lengths in manufactured cigarette butts were significantly shorter in the most deprived areas, relative to the least deprived areas (p = .035). Deformed manufactured cigarette butts (i.e., that potentially were stubbed out) showed the same pattern (p = .011 between the most and least deprived areas). We found no significant difference between deprivation areas in the proportion of RYO material found. The shorter mean unburnt tobacco length in the most deprived areas is consistent with more intensive smoking among smokers in those areas. This finding is consistent with other evidence of increased price sensitivity among poorer smokers, and with basic economic theory. Further evidence on observed smoking behavior in the field is necessary to better interpret these preliminary findings.

  17. Preliminary geologic map of the Sleeping Butte volcanic centers

    International Nuclear Information System (INIS)

    The Sleeping Butte volcanic centers comprise two, spatially separate, small-volume (3) basaltic centers. The centers were formed by mildly explosive Strombolian eruptions. The Little Black Peak cone consists of a main scoria cone, two small satellitic scoria mounds, and associated lobate lava flows that vented from sites at the base of the scoria cone. The Hidden Cone center consists of a main scoria cone that developed on the north-facing slope of Sleeping Butte. The center formed during two episodes. The first included the formation of the main scoria cone, and venting of aa lava flows from radial dikes at the northeast base of the cone. The second included eruption of scoria-fall deposits from the summit crater. The ages of the Little Black Peak and the Hidden Cone are estimated to be between 200 to 400 ka based on the whole-rock K-Ar age determinations with large analytical undertainty. This age assignment is consistent with qualitative observations of the degree of soil development and geomorphic degradation of volcanic landforms. The younger episode of the Hidden Cone is inferred to be significantly younger and probably of Late Pleistocene or Holocene age. This is based on the absence of cone slope rilling, the absence of cone-slope apron deposits, and erosional unconformity between the two episodes, the poor horizon- development of soils, and the presence of fall deposits on modern alluvial surfaces. Paleomagnetic data show that the centers record similar but not identical directions of remanent magnetization. Paleomagnetic data have not been obtained for the youngest deposits of the Hidden Cone center. Further geochronology, soils, geomorphic, and petrology studies are planned of the Sleeping Butte volcanic centers 20 refs., 3 figs

  18. Television system for automatic control of electrode position during argon arc welding of large-sized components

    International Nuclear Information System (INIS)

    The article deals with a TV system designed for controlling the position of electrode during argon-arc welding of butt joints with deep bevelling (levelling depth exceeds 10 mm). The operation of the system is based on the processing of bevelling images. The application of the system ensures the travel of the electrode along bevelling axis with an accuracy ±1 mm, minimum. 2 refs., 3 figs

  19. Diffusion welding

    International Nuclear Information System (INIS)

    After a brief recall of the principle, and of the advantages of the method, we give some examples of metallic bonding in a first part where we describe preliminary trials: Ta-Mo, Zr-Zr, Zr-Nb, Nb-stainless steel, Mo-stainless steel, aluminium-aluminium (A5-A5). The second part of the note is devoted to trials on construction elements: on tubular elements for bonding between Mo or Nb on one hand, and stainless steel on the other hand (We indicate in what conditions the bonding are tight and what are their mechanical strength and their resistance to thermic cycles). We indicate, in this chapter, a method to obtain radiation windows in Be welded on an element made of stainless steel. (authors)

  20. Laser Seam welding method

    International Nuclear Information System (INIS)

    The present invention provides a laser seam welding method for welding spacers to be used in nuclear fuel assemblies at a stable quality. Namely, the laser seam welding method comprises irradiating, while moving, laser beams to a portion to be welded. In this case, data of the shapes and characteristics of the portion to be welded are inputted to restrict the range of the welding of the portion to be welded. The power, moving speed, distance to a focal point and energy of the laser beams are controlled in the midway of the range for the welding. Then, a welding nugget having a shape defined to a portion to be welded can be formed thereby enabling to keep the portion to be welded to stable quality. As a result, failed welding can be eliminated, and strength of joint can be guaranteed. In addition, auxiliary products of portions to be welded, for example, springs are not failed by laser beams. As a result, satisfactory spacers can be provided. (I.S.)

  1. Dissimilar welding of WC-Co cemented carbide to Ni42Fe50.9C0.6Mn3.5Nb3 invar alloy by laser-tungsten inert gas hybrid welding

    International Nuclear Information System (INIS)

    Dissimilar welding between cemented carbide and invar alloy was carried out using CO2 laser beam and argon arc as heat sources. η Phase was formed near WC-Co/weld interface and precipitations in the fracture were discovered. In order to disclose the microstructure and mechanical property, firstly, η phase's morphology and composition at interface were investigated using backscattered electron imaging (BEI); and element diffusion across heat affected zone near WC-Co/weld interface was further studied. Secondly, bend strength values of butt joint with different welding parameters were tested by four-point bend strength experiment. Finally, WC migration mechanism was further discussed and the bend strength was measured. The results showed: (1) microstructures consisted of columnar crystals, cellular crystals, eutectic structure and fir-tree crystal and dendritic crystals. The columnar crystals were surrounded by lots of fir-tree crystals. (2) WC migration was driven by stirring effects of welds, high pressure of molten materials and ionized shielding gas, interface reaction and surface tension. (3) η Phases dispersion did not decrease bend strength of butt joint. And the maximum bend strength was 1493.56 MPa, which was attributed to NbC precipitations featured with super-fine fir-tree.

  2. Corrosion resistance of SAW duplex joints welded with high heat input

    Directory of Open Access Journals (Sweden)

    J. Nowacki

    2007-08-01

    Full Text Available Purpose: test if the welding heat input exceeding the recommended values has negative impact on strength properties and corrosion resistance of the executed welded joints as well as description of influence of the heat input of submerged arc welding (SAW of duplex steel UNS S31803 (0.032%C, 23.17%Cr, 9.29%Ni, 3.48%Mo, 0.95%Mn, 0.7%Si, 0.16%N, 0.017P, 0.006%S, 0.11%Cu on welded joints microstructure, particularly average values of ferrite volume fraction, mechanical properties, and corrosion resistance.Design/methodology/approach: analysis of welding heat input influence on mechanical properties, value of ferrite share, and corrosion of test joints has been done. Non-destructive and destructive testing, e. g. visual examinations, microstructure examination, corrosion resistance tests according to ASTM G48 Method A, HV5 hardness tests, impact and tensile test were carried out. For analysis of welding heat input influence on creation of welding imperfections, there were executed welding of sheet of thickness 9, 14, 28 mm. Butt joints on plates of different thickness were made where the applied heat input of welding exceeded the 2.5 kJ/mm value. Maximum heat input level was HI ≤ 3.0; HI ≤ 3.5; HI ≤ 4.0; HI ≤ 4.5; HI ≤ 5.0.Findings: based on the performed tests the conclusion is that according to DNV Rules the welding heat input exceeding the recommended values has no negative impact on strength properties and corrosion resistance of the executed welded joints. It was shown that submerged arc welding of duplex steel with the heat input from 2.5 kJ/mm up to 5.0 kJ/mm has no negative influence on properties of the joints.Research limitations/implications: the welding heat input exceeding the recommended values may influenced the precipitation processes in the HAZ, what need further experiments.Practical implications: application of high value of the welding heat input will be profitable in terms of the welding costs.Originality/value: an

  3. The Investigation on Welding Processes for SUS316LN Tubes Used in Superconducting Magnetic System of EAST

    Institute of Scientific and Technical Information of China (English)

    Wu Jiefeng; Chen Siyue; Weng Peide; Gao Daming

    2005-01-01

    The force flow cooled superconducting cable-in-conduit conductor (CICC) is used in both of EAST toroidal field (TF) and poloidal field (PF) coils. The conductor consists of multi-stage NbTi superconducting cable and 1.5 mm thick square jacket. The cable is pulled through in a thin wall circular jacket and then compacted to square cross-section conductor. The jacket material is SUS316LN austenitic stainless steel seamless tubes (about 10 m each), which is assembled by butt-welding up to 600 m. The results of the welding procedure investigation and quality assurance procedures carrying out are described in this paper.

  4. The Investigation on Welding Processes for SUS316LN Tubes Used in Superconducting Magnetic System of EAST

    Science.gov (United States)

    Wu, Jiefeng; Chen, Siyue; Weng, Peide; Gao, Daming

    2005-08-01

    The force flow cooled superconducting cable-in-conduit conductor (CICC) is used in both of EAST toroidal field (TF) and poloidal field (PF) coils. The conductor consists of multi-stage NbTi superconducting cable and 1.5 mm thick square jacket. The cable is pulled through in a thin wall circular jacket and then compacted to square cross-section conductor. The jacket material is SUS316LN austenitic stainless steel seamless tubes (about 10 m each), which is assembled by butt-welding up to 600 m. The results of the welding procedure investigation and quality assurance procedures carrying out are described in this paper.

