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Sample records for butt joint welding

  1. 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.

  2. 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...

  3. 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.

  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. 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.

  6. 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.

  7. 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...

  8. 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.

  9. 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)

  10. 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...

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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...

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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)

  16. 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

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  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. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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 ...

  7. 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 .

  8. 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。

  9. 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)

  10. 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

  11. 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.

  12. 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...

  13. 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...

  14. 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.%

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Numerical Simulation of Mechanical Behaviors of the TiNi Shape Memory Alloy Welded Joints in the Precise Pulse Resistance Butt-Welding

    Institute of Scientific and Technical Information of China (English)

    Lijun HAN; Junjie ZHU; Lihong HAN

    2003-01-01

    The hysteresis unit system was introduced to mechanical structure behavior of the TiNi SMA joint based on the structure characteristics of the martensite variants in the joints, and some functions reflecting its inner structure characteristics and micro-behavior such as density function, phase transformation function were set up from micropoints. Finally, the structure behavior relationship and corresponding mathematic model reflecting the relationship among hysteresis strain, stress and phase transformation strain were provided, which could predict the stress-strain behavior of the TiNi SMA joint to large extent.

  20. 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.

  1. 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....

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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)

  4. 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.

  5. 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 .

  6. 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)

  7. 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...

  8. 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...

  9. 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,...

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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。

  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. 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...

  18. 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.

  19. 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

  20. 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.

  1. 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)

  2. 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)

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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)

  10. 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).

  11. 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.

  12. 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),...

  13. 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...

  14. 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...

  15. 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)

  16. 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.

  17. 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.

  18. 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

  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. Recent Corrosion Research Trends in Weld Joints

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwan Tae; Kil, Sang Cheol [Korea Institute of Science and Technology Information, Seoul (Korea, Republic of); Hwang, Woon Suk [Inha University, Incheon (Korea, Republic of)

    2007-04-15

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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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)

  6. 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.

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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...

  14. 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.

  15. 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.

  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. 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.

  18. 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.

  19. 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.

  20. 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

  1. Materials participation in welded joints manufacturing

    Science.gov (United States)

    Ghenghea, L. D.

    2016-08-01

    Management of materials dilution to form a joint with higher features asked by complex metallic structures is a problem that took attention and efforts of welding processes researchers and this communication will give a little contribution presenting some scientific and experimental results of dilution processes studied by Welding Research Group from Iasi, Romania, TCM Department. Liquid state welding processes have a strong dependence related to dilution of base and filler materials, the most important are for automatic joining using welding. The paper presents a review of some scientific works already published and their contributions, results of dilution coefficient evaluation using weighing, graphics and software applied for shielded metal arc welding process. Paper results could be used for welders’ qualification, welding procedure specification and other welding processes researchers’ activities. The results of Welding Research Group from Iasi, Romania, TCM Department, show dilution coefficient values between 20-30 % of base material and 70-80 % of filler material for studied welding process.

  2. 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.

  3. 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...

  4. 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。

  5. 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.

  6. 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.

  7. 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.

  8. Microstructures of 2219 twin wire welded joints

    Institute of Scientific and Technical Information of China (English)

    Xu Wenli; Li Qingfen; Meng Qingguo; Gao Na; Fang Hongyuan

    2005-01-01

    With thick plates of 2219 high-strength alloy, the microstructures of welded joints with twin wire MIG welding were analyzed. Experimental results show that no hot crack was found in the weld due to discontinuous distribution of cocrystallization with low melting temperature, but porosity is serious in the first weld seam that is mainly composed of equiaxial grains with uneven sizes. As the poor position of the whole welded joint, fusion zone has big and coarse grains,uneven microstructures ; In quenching zone, there exist a lot of soaked microstructures that cocrystallization with low melting temperature solute into matrix, thus strengthening the metal in this zone; In excessive aging zone, much more phases that distribute evenly will be separated from the matrix; Outside this zone, properties and microstructures of the metal are basically similar to matrix due to the relatively low temperature or unaffected heat in the zone during welding.

  9. Multiple crack propagation by DBEM in a riveted butt-joint: a simplified bidimensional approach

    Directory of Open Access Journals (Sweden)

    R. Citarella

    2016-03-01

    Full Text Available A Multi-Site Damage (MSD crack growth simulation is presented, carried out by means of Dual Boundary Element Method (DBEM, in a two-dimensional analysis of a cracked butt-joint made of aluminium 2024 T3. An equivalent crack length is proposed for an approximated 2D analysis of a 3D problem where the crack front assumes a part elliptical shape due to secondary bending effects. The assumptions made to perform such simplified bidimensional analyses are validated by comparing numerical results with experimental data, the latter obtained from a fatigue tested riveted butt-joint.

  10. 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

  11. 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 ...

  12. Development of Fatigue Life Improvement Technology of Butt Joints Using Friction Stir Processing

    OpenAIRE

    Jeong-Ung Park; GyuBaek An; Heung-ju Kim; Jae-hyouk Choi

    2014-01-01

    Burr grinding, tungsten inert gas (TIG) dressing, ultrasonic impact treatment, and peening are used to improve fatigue life in steel structures. These methods improve the fatigue life of weld joints by hardening the weld toe, improving the bead shape, or causing compressive residual stress. This study proposes a new postweld treatment method improving the weld bead shape and metal structure at the welding zone using friction stir processing (FSP) to enhance fatigue life. For that, a pin-shape...

  13. 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)

  14. 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.

  15. 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.

  16. 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 ...

  17. 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...

  18. 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;...

  19. 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...

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

    Science.gov (United States)

    Looney, Alan

    1991-01-01

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

  1. 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%.

  2. 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...

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. The effect of controlled shot peening on fusion welded joints

    International Nuclear Information System (INIS)

    This work examines the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel welded joint. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity, inclusions, lack of penetration, and undercut found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed joints were compared. It was observed that the effect of the CSP and skimming processes improved the fatigue life of the fusion weld by 50% on MMA-welded, 63% on MIG-welded, and 60% on TIG-welded samples.

  10. 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.

  11. 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.

  12. 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

  13. Electric pulse treatment of welded joint of aluminum alloy

    Directory of Open Access Journals (Sweden)

    A.A. Mitiaev

    2013-08-01

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

  14. 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.

  15. 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)

  16. 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)

  17. Assessment Of Joints Using Friction Stir Welding And Refill Friction Stir Spot Welding Methods

    OpenAIRE

    Lacki P.; Więckowski W.; Wieczorek P.

    2015-01-01

    FSW (Friction Stir Welding) and RFSSW (Refill Friction Stir Spot Welding) joints have been increasingly used in industrial practice. They successfully replace fusion-welded, riveted or resistance-welded joints. In the last two decades, dynamic development of this method has stimulated investigations of the fast methods for joint diagnostics. These methods should be non-destructive and easy to be used in technological processes. The methods of assessment of joint quality are expected to detect...

  18. 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...

  19. Interface microstructure and mechanical properties of laser welding copper-steel dissimilar joint

    Science.gov (United States)

    Yao, Chengwu; Xu, Binshi; Zhang, Xiancheng; Huang, Jian; Fu, Jun; Wu, Yixiong

    2009-07-01

    Relatively the high reflectivity of copper to CO 2 laser led to the difficulty in joining copper to steel using laser welding. In this paper, a new method was proposed to complete the copper-steel laser butt welding. The scarf joint geometry was used, i.e., the sides of the copper and steel were in obtuse and acute angles, respectively. During the welding process, the laser beam was fixed on the steel side and the dilution ratio of copper to steel was controlled by properly selecting the deviation of the laser beam. The offset of laser beam depended on the scarf angle between the copper and steel, the thickness of plate and the processing parameters used in the laser welding. The microstructure near the interface between Cu plate and the intermixing zone was investigated. Experimental results showed that for the welded joint with high dilution ratio of copper, there was a transition zone with numerous filler particles near the interface. However, if the dilution ratio of copper is low, the transition zone is only generated near the upper side of the interface. At the lower side of the interface, the turbulent bursting behavior in the welding pool led to the penetration of liquid metal into Cu. The welded joint with lower dilution ratio of copper in the fusion zone exhibited higher tensile strength. On the bases of the microstructural evaluation at the interface of the welded joint, a physical model was proposed to describe the formation mechanism of the dissimilar joint with low dilution ratio of copper.

  20. 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.

  1. Project of integrity assessment of flawed components with structural discontinuity (IAF). Data book for residual stress analysis in weld joint. Weld joint in shroud support (H8, H9, H10 and H11 welds)

    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

  2. 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。

  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

    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.

  4. 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.

  5. 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。

  6. Fatigue assessment of load-carrying welded cruciform joints

    Directory of Open Access Journals (Sweden)

    S.V. Petinov

    2013-04-01

    Full Text Available T-form and cruciform joints in which the stress flow is transferred via weld material are widely applied in welded structures. A special type of these joints is presented by fillet-welded joints with incomplete penetration used by economical and manufacturing reasons. At a certain width of the cavity it becomes an active notch which in current design rules is regarded as an initial crack. In that way, fatigue life of the joint is characterized by the crack extensions towards the outer surface of weld bead. Fatigue assessment of these joints requires reliable data on the stress intensity factors values along the crack path. The results of systematic FEA-based calculations of stress intensity factors and respective S-N curves for the considered welded joints are presented. Main results obtained during this investigation can be used in solution of engineering tasks in reference to the fatigue assessment of welded cruciform joints with incomplete penetration.

  7. Fatigue Strength of Friction Stir Welded Joints in Aluminium

    OpenAIRE

    Ericsson, Mats

    2005-01-01

    Solid state Friction stir welding (FSW) is of major interest in the welding of aluminium since it improves the joint properties. Many applications where Al-alloys are used are subject to varying load conditions, making fatigue failure a critical issue. In the scope of this thesis, the fatigue performance of friction stir welded AlMgSi-alloy 6082 has been investigated. Static and dynamic properties of different joint configurations and welds produced with varying process parameters have been d...

  8. Stresses at weld toes in tubular joints in offshore structures

    OpenAIRE

    Elliott, Kim S.

    1987-01-01

    The accurate prediction of stress concentration factors (SCF) at weld toes is recognised as one of the most important factors in the design, against fatigue failure, of welded tubular joints in offshore structures. The objectives of this work are i) to study the influence of some important tubular joint and weld profile geometric parameters on the elastic SCFs at weld toes, ii) compare these values with strains which could be measured by strain gauges, and iii) to determine plastic-elastic st...

  9. Micro-mechanical properties of 2219 welded joints with twin wire welding

    Institute of Scientific and Technical Information of China (English)

    Xu Wenli; Li Qingfen; Meng Qingguo; Fang Hongyuan; Gao Na

    2006-01-01

    Nanoindentation method was adopted to investigate the distribution regularities of micro-mechanical properties of 2219 twin wire welded joints, thus providing the necessary theoretical basis and guidance for joint strengthening and improvement of welding procedure.Experimental results show that in weld zone, micro-mechanical properties are seriously uneven.Both hardness and elastic modulus distribute as uneven sandwich layers, while micro-mechanical properties in bond area are much more uniform than weld zone;In heat-affected zone of 2219 twin wire welded joint, distribution regularity of hardness is similar to elastic modulus.The average hardness in quenching zone is higher than softening zone, and the average elastic modulus in solid solution zone is slightly higher than softening zone.As far as the whole welded joint is concerned,metal in weld possesses the lowest hardness.For welded specimens without reinforcement, fracture position is the weld when tensioning.While for welded specimens with reinforcement, bond area is the poorest position with joint strength coefficient of 61%.So, it is necessary to strengthen the poor positions-weld and bond area of 2219 twin wire welded joint in order to solve joint weakening of welding this kind of alloy.

  10. Predicting effects of diffusion welding parameters on welded joint properties by artificial neural network

    Institute of Scientific and Technical Information of China (English)

    刘黎明; 祝美丽; 牛济泰; 张忠典

    2001-01-01

    The static model for metal matrix composites in diffusion welding was established by means of artificial neural network method. The model presents the relationship between weld joint properties and welding parameters such as welding temperature, welding pressure and welding time. Through simulating the diffusion welding process of SiCw/6061Al composite, the effects of welding parameters on the strength of welded joint was studied and optimal technical parameters was obtained. It is proved that this method has good fault-tolerant ability and versatility and can overcome the shortage of the general experiment. The established static model is in good agreement with the actual welding process, so it becomes a new path for studying the weldability of new material.

  11. Measurement of inhomogeneous strength in weld joint by 3D image correlation technique

    International Nuclear Information System (INIS)

    It is possible for stress corrosion cracking to occur in weld joints and their neighborhood of nuclear power plants. Crack growth prediction and fracture assessment based on fitness-for-service is applied to initiated cracks. Yield point and tensile strength of material is used for fracture assessment. However, the material strength distribution of a welded part is usually not uniform. Therefore, to assess structural integrity correctly, it is important to understand the inhomogeneous strength distribution. In this study, identification of an inhomogeneous material strength distribution of a welded part was tried using a digital image correlation technique (DIC). A specimen was taken from a butt welded joint and the displacement of the specimen surface during a tensile test was measured using the DIC. It was shown that the nominal stress-local strain curves on a specimen surface and 0.2% proof strength distribution around the weld part could be corrected by the DIC. Furthermore, change in the cross-section during the tensile test was estimated by the DIC, and the local stress (true stress) at an arbitrary cross-section of the specimen could be identified. (author)

  12. 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.

  13. Virtual Welded - Joint Design Integrating Advanced Materials and Processing Technology

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhishang; Ludewig, Howard W.; Babu, S. Suresh

    2005-06-30

    Virtual Welede-Joint Design, a systematic modeling approach, has been developed in this project to predict the relationship of welding process, microstructure, properties, residual stress, and the ultimate weld fatique strength. This systematic modeling approach was applied in the welding of high strength steel. A special welding wire was developed in this project to introduce compressive residual stress at weld toe. The results from both modeling and experiments demonstrated that more than 10x fatique life improvement can be acheived in high strength steel welds by the combination of compressive residual stress from the special welding wire and the desired weld bead shape from a unique welding process. The results indicate a technology breakthrough in the design of lightweight and high fatique performance welded structures using high strength steels.

  14. 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.

  15. 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。

  16. Seam-Tracking for Friction Stir Welded Lap Joints

    Science.gov (United States)

    Fleming, Paul A.; Hendricks, Christopher E.; Cook, George E.; Wilkes, D. M.; Strauss, Alvin M.; Lammlein, David H.

    2010-11-01

    This article presents a method for automatic seam-tracking in friction stir welding (FSW) of lap joints. In this method, tracking is accomplished by weaving the FSW tool back-and-forth perpendicular to the direction of travel during welding and monitoring force and torque signals. Research demonstrates the ability of this method to automatically track weld seam positions. Additionally, tensile and S-bend test result comparisons demonstrate that weaving most likely does not reduce weld quality. Finally, benefits of this weave-based method to FSW of lap joints are discussed and methods for incorporating it into existing friction stir welding control algorithms (such as axial load control) are examined.

  17. The impact of welding wire on the mechanical properties of welded joints

    Directory of Open Access Journals (Sweden)

    Magdalena Mazur

    2014-06-01

    Full Text Available This paper presents results of the mechanical properties of Hardox 450 steel welded joints. These welded joints were made in accordance with welding procedure specifications (WPS, which was prepared and  applied in the Wielton company. Fillers were provided by welding wires with two different diameters. The welding wire was G4Sil with diameter of 1.0 mm and 1.2 mm. The aim of this study was to examine whether the thickness of the welding wire has a direct effect on the properties of welded joints. Test specimens were made in similar parameters of the welding process. Then they were subjected to macroscopic research, tensile strength, impact strength and hardness

  18. Fatigue resistance of titanium laser and hybrid welded joints

    International Nuclear Information System (INIS)

    This paper presents a detailed study on fatigue strength of welded joints made of two titanium alloys, grade 2 and grade 5, and welded by laser or hybrid process. Fatigue strength curves obtained for each alloy and each welding technique are compared in terms of safety factors with fatigue design curves of welded joints provided by standards. Material and welding process effects on fatigue strength are discussed; the influence of the weld seam geometry is assessed by evaluating the fatigue strength reduction factor. This parameter is computed by using the Volumetric Method of the Notch Fracture Mechanics and defined as the ratio of the effective stress and the gross stress. Effective stress is defined on the weld toe stress distribution by the minimum of relative stress gradient method. Distribution of opening stress at weld toe is analysed also with the finite element analysis.