  5. Nondestructive testing of welds in steam generators for advanced gas cooled reactors at Heyshamm II and Torness

    International Nuclear Information System (INIS)

    The paper concerns non-destructive testing (NDT) of welds in advanced gas cooled steam generators for Heysham II and Torness nuclear power stations. A description is given of the steam generator. The selection of NDT techniques is also outlined, including the factors considered to ascertain the viability of a technique. Examples are given of applied NDT methods which match particular fabrication processes; these include: microfocus radiography, ultrasonic testing of austenitic tube butt welds, gamma-ray isotope projection system, surface crack detection, and automated radiography. Finally, future trends in this field of NDT are highlighted. (UK)

  6. Friction Stir Lap Welding: material flow, joint structure and strength

    Directory of Open Access Journals (Sweden)

    Z.W. Chen

    2012-12-01

    Full Text Available Friction stir welding has been studied intensively in recent years due to its importance in industrial applications. The majority of these studies have been based on butt joint configuration and friction stir lap welding (FSLW has received considerably less attention. Joining with lap joint configuration is also widely used in automotive and aerospace industries and thus FSLW has increasingly been the focus of FS research effort recently. number of thermomechancal and metallurgical aspects of FSLW have been studied in our laboratory. In this paper, features of hooking formed during FSLW of Al-to-Al and Mg-to-Mg will first be quantified. Not only the size measured in the vertical direction but hook continuity and hooking direction have been found highly FS condition dependent. These features will be explained taking into account the effects of the two material flows which are speed dependent and alloy deformation behaviour dependent. Strength values of the welds will be presented and how strength is affected by hook features and by alloy dependent local deformation behaviours will be explained. In the last part of the paper, experimental results of FSLW of Al-to-steel will be presented to briefly explain how joint interface microstructures affect the fracturing process during mechanical testing and thus the strength. From the results, tool positioning as a mean for achieving maximum weld strength can be suggested.

  7. Effect of welding process, type of electrode and electrode core diameter on the tensile property of 304L austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Akinlabi OYETUNJI

    2014-11-01

    Full Text Available The effect of welding process, type of electrode and electrode core diameter on the tensile property of AISI 304L Austenitic Stainless Steel (ASS was studied. The tensile strength property of ASS welded samples was evaluated. Prepared samples of the ASS were welded under these three various variables. Tensile test was then carried out on the welded samples. It was found that the reduction in ultimate tensile strength (UTS of the butt joint samples increases with increase in core diameter of the electrode. Also, the best electrode for welding 304L ASS is 308L stainless steel-core electrode of 3.2 mm core diameter. It is recommended that the findings of this work can be applied in the chemical, food and oil industries where 304L ASS are predominantly used.

  8. Acute fatal pericardial effusion induced by accidental ingestion of cigarette butts in a dog.

    Science.gov (United States)

    Kim, Jung-Hyun; Lim, Jae-Hyun

    2016-02-01

    A dog was referred for collapse and tachypnea after ingesting cigarette butts. Thoracic radiography and echocardiography indicated pericardial effusion, and an electrocardiogram showed tachycardia, variable QRS complexes, and ventricular premature complexes. This is the first description of fatal pericardial effusion associated with cigarette butt ingestion in a veterinary patient.

  9. On the mechanical behaviour of a butt jointed thermoplastic composite under bending

    NARCIS (Netherlands)

    Baran, I.; Warnet, L.; Akkerman, R.; Thomsen, O.T

    2015-01-01

    In the present work, the mechanical behavior of a recently developed novel butt jointed thermoplastic composite was investigated under bending conditions. The laminated skin and the web were made of carbon fiber (AS4) and polyetherketoneketone (PEKK). The butt joint (filler) was injection molded fro

  10. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

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

  11. Position welding using disk laser-GMA hybrid welding

    OpenAIRE

    C.-H. Kim; H.-S. Lim; J.-K. Kim

    2008-01-01

    Purpose: Position welding technology was developed by using disk laser-GMA hybrid welding in this research.Design/methodology/approach: The effect of hybrid welding parameters such as the shielding gas composition and laser-arc interspacing distance were investigated for the bead-on-plate welding. The pipe girth welding was implemented and the adequate arc welding parameters were selected according to the welding position from a flat position to an overhead position.Findings: The optimized sh...

  12. Residual stress measurement of large scaled welded pipe using neutron diffraction method. Effect of SCC crack propagation and repair weld on residual stress distribution

    International Nuclear Information System (INIS)

    The RESA-1 neutron engineering diffractometer in the JRR-3 (Japan Research Reactor No.3) at the Japan Atomic Energy Agency, which is used for stress measurements, was upgraded to realize residual stress measurements of large scaled mechanical components. A series of residual stress measurements was made to obtain through-thickness residual stress distributions in a Type 304 stainless steel butt-welded pipe of 500A-sch.80 using the upgraded RESA-1 diffractometer. We evaluated effects of crack propagation such as stress corrosion cracking (SCC) and a part-circumference repair weld on the residual stress distributions induced by girth welding. Measured residual stress distributions near original girth weld revealed good agreement with typical results shown in some previous works using finite element method, deep hole drilling as well as neutron diffraction. After introducing a mock crack with 10 mm depth in the heat affected zone on the inside wall of the pipe by electro discharge machining, the axial residual stresses were found to be released in the part of the mock crack. However, changes in the through-wall bending stress component and the self-equilibrated stress component were negligible and hence the axial residual stress distribution in the ligament was remained in the original residual stresses near girth weld without the mock crack. Furthermore, changes in hoop and radial residual stress were also small. The residual stress distributions after a part repair welding on the outer circumference of the girth weld were significantly different from residual stress distributions near the original girth weld. The through-thickness average axial residual stress was increased due to increase of the tensile membrane stress and mitigation of the bending stress after repair welding. Throughout above studies, we evidenced that the neutron diffraction technique is useful and powerful tool for measuring residual stress distributions in large as well as thick mechanical

  13. Welding of girders to insert plates of composite steel-concrete structure of tower in Kuwait

    Directory of Open Access Journals (Sweden)

    A. Lisiecki

    2007-07-01

    Full Text Available Purpose: A study of influence of preheating and MMA welding technique of tee-joints of plate girders to insert plates of a composite steel-concrete structure of the telecommunication tower, on the properties and quality of the concrete in the region of the insert plate has been carried out.Design/methodology/approach: Studies of thermo-mechanical phenomena during manual arc welding MMA of tee-joints between plate girders and insert plates were carried out to identify possible sources of the concrete damage due to high welding temperature and stresses.Findings: It was shown that MMA welding at vertical-up position, by a rutile coated electrode of diameter 3,2 [mm], at welding current 110-120 [A], of the butt welds of tee-joints of girders and the insert plate does not cause any harmful and damaging effect to concrete, which temperature in a region of the contact with the bottom surface of the insert plate does not exceed 240 [°C] during full cycle of welding. Tensile and compression stresses of concrete are transmitted mainly by anchoring bars, fixed in concrete and also by reinforcing fabric of concrete, and do not cause any cracks of concrete.Research limitations/implications: To achieve more consistent results of the numerical analysis of stresses and deformation distribution in the insert plate with experimental results, it is necessary to calculate plastic deformation of materials and also take into consideration nonlinear change of yield point (plasticity as a function of temperature.Practical implications: The technology was applied for welding of the girders to insert plates of the telecommunication tower in Kuwait.Originality/value: Welding procedure specification ensuring high quality of the welded joints of girders and insert plate of composite steel-concrete structure.

  14. Welding of girders to insert plates of composite steel-concrete structure

    Directory of Open Access Journals (Sweden)

    A. Klimpel

    2007-09-01

    Full Text Available Purpose: of this paper: A study of influence of preheating and MMA welding technique of tee-joints of plate girders to insert plates of a composite steel-concrete structure of the telecommunication tower, on the properties and quality of the concrete in the region of the insert plate has been carried out.Design/methodology/approach: Studies of thermo-mechanical phenomena during manual arc welding MMA of tee-joints between plate girders and insert plates were carried out to identify possible sources of the concrete damage due to high welding temperature and stresses.Findings: It was shown that MMA welding at vertical-up position, by a rutile coated electrode of diameter 3,2 [mm], at welding current 110-120 [A], of the butt welds of tee-joints of girders and the insert plate does not cause any harmful and damaging effect to concrete, which temperature in a region of the contact with the bottom surface of the insert plate does not exceed 240 [˚C] during full cycle of welding. Tensile and compression stresses of concrete are transmitted mainly by anchoring bars, fixed in concrete and also by reinforcing fabric of concrete, and do not cause any cracks of concrete.Research limitations/implications: To achieve more consistent results of the numerical analysis of stresses and deformation distribution in the insert plate with experimental results, it is necessary to calculate plastic deformation of materials and also take into consideration nonlinear change of yield point (plasticity as a function of temperature.Practical implications: The technology was applied for welding of the girders to insert plates of the telecommunication tower in Kuwait.Originality/value: Welding procedure specification ensuring high quality of the welded joints of girders and insert plate of composite steel-concrete structure.

  15. Some Studies of Optimal Process Parameters For Solid Wire Gas Metal Arc Welding Using Neural Network Technique And Simulation Using Ansys

    Directory of Open Access Journals (Sweden)

    Saritprava Sahoo

    2013-08-01

    Full Text Available GMAW (Gas Metal Arc Welding is an arc welding process which is widely used in industry to join the metals. In this present work we have investigated the effect of varying welding parameters on the weld bead quality of Mild Steel flat having 12mm thickness. The chosen input parameters for the study are Welding Voltage, Welding Current and the travel speed of welding torch. The output parameters chosen are Weld Bead Width, Weld Bead Height, Depth of Penetration and Depth of Heat Affected Zone (HAZ. The four levels of experimental set-ups for each of the input parameters are considered and other process parameters are kept constant for the study. Hence the total numbers of experimental set-ups are 64 and the corresponding values of output parameters are found. As this is a Multi-Response Problem, it is being optimized to Single-Response Problem using Weighted Principal Components (WPC Method. Artificial Neural Networks (sANN, Error Back Propagation Procedure is being used for the prediction of optimal process parameters for GMAW process in this present work. The finite element analysis of residual stresses in butt welding of two similar plates is performed with the ANSYS software.

  16. Microstructures and mechanical properties of magnesium alloy and stainless steel weld-joint made by friction stir lap welding

    International Nuclear Information System (INIS)

    Highlights: → Friction stir lap welding technology with cutting pin was successfully employed to form lap joint of magnesium and steel. → The cutting pin made the lower steel participate in deformation and the interface was no longer flat. → A saw-toothed structure formed due to a mechanical mixing of the magnesium and steel was found at the interface. → A high-strength joint was produced which fractured in the magnesium side. -- Abstract: Friction stir lap welding was conducted on soft/hard metals. A welding tool was designed with a cutting pin of rotary burr made of tungsten carbide, which makes the stirring pin possible to penetrate and cut the surface layer of the hard metal. Magnesium alloy AZ31 and stainless steel SUS302 were chosen as soft/hard base metals. The structures of the joining interface were analyzed by scanning electron microscopy (SEM). The joining strength was evaluated by tensile shear test. The results showed that flower-like interfacial morphologies were presented with steel flashes and scraps, which formed bonding mechanisms of nail effect by long steel flashes, zipper effect by saw-tooth structure and metallurgical bonding. The shear strength of the lap joint falls around the shear strength of butt joint of friction stir welded magnesium alloy.

  17. Quantitative analysis of the DNA distribution on cigarette butt filter paper.

    Science.gov (United States)

    Casey, Lisa; Engen, Sarah; Frank, Greg

    2013-03-01

    The distribution of DNA on the filter paper of smoked cigarette butts was quantitatively mapped using real-time quantitative polymerase chain reaction. The filter papers from smoked cigarette butts collected from indoor and outdoor sources were sliced into equal pieces and the amount of DNA on each slice was determined. This study found that the cigarette butt filter papers sliced parallel to the seam of the cigarette had more uniformly distributed DNA on the slices and in most cases, there was enough DNA on each slice to obtain a complete DNA profile. The perpendicular slices had a less uniform pattern of distribution and some slices did not have enough DNA to obtain an interpretable DNA profile. Cigarette butts found indoors also had more DNA per cigarette on average than cigarette butts found outdoors.

  18. Investigation and Analysis of Weld Induced Residual Stresses in Two Dissimilar Pipes by Finite Element Modeling

    Science.gov (United States)

    Nadimi, S.; Khoushehmehr, R. J.; Rohani, B.; Mostafapour, A.

    In the present study, Manual Metal Arc Welding (MMAW) of austenitic stainless steel to carbon steel were studied. The Schaeffler diagram were used in determining suitable filler metal for this process and then the finite element analysis of residual stresses in butt welding of two dissimilar pipes is performed with the commercial software ANSYS, which includes moving heat source, material deposit, temperature dependant material properties, metal plasticity and elasticity, transient heat transfer and mechanical analysis. The residual stresses distribution and magnitude in the hoop and axial directions in the inner and outer surfaces of two dissimilar pipes were obtained. Welding simulation considered as a sequentially coupled thermo-mechanical analysis and the element birth and death technique was employed for simulation of filler metal deposition.

  19. Numerical modelling of liquid material flow in the fusion zone of hybrid welded joint

    Directory of Open Access Journals (Sweden)

    M. Kubiak

    2011-04-01

    Full Text Available This paper concerns modelling of liquid metal motion in the fusion zone of laser-arc hybrid butt-welded plate. Velocity field in the fusion zone and temperature field in welded plate were obtained on the basis of the solution of mass, momentum and energy conservationsequations. Differential equations were solved using Chorin’s projection method and finite volume method. Melting and solidificationprocesses were taken into account in calculations assuming fuzzy solidification front where fluid flow is treated as a flow through porous medium. Double-ellipsoidal heat source model was used to describe electric arc and laser beam heat sources. On the basis of developed solution algorithms simulation of hybrid welding process was performed and the influence of liquid metal motion in the fusion zone on the results of calculations was analyzed.

  20. The influence of distance between heat sources in hybrid welded plate on fusion zone geometry

    Directory of Open Access Journals (Sweden)

    W. Piekarska

    2011-04-01

    Full Text Available Results of numerical analysis into temperature field in hybrid laser-arc welding process with motion of liquid material taken intoaccount are presented in this study. On the basis of obtained results the influence of the distance between the arc foot point and the laserbeam focal point on the shape and size of fusion zone in hybrid butt welded plate. Temperature field was calculated on the basis ofsolution of transient heat transfer equation. The solution of Navier-Stokes equation allowed for simulation of fluid flow in the fusion zone.Fuzzy solidification front was assumed in calculations with linear approximation of solid fraction in solid-liquid region where liquidmaterial flow through porous medium is taken into consideration. Numerical solution algorithms were developed for three-dimensionalproblem. Established numerical model of hybrid welding process takes into account different electric arc and laser beam heat sourcespower distributions.

  1. Development of an automatic post-weld inspection system based on laser vision

    Institute of Scientific and Technical Information of China (English)

    Fu Xibin; Lin Sanbao; Fan Chenglei; Yang Chunli; Luo Lu

    2008-01-01

    In order to overcome the limitations of manual post-weld visual inspection approach, an automated inspection system is developed which uses three-dimensional laser vision system based on the principle of optical triangulation. The system hardware consists of a modular development kit (MDK), a computer, an actuating mechanism and so on. In image processing algorithms, extraction accuracy of centric line of laser stripe is the critical factor that determines the system performance. So according to the features of laser stripe image, a novel algorithm is developed to detect the central line of laser stripe fast and accurately. Experiments have demonstrated that this system can be used in various weld features inspection of both butt and fillet types of weld. Compared with traditional manual inspection method, this method has obvious dominance. The three-dimensional reconstruction result shows that this system has high accuracy and reliability.

  2. Fatigue Crack Growth Behavior of Gas Metal Arc Welded AISI 409 Grade Ferritic Stainless Steel Joints

    Science.gov (United States)

    Lakshminarayanan, A. K.; Shanmugam, K.; Balasubramanian, V.

    2009-10-01

    The effect of filler metals such as austenitic stainless steel, ferritic stainless steel, and duplex stainless steel on fatigue crack growth behavior of the gas metal arc welded ferritic stainless steel joints was investigated. Rolled plates of 4 mm thickness were used as the base material for preparing single ‘V’ butt welded joints. Center cracked tensile specimens were prepared to evaluate fatigue crack growth behavior. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN was used to evaluate the fatigue crack growth behavior of the welded joints. From this investigation, it was found that the joints fabricated by duplex stainless steel filler metal showed superior fatigue crack growth resistance compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Higher yield strength and relatively higher toughness may be the reasons for superior fatigue performance of the joints fabricated by duplex stainless steel filler metal.

  3. Comparing Laser Welding Technologies with Friction Stir Welding for Production of Aluminum Tailor-Welded Blanks

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Carsley, John; Carlson, Blair; Hartfield-Wunsch, Susan; Pilli, Siva Prasad

    2014-01-15

    A comparison of welding techniques was performed to determine the most effective method for producing aluminum tailor-welded blanks for high volume automotive applications. Aluminum sheet was joined with an emphasis on post weld formability, surface quality and weld speed. Comparative results from several laser based welding techniques along with friction stir welding are presented. The results of this study demonstrate a quantitative comparison of weld methodologies in preparing tailor-welded aluminum stampings for high volume production in the automotive industry. Evaluation of nearly a dozen welding variations ultimately led to down selecting a single process based on post-weld quality and performance.

  4. 75 FR 60804 - Notice of Availability of the Final Environmental Impact Statement for the West Butte Wind Power...

    Science.gov (United States)

    2010-10-01

    ... Butte Wind Power Right-of-Way, Crook and Deschutes Counties, OR AGENCY: Bureau of Land Management... prepared a Final Environmental Impact Statement (EIS) for the West Butte Wind Power Right-of-Way and by... Federal Register notice. FOR FURTHER INFORMATION CONTACT: Steve Storo, BLM West Butte Wind Power Right...

  5. Characteristics of Welding Fumes

    OpenAIRE

    Johansson, Gerd; Malmqvist, Klas; Bohgard, Mats; Akselsson, Roland

    1981-01-01

    The aerosols from 13 common electric arc welding processes have been characterized regarding total emission, particle size distribution, elemental composition and, when applicable, the oxidation state of chromium. The characterizations have been performed systematically for different combinations of welding current and welding voltage.

  6. Instructional Guidelines. Welding.

    Science.gov (United States)

    Fordyce, H. L.; Doshier, Dale

    Using the standards of the American Welding Society and the American Society of Mechanical Engineers, this welding instructional guidelines manual presents a course of study in accordance with the current practices in industry. Intended for use in welding programs now practiced within the Federal Prison System, the phases of the program are…

  7. Welding Course Curriculum.

    Science.gov (United States)

    Genits, Joseph C.

    This guide is intended for use in helping students gain a fundamental background on the major aspects of the welding trade. The course emphasis is on mastery of the manipulative skills necessary to develop successful welding techniques and on acquisition of an understanding of the specialized tools and equipment used in welding. The first part…

  8. Coil Welding Aid

    Science.gov (United States)

    Wiesenbach, W. T.; Clark, M. C.

    1983-01-01

    Positioner holds coil inside cylinder during tack welding. Welding aid spaces turns of coil inside cylinder and applies contact pressure while coil is tack-welded to cylinder. Device facilitates fabrication of heat exchangers and other structures by eliminating hand-positioning and clamping of individual coil turns.