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

    Science.gov (United States)

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

    2016-11-01

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

  20. 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.

  1. Weldability of dissimilar joint between F82H and SUS316L under fiber laser welding

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, Hisashi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Mori, Daiki; Shirai, Yuma; Ogiwara, Hiroyuki; Mori, Hiroaki [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-10-15

    Highlights: • The microstructure of F82H/SUS316L dissimilar joint can be divided into four regions. • In the case without beam position shift, hardness of WM cannot be reduced by PWHT. • The fiber laser welding would be applicable for constructing the dissimilar joint. -- Abstract: As one of the high beam quality heat sources, 4 kW fiber laser was applied for joining between reduced activation ferritic/martensitic steel, F82H and SUS316L austenitic stainless steel, and the microstructural analyses and Vickers hardness measurements were carried out before and after post-weld heat treatment (PWHT). The microstructure of joint can be divided into four regions which are base metal of F82H, heat affected zone (HAZ) in F82H, weld metal (WM) and base metal of SUS316L. Also, it is revealed that the high-power fiber laser can be employed for constructing butt joint between F82H and SUS316L by applying PWHT and shifting the laser beam position to SUS316L, where the distance between the contact face and beam should be set as a range from radius to diameter of laser beam.

  2. Inhibition of the formation of intermetallic compounds in aluminum-steel welded joints by friction stir welding

    OpenAIRE

    Torres López, Edwar A.; Ramirez, Antonio J.

    2015-01-01

    Formation of deleterious phases during welding of aluminum and steel is a challenge of the welding processes, for decades. Friction Stir Welding (FSW) has been used in an attempt to reduce formation of intermetallic compounds trough reducing the heat input. In this research, dissimilar joint of 6063-T5 aluminum alloy and AISI-SAE 1020 steel were welded using this technique. The temperature of welded joints was measured during the process. The interface of the welded joints was characterized u...

  3. Fatigue behaviour of coated sheets but joints welded by laser process

    International Nuclear Information System (INIS)

    The fatigue strength and the fracture mechanism studies of butt laser welded joints in A155-Zn coated steel sheets, 0,62 and 1.16 mm thick, have been continued. The 2 x 10''6 cycles fatigue strength for both thicknesses has been finally established in 130 and 175 MPa, respectively, and the big ferritic grain -300μm-produced by symmetrical solidification from the fusion zone centre has been confirmed. Initiation and extension fracture zones are analysed by SEM and so are the involved microstructures. The first ones are concerned with high stress concentration zones, mainly undercut or lack of penetration, from which the fatigue cracks extend in semiellipses, longitudinally and through thickness, along the fusion line or the HAZ. The final fracture is produced by tearing of the residual fatigue crack bound and crack deviation towards the central gross grain line of the welds. (Author) 13 refs

  4. A Probabilistic Damage Tolerance Concept for Welded Joints

    DEFF Research Database (Denmark)

    Lassen, T.; Sørensen, John Dalsgaard

    2002-01-01

    The present paper presents the necessary crack growth statistics and suggests stochastic models for a reliability analysis of the fatigue fracture of welded steel plate joints. The reliability levels are derived from extensive testing with fillet-welded joints for which the entire crack growth...

  5. 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)

  6. FATIGUE WELDING JOINT RESISTANCE OF MINING DUMP TRUCK BEARING CONSTRUCTIONS

    Directory of Open Access Journals (Sweden)

    A. A. Rakitsky

    2010-01-01

    Full Text Available The paper investigates a possibility to apply European norms on designing of welded constructions for frames of heavy-load mining dump trucks. Comparison of results concerning tests of welding joint specimen made of local steel with recommended standards of fatigue curves is executed in the paper. The paper reveals that while forecasting resource of automotive constructions with the accepted practical accuracy it is possible to use generalized fatigue resistance characteristics of standard welding joints

  7. Study the Factors Effecting on Welding Joint of Dissimilar Metals

    Directory of Open Access Journals (Sweden)

    Esam J. Ebraheam

    2011-01-01

    Full Text Available The aim of this work is to study the factors that affect the welding joint of dissimilar metals. Austenitic stainless steel-type AISI (316L with a thickness of (2mm was welded to carbon steel (1mm using an MIG spot welding. The filler metal is a welding wire of the type E80S-G (according to AWS is used with (1.2mm diameter and CO2 is used as shielding gas with flow rate (7L/min for all times was used in this work. The results indicate that the increase of the welding current tends to increase the size of spot weld, and also increases the sheer force. Whereas the sheer force increased inversely with the time of welding. Furthermore, the results indicate that increasing the current and time of welding increases the diameter of weld zone, and decreases the sheer force.

  8. Structure and properties of welded joints under laser and arc welding of Zr-2.5%Nb alloy

    International Nuclear Information System (INIS)

    Laser welding was used for improving plasticity of welded joints of Zr-2.5%Nb compositions. It is noted that laser welding of Zr-2.5%Nb alloy at 100-120 m/h rate allows to produce joints featuring high quality, high strength and plasticity of welds whose bend angel equals 160-180 deg. Corrosion resistance of joints in sulphuric, nitric and acetic acids is at the level of basic metal resistance. Decrease of weld width, heat contribution and chemical inhomogeneity of weld metal and HAZ under laser welding conditions reduces the tendency of weld joints to intercrystal corrosion in a 70% solution of sulphuric acid

  9. Influence of Specific Features of Twin Arc Welding on Properties of Weld Joints

    Science.gov (United States)

    Sholokhov, M. A.; Melnikov, A. U.; Fiveyskiy, A. M.

    2016-04-01

    The present article covers the influence of standard and narrow gap twin arc welding on properties of weld joints from high-strength steels. While analyzing microsections we established that distribution of micro structure and phase terms, as well the distribution of micro-hardness, were more homogeneous under narrow gap twin arc welding.

  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. Models for selecting GMA Welding Parameters for Improving Mechanical Properties of Weld Joints

    Science.gov (United States)

    Srinivasa Rao, P.; Ramachandran, Pragash; Jebaraj, S.

    2016-02-01

    During the process of Gas Metal Arc (GMAW) welding, the weld joints mechanical properties are influenced by the welding parameters such as welding current and arc voltage. These parameters directly will influence the quality of the weld in terms of mechanical properties. Even small variation in any of the cited parameters may have an important effect on depth of penetration and on joint strength. In this study, S45C Constructional Steel is taken as the base metal to be tested using the parameters wire feed rate, voltage and type of shielding gas. Physical properties considered in the present study are tensile strength and hardness. The testing of weld specimen is carried out as per ASTM Standards. Mathematical models to predict the tensile strength and depth of penetration of weld joint have been developed by regression analysis using the experimental results.

  12. Forming Completely Penetrated Welded T-joints when Pulsed Arc Welding

    Science.gov (United States)

    Krampit, N. Yu; Krampit, M. A.; Sapozhkov, A. S.

    2016-04-01

    The paper is focused on revealing the influence of welding parameters on weld formation when pulsed arc welding. As an experimental sample a T-joint over 10 mm was selected. Welding was carried out in flat position, which required no edge preparation but provided mono-directional guaranteed root penetration. The following parameters of welding were subjected to investigation: gap in the joint, wire feed rate and incline angles of the torch along and across the weld axis. Technological recommendations have been made with respect to pulsed arc welding; the cost price of product manufacturing can be reduced on their basis due to reduction of labor input required by machining, lowering consumption of welding materials and electric power.

  13. 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。

  14. Modelling of damage development and ductile failure in welded joints

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    This thesis focuses on numerical analysis of damage development and ductile failure in welded joints. Two types of welds are investigated here. First, a study of the localization of plastic flow and failure in aluminum sheets, welded by the relatively new Friction Stir (FS) Welding method, has been...... conducted ([P1], [P2], [P7]-[P9]). The focus in the thesis is on FS-welded 2xxx and 6xxx series of aluminum alloys, which are attractive, for example, to the aerospace industry, since the 2024 aluminum in particular, is typically classified as un-weldable by conventional fusion welding techniques. Secondly......, a study of the damage development in Resistance SpotWelded joints, when subject to the commonly used static shear-lab or cross-tension testing techniques, has been carried out ([P3]-[P6]). The focus in thesis is on the Advanced High Strength Steels, Dual-Phase 600, which is used in for example...

  15. Tensile and shear behavior of undermatched welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Ferrel, M.; Dexter, R.J. [Lehigh Univ., Bethlehem, PA (United States)

    1995-12-31

    Large-scale specimens were made from HSLA-100 steel plate (690 MPa minimum yield strength) featuring groove welds with varying strength ranging from overmatched to significantly undermatched. Tensile tests with transverse groove welds demonstrated that moderately undermatched joints (15% or less) can achieve strength and ductility as good as the overmatched welds. Severely undermatched joints (> 25%) provide full strength, but only limited ductility. The constraint in the large-scale specimens, as in the actual structures, increases the load capacity of the undermatched joints. Unlike the large-scale specimens, conventional flat-strap cross-weld tension specimens cut from the same undermatched welds fail prematurely due to lack of constraint. Shear tests showed that undermatched groove welds do not affect shear strength and ductility. The test results could be reasonably simulated using small-strain elastoplastic finite-element analysis.

  16. 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.

  17. Comparative study on welding characteristics of laser-additional current hybrid welded T-joint of aluminium and titanium alloy

    OpenAIRE

    Zhang Xinge; Li Liqun; Chen Yanbin; Zhu Xiaocui; Li Yansheng; Guo Xinjian

    2015-01-01

    In order to improve the properties of laser overlap welded T-joint, laser-additional current hybrid welding process is put forward. In this paper, the welding characteristics of laser-additional current hybrid welded aluminum and titanium alloy T-joint were conducted and compared. The weld width at faying surface increase, which results in tensile shear load increasing compared with those of laser welding for both aluminum and titanium alloy, but the effect of current on aluminum alloy is mor...

  18. Mechanical behavior study of laser welded joints for DP steel

    Science.gov (United States)

    Yan, Qi

    2008-03-01

    Advanced High Strength Steels (AHSS) are gaining considerable market shares in the automotive industry. The development and application of Dual Phase (DP) steel is just a consistent step towards high-strength steel grades with improved mechanical behavior. Tailor welded blanks with DP steel are promoted in the application of Body-In-White (BIW) structure by the automotive industry. A tailor welded blank consists of several flat sheets that are laser welded together before stamping. Applied cases of tailor welded blanks of high strength steels on the automotive structural parts are investigated in this paper. The mechanical behavior of laser welded joints for DP steel is studied. Microstructure of laser welded joints for DP steel was observed by SEM. Martensite in the weld seam explains the higher strength of welded joints than the base metal. Results show that the strain safety tolerance of laser welded seam for high strength steel can meet the requirement of automobile parts for stamping if the location of laser welded seam is designed reasonably.

  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. 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.

  1. Moiré method analysis for tensile strain field of 2024 aluminum alloy welded joint

    Institute of Scientific and Technical Information of China (English)

    徐文立; 魏艳红; 刘雪松; 方洪渊; 赵敏; 田锡唐

    2003-01-01

    Using experimental mechanics method of moiré analysis, strain field distributions of 2024 aluminum alloy welded joints under different conditions were investigated. The results show that moiré stripes of welded joint without trailing peening just before fracture are not only few and scattered but also uneven, and the stress mainly concentrates on the poor position-welded toes during the tensioning process with the relatively poor mechanical properties of welded joints; When the method of welding with trailing peening is adopted, moiré stripes of welded joint just before fracture are relatively thick and even due to the strengthening welded toes during the welding process, and fracture position transfers from the welded toes to weld, at the same time the mechanical properties of welded joints are improved greatly than conventional welding which can show that the technology of trailing peening is effective to strengthen welded joints of aluminum alloy with high strength.

  2. Corrosion Behavior of Aluminum-Steel Weld-Brazing Joint

    Science.gov (United States)

    Shi, Yu; Li, Jie; Zhang, Gang; Huang, Jiankang; Gu, Yufen

    2016-05-01

    Dissimilar metals of 1060 aluminum and galvanized steel were joined with a lap joint by pulsed double-electrode gas metal arc weld brazing with aluminum-magnesium and aluminum-silicon filler metals. The corrosion behavior of the weld joints was investigated with immersion corrosion and electrochemical corrosion tests, and the corrosion morphology of the joints was analyzed with scanning electron microscopy (SEM). Galvanic corrosion was found to occur when the samples were immersed in corrosive media, and the corrosion rate of joints was increased with increased heat input of the workpiece. Comparison of the corrosion properties of weld joints with different filler wires indicated that the corrosion rate of weld joints with aluminum-silicon filler wire was larger than that of weld joints with aluminum-magnesium filler wire. Results also showed that the zinc-rich zone of weld joints was prone to corrosion. The corrosion behavior of zinc-rich zone was analyzed with SEM equipped with an energy-dispersive x-ray spectroscopy analysis system based on the test results.

  3. Low cycle fatigue of mechanically heterogeneous welded joints

    International Nuclear Information System (INIS)

    A consideration is given to welded joints made of two dissimilar materials, namely, a material M of lesser strength and a material T of higher strength. It is shown that in near the contact mild - hard material zones under elastic - plastic deformation of the material M a triaxial stress state is realized as the strains are distributed irregularly. An increase in the rigidity of stress state results in a decrease of plasticity and durability of M material. Mild interlayers have a stronger effect on the strength of welded joint, especially, when low cycle loading. In mechanically nonuniform welded joints with V- and X- shaped welds in the most loaded zones the intensity of strains increases with a decrease of relative thickness of a root of penetration α0 for a mild weld, and with an increase of 2α angle for a hard material. Then, it is not recommended to take α048 grad

  4. Mechanical Properties and Microstructure of Dissimilar Material Welded Joints

    OpenAIRE

    Ziewiec A.; Tasak E.; Ziewiec K.; Formowicz K.

    2014-01-01

    The paper presents results of the mechanical testing and the microstructure analysis of dissimilar welded joint of the R350HT steel and the high-manganese (Hadfield) cast steel using Cr-Ni cast steel spacer. The simulation tests of the welded joint surface deformation were carried out. The macroscopic and microscopic investigation were made using light microscopy (LM) and scanning electron microscopy (SEM). Content of the magnetic phase was measured using magnetoscope. The quantitative metall...

  5. Evaluation of cold crack susceptibility on HSLA steel welded joints

    OpenAIRE

    Silverio-Freire Júnior, R. C.; Moura-Maciel, T.; Guedes da Silva, P.

    2003-01-01

    The present study addresses an evaluation of the effect of several welding parameters on cold cracking formation in welded joints of High Strength and Low Alloy steels, as well as the resulting microstructures and hardness values. The main parameters studied include the variation of the preheating temperature, drying time of the electrode, chemical composition and thickness of the base metal. The presence of cold cracking in the joints was analyzed from Tekken tests using steel plates made of...