  9. Analysis of Welding Technology about Bimetal-lined Pipe%双金属复合管焊接技术分析

    Institute of Scientific and Technical Information of China (English)

    李发根; 孟繁印; 郭霖; 常泽亮

    2014-01-01

    双金属复合管的焊接接头结构复杂,焊接难度较大。通过对双金属复合管端面处理工艺和对接焊接工艺分析,提出了端部堆焊工艺较端部封焊工艺易于焊接但不够经济的现状,指出对于薄壁小直径双金属复合管道的焊接宜采用合金焊丝对接焊工艺,而对于厚壁大直径双金属复合管道则宜采用过渡焊方法焊接。另外,还分析了当前的焊接评定标准,强调了制定适宜复合管的焊接工艺评定标准的必要性。%The welded joint structure of bimetal-lined pipe is complex and is difficult to be welded. Through analysis on pipe end treatment and butt welding procedure for bimetal-lined pipe, it indicated the overlaying was easy to weld but not to be economic comparing with seal welding, it also pointed out that alloy wire butt welding might be used to weld thin wall and small diameter bimetal-lined pipes, while for thick wall and large diameter pipes the buffer layer welding method can be used. Additionally, the existing standards about welding procedure qualification were analyzed in the paper, and the necessity of drafting welding procedure qualification standard about bimetal-lined pipes was emphasized.

  10. High temperature fatigue experiments on welded stainless steel tubular elements

    International Nuclear Information System (INIS)

    A test rig has been designed to perform high temperature fatigue experiments on AISI 304 stainless steel tubular elements of 500 mm length, 60.3 mm outer diameter and 2 mm thickness; they are composed by two butt welded tubular elements with welded end flanges. During the experiments it is possible to control the axial strain range, the strain rate and the hold time; the specimen temperature is obtained by an inner heating device, controlled by a series of measuring thermocouples; until now the imposed temperature is 6500C. A preliminary series of experiments has been carried out, with the aim at getting informations for a proper development of the main experimental program, while in the meantime the adjustment of the specimen manufacturing process and its characterization have been performed. Each specimen is welded on the same TIG welding rig, which accounts both for a uniformly reliable welding process and for a proper alignment of the tubular elements. The specimens are then marked by a high precision grid which allows a measurement of the residual localized plastic strain along some generatrix of the specimen and on its thickness. The basic fatigue data have to be measured through a series of standard tests carried out on small size specimens obtained either from the base material and around the welded, heat affected zone. It is also planned to carry out a detailed study on the crack surfaces and to use acoustical emission techniques to properly assess the initial crack propagation. The first results show a marked reduction of the number of cycles at failure, if compared with existing data about small size specimens; the measurement of residual plastic strains shows clearly non-uniform distribution of the plastic zones

  11. Role of the micro/macro structure of welds in crack nucleation and propagation in aerospace aluminum-lithium alloy

    Science.gov (United States)

    Talia, George E.

    1996-01-01

    Al-Li alloys offer the benefits of increased strength, elastic modulus and lower densities as compared to conventional aluminum alloys. Martin Marietta Laboratories has developed an Al-Li alloy designated 2195 which is designated for use in the cryogenic tanks of the space shuttle. The Variable Polarity Plasma Arc (VPPA) welding process is currently being used to produce these welds [1]. VPPA welding utilizes high temperature ionized gas (plasma) to transfer heat to the workpiece. An inert gas, such as Helium, is used to shield the active welding zone to prevent contamination of the molten base metal with surrounding reactive atmospheric gases. [1] In the Space Shuttle application, two passes of the arc are used to complete a butt-type weld. The pressure of the plasma stream is increased during the first pass to force the arc entirely through the material, a practice commonly referred to as keyholing. Molten metal forms on either side of the arc and surface tension draws this liquid together as the arc passes. 2319 Al alloy filler material may also be fed into the weld zone during this pass. During the second pass, the plasma stream pressure is reduced such that only partial penetration of the base material is obtained. Al 2319 filler material is added during this pass to yield a uniform, fully filled welded joint. This additional pass also acts to alter the grain structure of the weld zone to yield a higher strength joint.

  12. Finite element thermal analysis of the fusion welding of a P92 steel pipe

    Directory of Open Access Journals (Sweden)

    A. H. Yaghi

    2012-05-01

    Full Text Available Fusion welding is common in steel pipeline construction in fossil-fuel power generation plants. Steel pipes in service carry steam at high temperature and pressure, undergoing creep during years of service; their integrity is critical for the safe operation of a plant. The high-grade martensitic P92 steel is suitable for plant pipes for its enhanced creep strength. P92 steel pipes are usually joined together with a similar weld metal. Martensitic pipes are sometimes joined to austenitic steel pipes using nickel based weld consumables. Welding involves severe thermal cycles, inducing residual stresses in the welded structure, which, without post weld heat treatment (PWHT, can be detrimental to the integrity of the pipes. Welding residual stresses can be numerically simulated by applying the finite element (FE method in Abaqus. The simulation consists of a thermal analysis, determining the temperature history of the FE model, followed by a sequentially-coupled structural analysis, predicting residual stresses from the temperature history.

    In this paper, the FE thermal analysis of the arc welding of a typical P92 pipe is presented. The two parts of the P92 steel pipe are joined together using a dissimilar material, made of Inconel weld consumables, producing a multi-pass butt weld from 36 circumferential weld beads. Following the generation of the FE model, the FE mesh is controlled using Model Change in Abaqus to activate the weld elements for each bead at a time corresponding to weld deposition. The thermal analysis is simulated by applying a distributed heat flux to the model, the accuracy of which is judged by considering the fusion zones in both the parent pipe as well as the deposited weld metal. For realistic fusion zones, the heat flux must be prescribed in the deposited weld pass and also the adjacent pipe elements. The FE thermal results are validated by comparing experimental temperatures measured by five thermocouples on the

  13. The analysis of Ukraine E.O.Paton Electric Welding Institute's three-phase symmetric Device%乌克兰巴顿电焊研究所三相对称装置的性能分析

    Institute of Scientific and Technical Information of China (English)

    王志伟; 易琼

    2012-01-01

    In this article,author analyze the Ukriane E.O.Paton Electric Welding Institute's three-phase symmetric device design features and functions.Though practice,it can proved that those functions will effect rail flash butt welding process.With experiment of model machine,find out that this three-phase symmetric device badly hurt the stability of rail flash butt welding process,and cannot change welding waveform,it unsuitable for rail flash butt welding.%从理论上分析了乌克兰巴顿电焊研究所研制的三相对称装置的设计特点和性能,并从实验上证实了这些性能对钢轨闪光焊接的作用和影响,通过样机试验,发现该三相对称装置对钢轨闪光焊的稳定性有不良影响,无法改变焊接波形,不适合应用于钢轨闪光焊.

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

    OpenAIRE

    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 Hz indicates excessive welding through; the occurrence of voltage variations with only frequency components above 100 Hz indicates in sufficient welding through; a welding process showing proper we...

  15. Effect of welding parameters of Gas Metal Arc welding on weld bead geometry: A Review

    Directory of Open Access Journals (Sweden)

    Pushp Kumar Baghel

    2012-07-01

    Full Text Available Weld quality comprises bead geometry and its microstructure, which influence the mechanical properties of the weld. This brief review illustrates the effect of pulse parameters on weld quality. The responsefactors, namely bead penetration, weld width, reinforcement height, weld penetration shape factor and weld reinforcement form factor as affected by arc voltage, wire feed rate, welding speed, gas flow rate and nozzle-toplate distance has also been analysed

  16. Press formability YAG laser welded TRIP/DP tailored blanks

    Science.gov (United States)

    Nagasaka, A.; Sugimoto, K. I.; Kobayashi, M.; Makii, K.; Ikeda, S.

    2004-06-01

    In the present work, to improve the press formability of the combination of the TRIP steel and ferrite-martensite dual-phase (DP) steel, the mechanical properties and press formability (stretch-formability) of YAG laser welded TRIP/DP tailored blanks were investigated. An as-cold-rolled sheet steel with the chemical composition of (0.1 0.3)C 1.5Si 1.5Mn (mass%) was used in this study. For comparison, 0.14C 0.22Si 1.78Mn (mass%) DP steel was also prepared. The quenched DP steel is called MDP0, and the tempered MDP0 steel is called MDP4. For butt welding, the blank obtained after the heat treatment was cut using a fine cutter, and YAG laser processing equipment was used. The press formability was evaluated from the maximum stretch-height (Hmax). Tensile tests and stretch forming tests have been conducted for laser butt welded joints obtained from the combination of the different steel. The Hmax value of the MDP0 steel was not controlled at the strength level of the DP steel, and was not different from the Hmax value of the MDP4 steel. It is thought that this was assisted to TRIP of the TDP steel because the tensile strength of the TDP steel is consequentially lower than that of the MDP0 steel. High ductility and the high stretch-formability were able to be secured by the high strength TRIP/DP tailored blanks.

  17. Optically controlled welding system

    Science.gov (United States)

    Gordon, Stephen S. (Inventor)

    1989-01-01

    An optically controlled welding system (10) wherein a welding torch (12) having through-the-torch viewing capabilities is provided with an optical beam splitter (56) to create a transmitted view and a reflective view of a welding operation. These views are converted to digital signals which are then processed and utilized by a computerized robotic welder (15) to make the welding torch responsive thereto. Other features includes an actively cooled electrode holder (26) which minimizes a blocked portion of the view by virtue of being constructed of a single spoke or arm (28) and a weld pool contour detector (14) comprising a laser beam directed onto the weld pool with the position of specular radiation reflected therefrom being characteristic of a penetrated or unpenetrated condition of the weld pool.