  6. MODELLING AND CHARACTERIZATION OF LASER WELDED INCOLOY 800 HT JOINTS

    Directory of Open Access Journals (Sweden)

    Sathiya Paulraj

    2016-06-01

    Full Text Available This study aims at finding the effect of laser welding speed on incoloy 800 HT. This alloy is one of the potential materials for Generation IV nuclear plants. Laser welding has several advantages over arc welding such as low fusion zone, low heat input and concentrated heat intensity. Three different welding speeds were chosen and CO2 laser welding was performed. 2D modeling and simulation were done using ANSYS 15 to find out the temperature distribution at different welding speeds and it was found that an increase in the welding speed decreased the temperature. Mechanical properties such as tensile strength, toughness and hardness were evaluated. The effect of welding speed on metallurgical characteristics was studied using optical microscopy (OM, Scanning Electron Microscopy (SEM with EDS, X-Ray Diffraction (XRD technique and fractographic analysis. From the results it was found that high welding speed (1400 mm/min decreased the joint strength. The M23C6 and Ni3Ti carbides were formed in a discrete chain and in a globular form along the grain boundaries of the weld region which increased the strength of the grain boundaries. Fractographic evaluations of the tested specimens for welding speed (1000 and 1200 mm/min showed deep and wide dimples indicating ductile failures.

  7. Fatigue propagation through welded joints of pressure vessels

    International Nuclear Information System (INIS)

    An assessment was made of the behaviour under cyclic load (crack propagation rate and low cycle fatigue) of the metal deposited and of the area affected by the heat of the welded joints assembling the components of the primary circuit. In order to be sure that the results are as representative as possible, the tests were made on metal from joints carried out with the same parameters as actual joints. The studies described here concerned the deposited metal of the welded joints of vessels and the deposited metal in Ni-Cr-Fe alloy of INCONEL 600 type joining the plates at the bottom of steam generators

  8. Comparative study on welding characteristics of laser-additional current hybrid welded T-joint of aluminium and titanium alloy

    Directory of Open Access Journals (Sweden)

    Zhang Xinge

    2015-01-01

    Full Text Available In order to improve the properties of laser overlap welded T-joint, laser-additional current hybrid welding process is put forward. In this paper, the welding characteristics of laser-additional current hybrid welded aluminum and titanium alloy T-joint were conducted and compared. The weld width at faying surface increase, which results in tensile shear load increasing compared with those of laser welding for both aluminum and titanium alloy, but the effect of current on aluminum alloy is more obvious. The porosity defect within the laser-additional current hybrid welded joint sharply reduces compared with that within laser welding. The tensile shear load of aluminum alloy and titanium alloy hybrid welded joints respectively increase 21% and 15%. The effects of additional current on welding characteristics of aluminum alloy and titanium alloy are compared and analyzed.

  9. 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

  10. 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.

  11. Orbital TIG (GTAW) welding for highest weld joint quality requirements

    International Nuclear Information System (INIS)

    Due to its many advantages orbital TIG (GTAW) welding has become the major standard for mechanised tube and pipe weldings in various industries such as: Semiconductor, food and beverage, dairy and brewery, chemical and bio-/pharmaceutical industry, vessel construction, aerospace, offshore and shipbuilding, heat-exchanger, fossil and nuclear power generation. Today's state-of-the-art technology allows orbital weldings of tubes, pipes, fittings or similar parts from 2,3 mm O.D. up to unlimited sizes (including flat plate). Wall thicknesses from 0,3 mm to 175 mm (narrow groove) can easily be accommodated. For difficult applications like inbore weldings, valve seat repairs or video-controlled remote welds, special equipment can be provided or individually manufactured on customer's demand. (orig.)

  12. Characterizations of InAs quantum dot lasers butt-joint coupled with silicon photonics waveguides

    Science.gov (United States)

    Wang, Zihao; Yao, Ruizhe; Preble, Stefan; Lee, Chi-Sen; Guo, Wei

    2016-03-01

    InAs quantum dot (QD) laser heterostructures are grown by molecular beam epitaxy (MBE) system on GaAs substrates and fabricated. The InAs QD lasers exhibit comparable properties of the state-of-the-art QD lasers with the threshold current density Jth and efficiency ηi of 475A/cm2 and 72.6%, respectively, at room temperature. The quantum dot laser emission is butt-joint coupled into silicon photonics waveguides by aligning the laser and silicon photonics chips with two translation stages. Due to the optical feedback to the laser cavity at the air/Si interface, the laser power self-pulsation and reduced threshold current density are observed. And the effective facet reflectivity, Reff, of 62.7% is obtained from the theoretically analysis of the laser characteristics. Furthermore, the silicon photonics waveguides interface is coated with the SiO2/TiO2 antireflection (AR) coating layers, and no laser performance interference is observed owing the reduced optical feedback.

  13. Optimal parameters determination of the orbital weld technique using microstructural and chemical properties of welded joint

    International Nuclear Information System (INIS)

    The paper deals with the study of the main parameters of thermal cycle in Orbital Automatic Weld, as a particular process of the GTAW Weld technique. Also is concerned with the investigation of microstructural and mechanical properties of welded joints made with Orbital Technique in SA 210 Steel, a particular alloy widely use during the construction of Economizers of Power Plants. A number of PC software were used in this sense in order to anticipate the main mechanical and structural characteristics of Weld metal and the Heat Affected Zone (HAZ). The papers also might be of great value during selection of optimal Weld parameters to produce sound and high quality Welds during the construction / assembling of structural components in high requirements industrial sectors and also to make a reliable prediction of weld properties

  14. Microstructures of a welded joint using an irradiated wrapper tube

    International Nuclear Information System (INIS)

    The behavior of helium in welded joint fabricated using tungsten inert gas (TIG) welding process for a type 316 stainless steel wrapper tube irradiated in a fast reactor was investigated. The wrapper tube was irradiated to (1.5 - 4.2) x 1026 n/m2 (helium level of 3 to 9 appm) at 395 - 410 degrees C. All welded joints fractured in the heat-affected zone (HAZ). The microstructures of each portion of the base metal, the HAZ and the fusion zone in a welded joint were examined through a transmission electron microscope. Small helium bubbles were observed in number density of 2 x 1020 m-3 in the matrix and rarely found on the grain boundaries of the base metal. In the HAZ, small and large helium bubbles mixed and lined up along the grain boundaries. In particular, some of them elongated along the grain boundary. In the matrix of the fusion zone, delta-ferrite phases and unresolved carbides were scattered. Large cavities were attached to these precipitates and also occurred along grain boundaries. These results suggest that the failure in the HAZ of welded joints is attributed to the preferential growth and coalescence of helium bubbles in the grain boundaries of the HAZ caused by weld heat input and stress during welding

  15. Residual stress simulation of circumferential welded joints

    Directory of Open Access Journals (Sweden)

    Melicher R.

    2007-11-01

    Full Text Available Residual stresses are an important consideration in the component integrity and life assessment of welded structure. The welding process is very complex time dependent physical phenomenon with material nonlinearity. The welding is a thermal process with convection between fluid flow and welding body, between welding bodyand environment. Next type of boundary conditions is radiation and thermo-mechanical contact on the outer surface of gas pipe in the near of weld. The temperature variation so obtained is utilised to find the distribution of the stress field.In this paper, a brief review of weld simulation and residual stress modelling using the finite element method (FEM by commercial software ANSYS is presented. Thermo-elastic-plastic formulations using a von Mises yield criterion with nonlinear kinematics hardening has been employed. Residual axial and hoop stresses obtained from the analysis have been shown. The commercial FEM code ANSYS was used for coupled thermalmechanical analysis.

  16. New Developed Welding Electrode for Improving the Fatigue Strength of Welded Joints

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new welding electrode, low transformation temperatur e electrode (LTTE), was introduced in this paper. It was described in design principle, mechanics, chemical compositions of their deposited metal and manufacturing methods.It was proved that the best transformation starting temperature from austenite to martensite of the deposited metal of LTTE was at about 191℃ and it was obtained by adding alloying elements such as Cr, Ni, Mn and Mo. The microstructure of the weld metal of the LTTE was low carbon martensite and residual austenite. The compressive residual stress was induced around the weld of the LTTE and the -145 MPa in compression could be obtained in middle of weld metal. The fatigue tests showed that the fatigue strength of the longitudinal welded joints welded with the LTTE at 2×106 cycles was improved by 59% compared with that of the same type of welded joints welded with conventional E5015 and the fatigue life was increased by 47 times at 162 MPa. It is a very valuable method to improve the fatigue performance of welded joints.

  17. Hydrogen effects in duplex stainless steel welded joints - electrochemical studies

    Science.gov (United States)

    Michalska, J.; Łabanowski, J.; Ćwiek, J.

    2012-05-01

    In this work results on the influence of hydrogen on passivity and corrosion resistance of 2205 duplex stainless steel (DSS) welded joints are described. The results were discussed by taking into account three different areas on the welded joint: weld metal (WM), heat-affected zone (HAZ) and parent metal. The corrosion resistance was qualified with the polarization curves registered in a synthetic sea water. The conclusion is that, hydrogen may seriously deteriorate the passive film stability and corrosion resistance to pitting of 2205 DSS welded joints. The presence of hydrogen in passive films increases corrosion current density and decreases the potential of the film breakdown. It was also found that degree of susceptibility to hydrogen degradation was dependent on the hydrogen charging conditions. WM region has been revealed as the most sensitive to hydrogen action.

  18. Properties of bainitic T/P24 steel welded joints

    International Nuclear Information System (INIS)

    Examination results of T/P24 steel tube and pipe welded joints are presented, which find their application in conventional power installations for water-walls, headers and superheater tubes. Welded test joints without post-weld heat treatment (PWHT) and after stress relieving have been subjected to examinations and tests. The examination results proof, that PWHT is not necessary for thin-walled tubes made of T24 steel. In the case of thick elements, as the tested P24 steel pipes (φ 406 x 32 mm), PWHT is mandatory, but their application not always ensures the required impact strength 41 J. The decisive influence on the impact strength of welded joints, made in P24 steel pipes, has the bead deposition technique. (author)

  19. 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.

  20. Assessment Of Joints Using Friction Stir Welding And Refill Friction Stir Spot Welding Methods

    Directory of Open Access Journals (Sweden)

    Lacki P.

    2015-09-01

    Full Text Available FSW (Friction Stir Welding and RFSSW (Refill Friction Stir Spot Welding joints have been increasingly used in industrial practice. They successfully replace fusion-welded, riveted or resistance-welded joints. In the last two decades, dynamic development of this method has stimulated investigations of the fast methods for joint diagnostics. These methods should be non-destructive and easy to be used in technological processes. The methods of assessment of joint quality are expected to detect discontinuities in the structures welded using FSW and FSSW methods. Reliable detection of flaws would substantially extend the range of applications of FSW joints across many sectors of industry, including aviation. The investigations carried out in this paper allowed for characterization of defects present in FSW and RFSSW joints. Causes of these defects were also stressed. An overview of the methodologies for assessment of joint quality was presented. Results of assessment of the quality of joints made of 2024T6 aluminium sheet metal using FSW and RFSSW method were presented.

  1. 49 CFR 192.113 - Longitudinal joint factor (E) for steel pipe.

    Science.gov (United States)

    2010-10-01

    ... resistance welded 1.00 Electric flash welded 1.00 Submerged arc welded 1.00 Furnace butt welded .60 Other... class Longitudinal joint factor (E) ASTM A 53/A53M Seamless 1.00 Electric resistance welded 1.00 Furnace....00 ASTM A 381 Double submerged arc welded 1.00 ASTM A 671 Electric-fusion-welded 1.00 ASTM A...

  2. Effect of joint design on ballistic performance of quenched and tempered steel welded joints

    International Nuclear Information System (INIS)

    Highlights: • Traditional usage of austenitic stainless steel filler for armour steel welding shows poor ballistic performance. • Earlier efforts show dubious success on ballistic resistance of armour steel joints. • Comparative evaluation of equal/unequal joint design on ballistic performance. • Effect of joint design covers the main aspects of successful bullet stoppage. - Abstract: A study was carried out to evaluate the effect of joint design on ballistic performance of armour grade quenched and tempered steel welded joints. Equal double Vee and unequal double Vee joint configuration were considered in this study. Targets were fabricated using 4 mm thick tungsten carbide hardfaced middle layer; above and below which austenitic stainless steel layers were deposited on both sides of the hardfaced interlayer in both joint configurations. Shielded metal arc welding process was used to deposit for all layers. The fabricated targets were evaluated for its ballistic performance and the results were compared in terms of depth of penetration on weld metal. From the ballistic test results, it was observed that both the targets successfully stopped the bullet penetration at weld center line. Of the two targets, the target made with unequal double Vee joint configuration offered maximum resistance to the bullet penetration at weld metal location without any bulge at the rear side. The higher volume of austenitic stainless steel front layer and the presence of hardfaced interlayer after some depth of soft austenitic stainless steel front layer is the primary reason for the superior ballistic performance of this joint

  3. Creep Rupture Properties of Welded Joints of Heat Resistant Steels

    Science.gov (United States)

    Yamazaki, Masayoshi; Watanabe, Takashi; Hongo, Hiromichi; Tabuchi, Masaaki

    In this study, the high-temperature mechanical and creep rupture properties of Grade 91/Grade 91 (Mod. 9Cr-Mo) similar welded joints and Grade 91/Inconel 82/SUS304 dissimilar welded joints were examined. The effects of temperature and stress on the failure location in the joints were also investigated. Creep rupture tests were conducted at 823, 873, and 923 K; the applied stress ranges were 160-240, 80-160, and 40-80 MPa, respectively. The creep rupture strengths of the specimens with welded joints were lower than those of the specimens of the base metal at all temperature levels; in addition, these differences in creep strength increased with temperature. After being subjected to long-term creep rupture tests, the fracture type exhibited by the dissimilar welded joints was transformed from Types V and VII to Type IV. It was estimated that the fracture type exhibited by the dissimilar welded joints after 100,000-h rupture strength tests at 823 K and 873 K was Type IV fracture.

  4. 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...

  5. Portable power tool machines weld joints in field

    Science.gov (United States)

    Spier, R. A.

    1966-01-01

    Portable routing machine for cutting precise weld joints required by nonstandard pipe sections used in the field for transfer of cryogenic fluids. This tool is adaptable for various sizes of pipes and has a selection of router bits for different joint configurations.

  6. Fatigue classification of welded joints in orthotropic steel bridge decks

    NARCIS (Netherlands)

    Kolstein, M.H.

    2007-01-01

    This dissertation presents the research into fatigue classifications of welded joints in orthotropic steel bridge decks. These classifications are needed to calculate the fatigue life of these joints and should be included in the design codes. For years bridge design was mainly based on static loadi

  7. Technology of Welding Joints Mixed with Duplex Steel

    OpenAIRE

    Słania J.; Krawczyk R.; Masłoń D.

    2016-01-01

    Results of the examinations of sample plates of mixed joints with the duplex steel were discussed. Examinations were taken on the sample plates of mixed joints of sheet plates type P355NL1 and X2CrNiMoN22-5-3 welded by the flux-cored wire DW-329A by the Kobelco company of the following category T 22 9 3 NL RC/M3 in the gas shroud M21 (Ar+18%CO2) (plate no.1), and nickel covered electrodes E Ni 6082 by the Böhler company (plate no. 2). Results of the side bend test of welded joint, transverse ...

  8. Influence of welding parameters and post-weld aging on tensile properties and fracture location of AA2139-T351 friction-stir-welded joints

    Directory of Open Access Journals (Sweden)

    Umberto Prisco

    2013-01-01

    Full Text Available Tensile properties and fracture location of AA2139-T351 friction stir welded joints are studied in the as-welded and post-weld aged condition. The experimental results show that when the joints are free of welding defects, they fail on the advancing side of the HAZ exhibiting a large amount of plastic deformation. When the revolutionary pitch exceeds a threshold value, some micro-defects are formed in the weld nugget due to insufficient heat input. In this case, the joints fail near the weld center, and the fracture occurs in a mixed mode, both ductile and brittle. However, being less ductile, post-weld aged joints are less defect-tolerant and, then, they fracture closer to the weld center, showing a reduced elongation at fracture and an UTS within the order of magnitude of the as-welded joints.

  9. Radiographic and ultrasonic testings of welded joints of 6063 aluminium alloy

    International Nuclear Information System (INIS)

    A study on evaluation of weld defects in aluminium butt joints was made in a comparative way through the radiographic and ultrasonic testing. This work was conducted with pipes 5 IPS (6,35 mm thickness) of 6063 aluminium alloy, circumferential TIG welded, due to the difficulty on performing non-destructive testing with this schedule. It was concluded thta ultrasonic testing has adequate sensitivity when setting gain adjustment is made with aid of a reference curve constructed by using a Reference Block (among others studied) with 1,5 mm dia. Hole as reference reflector, and a 5 MHz angle beam search-unit. In this case the ultrasonic testing is more accurate than radiographic testing to detect planar defects like lack of fusion and lack of penetration. Defect sizing by ultrasonic methods employed were 6 and 20 dB drop methods. In spite of your observed limitations concerning the establishment of the real size of defects, the procedure applied was precise for locate and define the weld defects that where found in this study. (author)

  10. 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。

  11. Characterization of Nitinol Laser-Weld Joints by Nondestructive Testing

    Science.gov (United States)

    Wohlschlögel, Markus; Gläßel, Gunter; Sanchez, Daniela; Schüßler, Andreas; Dillenz, Alexander; Saal, David; Mayr, Peter

    2015-12-01

    Joining technology is an integral part of today's Nitinol medical device manufacturing. Besides crimping and riveting, laser welding is often applied to join components made from Nitinol to Nitinol, as well as Nitinol components to dissimilar materials. Other Nitinol joining techniques include adhesive bonding, soldering, and brazing. Typically, the performance of joints is assessed by destructive mechanical testing, on a process validation base. In this study, a nondestructive testing method—photothermal radiometry—is applied to characterize small Nitinol laser-weld joints used to connect two wire ends via a sleeve. Two different wire diameters are investigated. Effective joint connection cross sections are visualized using metallography techniques. Results of the nondestructive testing are correlated to data from destructive torsion testing, where the maximum torque at fracture is evaluated for the same joints and criteria for the differentiation of good and poor laser-welding quality by nondestructive testing are established.

  12. Fatigue behaviour of welded joints assembled by longitudinal corrugated plates

    Institute of Scientific and Technical Information of China (English)

    王志宇; 王清远; 刘永杰; 孙美

    2015-01-01

    Fatigue is usually the cause for the cracks identified at bridge elements in service. With an increase in the introduction of corrugated steel web girders in recent highway bridge construction, the understanding of the fatigue behaviour of welded details in such structures becomes an important issue for the design. The typical welded details were represented as welded joints assembled by longitudinal corrugated plates. All the experiments were performed under fatigue loading using a servo-control testing machine. The test results from the failure mode observation with the aid of infrared thermo-graph technology show that the failure manner of these welded joints is comparable to that of the corrugated steel web beams reported previously. It is indicated from the stiffness degradation analysis that the welded joints with larger corrugation angle have higher stiffness and greater stiffness degradation in the notable stiffness degradation range. It is shown from the testS−N relations based on the free regression and forced regression analyses that there is a good linear dependence between lg(N) and lg(ΔS). It is also demonstrated that the proposed fracture mechanics analytical model is able to give a prediction slightly lower but on the safe side for the mean stresses at 2 million cycles of the test welded joints.

  13. The Investigation of Structure Heterogeneous Joint Welds in Pipelines

    Directory of Open Access Journals (Sweden)

    Lyubimova Lyudmila

    2016-01-01

    Full Text Available Welding joints of dissimilar steels don’t withstand design life. One of the important causes of premature destructions can be the acceleration of steel structural degradation due to cyclic mechanical and thermal gradients. Two zones of tube from steel 12H18N9T, exhibiting the structural instability at early stages of the decomposition of a supersaturated solid austenite solution, were subjected to investigation. Methods of x-ray spectral and structure analysis, micro hardnessmetry were applied for the research. Made the following conclusions, inside and outside tube wall surfaces of hazardous zones in welding joint have different technological and resource characteristics. The microhardness very sensitive to changes of metal structure and can be regarded as integral characteristic of strength and ductility. The welding processes are responsible for the further fibering of tube wall structure, they impact to the characteristics of hot-resistance and long-term strength due to development of ring cracks in the welding joint of pipeline. The monitoring of microhardness and structural phase conversions can be used for control by changes of mechanical properties in result of post welding and reductive heat treatment of welding joints.

  14. 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.

  15. Spot weld arrangement effects on the fatigue behavior of multi-spot welded joints

    International Nuclear Information System (INIS)

    In the present study, the effects of spot weld arrangements in multi-spot welded joints on the fatigue behavior of the joints are studied. Three different four-spot welded joints are considered: one-row four-spot parallel to the loading direction, one-row four-spot perpendicular to the loading direction and two-row four-spot weld specimens. The experimental fatigue test results reveal that the differences between the fatigue lives of three spot welded types in the low cycle regime are more considerable than those in the high cycle regime. However, all kinds of spot weld specimens have similar fatigue strength when approaching a million cycles. A non-linear finite element analysis is performed to obtain the relative stress gradients, effective distances and notch strength reduction factors based on the volumetric approach. The work here shows that the volumetric approach does a very good job in predicting the fatigue life of the multi-spot welded joints

  16. 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.

  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. 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...

  19. 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.

  20. Fatigue Reliability Assessment of Correlated Welded Web-frame Joints

    Institute of Scientific and Technical Information of China (English)

    W. Huang; Y. Garbatov; C. Guedes Soares

    2014-01-01

    The objective of this work is to analyze the fatigue reliability of complex welded structures composed of multiple web-frame joints, accounting for correlation effects. A three-dimensional finite element model using the 20-node solid elements is generated. A linear elastic finite element analysis was performed, hotspot stresses in a web-frame joint were analyzed and fatigue damage was quantified employing the S-N approach. The statistical descriptors of the fatigue life of a non-correlated web-frame joint containing several critical hotspots were estimated. The fatigue reliability of a web-frame joint wasmodeled as a series system of correlated components using the Ditlevsen bounds. The fatigue reliability of the entire welded structure with multiple web-frame joints, modeled as a parallel system of non-correlated web-frame joints was also calculated.

  1. Research on the properties of laser welded joints of aluminum killed cold rolled steel

    Institute of Scientific and Technical Information of China (English)

    阎启; 曹能; 俞宁峰

    2002-01-01

    Aluminum killed cold rolled steel used for automobiles was welded shows that high quality of welding can be realized at welding speed of laser welded joints for aluminum killed cold rolled steel increased compared to those of the base metal while the formability decreased. Forming limit diagram of joint material indicated that the laser weld seam should avoid the maximum deformation area of automobile parts during the designing period for the position of weld seam.

  2. Development of a technology for laser welding of the 1424 aluminum alloy with a high strength of the welded joint

    Science.gov (United States)

    Annin, B. D.; Fomin, V. M.; Karpov, E. V.; Malikov, A. G.; Orishich, A. M.; Cherepanov, A. N.

    2015-11-01

    Results of an experimental study of properties of joints obtained by using different regimes of laser welding of the 1424 alloy (Al-Mg-Li) are reported. The strength and structure of the welded joints are determined. The influence of various types of welded joint straining on its strength is studied. It is demonstrated that the joint strength increases in the case of plastic straining.

  3. Experimental examination of fatigue life of welded joint with stress concentration

    Directory of Open Access Journals (Sweden)

    Miodrag Arsic

    2016-03-01

    Full Text Available This paper presents results of experimental examinations of stress concentration influence to fatigue life of butt welded joints with K-groove, produced from the most frequently used structural steel S355J2+N. One group of experiments comprised examinations carried out on the K-groove specimens with stress concentrators of edged notch type. Specimens with short cracks (limited length of initial crack, defined on the basis of the experience from fracture mechanics by the three points bending examinations, have been examined according to standard for the determination of S-N curve, and aimed to determine fatigue strengths for different lengths of initial crack and Relationship between fatigue strength and crack length. Other group of experiments comprised examinations of specimens with edge notch, prepared in accordance with ASTM E 399 for three points bending, in order to establish regularity between crack growth and range of exerted stress intensity factor aimed to determine resistance of welded joint to initial crack growth, namely fatigue threshold (ΔKth.

  4. Experimental and Fe Analysis of Eccentric Loaded Welded Joint Structure

    Directory of Open Access Journals (Sweden)

    Harish N. Sayankar

    2014-08-01

    Full Text Available Arc welded structures are widely used in automobiles, constructions & power plants. As the main cause of weldment failure is design defect & overload, hence it is necessary to analyze the maximum stresses in the weldment. In this project experimentation is carried out on symmetrical and unsymmetrical eccentric loaded welded joint to determine the breaking stress in the weldment. The FE analysis & analytical estimation of breaking stress is also carried out to verify the experimental results. The stress distribution along weld size & throat thickness is evaluated and also compared with reported findings under same loading condition. Further eccentric loaded welded joint is analyzed under eccentric load by varying the gap between parent plates.

  5. A Probabilistic Damage Tolerance Concept for Welded Joints

    DEFF Research Database (Denmark)

    Lassen, T.; Sørensen, John Dalsgaard

    2002-01-01

    are presented as dimensionless matrices and suggested for use in support of decision-making at the design stage, without any advanced fracture mechanics modelling and stochastic simulation. One important advantage of this format is that the probability levels are presented regardless of actual weld class......The first part of this paper presented the required statistics and stochastic models for reliability analysis of the fatigue fracture of welded plate joints. This present Part 2 suggests a probabilistic damage tolerance supplement to the design S–N curves for welded joints. The goal is to provide...... and target service life (TSL). This is obtained by introducing the FDF as a key parameter to the results. This parameter is defined as the ratio of predicted fatigue life over TSL. FDF is always calculated in the S–N approach which is mandatory in fatigue life prediction. Various welded details (classes...

  6. FE MODELING & ANALYSIS OF ARC WELDED T-JOINT

    Directory of Open Access Journals (Sweden)

    S.N.Pilare

    2012-06-01

    Full Text Available Arc welded structures are widely used in automobiles, constructions & power plants. As the main cause of weldment failure is design defect & overload, hence it is necessary to analyze the maximum stresses inthe weldment. In this paper an experimentation is carried out on welded T-joint to determine the breaking stress in the weldment. The FE analysis & analytical estimation of breaking stress is also carried out to verify the experimental results. The stress distribution along weld size & throat thickness is evaluated and also compared with reported findings. Further T-joint weld is analyzed under static tensile & bending load by varying the gap between parent plates with and without chamfer at weldment edges. The fatigue analysis under alternating tensile and bending load is also carried out and fatigue life of weldment is predicted with variation in the gap between parent plates.

  7. 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.”

  8. Definition of welded joints arrangement in pressure vessels

    International Nuclear Information System (INIS)

    The arrangement of welded joints in a pressure vessel is normally a tiresome and lengthy task. This is especially so when long vessels are provided with a great concentration of nozzles, reinforcements, rings and many other accessories. The manual solution is seldom economical from the viewpoint of minimum waste of plates and minimum labor for cutting, bevelling and welding. This paper presents a computer application that allows a more economical solution in a shorter time. (Author)

  9. Impact tests on welded joints between the steel X 20 CrMoV 12 1 and 10 CrMo 9 10

    Energy Technology Data Exchange (ETDEWEB)

    Dueren, C.; Jahn, E.; Langhardt, W.; Schleimer, W.

    1982-05-03

    In a joint study of four works the toughness behaviour in the heat affected zone of welded joints between the steels X 20 CrMoV 12 1 and 10 CrMo 9 10 has been investigated. For manual arc and submerged arc welds using filler metals similar to X 20 CrMoV 12 1 or 10 CrMo 9 10, impact values were measured at room temperature on these weld junction sides where the different metals partner butt, which were partly lower than the minimum value of 34 J on the DVM transverse specimen required for the parent metals. The cause was the carbon diffusion during tempering after welding which, at the interface between the two steels, lead to the formation of a decarburized zone in the steel and weld metal 10 CrMo 9 10 and of a carbide seam in the steel and weld metal X 20 CrMoV 12 1. This phenomenon was especially pronounced in welds using a filler metal similar to 10 CrMo 9 10. It was further intensified by quenching and tempering. THis decrease of toughness did not occur when, by using the high-nickel filler metal S-NiCr 15 FeMn, carbon diffusion was largely suppressed during usual tempering after welding.

  10. 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

  11. Numerical Simulation of Residual Stresses in Linear Friction Welded Joints

    Directory of Open Access Journals (Sweden)

    R. Nikiforov

    2015-09-01

    Full Text Available A thermo-mechanical model of linear friction welding has been developed. The temperature distribution during the heating process was determined using a one-dimensional model. The distribution of temperature and stress field during the forging phase was determined by solving the coupled problem in ANSYS. The model allows to predict the effect of welding parameters on the stress field, whereas modeling data are consistent with the residual stresses in welded joints of the Ti6Al4V alloy obtained during the experiment.

  12. Damage tolerance reliability analysis of automotive spot-welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Mahadevan, Sankaran; Ni Kan

    2003-07-01

    This paper develops a damage tolerance reliability analysis methodology for automotive spot-welded joints under multi-axial and variable amplitude loading history. The total fatigue life of a spot weld is divided into two parts, crack initiation and crack propagation. The multi-axial loading history is obtained from transient response finite element analysis of a vehicle model. A three-dimensional finite element model of a simplified joint with four spot welds is developed for static stress/strain analysis. A probabilistic Miner's rule is combined with a randomized strain-life curve family and the stress/strain analysis result to develop a strain-based probabilistic fatigue crack initiation life prediction for spot welds. Afterwards, the fatigue crack inside the base material sheet is modeled as a surface crack. Then a probabilistic crack growth model is combined with the stress analysis result to develop a probabilistic fatigue crack growth life prediction for spot welds. Both methods are implemented with MSC/NASTRAN and MSC/FATIGUE software, and are useful for reliability assessment of automotive spot-welded joints against fatigue and fracture.

  13. Technology of Welding Joints Mixed with Duplex Steel

    Directory of Open Access Journals (Sweden)

    Słania J.

    2016-03-01

    Full Text Available Results of the examinations of sample plates of mixed joints with the duplex steel were discussed. Examinations were taken on the sample plates of mixed joints of sheet plates type P355NL1 and X2CrNiMoN22-5-3 welded by the flux-cored wire DW-329A by the Kobelco company of the following category T 22 9 3 NL RC/M3 in the gas shroud M21 (Ar+18%CO2 (plate no.1, and nickel covered electrodes E Ni 6082 by the Böhler company (plate no. 2. Results of the side bend test of welded joint, transverse tensile test, stretching of the weld metal, impact strength, micro and macroscopic metallographic examinations, and measurements of the delta ferrite content were presented.

  14. Quantitative Metal Magnetic Memory Reliability Modeling for Welded Joints

    Institute of Scientific and Technical Information of China (English)

    XING Haiyan; DANG Yongbin; WANG Ben; LENG Jiancheng

    2016-01-01

    Metal magnetic memory(MMM) testing has been widely used to detect welded joints. However, load levels, environmental magnetic field, and measurement noises make the MMM data dispersive and bring difficulty to quantitative evaluation. In order to promote the development of quantitative MMM reliability assessment, a new MMM model is presented for welded joints. Steel Q235 welded specimens are tested along the longitudinal and horizontal lines by TSC-2M-8 instrument in the tensile fatigue experiments. The X-ray testing is carried out synchronously to verify the MMM results. It is found that MMM testing can detect the hidden crack earlier than X-ray testing. Moreover, the MMM gradient vector sumKvs is sensitive to the damage degree, especially at early and hidden damage stages. Considering the dispersion of MMM data, theKvs statistical law is investigated, which shows thatKvs obeys Gaussian distribution. SoKvs is the suitable MMM parameter to establish reliability model of welded joints. At last, the original quantitative MMM reliability model is first presented based on the improved stress strength interference theory. It is shown that the reliability degree R gradually decreases with the decreasing of the residual life ratioT, and the maximal error betweenprediction reliability degreeR1and verification reliability degreeR2 is 9.15%. This presented method provides a novel tool of reliability testing and evaluating in practical engineering for welded joints.