  18. Friction stir welding of F82H steel for fusion applications

    Science.gov (United States)

    Noh, Sanghoon; Ando, Masami; Tanigawa, Hiroyasu; Fujii, Hidetoshi; Kimura, Akihiko

    2016-09-01

    In the present study, friction stir welding was employed to join F82H steels and develop a potential joining technique for a reduced activation ferritic/martensitic steel. The microstructures and mechanical properties on the joint region were investigated to evaluate the applicability of friction stir welding. F82H steel sheets were successfully butt-joined with various welding parameters. In welding conditions, 100 rpm and 100 mm/min, the stirred zone represented a comparable hardness distribution with a base metal. Stirred zone induced by 100 rpm reserved uniformly distributed precipitates and very fine ferritic grains, whereas the base metal showed a typical tempered martensite with precipitates on the prior austenite grain boundary and lath boundary. Although the tensile strength was decreased at 550 °C, the stirred zone treated at 100 rpm showed comparable tensile behavior with base metal up to 500 °C. Therefore, friction stir welding is considered a potential welding method to preserve the precipitates of F82H steel.

  19. A Study of Microstructure and Mechanical Properties of Grade 91 Steel A-TIG Weld Joint

    Science.gov (United States)

    Arivazhagan, B.; Vasudevan, M.

    2013-12-01

    In the present study, A-TIG welding was carried out on grade 91 steel plates of size 220 × 110 × 10 mm using the in-house developed activated flux to produce butt-joints. The room-temperature impact toughness of the A-TIG as-welded joint was low due to the presence of untempered martensite matrix despite the low microinclusion density caused by activated flux and also low δ-ferrite (Toughness after postweld heat treatment (PWHT) at 760 °C-2 h was 20 J as against the required value of 47 J as per the specification EN: 1557:1997. However, there was a significant improvement in impact toughness after PWHT at 760 °C for 3 h. The improvement in toughness was attributed to softening of martensite matrix caused by precipitation of carbides due to tempering reactions. The precipitates are of type M23C6, and they are observed at grain boundary as well as within the grains. The A-TIG-processed grade 91 steel weld joint was found to meet the toughness requirements after PWHT at 760 °C-3 h. Observations of fracture surfaces using SEM revealed that the as-welded joint failed by brittle fracture, whereas post-weld heat-treated weld joints failed by decohesive rupture mode.

  20. Microstructural Evolution and Fracture Behavior of Friction-Stir-Welded Al-Cu Laminated Composites

    Science.gov (United States)

    Beygi, R.; Kazeminezhad, Mohsen; Kokabi, A. H.

    2014-01-01

    In this study, we attempt to characterize the microstructural evolution during friction stir butt welding of Al-Cu-laminated composites and its effect on the fracture behavior of the joint. Emphasis is on the material flow and particle distribution in the stir zone. For this purpose, optical microscopy and scanning electron microscopy (SEM) images, energy-dispersive spectroscopy EDS and XRD analyses, hardness measurements, and tensile tests are carried out on the joints. It is shown that intermetallic compounds exist in lamellas of banding structure formed in the advancing side of the welds. In samples welded from the Cu side, the banding structure in the advancing side and the hook formation in the retreating side determine the fracture behavior of the joint. In samples welded from the Al side, a defect is formed in the advancing side of the weld, which is attributed to insufficient material flow. It is concluded that the contact surface of the laminate (Al or Cu) with the shoulder of the FSW tool influences the material flow and microstructure of welds.

  1. Incidence of root and butt rot in consecutive rotations of Picea abies

    Energy Technology Data Exchange (ETDEWEB)

    Roennberg, Jonas [Swedish Univ. of Agricultural Sciences, Alnarp (Sweden). Southern Swedish Forest Research Centre; Joergensen, B.B. [Danish Forest and Landscape Research Inst., Hoersholm (Denmark)

    2000-07-01

    The incidence of butt rot in two consecutive rotations of Norway spruce [Picea abies (L.) Karst.] in 28 permanent sample plots at four different sites in Denmark was evaluated. Incidence of butt rot was estimated by visual examination of stumps at final felling of the previous rotation and by examination of bore cores taken at the butt from a random sample of trees before first thinning of the subsequent rotation. There was no correlation between the incidence of butt rot at final felling of the previous rotation of Norway spruce and the incidence of butt rot at first thinning of the subsequent rotation of Norway spruce. The incidence of butt rot at final felling was between 19 and 100%, and at first thinning between 0 and 20%. The S-form of Heterobasidion annosum (Fr.) Bref. was the most commonly found decay-causing organism at all sites. Root systems of 28 trees without decay at stump height in the present rotation were excavated to estimate the incidence of root rot. Heterobasidion annosum was found in only one root. Resinicium bicolor (Alb. and Schw. ex Fr.) Parm. was found in 25% of the excavated root systems. The result of the study shows that the incidence of butt rot at first thinning of Norway spruce is not necessarily higher on sites where the previous rotation was heavily infected than on sites where infection in the previous rotation was low.

  2. Position welding using disk laser-GMA hybrid welding

    Directory of Open Access Journals (Sweden)

    C.-H. Kim

    2008-05-01

    Full Text Available Purpose: Position welding technology was developed by using disk laser-GMA hybrid welding in this research.Design/methodology/approach: The effect of hybrid welding parameters such as the shielding gas composition and laser-arc interspacing distance were investigated for the bead-on-plate welding. The pipe girth welding was implemented and the adequate arc welding parameters were selected according to the welding position from a flat position to an overhead position.Findings: The optimized shielding gas composition and laser-arc interspacing distance for disk laser-GMA hybrid welding were 80% Ar- 20% CO2 and 2mm, respectively for the bead-on-plate welding. The sound welds could be achieved even in the pipe girth welding, but the proper joint shape should be prepared.Research limitations/implications: The laser-arc hybrid welding was implemented for pipe girth welding as a kind of 3-dimensional laser welding and the process parameters could be optimized according to the various target materials and sizes.Practical implications: The optimized process parameters for the disk laser-arc hybrid welding can extend the application of the laser hybrid welding technology.Originality/value: This research showed the possibility of the disk laser-GMA hybrid welding as new pipe girth welding technique. The behaviour of molten pool and droplet transfer could enhance understanding of the hybrid welding.

  3. BUSTED BUTTE TEST FACILITY GROUND SUPPORT CONFIRMATION ANALYSIS

    International Nuclear Information System (INIS)

    The main purpose and objective of this analysis is to confirm the validity of the ground support design for Busted Butte Test Facility (BBTF). The highwall stability and adequacy of highwall and tunnel ground support is addressed in this analysis. The design of the BBTF including the ground support system was performed in a separate document (Reference 5.3). Both in situ and seismic loads are considered in the evaluation of the highwall and the tunnel ground support system. In this analysis only the ground support designed in Reference 5.3 is addressed. The additional ground support installed (still work in progress) by the constructor is not addressed in this analysis. This additional ground support was evaluated by the A/E during a site visit and its findings and recommendations are addressed in this analysis

  4. The Western Environmental Technology Office (WETO), Butte, Montana, technology summary

    International Nuclear Information System (INIS)

    This document has been prepared by the DOE Environmental Management (EM) Office of Technology Development (OTD) to highlight its research, development, demonstration, testing, and evaluation activities funded through the Western Environmental Technology Office (WETO) in Butte, Montana. Technologies and processes described have the potential to enhance DOE's cleanup and waste management efforts, as well as improve US industry's competitiveness in global environmental markets. WETO's environmental technology research and testing activities focus on the recovery of useable resources from waste. Environmental technology development and commercialization activities will focus on mine cleanup, waste treatment, resource recovery, and water resource management. Since the site has no record of radioactive material use and no history of environmental contamination/remediation activities, DOE-EM can concentrate on performing developmental and demonstration activities without the demands of regulatory requirements and schedules. Thus, WETO will serve as a national resource for the development of new and innovative environmental technologies

  5. Remote Operations and Nightly Automation of The Red Buttes Observatory

    CERN Document Server

    Kasper, David H; Yeigh, Rex R; Kobulnicky, Henry A; Jang-Condell, Hannah; Kelley, Mark; Bucher, Gerald J; Weger, James S

    2016-01-01

    We have implemented upgrades to the University of Wyoming's Red Buttes Observatory (RBO) to allow remote and autonomous operations using the 0.6 m telescope. Detailed descriptions of hardware and software components provide sufficient information to guide upgrading similarly designed telescopes. We also give a thorough description of the automated and remote operation modes with intent to inform the construction of routines elsewhere. Because the upgrades were largely driven by the intent to perform exoplanet transit photometry, we discuss how this science informed the automation process. A sample exoplanet transit observation serves to demonstrate RBO's capability to perform precision photometry. The successful upgrades have equipped a legacy observatory for a new generation of automated and rapid-response observations.

  6. Enabling Remote and Automated Operations at The Red Buttes Observatory

    Science.gov (United States)

    Ellis, Tyler G.; Jang-Condell, Hannah; Kasper, David; Yeigh, Rex R.

    2016-01-01

    The Red Buttes Observatory (RBO) is a 60 centimeter Cassegrain telescope located ten miles south of Laramie, Wyoming. The size and proximity of the telescope comfortably make the site ideal for remote and automated observations. This task required development of confidence in control systems for the dome, telescope, and camera. Python and WinSCP script routines were created for the management of science images and weather. These scripts control the observatory via the ASCOM standard libraries and allow autonomous operation after initiation.The automation tasks were completed primarily to rejuvenate an aging and underutilized observatory with hopes to contribute to an international exoplanet hunting team with other interests in potentially hazardous asteroid detection. RBO is owned and operated solely by the University of Wyoming. The updates and proprietor status have encouraged the development of an undergraduate astronomical methods course including hands-on experience with a research telescope, a rarity in bachelor programs for astrophysics.