  15. Strength Investigation of Thick Welded T-Joint using Finite Element Modelling

    OpenAIRE

    Aidy Ali; Tun Chun Yung; Z. A. Zulkefli; Nuraini Abdul Aziz; B. B. Sahari; M. Zadeh

    2010-01-01

    The paper discusses the computation of finite element modelling (FEM) of a thick welded joint as a high load transfer joint. The FEM utilises MSC PATRAN/NASTRAN software programs to predict and simulate the critical area of a welded joint. The elasticity limit for the specimen was determined and stress distribution was achieved in the joint to indicate critical parts of a welded T-joint and predict the critical locations for crack initiation in this kind of joint. Simulation and experimental ...

  16. Design consideration for wet welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Szelagowski, P.; Osthus, V. [GKSS Research Center, Geesthacht (Germany); Petershagen, H.; Pohl, R. [Univ. Hamburg (Germany). Inst. fuer Schiffbau; Lafaye, G. [Stolt Comex Seaway S.A., Marseille (France)

    1996-12-01

    Wet welding has become a joining technique that under certain circumstances can provide results which cannot be distinguished between wet or dry production and the achievable mechanical quality is comparable to dry atmospheric welds. Wet welding is not a process which can be applied easily and which can be properly handled by untrained diver welders. Wet welding is more than any other kind of welding process or procedure a joining technique that requires the full job-concentration and -knowledge of an excellent trained and skilled diver welder throughout the whole production time, who is 100% identifying himself with his task. Furthermore he must be fully aware of the production requirements and possible metallurgical/environmental reactions and outcomes. He must be able to be fully concentrated on the process performance throughout his total work shift. In short: he must be an outstanding expert in his field. The following paper will highlight these subjects and show the necessity of their exact observation to achieve excellent quality in wet welding.

  17. Interface and properties of the friction stir welded joints of titanium alloy Ti6Al4V with aluminum alloy 6061

    International Nuclear Information System (INIS)

    Highlights: • Friction stir butt welding of titanium alloy Ti6Al4V and aluminum alloy A6061-T6. • Welding parameters affect interfacial microstructure of the joint. • Welding parameters affect the mechanical property of joint and fracture position. • Joining mechanism of Ti6Al4V/A6061 dissimilar alloys by FSW is investigated. - Abstract: Titanium alloy Ti6Al4V and aluminum alloy 6061 dissimilar material joints were made with friction stir welding (FSW) method. The effects of welding parameters, including the stir pin position, the rotating rate and the travel speed of the tool, on the interface and the properties of the joints were investigated. The macrostructure of the joints and the fracture surfaces of the tensile test were observed with optical microscope and scanning electron microscope (SEM). The interface reaction layer was investigated with transmission electron microscopy (TEM). The factors affecting the mechanical properties of the joints were discussed. The results indicated that the tensile strength of the joints and the fracture location are mainly dependent on the rotating rate, and the interface and intermetallic compound (IMC) layer are the governing factor. There is a continuous 100 nm thick TiAl3 IMC at the interface when the rotating rate is 750 rpm. When the welding parameters were appropriate, the joints fractured in the thermo-mechanically affected zone (TMAZ) and the heat affected zone (HAZ) of the aluminum alloy and the strength of the joints could reach 215 MPa, 68% of the aluminum base material strength, as well as the joint could endure large plastic deformation

  18. Microstructural Characterization of Friction Stir Welded Aluminum-Steel Joints

    Science.gov (United States)

    Patterson, Erin E.; Hovanski, Yuri; Field, David P.

    2016-06-01

    This work focuses on the microstructural characterization of aluminum to steel friction stir welded joints. Lap weld configuration coupled with scribe technology used for the weld tool have produced joints of adequate quality, despite the significant differences in hardness and melting temperatures of the alloys. Common to friction stir processes, especially those of dissimilar alloys, are microstructural gradients including grain size, crystallographic texture, and precipitation of intermetallic compounds. Because of the significant influence that intermetallic compound formation has on mechanical and ballistic behavior, the characterization of the specific intermetallic phases and the degree to which they are formed in the weld microstructure is critical to predicting weld performance. This study used electron backscatter diffraction, energy dispersive spectroscopy, scanning electron microscopy, and Vickers micro-hardness indentation to explore and characterize the microstructures of lap friction stir welds between an applique 6061-T6 aluminum armor plate alloy and a RHA homogeneous armor plate steel alloy. Macroscopic defects such as micro-cracks were observed in the cross-sectional samples, and binary intermetallic compound layers were found to exist at the aluminum-steel interfaces of the steel particles stirred into the aluminum weld matrix and across the interfaces of the weld joints. Energy dispersive spectroscopy chemical analysis identified the intermetallic layer as monoclinic Al3Fe. Dramatic decreases in grain size in the thermo-mechanically affected zones and weld zones that evidenced grain refinement through plastic deformation and recrystallization. Crystallographic grain orientation and texture were examined using electron backscatter diffraction. Striated regions in the orientations of the aluminum alloy were determined to be the result of the severe deformation induced by the complex weld tool geometry. Many of the textures observed in the weld

  19. Comparison of Post Weld Treatment of High Strength Steel Welded Joints in Medium Cycle Fatigue

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Mouritsen, Ole Ø.; Hansen, Michael Rygaard;

    2010-01-01

    This paper presents a comparison of three post-weld treatments for fatigue life improvement of welded joints. The objective is to determine the most suitable post-weld treatment for implementation in mass production of certain crane components manufactured from very high-strength steel. The...... the stress range can exceed the yield-strength of ordinary structural steel, especially when considering positive stress ratios (R > 0). Fatigue experiments and qualitative evaluation of the different post-weld treatments leads to the selection of TIG dressing. The process of implementing TIG dressing...... in mass production and some inherent initial problems are discussed. The treatment of a few critical welds leads to a significant increase in fatigue performance of the entire structure and the possibility for better utilization of very high-strength steel....

  20. Equalization of Ti-6Al-4 V alloy welded joint by scanning electron beam welding

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The equalization of Ti-6Al-4V alloy welded joint with base metal on corrosion resistance, strength and ductility was studied. The solidification microstructure is transformed from 650 μm columnar grains to 100 μm equiaxed grains by scanning electron beam welding. The anodic polarization curve of 150 μm equiaxed grains coincides with that of base metal. Equal corrosion resistance between weld metal and base metal was ob tained. Uniform microstructure and solutedistribution are the basis of equalization. Corrosion rate of weld with 150 μm equiaxed grains is the lowest, 2.45 times lower than that of 650 μm columnar grains. Weld strength is 98% as much as that of base metal, yield-strength ratio is 99.5%, which is 3.6% higher than that of base metal.

  1. Residual stress and microstructure evolution by manufacturing processes for welded pipe joint in austenitic stainless steel type 316L

    International Nuclear Information System (INIS)

    Stress corrosion cracking (SCC) has been observed near the heat affected zone (HAZ) of welded pipe joint made of austenitic stainless steel type 316L, even though sensitization is not observed. Therefore, It can be considered that the effect of residual stress on SCC is more important. In the joining process of pipes, butt-welding is conducted after machining. Residual stress is generated by both processes. In case of welding after machining, it can be considered that residual stress due to machining is changed by welding thermal cycle. In this study, residual stress and microstructure evolution due to manufacturing processes is investigated. Change of residual stress distribution caused by processing history is examined by X-ray diffraction method. Residual stress distribution has a local maximum stress in the middle temperature range of the HAZ caused by processing history. Hardness measurement result also has a local maximum hardness in the same range of the HAZ. By using FE-SEM/EBSD, it is clarified that microstructure shows recovery in the high temperature range of HAZ. Therefore, residual stress distribution is determined by microstructure evolution and superposition effect of processing history. In summary, not only any part of manufacturing processes such as welding or machining but also treating all processes as processing history of pipes are important to evaluate SCC. (author)

  2. 复相钢CP800焊缝冷裂纹敏感性研究%COLD CRACKING SUSCEPTIBILITY OF WELDED JOINT OF CP800 STEEL

    Institute of Scientific and Technical Information of China (English)

    韩坤; 李清山; 李健; 孙慧珺; 张梅; 徐云峰

    2012-01-01

    The butt joint, Y shape butt joint, tee joint and control thermal severity (CTS) of the welded joint (lap joint) were studied after the gas shielded arc welding for CP800 steel. The macroscopic morphology, microstructure and properties of different welding points were measured to study the weld ability and cold cracking susceptibility of CP800 steel. The test results showed that the steel was appropriate for various welding forms of automobile parts due to the lower weld cold cracking susceptibility. The microstructure of heat affected zone was granular ferrite, bainite and a small amount of lath bainite, which were well distributed and the fusion was good. The hardness distribution of the four different welding forms was similar and the maximum hardness value was 320 HV, lower than 350 HV. The impact toughness of base metal, heat affected zone and fusion zone of Y shape butt joint was higher than 23 J, and the fracture surface was dimple fracture under the scanning electron microscope.%采用气体保护焊对试验钢CP800分别进行对接、斜Y、T型(角接)、CTS(搭接)焊接,测试分析不同焊接接头形式下的宏观形貌、微观组织和性能的变化,以研究CP800钢的可焊性和冷裂纹敏感性.实验结果表明:试验钢适用于各种焊接形式下的汽车结构件,具有很低的焊缝冷裂纹敏感性.焊接热影响区的组织为粒状铁素体、贝氏体以及少量的板条贝氏体,分布均匀,焊缝熔合良好.4种不同焊接方式下的焊缝硬度分布一致,最高硬度值为320 HV,小于350 HV.斜Y坡口对接接头处的母材、热影响区以及熔合区的冲击性能均大于23 J,其断口形貌均为韧窝形状.

  3. Fatigue life estimation of ultrasonic spot welded Mg alloy joints

    International Nuclear Information System (INIS)

    Highlights: • Fatigue life test of USWed similar Mg alloy was investigated. • USW joints exhibited a superior fatigue life compared with other welding processes. • Life prediction model agreed fairly well with the obtained experimental results. • The fatigue failure mode changed with decreasing cyclic load level. - Abstract: Lightweight magnesium alloys are increasingly used in automotive and other transportation industries for weight reduction and fuel efficiency improvement. The structural application of magnesium components requires proper welding and fatigue resistance to guarantee their durability and safety. The objective of this investigation was to identify failure mode and estimate fatigue life of ultrasonic spot welded (USWed) lap joints of an AZ31B-H24 magnesium alloy. It was observed that the solid-state USWed joints exhibited a superior fatigue life compared with other welding processes. Fatigue failure mode changed from interfacial failure to transverse-through-thickness crack growth with decreasing cyclic load level, depending on the welding energy. Fatigue crack initiation and propagation occurred from both the notch tip inside the faying surface and the edge of sonotrode indentation-footprints due to the presence of stress concentration. A life prediction model for the spot welded lap joints developed by Newman and Dowling was adopted to estimate the fatigue lives of the USWed magnesium alloy joints. The fatigue life estimation, based on the fatigue crack growth model with the global and local stress intensity factors as a function of kink length and the experimentally determined kink angle, agreed fairly well with the obtained experimental results

  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. Laser Shock Processing of Metal Sheet and Welded Joints

    Institute of Scientific and Technical Information of China (English)

    ZOU Shi-kun; TAN Yong-sheng; ZHANG Xiao-bin; LIU Fang-jun

    2004-01-01

    In order to study the application of laser shock processing(LSP) as a post weld treatment technology and a strengthening technology, a series experiments and analysis were taken in this paper. The hardness of the laser shock processed zone of Al-Li alloy was measured, and the microstructure and mechanical properties of the welded joints of the Ni-based superalloy GH30 and the Austenitic stainless steel 1Cr18Ni9Ti were compared with those without LSP in this paper. The results showed that the size of strengthened zone was similar to that of laser spot and strengthened layer was about 1mm deep, and the high intense dislocations and twins produced in the shocked zone. Plastic strain also gained surface residual compress stress, which is benefit for the fatigue properties of welded zones. In this test, the surface hardness of welding zone of the superalloy GH30 improved obviously and tensile strength increased by 12%, but the improvement of fatigue life was not obvious; Martensite phase is formed in plasma welding 1Cr18Ni9Ti, which reduced the effect of strain deformation martensite induced by laser shock processing, but the surface residual compress stress gained by laser shock processing can obviously improve the fatigue life of 1Cr1 8Ni9Ti welded joints.

  6. Laser Shock Processing of Metal Sheet and Welded Joints

    Institute of Scientific and Technical Information of China (English)

    ZOUShi-kun; TANYong-sheng; ZHANGXiao-bin; LIUFang-jun

    2004-01-01

    In order to study the application of laser shock processing(LSP) as a post weld treatment technology and a strengthening technology, a series experiments and analysis were taken in this paper. The hardness of the laser shock processed zone of A1-Li alloy was measured, and the microstructure and mechanical properties of the welded joints of the Ni-based superalloy GH30 and the Austenitic stainless steel 1Crl8Ni9Ti were compared with those without LSP in this paper. The results showed that the size of strengthened zone was similar to that of laser spot and strengthened layer was about lmm deep, and the high intense dislocations and twins produced in the shocked zone. Plastic strain also gained surface residual compress stress, which is benefit for the fatigue properties of welded zones. In this test, the surface hardness of welding zone of the superalloy GH30 improved obviously and tensile strength increased by 12%, but the improvement of fatigue life was not obvious; Martensite phase is formed in plasma welding 1Crl8Ni9Ti, which reduced the effect of strain deformation martensite induced by laser shock processing, but the surface residual compress stress gained by laser shock processing can obviously improve the fatigue life of 1Crl 8Ni9Ti welded joints.

  7. Size effect of welded thin-walled tubular joints

    OpenAIRE

    Mashiri, Fidelis Rutendo; Zhao, Xiao-Ling; Hirt, Manfred A.; NUSSBAUMER, Alain

    2007-01-01

    This paper clarifies the terminologies used to describe the size effect on fatigue behaviour of welded joints. It summarizes the existing research on size effect in the perspective of newly defined terminologies. It identifies knowledge gaps in designing tubular joints using the hot spot stress method, i.e. thin-walled tubular joints with wall thickness less than 4 mm and thick-walled tubular joints with wall thickness larger than 50 mm or diameter to thickness ratio less than 24. It is the t...

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

    Directory of Open Access Journals (Sweden)

    Kęstutis Dauskurdis

    2015-03-01

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

  9. Inhibition of the formation of intermetallic compounds in aluminum-steel welded joints by friction stir welding

    International Nuclear Information System (INIS)

    Formation of deleterious phases during welding of aluminum and steel is a challenge of the welding processes, for decades. Friction Stir Welding (FSW) has been used in an attempt to reduce formation of intermetallic compounds trough reducing the heat input. In this research, dissimilar joint of 6063-T5 aluminum alloy and AISI-SAE 1020 steel were welded using this technique. The temperature of welded joints was measured during the process. The interface of the welded joints was characterized using optical microscopy, scanning and transmission electron microscopy. Additionally, composition measurements were carried out by X-EDS and DRX. The experimental results revealed that the maximum temperature on the joint studied is less than 360 degree centigrade. The microstructural characterization in the aluminum-steel interface showed the absence of intermetallic compounds, which is a condition attributed to the use of welding with low thermal input parameters. (Author)

  10. Experiments on Large-Diameter Welded Hollow Spherical Joint

    Institute of Scientific and Technical Information of China (English)

    CHEN Hai-zhong; ZHU Hong-ping; XIONG Shi-shu

    2009-01-01

    We experimented on welded hollow spherical joint of a stadium steel roof to investigate the stress and strain distributions on the surface of the joint and determine the ultimate bearing capacity. Then, finite element analysis was made to cross-examine the experimental results. When the test load was 140% of the design load, the stress at the bottom of the fourth wimble pipe reached the yield point. The experimental results agree with the analytical results well.