  7. The Western Environmental Technology Office (WETO) Butte, Montana

    International Nuclear Information System (INIS)

    This document has been prepared to highlight the research, development, demonstration, testing and evaluation activities funded through the Western Environmental Technology Office (WETO) in Butte, Montana. Technologies and processes described have the potential to enhance DOE's cleanup and waste management efforts, as well as improve US industry's competitiveness in global environmental markets. This information has been assembled from recently produced Office of Technology Development (OTD) documents which highlight technology development activities within each of the OTD program elements. Projects include: Heavy metals contaminated soil project; In Situ remediation integrated program; Minimum additive waste stabilization program; Resource recovery project; Buried waste integrated demonstration; Mixed waste integrated program; Pollution prevention program; and Mine waste technology program

  8. Remote Operations and Nightly Automation of the Red Buttes Observatory

    Science.gov (United States)

    Kasper, David H.; Ellis, Tyler G.; Yeigh, Rex R.; Kobulnicky, Henry A.; Jang-Condell, Hannah; Kelley, Mark; Bucher, Gerald J.; Weger, James S.

    2016-10-01

    We have implemented upgrades to the University of Wyoming’s Red Buttes Observatory (RBO) to allow remote and autonomous operations using the 0.6 m telescope. Detailed descriptions of hardware and software components provide sufficient information to guide upgrading similarly designed telescopes. We also give a thorough description of the automated and remote operation modes with intent to inform the construction of routines elsewhere. Because the upgrades were largely driven by the intent to perform exoplanet transit photometry, we discuss how this science informed the automation process. A sample exoplanet transit observation serves to demonstrate RBO’s capability to perform precision photometry. The successful upgrades have equipped a legacy observatory for a new generation of automated and rapid-response observations.

  9. [Clarification of a break-in theft crime by multiplex PCR analysis of cigarette butts].

    Science.gov (United States)

    Hochmeister, M; Haberl, J; Borer, V; Rudin, O; Dirnhofer, R

    1995-01-01

    This paper describes the first use of multiplex PCR amplification kits for the analysis of DNA extracted from cigarette butts in a criminal case. Two suspects could be excluded as potential contributors to the samples, whereas the multi locus PCR-based DNa profile derived from the cigarette butts was consistent with a DNA profile derived from a third suspect. For identity testing in criminal cases where cigarette butts are involved, commercially available PCR amplification kits provide currently the most powerful tool. Furthermore this PCR-based analysis can be implemented into most application orientated laboratories.

  10. Development of temper bead welding by under water laser welding

    International Nuclear Information System (INIS)

    Toshiba has developed temper bead welding by under water laser welding as SCC counter measure for aged components in PWR and BWR nuclear power plants. Temper bead welding by under water laser welding technique recovers toughness of low alloy steel reactor vessel by employing proper the number of cladding layers and their welding conditions. In this report, some evaluation results of material characteristics of temper bead welded low alloy steel are presented. (author)

  11. New welding technologies for car body frame welding

    OpenAIRE

    T. Węgrzyn; J. Piwnik; R. Burdzik; G. Wojnar; D. Hadryś

    2012-01-01

    Purpose: of that paper was analysing main welding process for car body welding. The main reason of it was investigate possibilities of getting varied amount of acicular ferrite (AF) in WMD (weld metal deposit). High amount of acicular ferrite influences positively impact toughness of weld. For optimal amount of AF it is necessary to have optimal chemical composition in WMD. Important role plays especially Ni. There were also tested new welding technology: welding with micro-jet cooling.Design...

  12. Peculiarities of weld crystallization in the process of laser welding

    International Nuclear Information System (INIS)

    The effect of the process of laser welding of 08Kh18N10T steel on weld formation and crystallization is investigated. It is shown that at vsub(weld.) >= 40 m/h the lower sinked part of the weldpool stretched along the weld axis is crystallized quickly. Improvement in hot cracking resistance of weld metal in the process of laser welding results from the additional feeding with a liquid metal of the crystallizing part of the weldpool

  13. Comparison of Measured Residual Stress in an Extra Thick Multi-pass Weld Using Neutron Diffraction Method and Inherent Strain Method

    Energy Technology Data Exchange (ETDEWEB)

    Park, JeongUng [Chosun University, Gwangu (Korea, Republic of); An, GyuBaek [POSCO Technical Research Laboratories, Pohang (Korea, Republic of); Woo, Wan Chuck [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    With the increase of large-scale containership, a large amount of high-strength steels with extra thick plates is being extensively used. The welding stress existing in the extra thick welded plates has a significant effect on the integrity of the component in terms of brittle fracture and fatigue behavior. It has been reported that welding residual stress distribution in an extra thick plate can affect the propagation path of the crack. Therefore, it is important to measure the distribution of welding residual stresses for the reliable design of the welded structures. So far various researches have been carried out for the determination of residual stresses on the surface of steels. In this paper, the total residual stresses in the 70 mm thick multipass FACW butt joint were measured by integrating initial stress into ISM. Concretely, two methods named as initial stress integrated ISM and initial inherent strain integrated ISM were employed to determine the total residual stresses. Furthermore, the distributions of residual stresses were compared with the results of the Neutron Diffraction Method(NDM). In order to measure the three dimensional residual stresses in the welded joint with initial stresses existing before welding, initial stress integrated ISM and initial inherent strain integrated ISM were developed. The residual stresses in 70 mm-thick butt joint by flux cored arc welding were carried out with a good accuracy using the two developed methods. The residual stresses in welded joint using both initial stress integrated ISM and initial inherent strain integrated ISM agreed well with the results measured by Neutron Diffraction Method. This suggests that the integrated ISM is a reliable method for residual stress measurement if initial stress existed.

  14. VPPA weld model evaluation

    Science.gov (United States)

    McCutcheon, Kimble D.; Gordon, Stephen S.; Thompson, Paul A.

    1992-07-01

    NASA uses the Variable Polarity Plasma Arc Welding (VPPAW) process extensively for fabrication of Space Shuttle External Tanks. This welding process has been in use at NASA since the late 1970's but the physics of the process have never been satisfactorily modeled and understood. In an attempt to advance the level of understanding of VPPAW, Dr. Arthur C. Nunes, Jr., (NASA) has developed a mathematical model of the process. The work described in this report evaluated and used two versions (level-0 and level-1) of Dr. Nunes' model, and a model derived by the University of Alabama at Huntsville (UAH) from Dr. Nunes' level-1 model. Two series of VPPAW experiments were done, using over 400 different combinations of welding parameters. Observations were made of VPPAW process behavior as a function of specific welding parameter changes. Data from these weld experiments was used to evaluate and suggest improvements to Dr. Nunes' model. Experimental data and correlations with the model were used to develop a multi-variable control algorithm for use with a future VPPAW controller. This algorithm is designed to control weld widths (both on the crown and root of the weld) based upon the weld parameters, base metal properties, and real-time observation of the crown width. The algorithm exhibited accuracy comparable to that of the weld width measurements for both aluminum and mild steel welds.

  15. Welding arc plasma physics

    Science.gov (United States)

    Cain, Bruce L.

    1990-01-01

    The problems of weld quality control and weld process dependability continue to be relevant issues in modern metal welding technology. These become especially important for NASA missions which may require the assembly or repair of larger orbiting platforms using automatic welding techniques. To extend present welding technologies for such applications, NASA/MSFC's Materials and Processes Lab is developing physical models of the arc welding process with the goal of providing both a basis for improved design of weld control systems, and a better understanding of how arc welding variables influence final weld properties. The physics of the plasma arc discharge is reasonably well established in terms of transport processes occurring in the arc column itself, although recourse to sophisticated numerical treatments is normally required to obtain quantitative results. Unfortunately the rigor of these numerical computations often obscures the physics of the underlying model due to its inherent complexity. In contrast, this work has focused on a relatively simple physical model of the arc discharge to describe the gross features observed in welding arcs. Emphasis was placed of deriving analytic expressions for the voltage along the arc axis as a function of known or measurable arc parameters. The model retains the essential physics for a straight polarity, diffusion dominated free burning arc in argon, with major simplifications of collisionless sheaths and simple energy balances at the electrodes.

  16. Friction Stir Welding of HSLA-65 Steel: Part II. The Influence of Weld Speed and Tool Material on the Residual Stress Distribution and Tool Wear

    Science.gov (United States)

    Steuwer, A.; Barnes, S. J.; Altenkirch, J.; Johnson, R.; Withers, P. J.

    2012-07-01

    A set of single pass full penetration friction stir bead-on-plate and butt welds in HSLA-65 steel were produced using a range of traverse speeds (50 to 500 mm/min) and two tool materials (W-Re and PCBN). Part I described the influence of process and tool parameters on the microstructure in the weld region. This article focuses on the influence of these parameters on residual stress, but the presence of retained austenite evident in the diffraction pattern and X-ray tomographic investigations of tool material depositions are also discussed. The residual stress measurements were made using white beam synchrotron X-ray diffraction (SXRD). The residual stresses are affected by the traverse speed as well as the weld tool material. While the peak residual stress at the tool shoulders remained largely unchanged (approximately equal to the nominal yield stress (450 MPa)) irrespective of weld speed or tool type, for the W-Re welds, the width of the tensile section of the residual stress profile decreased with increasing traverse speed (thus decreasing line energy). The effect of increasing traverse speed on the width of the tensile zone was much less pronounced for the PCBN tool material.

  17. Experimental Investigations on Pulsed Nd:YAG Laser Welding of C17300 Copper-Beryllium and 49Ni-Fe Soft Magnetic Alloys

    Science.gov (United States)

    Mousavi, S. A. A. Akbari; Ebrahimzadeh, H.

    2011-01-01

    Copper-beryllium and soft magnetic alloys must be joined in electrical and electro-mechanical applications. There is a high difference in melting temperatures of these alloys which cause to make the joining process very difficult. In addition, copper-beryllium alloys are of age hardenable alloys and precipitations can brittle the weld. 49Ni-Fe alloy is very hot crack sensitive. Moreover, these alloys have different heat transfer coefficients and reflection of laser beam in laser welding process. Therefore, the control of welding parameters on the formation of adequate weld puddle composition is very difficult. Laser welding is an advanced technique for joining of dissimilar materials since it can precisely control and adjust the welding parameters. In this study, a 100W Nd:YAG pulsed laser machine was used for joining 49Ni-Fe soft magnetic to C17300 copper-beryllium alloys. Welding of samples was carried out autogenously by changing the pulse duration, diameter of beam, welding speed, voltage and frequency. The spacing between samples was set to almost zero. The ample were butt welded. It was required to apply high voltage in this study due to high reflection coefficient of copper alloys. Metallography, SEM analysis, XRD and microhardness measurement was used for survey of results. The results show that the weld strength depends upon the chemical composition of the joints. To change the wells composition and heat input of the welds, it was attempted to deviate the laser focus away from the weld centerline. The best strength was achieved by deviation of the laser beam away about 0.1mm from the weld centerline. The result shows no intermetallic compounds if the laser beam is deviated away from the joint.

  18. Experimental Investigations on Pulsed Nd:YAG Laser Welding of C17300 Copper-Beryllium and 49Ni-Fe Soft Magnetic Alloys

    International Nuclear Information System (INIS)

    Copper-beryllium and soft magnetic alloys must be joined in electrical and electro-mechanical applications. There is a high difference in melting temperatures of these alloys which cause to make the joining process very difficult. In addition, copper-beryllium alloys are of age hardenable alloys and precipitations can brittle the weld. 49Ni-Fe alloy is very hot crack sensitive. Moreover, these alloys have different heat transfer coefficients and reflection of laser beam in laser welding process. Therefore, the control of welding parameters on the formation of adequate weld puddle composition is very difficult. Laser welding is an advanced technique for joining of dissimilar materials since it can precisely control and adjust the welding parameters. In this study, a 100W Nd:YAG pulsed laser machine was used for joining 49Ni-Fe soft magnetic to C17300 copper-beryllium alloys. Welding of samples was carried out autogenously by changing the pulse duration, diameter of beam, welding speed, voltage and frequency. The spacing between samples was set to almost zero. The ample were butt welded. It was required to apply high voltage in this study due to high reflection coefficient of copper alloys. Metallography, SEM analysis, XRD and microhardness measurement was used for survey of results. The results show that the weld strength depends upon the chemical composition of the joints. To change the wells composition and heat input of the welds, it was attempted to deviate the laser focus away from the weld centerline. The best strength was achieved by deviation of the laser beam away about 0.1mm from the weld centerline. The result shows no intermetallic compounds if the laser beam is deviated away from the joint.

  19. Influences of post weld heat treatment on fatigue crack growth behavior of TIG welding of 6013 T4 aluminum alloy joint (Part 1. Fatigue crack growth across the weld metal)

    International Nuclear Information System (INIS)

    The present study evaluates the influences of PWHT on FCG behavior and tensile properties of TIG butt welded Al 6013-T4 sheets. Crack propagation tests were carried out on compact tension (CT) specimens. The T82 heat treatment was varied in three artificial aging times (soaking) of 6, 18 and 24 hours. The results of T82 heat treatment with artificial aging variations were tested for their fatigue crack growth rates at the main metal zone, the heat-affected zone (HAZ), and the welded metal zone. It has been observed that the various agings in heat treatment T82 are sensitive to the mechanical properties (fatigue crack growth rate test, tensile test). The results show that PWHT-T82 for 18 hours aging is the highest fatigue resistance, while the aging 18 hours provided the highest tensile test result

  20. Influences of post weld heat treatment on fatigue crack growth behavior of TIG welding of 6013 T4 aluminum alloy joint (Part 1. Fatigue crack growth across the weld metal)

    Energy Technology Data Exchange (ETDEWEB)

    Haryadi, Gunawan Dwi; Kim, Seon Jin [Pukyong National University, Busan (Korea, Republic of)

    2011-09-15

    The present study evaluates the influences of PWHT on FCG behavior and tensile properties of TIG butt welded Al 6013-T4 sheets. Crack propagation tests were carried out on compact tension (CT) specimens. The T82 heat treatment was varied in three artificial aging times (soaking) of 6, 18 and 24 hours. The results of T82 heat treatment with artificial aging variations were tested for their fatigue crack growth rates at the main metal zone, the heat-affected zone (HAZ), and the welded metal zone. It has been observed that the various agings in heat treatment T82 are sensitive to the mechanical properties (fatigue crack growth rate test, tensile test). The results show that PWHT-T82 for 18 hours aging is the highest fatigue resistance, while the aging 18 hours provided the highest tensile test result.

  1. Fiber laser welding of dual-phase galvanized sheet steel (DP590): traditional analysis and new quality assessment techniques

    Science.gov (United States)

    Miller, Stephanie; Pfeif, Erik; Kazakov, Andrei; Baumann, Esther; Dowell, Marla

    2016-03-01

    Laser welding has many advantages over traditional joining methods, yet remains underutilized. NIST has undertaken an ambitious initiative to improve predictions of weldability, reliability, and performance of laser welds. This study investigates butt welding of galvanized and ungalvanized dual-phase automotive sheet steels (DP 590) using a 10 kW commercial fiber laser system. Parameter development work, hardness profiles, microstructural characterization, and optical profilometry results are presented. Sound welding was accomplished in a laser power range of 2.0 kW to 4.5 kW and travel speed of 2000 mm/min to 5000 mm/min. Vickers hardness ranged from approximately 2 GPa to 4 GPa across the welds, with limited evidence of heat affected zone softening. Decreased hardness across the heat affected zone directly correlated to the appearance of ferrite. A technique was developed to non-destructively evaluate weld quality based on geometrical criteria. Weld face profilometry data were compared between light optical, metallographic sample, and frequency-modulated continuous-wave laser detection and ranging (FMCW LADAR) methods.

  2. Evaluation of post-weld heat treatment behavior in modified 9Cr–1Mo steel weldment by magnetic Barkhausen emission

    International Nuclear Information System (INIS)

    The butt joint of two sight tubes of modified 9Cr–1Mo steel is welded by TIG technique. Subsequently, the post-weld heat treatment (PWHT) of the tubes has been carried out at 650, 700 and 750 °C temperatures for 3 h. Magnetic Barkhausen emission (MBE) measurements are performed in fusion zone, heat affected zone (HAZ) and base metal region of as-welded and all the post-weld heat treated samples. In each weldment, the variation of the MBE signal emanated from fusion zone, HAZ and base metal has been examined. It is found that the RMS voltage of MBE signal increases with PWHT temperature. The conversion of retained austenite to alpha ferrite during PWHT makes the fusion region as a softer zone in the weldment. The variation of magnetic parameters with different PWHT is correlated with hardness and microstructures. This study can be used as an effective tool in evaluation of PWHT parameters in modified 9Cr–1Mo weld joint. - Highlights: • Effect of post-welding heat treatment (PWHT) on microstructure, mechanical properties and magnetic properties of 9Cr–1Mo steel. • Correlation of mechanical and microstructural parameters with magnetic properties. • An effective tool in evaluation of PWHT parameters in modified 9Cr–1Mo weld joint

  3. Microstructure- and Strain Rate-Dependent Tensile Behavior of Fiber Laser-Welded DP980 Steel Joint

    Science.gov (United States)

    Jia, Qiang; Guo, Wei; Peng, Peng; Li, Minggao; Zhu, Ying; Zou, Guisheng

    2016-02-01

    DP980 steels were butt-welded by fiber laser welding. The microstructures, microhardness distribution, and tensile behavior of the joint were investigated. The results showed that the fusion zone (FZ) consisted of fully martensite with higher hardness compared to the base metal (BM). A softened zone (20 HV0.2 drop) was produced in heat-affected zone due to martensite tempering during the laser welding. The ultimate tensile strength (UTS) and yield strength (YS) of the laser-welded joint were not degraded compared to BM with the existence of softened zone. The UTS and YS of the welded joint increased with the increase of tensile strain rate. The work hardening exponents of the BM and welded joint showed weak positive strain rate dependence. The deformation of softened zone was restrained by the hardened FZ during loading, resulting in a higher work hardening rate of softened zone than that of BM. The failure of welded joint occurred in the BM instead of softened zone. The fracture surfaces of the joint exhibited typical ductile fracture over strain rate from 0.0001 to 0.1 s-1.

  4. 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.