  11. Research on the Electrochemical Corrosion Behavior of Carbon Steel Pipe Welded Joint%碳钢管线焊接接头的电化学腐蚀行为研究

    Institute of Scientific and Technical Information of China (English)

    李维锋; 韩永典; 路永新; 孙紫麾; 陈英; 舒欣欣; 许威; 杨鹏; 毛晓军; 杨寿海; 徐连勇

    2015-01-01

    母材选用 A106B 管线钢,焊丝选用2.4 mm 的实芯焊丝 ER70S-G,使用两种焊接工艺(GTAW+SMAW和GTAW)进行钢管对接焊,试样焊接前后均无热处理。通过对焊接接头的焊缝、热影响区和母材的极化曲线测量,研究了两种焊接工艺所得焊接接头各区域的腐蚀行为。结果表明,两种接头不同区域的耐蚀性为:母材>热影响区>焊缝。%In this article, it used two kinds of welding process (GTAW+SMAW and GTAW)to carry out butt welding for A106B pipeline steel, selecting 2.5 mm solid core welding wire of ER70S-G, without heat treatment for test sample before and after welding. Through polarization curve measurement for welded joint weld, HAZ and base metal, the corrosion behavior of welded joints various regions under two welding process were studied. The results showed that the corrosion resistance of two kinds of welded joints various regions are as follows:the base metal>HAZ>weld.

  12. Relationship between microstructures and mechanical properties of resistance spot welded joint of spring steel

    Institute of Scientific and Technical Information of China (English)

    Xu Guocheng; Wang Chunsheng; Zhao Xihua; Cheng Guoli

    2006-01-01

    Based on mechanical properties tests and microstructures investigations, the relationship between microstructures and mechanical properties of resistance spot welded joints of spring steel is studied.The agglomeration of precipitated carbide is the sign that indicates spot welded joints structure of spring steel is fully tempered.Spot welded joints microstructure of nickelplated spring steel is fully tempered in random tempering heat treatment process, and mechanical properties of the welded joints are advanced.This research results showed a new approach for increasing spot welded joints quality of spring steel and hardened steel.

  13. 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...

  14. Investigation of the Microstructure of Joints of Aluminum Alloys Produced by Friction Stir Welding

    Science.gov (United States)

    Kolubaev, E. A.

    2015-02-01

    Special features of the microstructure of joints of aluminum-magnesium and aluminum-copper alloys produced by friction stir welding are analyzed. It is demonstrated that a layered structure with ultradisperse grains is produced by friction stir welding at the center of the weld joint. An analogy is drawn between the microstructures of joints produced by friction stir welding and surface layer produced by sliding friction.

  15. 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.

  16. 低碳钢与不锈钢焊接接头弯曲性能的分析%Analysis of bending property of dissimilar steels welded joints

    Institute of Scientific and Technical Information of China (English)

    王瑞; 王凤会; 田华明; 只德瑞; 孙杰; 杜剑锋; 王惜宝

    2013-01-01

    通过对Q235-B和316L异种钢I形和Y形坡口埋弧焊对接接头Q235-B一侧熔合区显微组织和元素分布及显微硬度的观测和分析,指出了在碳素结构钢与不锈钢异种金属的焊接接头中,碳素结构钢一侧出现硬而脆的熔合区;提出了减小熔合区的宽度是提高异种钢焊接接头抗弯曲性能的关键.此外研究了不同焊接工艺对焊接接头抗弯曲性能的影响机制,采用小尺寸的Y形坡口和使用含镍量高的焊丝,既有效地减小了熔合区的宽度,提高了异种钢焊接接头的抗弯曲性能,避免在对接接头双面埋弧焊时发生烧穿焊接缺陷.%The dissimilar steel welded joints were made between Q235-B carbon steel and 316L stainless steel by submerge arc welding using Y and I patterns of welding groove. Based on the observation and analysis of the microstructure, elements distribution and micro hardness in the weld fusion zone near the Q235-B base metal, the hard and brittle transition layer would form in the fusion area near the carbon structural steel, when the dissimilar steels were welded. The decrease of width of brittle transition layer is the most important to improve the bending property of the dissimilar steels welded joint. Furthermore, the influences of different welding procedures on the bending property of the welded joint were investigated. The process of Y pattern groove and Ni-riched welding wire can minimize the width of brittle transition layer and raise the bending property of the welded joint. Besides, this welding procedure also avoids the welding fault of burning through when the butt joint of the dissimilar thin steel was welded by submerged arc welding on the double sides.

  17. Eddy-current inspection of welded joints of electro-welded pipes with using measurement result visualization

    International Nuclear Information System (INIS)

    Results on experimental studies of welded joints of electro-welded pipes with artificial defects through eddy currents are presented. Decoding and graphical interpretation of testing results are carried out through the computerized visualisation system of eddy currents signals converters. Possibility of evaluating the quality of pipe welding with eddy currents images decoding is shown. 8 refs., 3 figs

  18. Thermal-deformation effect of welding on A 1 reactor pressure vessel weld joints properties and state of stress

    International Nuclear Information System (INIS)

    The methods are compared of electroslag welding and of arc welding with a view to their possible application in welding the Bohunice A-1 reactor pressure vessel. Considered are the thermal deformation effects of welding on the physical properties and the stress present in welded joints. For testing, plates were used having the dimensions of 1100x2300x200 mm and rings with 4820 mm outer diameter, 1800 mm height and 170 mm thickness made of steel CSN 413O30 modified with Ni, Al+Ti. The deformation effect of welding on the residual surface and triaxial stress, the specific stored energy, the initiation temperature of brittle crack and the critical size of the initiation defect corresponding to the thermal deformation effect of welding were determined. It was found that for electroslag welding, there is a low probability of crack formation in the joints, a low level of residual stress and a low level of specific stored energy in a relatively wide joint zone. For arc welding there is a considerable probability of defect formation in the vicinity of the sharp boundary of the joint, a high level of the triaxial state of stress in the tensile region, and a high level of specific stored energy concentrated in the narrow zone of weld joints. The recommended thermal process is given for welding pressure vessels made of the CSN 413030 steel modified with Ni, Al+Ti, and 150 to 200 mm in thickness. (J.P.)

  19. Control of structure and properties of critical welded joints on basis of applying the pulsed welding production process

    International Nuclear Information System (INIS)

    A study is made into the influence of self-adjusting pulsed welding conditions on mechanical properties and structure of steel multilayer welded joints, in particular, when welding steel 12Kh1MF tubes for steam lines operating under high pressure and temperature conditions. It is stated that the regime suggested results in formation of dispersed and homogeneous structure, uniform distribution of microhardness and a welded joint ultimate strength increase by 10-15 % in comparison to the welding with a stationary-burning arc

  20. 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...

  1. Experimental investigation of laser beam welding of explosion-welded steel/aluminum structural transition joints

    International Nuclear Information System (INIS)

    The steel/aluminum structural transition joints are widely used in shipbuilding industry due to the advantages of joining these two materials with important weight savings while exploiting their best properties. The use of laser welding to strongly connect components made of Fe and Al alloys as base materials with Fe/Al structural transition joints is very attractive. The authors report results achieved during the laser welding of these particular joints with the scope to evaluate effects of the laser-induced thermal loads on the integrity of the Fe/Al bond interface, from metallurgical and mechanical points of view. The increase of both inter-metallic film thickness and extension were detected as a result of the laser beam induced heat on the Fe/Al bond interface. These increases did not cause severe reductions of the mechanical resistance of the investigated structural transition joint.

  2. Mechanical Properties and Microstructure of Dissimilar Material Welded Joints

    Directory of Open Access Journals (Sweden)

    Ziewiec A.

    2014-10-01

    Full Text Available The paper presents results of the mechanical testing and the microstructure analysis of dissimilar welded joint of the R350HT steel and the high-manganese (Hadfield cast steel using Cr-Ni cast steel spacer. The simulation tests of the welded joint surface deformation were carried out. The macroscopic and microscopic investigation were made using light microscopy (LM and scanning electron microscopy (SEM. Content of the magnetic phase was measured using magnetoscope. The quantitative metallographic investigation was used for assessment of ferrite and martensite contents and X-ray diffraction phase analysis was carried out. The results showed that during cooling of the spacer after welding, the transformation of metastable austenite into martensite proceeded. In addition to work hardening, the phase transformation of austenite into martensite occurs during the process of the superficial deformation of the spacer while simulated exploitation. This leads to a substantial increase of hardness, and at the same time, causes the increase of wear resistance of the welded joints of crossovers.

  3. Bench for mechanical cleaning of circular welded joints

    International Nuclear Information System (INIS)

    A special bench for weld reinforcement removal and mechanical cleaning of the heat affected zones was designed to provide for a possibility of an ultrasonic testing of welded joints in the course of steam generator section fabrication. The bench comprises a mechanized roller support for fixing and rotating the workpiece; a lap-cutting device for external machining; milling/grinding tractor for internal machining and a delivery table for tractor approach and departure. The bench performance and overall view are presented. The operation succession is described

  4. Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z.; Dong, P.; Liu, S.; Babu, S.; Olson, G.; DebRoy, T.

    2005-04-15

    The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high strength steels. In order to achieve high fatigue strength in a welded-joint it is necessary to manage the weld bead shape for lower stress concentration, produce preferable residual stress distribution, and obtain the desired microstructure for improved material toughness and strength. This is a systems challenge that requires the optimization of the welding process, the welding consumable, the base material, as well as the structure design. The concept of virtual welded-joint design has been proposed and established in this project. The goal of virtual welded-joint design is to develop a thorough procedure to predict the relationship of welding process, microstructure, property, residual stress, and the ultimate weld fatigue strength by a systematic modeling approach. The systematic approach combines five sub-models: weld thermal-fluid model, weld microstructure model, weld material property model, weld residual stress model, and weld fatigue model. The systematic approach is thus based on interdisciplinary applied sciences including heat transfer, computational fluid dynamics, materials science, engineering mechanics, and material fracture mechanics. The sub-models are based on existing models with further development. The results from modeling have been validated with critical experiments. The systematic modeling approach has been used to design high fatigue resistant welds considering the combined effects of weld bead geometry, residual stress, microstructure, and material property. In particular, a special welding wire has been developed in this project to introduce

  5. Acoustic testing of welded joints of steam pipelines with the cast stub tube of a slide valve

    International Nuclear Information System (INIS)

    Specific task has been made, i.e. to determine whether it is possible to conduct reliable inspection of a welded joint in a rolled pipe made of 12Kh1MF steel 18-22 mm thick with a cast branch piece of the lock gate made of 20KhMFL steel 27-40 mm thick, its outer diameter being 290 mm. The lock gate is intended for service under a pressure of 9.8 MPa and temperature of the working fluid 540 deg C. It is shown that acoustic testing of welded joints in the power engineering equipment with cast elements is possible with a sensitivity corresponding to the flat-bottom reflector area of at least 7 mm2, and minimal noise resistance of 2 dB in case of non-optimal angle of the butt end boring on the joint inner surface. Methodological recommendations on acoustic testing of the above-mentioned joints are made

  6. The study of measuring technology on the dynamic mechanical properties of welded joint with high strain rate

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, to meet the needs of studying work of dynamic mechanical properties of welded joint, the dynamic mechanical properties of welded joint were measured by means of SHPB(Split Hopkinson Pressure Bar).The dynamic mechanical property's curves of every part of welded joint were obtained. For studying the dynamic behavior of mechanical heterogeneity of welded joint, important data were offered. The method of test creates a new way of studying dynamic mechanical properties of welded joint.

  7. Ultrasonic flaw detection of the thin-walled articles weld joints

    International Nuclear Information System (INIS)

    Two versions of the weld joints ultrasonic flaw detections for thin-walled articles using computer-assisted flaw detector on display of which the color picture is formed are described. The detection method of weld joints flaws obtained at contact and diffusive welding is developed

  8. 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

    Directory of Open Access Journals (Sweden)

    Muhamad Tehyo

    2012-09-01

    Full Text Available 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 joined under two different tool rotation speeds (1,750 and 2,000 rpm and six welding speeds (20, 50, 80, 120, 160,and 200 mm/min, which are the two prime joining parameters in FSW. From the investigation, the higher tool rotation speedaffected the weaker material’s (SSM maximum tensile strength less than that under the lower rotation speed. As for weldingspeed associated with various tool rotation speeds, an increase in the welding speed affected lesser the base material’s tensilestrength up to an optimum value; after which its effect increased. Tensile elongation was generally greater at greater toolrotation speed. An averaged maximum tensile strength of 206.3 MPa was derived from a welded specimen produced at the toolrotation speed of 2,000 rpm associated with the welding speed of 80 mm/min. In the weld nugget, higher hardness was observedin the stir zone than that in the thermo-mechanically affected zone. Away from the weld nugget, hardness levels increased backto the levels of the base materials. The microstructures of the welding zone in the FS welded dissimilar joint can be characterizedboth by the recrystallization of SSM356-T6 grains and AA6061-T651 grain layers.

  9. Technical Letter Report - Preliminary Assessment of NDE Methods on Inspection of HDPE Butt Fusion Piping Joints for Lack of Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Susan L.; Cumblidge, Stephen E.; Doctor, Steven R.; Hall, Thomas E.; Anderson, Michael T.

    2008-05-29

    The U.S. Nuclear Regulatory Commission (NRC) has a multi-year program at the Pacific Northwest National Laboratory (PNNL) to provide engineering studies and assessments of issues related to the use of nondestructive evaluation (NDE) methods for the reliable inspection of nuclear power plant components. As part of this program, there is a subtask 2D that was set up to address an assessment of issues related to the NDE of high density polyethylene (HDPE) butt fusion joints. This work is being driven by the nuclear industry wanting to employ HDPE materials in nuclear power plant systems. This being a new material for use in nuclear applications, there are a number of issues related to its use and potential problems that may evolve. The industry is pursuing ASME Code Case N-755 entitled “Use of Polyethylene (PE) Plastic Pipe for Section III, Division 1, Construction and Section XI Repair/Replacement Activities” that contains the requirements for nuclear power plant applications of HDPE. This Code Case requires that inspections be performed after the fusion joint is made by visually examining the bead that is formed and conducting a pressure test of the joint. These tests are only effective in general if gross through-wall flaws exist in the fusion joint. The NRC wants to know whether a volumetric inspection can be conducted on the fusion joint that will reliably detect lack-of-fusion conditions that may be produced during joint fusing. The NRC has requested that the work that PNNL is conducting be provided to assist them in resolving this inspection issue of whether effective volumetric NDE can be conducted to detect lack of fusion (LOF) in the butt HDPE joints. PNNL had 24 HDPE pipe specimens manufactured of 3408 material to contain LOF conditions that could be used to assess the effectiveness of NDE in detecting the LOF. Basic ultrasonic material properties were measured and used to guide the use of phased arrays and time-of-flight diffraction (TOFD) work that

  10. EFFECT OF CARBON MIGRATION ON CREEP PROPERTIES OF Cr5Mo DISSIMILAR WELDED JOINTS WITH Ni-BASED AND AUSTENITIC WELD METAL

    Institute of Scientific and Technical Information of China (English)

    J.M. Gong; Y. Jiang; S.T. Tu

    2004-01-01

    In this paper, the effect of carbon migration on creep properties of Cr5Mo dissimilar welded joints with Ni-based (Inconel 182) and Cr23Ni13 (A302) austenitic weld metal was investigated. Carbon migration near the weld metal/ferritic steel interface of Cr5Mo dissimilar welded joints was analyzed by aging method. Local creep deformations of the dissimilar welded joints were measured by a long-term local creep deformation measuring technique. The creep rupture testing was performed for Cr5Mo dissimilar welded joints with Inconel 182 and A302 weld metal. The research results show that the maximum creep strain rate occurs in the decarburized zone located on heat affect zone (HAZ) of Cr5Mo ferritic steel. The creep rupture life of Cr5Mo dissimilar welded joints with A302 weld metal decreases due to carbon migration and is about 50% of that welded with Inconel 182 weld metal.

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

    Directory of Open Access Journals (Sweden)

    Muhamad Tehyo

    2011-08-01

    Full Text Available 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 profile, tool rotation speed, welding speed, and tool axial force influenced the mechanical properties of theFS welded joints significantly. For this experiment, the FS welded materials were joined under two different tool rotationspeeds (1,750 and 2,000 rpm and six welding speeds (20, 50, 80, 120, 160, and 200 mm/min, which are the two prime joiningparameters in FSW. A cylindrical pin was adopted as the welding tip as its geometry had been proven to yield better weldstrengths. From the investigation, the higher tool rotation speed affected the weaker material’s (SSM maximum tensilestrength less than that under the lower rotation speed. As for welding speed associated with various tool rotation speeds, anincrease in the welding speed affected lesser the base material’s tensile strength up to an optimum value; after which its effectincreased. Tensile elongation was generally greater at greater tool rotation speed. An averaged maximum tensile strength of197.1 MPa was derived for a welded specimen produced at the tool rotation speed of 2,000 rpm associated with the weldingspeed of 80 mm/min. In the weld nugget, higher hardness was observed in the stir zone and the thermo-mechanically affectedzone than that in the heat affected zone. Away from the weld nugget, hardness levels increased back to the levels of the basematerials. The microstructures of the welding zone in the FS welded dissimilar joint can be characterized both by the recrystallizationof SSM 356 grains and

  12. Ultrasonic inspection of AA6013 laser welded joints

    Directory of Open Access Journals (Sweden)

    Adriano Passini

    2011-09-01

    Full Text Available Interest in laser beam welding for aerospace applications is continuously growing, mainly for aluminum alloys. The joints quality is usually assessed by non-destructive inspection (NDI. In this work, bead on plate laser welds on 1.6 mm thick AA6013 alloy sheets, using a 2 kW Yb-fiber laser were obtained and inspected by pulse/echo ultrasonic phased-array technique. Good and poor quality welds were inspected in order to verify the limits of inspection, comparing also to X-ray radiography and metallographic inspections. The results showed that ultrasonic phased array technique was able to identify the presence of grouped porosity, through the attenuation of the amplitude of the echo signal. This attenuation is attributed to the scattering of the waves caused by micro pores, with individual size below the resolution limit of the equipment, but when grouped, can cause a perceptive effect on the reflection spectra.

  13. GTAW penetration based on electrode tip location versus weld joint center line

    Science.gov (United States)

    Daumeyer, G. J., III

    1992-11-01

    Gas Tungsten Arc Welding (GTAW) is often the chosen process for final enclosure welds of heat sensitive electrical and electronic product. GTAW is used to produce welds that satisfy design requirements (usually a penetration requirement) and not expose the product to such high heat that would cause unwanted damage. An important variable in the GTAW process is the location of the Electrode tip over the weld joint center line. This study shows the tolerance of positional location over a narrow scope. Using coupons which represent the W88 container weld joint geometry, penetration vs. electrode tip positional location (offset) is investigated. Results indicate a positional location tolerance of +/- 0.008 in. is acceptable. Several different major components (MC's) supporting various weapons programs require low heat input GTA welds. The electrode tip positional location tolerance is determined by each MC's weld joint tolerances and heat sensitivity. For this short study, the weld joint geometry of a container weld was used. These coupons were welded with the specified weld schedule and one additional weld schedule in order to show the relationship based on both travel speed and gap. Multiple coupon welds were made to eliminate error in the results. Within the scope of this research, a positional tolerance of +/- 0.008 in. of the electrode center over the weld joint center is required. For other MC's this tolerance may be tighter or more relaxed depending upon the specific considerations.

  14. 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...

  15. 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.

  16. 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...

  17. 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...

  18. Subsection method of fatigue design for welded joints treated by ultrasonic peening

    Institute of Scientific and Technical Information of China (English)

    Wang Ting; Wang Dongpo; Huo Lixing; Zhang Yufeng

    2006-01-01

    Concerning the notable difference between the S-N curve slope of welded joints treated by ultrasonic peening treatment (UPT) and that of as-welded joints, the subsection method is put forward for fatigue design of welded joints treated by UPT, using the design method of nominal S-N curves. Results show that, in medium life zone, strength grade of the fatigue design curves for UPT welded joints is two grades higher than that for as-welded joints. Furthermore, in medium life zone, strength grade of the fatigue design curves for UPT welded joints is three grades lower than that in long life zone.Conclusion of the comparison is that as for different joint types in different life zones, fatigue design should be processed according to different S-N curves respectively.

  19. Tensile properties and mechanical heterogeneity of friction stir welded joints of 2014 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yan-hua; LIN San-bao; WU Lin; QU Fu-xing

    2005-01-01

    2014 Al alloy of 8mm in thickness was successfully welded by friction stir welding method. The experimental results show that the tensile properties of the joints are significantly affected by the welding parameters. When the weld pitch is 0.25mm/r corresponding to the rotation speed of 400r/min and the welding speed of 100mm/min, the maximum ultimate strength of the joints is 78% that of the base material. For a certain weld joint, different parts possess different mechanical properties. In the three parts of the joint, the upper part is strongest and the middle part is poorest in mechanical properties. The mechanical properties and fracture locations of the joints are dependent on the microstructure variation and micro-hardness distributions of the joints, which attributes to the different thermo-mechanical actions on the different parts of the joints.

  20. Study of Microstructure and Properties of Non-Electric Welded Joints

    Institute of Scientific and Technical Information of China (English)

    MA Shi-ning; LUO Lin; HU Jun-zhi; XU Xiao-ping

    2004-01-01

    Non-electric welding, which combines the advantages of traditional welding and Self-propagating Hightemperature Synthesis (SHS), is a newly developed technology because of its simple process and no energy supplement during welding. In this paper, two pieces of 45 steel sheets were welded by Non-electric welding, and the properties of joints were studied. The microstructure and mechanical properties were investigated by SEM, EDAX, hardness tester and tensile tester.The interfaces of the joints and matrix show excellent metallurgical bonding, and the elements of joints have diffused into substrate. Welded joints have high mechanical properties. The bonding strength can reach 348 MPa, and the impact toughness is 44 J/cm2. Non-electric welding technology also can weld non-ferrous, and this technology especially suited to be used at the emergent maintenance of field.

  1. Laser welding process tailored to tube-sheet joint requirements for heat exchangers manufacturing for nuclear power plants

    International Nuclear Information System (INIS)

    The aim of this work is to highlight the viability of the laser welding process to weld tuba to tube-sheet joints. The laser welding process provides higher welding speed, narrower weld beads and lower heat input than arc processes. So the laser welding process of tuba to tube-sheet joints will be able to reduce the cycle time of the welding process in heat exchangers manufacturing, reducing also thermal distortions.

  2. Development of micro machining tools for finishing weld joint

    International Nuclear Information System (INIS)

    GE, Hitachi and Toshiba are jointly constructing advanced boiling water reactor (ABWR) Units 6 and 7 at Kashiwazaki Kariwa Nuclear Power Plant Station, Tokyo Electric Power Co. The ABWR features enhanced operability and safety as a whole plant through simplicity and improved performance. To achieve these improvement, one of the key features of technical innovation adopted in the ABWR design, ten reactor internal pumps (RIP) are adopted as the reactor recirculation system. The RIP casing to hold the RIP constituting the primary pressure boundary together with a RPV is welded to the nozzle on a RPV lower shell with Gas Tungsten Arc Welding (GTAW). The welding is on V-groove using automatic GTAW technique from the inside of the casing. The penetration bead (the back side of the weld) therefore needs to be finished with machining tools to inspect the qualification of the welding. This paper summarizes the development of the special purpose micro machines which are installed inside the narrow gap being provided between the RIP casing and the RPV (skirt) to finish the penetration bead. (author)

  3. On-line evaluating on quality of mild steel joints in resistance spot welding

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A method was developed to realize quality evaluation on every weld-spot in resistance spot welding based on information processing of artificial intelligent. Firstly, the signals of welding current and welding voltage, as information source, were synchronously collected. Input power and dynamic resistance were selected as monitoring waveforms. Eight characteristic parameters relating to weld quality were extracted from the monitoring waveforms. Secondly, tensile-shear strength of the spot-welded joint was employed as evaluating target of weld quality. Through correlation analysis between every two parameters of characteristic vector, five characteristic parameters were reasonably selected to found a mapping model of weld quality estimation. At last, the model was realized by means of the algorithms of Radial Basic Function neural network and sample matrixes. The results showed validations by a satisfaction in evaluating weld quality of mild steel joint on-line in spot welding process.

  4. Ultrasonic Welding of Thermoplastic Composite Coupons for Mechanical Characterization of Welded Joints through Single Lap Shear Testing.

    Science.gov (United States)

    Villegas, Irene F; Palardy, Genevieve

    2016-01-01

    This paper presents a novel straightforward method for ultrasonic welding of thermoplastic-composite coupons in optimum processing conditions. The ultrasonic welding process described in this paper is based on three main pillars. Firstly, flat energy directors are used for preferential heat generation at the joining interface during the welding process. A flat energy director is a neat thermoplastic resin film that is placed between the parts to be joined prior to the welding process and heats up preferentially owing to its lower compressive stiffness relative to the composite substrates. Consequently, flat energy directors provide a simple solution that does not require molding of resin protrusions on the surfaces of the composite substrates, as opposed to ultrasonic welding of unreinforced plastics. Secondly, the process data provided by the ultrasonic welder is used to rapidly define the optimum welding parameters for any thermoplastic composite material combination. Thirdly, displacement control is used in the welding process to ensure consistent quality of the welded joints. According to this method, thermoplastic-composite flat coupons are individually welded in a single lap configuration. Mechanical testing of the welded coupons allows determining the apparent lap shear strength of the joints, which is one of the properties most commonly used to quantify the strength of thermoplastic composite welded joints. PMID:26890931

  5. Finite element modelling of hybrid (spot welded/bonded) joints under service conditions

    OpenAIRE

    Dang, Weidong

    2015-01-01

    Spot welding and adhesive bonding are widely used in joining of sheet metals, such as assembling of car body-in-white. Recently, spot weld and adhesive are combined to make weld bonded joint, which is employed to join Advanced High Strength Steel to improve the stiffness and crashworthiness of car body. In industry, the assessment of designing prior to prototype requires reliable constitutive models in terms of the prediction of the mechanical behaviors. The FE model of weld bonded joint is a...

  6. Welded joint properties of 08Cr2.25Mo1NiNb type steel

    International Nuclear Information System (INIS)

    The results are given of a study into the effect of the chemical composition on the mechanical and structural properties of welded joint of steel 08Cr2.25Mo1NiNb. The welded joints were obtained by manual arc welding using coated electrodes. For assessing short-term strength and plastic properties, tensile tests at normal temperature, notch toughness tests, hardness measurements and bending tests were conducted. The welded joint microstructure was also analysed. The minimal values of the yield point can be obtained in welded joints of melts with the Nb content at a level of the stabilization ratio. The highest hardness values were obtained in the welding metal ranges, which, however, does not negatively affect the plastic properties of the joint. Lower values of notch toughness were found for welding metals with higher carbon content. (M.S.)

  7. Material test data of SUS304 welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Asayama, Tai [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Kawakami, Tomohiro [Nuclear Energy System Incorporation, Tokyo (Japan)

    1999-10-01

    This report summarizes the material test data of SUS304 welded joints. Numbers of the data are as follows: Tensile tests 71 (Post-irradiation: 39, Others: 32), Creep tests 77 (Post-irradiation: 20, Others: 57), Fatigue tests 50 (Post-irradiation: 0), Creep-fatigue tests 14 (Post-irradiation: 0). This report consists of the printouts from 'the structural material data processing system'. (author)

  8. Diffusion welding process and joint's microstructure behavior of SiCw/6061Al composite

    Institute of Scientific and Technical Information of China (English)

    LIU Liming; DONG Changfu; GAO Zhenkun

    2004-01-01

    The rules such as process parameters affecting joint properties and the evolution principle of weld's microstructure have been researched by adopting diffusion welding process to connect SiCw/6061Al composite. Experimental results show that there exists a critical temperature region between solid and liquid phase line of SiCw/6061Al composite, and the region will shrink with the increasing of welding pressure. When diffusion welding occurred under the critical temperature region, welding joint exhibits bad property of bonding, and the matrix and the reinforcement can't bond effectively. When diffusion welding occurred in the critical temperature region, the strength of welding joint changes widely with the variation of welding temperature. When welding temperature varies in 10℃, the strength of welding joint will change obviously.Only when welding temperature is higher than the critical temperature region, stable joint properties can be obtained. Simultaneously the matrix and the reinforcement has better interfacial bonded in diffusion welding interface, and no obvious interface reaction occurred, and thus diffusion welding of SiCw/6061Al composite can be successfully realized.

  9. Effect of post weld heat treatment on the microstructure and corrosion behavior of AA2219 aluminum alloy joints welded by variable polarity tungsten inert gas welding

    International Nuclear Information System (INIS)

    Highlights: • PWHT was used to improve the microstructure and properties of AA2219 joints. • Tensile strength increased by 44% and joint efficiency reached 76% after PWHT. • IGC and SCC resistance of PWHT joints was superior to that of welded joints. • Susceptibility to corrosion behavior was caused by formation of Al2Cu phase. - Abstract: AA2219 aluminum alloy was successfully welded by variable polarity tungsten inert gas (TIG) welding, and the effect of post weld heat treatment (PWHT) process on the microstructure, mechanical properties, and corrosion behavior of the welded joints was investigated. The PWHT process being used for the welded joints was consisted of solution treatment at 535 °C for 30 min, water quenching, and artificial aging at 175 °C for a soaking time of 12 h. The microstructure and precipitated phase of the as-welded joints and PWHT joints were analyzed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X ray diffraction (XRD) and transmission electron microscopy (TEM), while the corrosion behavior was evaluated by intergranular corrosion and stress corrosion cracking. The results showed that, by implementing PWHT, the microstructure of the joint was more homogeneous than the welded joint. Meanwhile, the tensile strength was increased by 44% and the joint efficiency reached 76%. Moreover, the corrosion resistance of the PWHT joint was superior to that of the welded joint. The heat affected zone (HAZ) was observed to be the most critical corroded zone, the susceptibility to corrosion behavior of the HAZ was attributed to the dissolution and segregation of Al2Cu phase along the grain boundaries

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-15

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

  12. Fatigue strength improvement of MIG-welded joint by shot peening

    Science.gov (United States)

    Azida Che Lah, Nur; Ali, Aidy

    2011-02-01

    In this study, the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel MIG-welded joint has been studied quantitatively. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity and inclusions found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed joints were compared. It was observed that the effect of the CSP and skimming processes improved the fatigue life of the fusion weld by 63% on MIG-welded samples.