  5. Weldability of reduced activation ferritic/martensitic steel under ultra power density fiber laser welding

    International Nuclear Information System (INIS)

    Full text of publication follows: Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems as it has been developed based on massive industrial experience of ferritic/martensitic steel replacing Mo and Nb of high chromium heat resistant martensitic steels (such as modified 9Cr-1Mo) with W and Ta, respectively. As one of RAFMS, F82H, which has been developed and studied in Japan, is designed with emphasis on high temperature property and weldablility, and was provided and evaluated in various countries as a part of the collaboration of IEA fusion materials development. Although F82H is the well perceived RAFM as ITER Test Blanket Module (TBM) structural material, the weldability was proved though TIG, EB and YAG laser weld tests using only 15 and 25 mm thickness plate. In order to reduce the welding distortion, the residual stress and the area of the heat affected zone, it is necessary to decrease the total heat input under the welding. Recently, as a result of R and D efforts about the sources of laser beam, a high-power fiber laser beam has been developed as one of the desirable heat sources for high-speed and deep-penetration welding. Since the power density of the fiber laser beam is very large, it is possible to increase the welding speed more than 10 m/min. So, in this study, the weldability of 1.5 mm thickness F82H plate and pipe was examined by using a ultra power density fiber laser, in order to reveal the excellent weldability of F82H. As a basic study of the butt welding between 1.5 mm plate and 1.5 mm thickness pipe with 11 mm outer diameter, the focus position, the beam position and the laser power were varied using 25 mm square plate and 25 mm length pipe. Then, by using the fiber laser with 1.1 MW/mm2 peak power density under the appropriate welding condition obtained from the basic study, a full penetrated weld bead with narrow width was formed in the butt welding

  6. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

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

  7. Underwater YAG laser welding technique

    International Nuclear Information System (INIS)

    When planning preventive maintenance of reactor components using welding, it is necessary to consider special environments such as narrow space or difficult accessibility while minimizing exposure to radiation in the reactor pressure vessel. Toshiba has developed an underwater neodymium: yttrium-aluminum-garnet (Nd: YAG) laser welding technique. The features of this welding technique are low-heat-input welding and compact welding machine dimensions for welding in narrow spaces. This paper provides a summary of the new welding technique as a reliable welding technology. (author)

  8. Manganese Content Control in Weld Metal During MAG Welding

    Science.gov (United States)

    Chinakhov, D. A.; Chinakhova, E. D.; Sapozhkov, A. S.

    2016-08-01

    The influence of the welding current and method of gas shielding in MAG welding on the content of manganese is considered in the paper. Results of study of the welded specimens of steels 45 when applying welding wire of different formulas and different types of gas shielding (traditional shielding and double-jet shielding) are given. It is found that in MAG welding the value of the welding current and the speed of the gas flow from the welding nozzle have a considerable impact on the chemical composition of the weld metal. The consumable electrode welding under double-jet gas shielding provides the directed gas-dynamics in the welding area and enables controlling the electrode metal transfer and the chemical composition of a weld.

  9. 78 FR 21540 - Revisions to the California State Implementation Plan, Butte County Air Quality Management...

    Science.gov (United States)

    2013-04-11

    ... Management District and Sacramento Metropolitan Air Quality Management District AGENCY: Environmental... revisions to the Butte County Air Quality Management District (BCAQMD) and Sacramento Metropolitan Air Quality Management District (SMAQMD) portions of the California State Implementation Plan (SIP)....

  10. Spatial Vegetation Data for Fossil Butte National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This polygon feature class represents vegetation communities mapped at Fossil Butte National Monument. The polygons were generated using guidelines set by the...

  11. Field Plot and Observation Points for Fossil Butte National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This point file contains 255 point locations of field plot and observation data used by, and collected for, the vegetation mapping project for Fossil Butte National...

  12. Willamette Valley - Oregon White Oak Restoration: North Baskett Butte and Maple Knoll RNA

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This project was the initial work needed to preserve the existing oak habitat on WVNWRC by eliminating the Douglas fir overstory. North Baskett Butte, on Baskett...

  13. True Color Orthophotography for Fossil Butte National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This photo mosaic of Fossil Butte National Monument was created from scanned 9x9s flown in 2004 in conjunction with the Vegetation Mapping Program. The photography...

  14. Welding by laser beam

    International Nuclear Information System (INIS)

    A laser which does not require a vacuum and the beam from which can be projected over a distance without loss of power is sited outside a welding zone and the beam projected through a replaceable laser transparent window. The window is designed and shaped to facilitate access of the beam of workpiece items to be welded in containment. Either the workpiece or the laser beam may be moved during welding. (author)

  15. Studies of welded joints

    Directory of Open Access Journals (Sweden)

    J. M. Krupa

    2010-07-01

    Full Text Available Studies of a welded joint were described. The joint was made as a result of the reconstruction of a truss and one of the possible means to make a repair. The studies were of a simulation character and were targeted at the detection of welding defects and imperfections thatshould be eliminated in a real structure. A model was designed and on this model the tests and examinations were carried out. The modelwas made under the same conditions as the conditions adopted for repair. It corresponded to the real object in shape and dimensions, and in the proposed technique of welding and welding parameters. The model was composed of five plates joined together with twelve beads.The destructive and non-destructive tests were carried out; the whole structure and the respective welds were also examined visually. Thedefects and imperfections in welds were detected by surface methods of inspection, penetration tests and magnetic particle flaw detection.The model of the welded joint was prepared by destructive methods, a technique that would never be permitted in the case of a realstructure. For the investigations it was necessary to cut out the specimens from the welded joint in direction transverse to the weld run. The specimens were subjected to metallographic examinations and hardness measurements. Additionally, the joint cross-section was examined by destructive testing methods to enable precise determination of the internal defects and imperfections. The surface methods were applied again, this time to determine the severity of welding defects. The analysis has proved that, fabricated under proper conditions and with parameters of the welding process duly observed, the welded joint has good properties and repairs of this type are possible in practice.

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

    International Nuclear Information System (INIS)

    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)

  17. Variation in, and causes of, toxicity of cigarette butts to a cladoceran and microtox.

    Science.gov (United States)

    Micevska, T; Warne, M St J; Pablo, F; Patra, R

    2006-02-01

    Cigarette butts are the most numerically frequent form of litter in the world. In Australia alone, 24-32 billion cigarette butts are littered annually. Despite this littering, few studies have been undertaken to explore the toxicity of cigarette butts in aquatic ecosystems. The acute toxicity of 19 filtered cigarette types to Ceriodaphnia cf. dubia (48-hr EC50 (immobilization)) and Vibrio fischeri (30-min EC50 (bioluminescence)) was determined using leachates from artificially smoked cigarette butts. There was a 2.9- and 8-fold difference in toxicity between the least and most toxic cigarette butts to C. cf. dubia and V. fischeri, respectively. Overall, C. cf. dubia was more inherently sensitive than V. fischeri by a factor of approximately 15.4, and the interspecies relationship between C. cf. dubia and V. fischeri was poor (R(2) = 0.07). This poor relationship indicates that toxicity data for cigarette butts for one species could not predict or model the toxicity of cigarette butts to the other species. However, the order of the toxicity of leachates can be predicted. It was determined that organic compounds caused the majority of toxicity in the cigarette butt leachates. Of the 14 organic compounds identified, nicotine and ethylphenol were suspected to be the main causative toxicants. There was a strong relationship between toxicity and tar content and between toxicity and nicotine content for two of the three brands of cigarettes (R(2 )> 0.70) for C. cf. dubia and one brand for V. fischeri. However, when the cigarettes were pooled, the relationship was weak (R(2) < 0.40) for both test species. Brand affected the toxicity to both species but more so for V. fischeri.

  18. Influence of friction stir welding parameters on metallurgical and mechanical properties of dissimilar joint between semi-solid metal 356-T6 and aluminum alloys 6061-T651

    OpenAIRE

    Muhamad Tehyo; Prapas Muangjunburee; Abdul Binraheem; Somchai Chuchom; Nisida Utamarat

    2012-01-01

    The objective of this research is to investigate the effect of welding parameters on the microstructure and mechanicalproperties of friction stir (FS) welded butt joints of dissimilar aluminum alloy sheets between Semi-Solid Metal (SSM) 356-T6and AA6061-T651 by a computerized numerical control (CNC) machine. The base materials of SSM356-T6 and AA6061-T651were located on the advancing side (AS) and on the retreating side (RS), respectively. For this experiment, the FS weldedmaterials were join...

  19. Gas Metal Arc Welding Process Modeling and Prediction of Weld Microstructure in MIL A46100 Armor-Grade Martensitic Steel

    Science.gov (United States)

    Grujicic, M.; Arakere, A.; Ramaswami, S.; Snipes, J. S.; Yavari, R.; Yen, C.-F.; Cheeseman, B. A.; Montgomery, J. S.

    2013-06-01

    A conventional gas metal arc welding (GMAW) butt-joining process has been modeled using a two-way fully coupled, transient, thermal-mechanical finite-element procedure. To achieve two-way thermal-mechanical coupling, the work of plastic deformation resulting from potentially high thermal stresses is allowed to be dissipated in the form of heat, and the mechanical material model of the workpiece and the weld is made temperature dependent. Heat losses from the deposited filler-metal are accounted for by considering conduction to the adjoining workpieces as well as natural convection and radiation to the surroundings. The newly constructed GMAW process model is then applied, in conjunction with the basic material physical-metallurgy, to a prototypical high-hardness armor martensitic steel (MIL A46100). The main outcome of this procedure is the prediction of the spatial distribution of various crystalline phases within the weld and the heat-affected zone regions, as a function of the GMAW process parameters. The newly developed GMAW process model is validated by comparing its predictions with available open-literature experimental and computational data.

  20. Experimental Study of the Forces Acting on the Tool in the Friction-Stir Welding of AA 2024 T3 Sheets

    Science.gov (United States)

    Astarita, A.; Squillace, A.; Carrino, L.

    2014-10-01

    In this paper, AA 2024 T3-rolled sheets were joined in butt joint configuration through the friction stir welding process. Different joints were carried out varying the principal process parameters (i.e., tool welding speed and tool rotational speed). The aim of this work was the study and the experimental characterization of the influence of the process parameters on the forces acting on the tool during the FSW process. Furthermore, it was studied the correlation between the forces and the grain size, in particular with the extension of the heat-affected zone. Forces acting along the axis parallel to the tool are actually greater than those acting along welding direction. All the recorded forces are strictly dependant on the process parameters adopted. No correlation has been found between the grain dimension within the weld bead and the recorded forces, while the greater the forces, the narrower the extension of the heat-affected zone.