  13. An Evaluation of Global and Local Tensile Properties of Friction-Stir Welded DP980 Dual-Phase Steel Joints Using a Digital Image Correlation Method

    Directory of Open Access Journals (Sweden)

    Hyoungwook Lee

    2015-12-01

    Full Text Available The effect of the microstructure heterogeneity on the tensile plastic deformation characteristic of friction-stir-welded (FSW dual-phase (DP steel was investigated for the potential applications on the lightweight design of vehicles. Friction-stir-welded specimens with a butt joint configuration were prepared, and quasi-static tensile tests were conducted, to evaluate the tensile properties of DP980 dual-phase steels. The friction-stir welding led to the formation of martensite and a significant hardness rise in the stir zone (SZ, but the presence of a soft zone in the heat-affected zone (HAZ was caused by tempering of the pre-existing martensite. Owing to the appearance of severe soft zone, DP980 FSW joint showed almost 93% joint efficiency with the view-point of ultimate tensile strength and relatively low ductility than the base metal (BM. The local tensile deformation characteristic of the FSW joints was also examined using the digital image correlation (DIC methodology by mapping the global and local strain distribution, and was subsequently analyzed by mechanics calculation. It is found that the tensile deformation of the FSW joints is highly heterogeneous, leading to a significant decrease in global ductility. The HAZ of the joints is the weakest region where the strain localizes early, and this localization extends until fracture with a strain near 30%, while the strain in the SZ and BM is only 1% and 4%, respectively. Local constitutive properties in different heterogeneous regions through the friction-stir-welded joint was also briefly evaluated by assuming iso-stress conditions. The local stress-strain curves of individual weld zones provide a clear indication of the heterogeneity of the local mechanical properties.

  14. Investigation of Residual Stresses and Distortion in Welded Pipe-Flange Joint of Different Classes

    OpenAIRE

    Muhammad Abid

    2012-01-01

    ABSTRACT: Pipe and flange joints are commonly used in petrochemical, nuclear and process industries. Commonly, welding is used to make these joints which produces residual stresses and distortions. These stresses have detrimental effects on the structural integrity and service performance of the welded pipe joints. The objective of this study is to investigate the residual stresses and distortions during Gas Metal Arc Welding of pipe of schedule 40, nominal diameter 200 mm with different ANSI...

  15. Durability of welded joints of heat resistant steels with crack-similar defects

    International Nuclear Information System (INIS)

    Estimation of the effect of cracks and crack-similar defects on supporting power of welded joints is important for estimation of workability and substantiation of control periodicity of welded joints of responsible elements of power equipment operating under creep. High-temperature welded joints of heat resistant steels of Cr-Mo-V system are shown to be characterized by low sensitivity to stress concentration

  16. Study of residual stresses in welded joints of dual phase HSLA steel used in automotive industry

    International Nuclear Information System (INIS)

    One way of weight reduction in automotive vehicles is through the use of high strength and low alloy (HSLA) steels, which enables the use of small thickness plates. Whereas the appearance of residual stresses is intrinsic to the welding process, this study evaluates the residual stresses generated in welded joints obtained by TIG and LASER welding processes and comparing them. Residual stresses were measured by X-rays diffraction technique, using a portable device with Crκα radiation applying the double exposure method. It also evaluates the influence of shot peening treatment applied after welding, in the bend tests conducted for both welding conditions and TIG welded joints showed higher stability of compressive stresses after welding. The metallographic analysis by optical microscopy complemented the welded joints characterization. (author)

  17. Simulation of hydrogen diffusion in welded joint of X80 pipeline steel

    Institute of Scientific and Technical Information of China (English)

    严春妍; 刘翠英; 张根元

    2014-01-01

    Hydrogen diffusion coefficients of different regions in the welded joint of X80 pipeline steel were measured using the electro-chemical permeation technique. Using ABAQUS software, hydrogen diffusion in X80 pipeline steel welded joint was studied in consideration of the inhomogeneity of the welding zone, and temperature-dependent thermo-physical and mechanical properties of the metals. A three dimensional finite element model was developed and a coupled thermo-mechanical-diffusion analysis was performed. Hydrogen concentration distribution across the welded joint was obtained. It is found that the postweld residual hydrogen exhibits a non-uniform distribution across the welded joint. A maximum equivalent stress occurs in the immediate vicinity of the weld metal. The heat affected zone has the highest hydrogen concentration level, followed by the weld zone and the base metal. Simulation results are well consistent with theoretical analysis.

  18. STUDY ON DYNAMIC J-INTEGRAL OF MECHANICAL HETEROGENEOUS WELDED JOINT

    Institute of Scientific and Technical Information of China (English)

    F.Q. Tian; D.Y. He; X.Y. Li; Y.W. Shi; D. Zhang

    2004-01-01

    Welded joint is a mechanical heterogeneous body, and mechanical heterogeneity has great effect on dynamic fracture behaviour of welded joints. In the present investigation, dynamic response curve and dynamic J-integral of practical undermatched welded joint and whole base and whole weld three-point-bend (TPB) models containing longitudinal crack are computed. Dynamic J-integral is evaluated using virtual crack extension (VCE) method and the computation is performed using MARC finite element code. Because of the effect of inertia,dynamic load response curve of computed model waves periodically. Dynamic J-integral evaluated by VCE method is path independent. The effect of inertia has little influence on dynamic J-integral curve. The value of dynamic J-integral of undermatched welded joint is lower than that of whole base metal and higher than that of whole weld metal. The results establish the foundation of safety evaluation for dynamic loaded welded structures.

  19. Evaluation of cold crack susceptibility on HSLA steel welded joints

    Directory of Open Access Journals (Sweden)

    Silverio-Freire Júnior, R. C.

    2003-04-01

    Full Text Available The present study addresses an evaluation of the effect of several welding parameters on cold cracking formation in welded joints of High Strength and Low Alloy steels, as well as the resulting microstructures and hardness values. The main parameters studied include the variation of the preheating temperature, drying time of the electrode, chemical composition and thickness of the base metal. The presence of cold cracking in the joints was analyzed from Tekken tests using steel plates made of SAR 80 T, 100 T and 120 T with of various thickness. The plates were welded by Shielded Metal Arc Welding either with or without pre-heating. Different preheating temperatures were studied, i.e., 375, 455 and 525 K. AWS E 12018 G and 11018 G electrodes were used under different conditions, i.e., not dried or dried up to 2, 3 and 4 h at 515 K. The results indicated the presence of cracks in the welded metals with the combination of hardness values above 230 HV and the formation of high contents of acicular ferrite (above 93 % in the welds without preheating. Higher crack susceptibility was also observed in the thick welded metal plates.

    Este trabajo evalúa la influencia de la variación de temperatura de precalentamiento, del tiempo de secado del electrodo, de la composición química y del espesor del metal base sobre la formación de fisuras en frío, inducidas por el hidrógeno en juntas soldadas de aceros de alta resistencia y baja aleación y su relación con la microestructura y dureza resultante. Para esto, se analizó la presencia de fisuras en frío en probetas para ensayos Tekken, fabricadas a partir de chapas de aceros SAR 80 T, 100 T y 120 T, con diferentes espesores y soldados por proceso de arco eléctrico con electrodo revestido, sin precalentamiento y con precalentamiento, a 375, 455 y 525 K, empleando electrodos AWS E 12018 G y 11018 G no secados y secados durante 2, 3 y 4 h. Los resultados obtenidos indicaron la presencia de fisuras

  20. Research on fatigue behavior and residual stress of large-scale cruciform welding joint with groove

    International Nuclear Information System (INIS)

    Highlights: • The fatigue behavior of the large-scale cruciform welding joint with groove was studied. • The longitudinal residual stress of the large-scale cruciform welding joint was tested by contour method. • The fatigue fracture mechanism of the large-scale cruciform welding joint with groove was analyzed. - Abstract: Fatigue fracture behavior of the 30 mm thick Q460C-Z steel cruciform welded joint with groove was investigated. The fatigue test results indicated that fatigue strength of 30 mm thick Q460C-Z steel cruciform welded joint with groove can reach fatigue level of 80 MPa (FAT80). Fatigue crack source of the failure specimen initiated from weld toe. Meanwhile, the microcrack was also found in the fusion zones of the fatigue failure specimen, which was caused by weld quality and weld metal integrity resulting from the multi-pass welds. Two-dimensional map of the longitudinal residual stress of 30 mm thick Q460C-Z steel cruciform welded joint with groove was obtained by using the contour method. The stress nephogram of Two-dimensional map indicated that longitudinal residual stress in the welding center is the largest

  1. Ultrasonic defect detection method for socket welding joint

    International Nuclear Information System (INIS)

    The present invention provides a method of detecting defects over a wide range of a socket weld portion of various kinds of pipelines used, for example, in a nuclear power plant. Namely, an inclined probe is disposed to a jig for detecting defects by ultrasonic waves. This is rotated at least by one turn along the peripheral surface of the material to be detected such as weld tube joints. Defects of weld portion of the material can be detected automatically by using ultrasonic waves during the rotation. The inclined probe for detecting defects by ultrasonic waves comprises a transmission portion having a planar transmittance oscillator disposed to a wedge on the transmission side and a receiving portion comprising a planar receiving oscillator disposed to a wedge on the receiving side. With such a constitution, ultrasonic waves are emitted from the transmission portion to the defect detection portion in the welded portion. If a defect is present, defective echo is reflected to the receiving portion disposed ahead of the probe. Since the defective echo changes depending on the height of the detective portion, the estimation of the height of the defect can be facilitated. (I.S.)

  2. MICROSTRUCTURE AND FATIGUE PROPERTIES OF DISSIMILAR SPOT WELDED JOINTS OF AISI 304 AND AISI 1008

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2013-06-01

    Full Text Available Carbon steel and stainless steel composites are being more frequently used for applications requiring a corrosion resistant and attractive exterior surface and a high strength structural substrate. Spot welding is a potentially useful and efficient jointing process for the production of components consisting of these two materials. The spot welding characteristics of weld joints between these two materials are discussed in this paper. The experiment was conducted on dissimilar weld joints using carbon steel and 304L (2B austenitic stainless steel by varying the welding currents and electrode pressing forces. Throughout the welding process; the electrical signals from the strain sensor, current transducer and terminal voltage clippers are measured in order to understand each and every millisecond of the welding process. In doing so, the dynamic resistances, heat distributions and forging forces are computed for various currents and force levels within the good welds’ regions. The other process controlling parameters, particularly the electrode tip and weld time, remained constant throughout the experiment. The weld growth was noted for the welding current increment, but in the electrode force increment it causes an adverse reaction to weld growth. Moreover, the effect of heat imbalance was clearly noted during the welding process due to the different electrical and chemical properties. The welded specimens finally underwent tensile, hardness and metallurgical testing to characterise the weld growth.

  3. Effect of post-weld aging treatment on mechanical properties of Tungsten Inert Gas welded low thickness 7075 aluminium alloy joints

    International Nuclear Information System (INIS)

    Highlights: → The effects of post-weld aging treatment on the properties of joints is studied. → The post-weld aging treatment increases the tensile strength of TIG welded joints. → The strengthening is due to a balance of dissolution, reversion and precipitation. → Simple post-weld aging at 140 oC enhances the properties of the welded joints. -- Abstract: This paper reports the influence of post-weld aging treatment on the microstructure, tensile strength, hardness and Charpy impact energy of weld joints low thickness 7075 T6 aluminium alloy welded by Tungsten Inert Gas (TIG). Hot cracking occurs in aluminium welds when high levels of thermal stress and solidification shrinkage are present while the weld is undergoing various degrees of solidification. Weld fusion zones typically exhibit microstructure modifications because of the thermal conditions during weld metal solidification. This often results in low weld mechanical properties and low resistance to hot cracking. It has been observed that the mechanical properties are very sensitive to microstructure of weld metal. Simple post-weld aging treatment at 140 oC applied to the joints is found to be beneficial to enhance the mechanical properties of the welded joints. Correlations between microstructures and mechanical properties were discussed.

  4. 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)

  5. Experimental characterization and modeling of the creep strength at 550 C of ASME Grade 92 steel welded joints

    International Nuclear Information System (INIS)

    In the framework of the development of Generation IV nuclear power plants, ASME Grade 92 ferritic-martensitic steel is a candidate material for components subjected to long-term creep at high temperature. The aim of this study is to characterize the microstructure of Grade 92 butt welded joints and to model their creep behavior at 550 C. Two filler rods were used for this study. The microstructure of the different weld regions was quantitatively characterized. In order to understand the weaker mechanical properties of the ICHAZ compared to the other regions of the welded joint, the microstructures of the base metal and the ICHAZ were compared at different scales (SEM, EBSD, TEM on thin foils and extractive replicas). No significant difference regarding micro-texture, sub-structure and precipitation state was highlighted between both microstructures. The origin of the weaker resistance of the ICHAZ to viscoplastic flow is still not fully understood. A softer zone was found in the base metal close to the ICHAZ, yet with finer sub-grains than the base metal. It was supposed to be a thermo-mechanically-affected zone (TMAZ). At high temperatures and low stress levels, Grade 92 welded joints may be sensitive to type IV cracking, which occurs in the inter-critical heat affected zone (ICHAZ). Creep tests conducted at 550 C on cross-weld specimens revealed that fracture takes place in the ICHAZ, even for short-term creep tests (i.e., lifetime lower than 1000 h). In order to model the creep behavior of the welded joint, viscoplastic constitutive equations for the different regions of the weld assembly were required. The viscoplastic behavior of the base metal, weld metal and of the ICHAZ were modeled using a phenomenological approach. The viscoplastic flow behavior of the weld metal and of the ICHAZ was experimentally determined (i) from tensile tests with displacement field measurements and (ii) from creep tests on tensile bars notched in the region of interest. An

  6. CHARACTERISATION OF SPOT WELD GROWTH ON DISSIMILAR JOINTS WITH DIFFERENT THICKNESSES

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2012-06-01

    Full Text Available A sound weld from spot welding is what most manufacturers desire and prefer for mechanical assemblies in their systems. The robustness is mainly attributed to the joining mechanism of mechanical parts. This paper focuses on the effect of parametric changes for dissimilar joints using 304 austenitic stainless steel and carbon steel of two different thicknesses. A pneumatic-based spot welder was used to accomplish the entire welding process. The parameters varied during the experiments are the welding current and welding time, while the electrode pressing force and electrode tip size are kept constant. The welding process began from a poor weld and moved on to a better weld by increasing the process parameters. However, this study is limited to the basic parametric variation to find the optimum parametric setup for 1 and 2 mm base metals. The welded specimens are subjected to tensile, hardness and metallurgical tests to characterise the spot weld growth for both thicknesses.

  7. A study on welded joint toughness of X-60 steel

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Charpy impact test and COD test were performed on the specimens subjected to simulated welded thermal cycle and the specimens taken from welded joint. The optical microscope, TEM, SEM, EDAX and XRD analysis have been used to investigate the behaviors of second phase particles and the effects of microstructure on toughness separately. The results are as follows. The dispersed second phase particles can effectively retard the growth of austenite grain in the coarse-grained HAZ (CGHAZ), and improve the toughness. When t8/5 is different, the behaviors of the particles are also different in dissolving, coarsening and re-precipitating. The ability of retarding the growth of austenite grain will be affected. When t8/5 increases from 10 s to 70 s, the microstructure of CGHAZ will transform from upper bainite and granular bainite to granular bainite, and the size of austenite grain will grow a little, thus the toughness of the materials decreases slightly.

  8. Microstructure and properties of Mg/Al joint welded by gas tungsten arc welding-assisted hybrid ultrasonic seam welding

    International Nuclear Information System (INIS)

    Graphical abstract: Gas tungsten arc welding (GTAW) was introduced into ultrasonic seam welding of Mg and Al dissimilar metals for the first time as shown in (a). The preceding GTAW can preheat the sheet metal to enhance the weldability. Without improving the ultrasonic power, the direct joining of 1 mm thick Al and Mg alloys sheets was accomplished and the maximum lap shear strength was 1 kN at a GTAW current of 30 A, approximately 40% of AZ31B Mg alloy base metal, as shown in (b). - Highlights: • Mg and Al were joined in solid state by hybrid ultrasonic seam welding. • The preceding GTAW heat source enhanced the acoustic bonding effect. • The maximum lap shear strength was 1 kN at a GTAW current of 30 A. - Abstract: A novel gas tungsten arc welding (GTAW) assisted hybrid ultrasonic seam welding MgAZ31B and Al6061 alloy sheets with satisfactory joint strength were successfully achieved using a previous GTAW preheating heat source. The preceding GTAW reduced the sheet hardness but enhanced the acoustic softening effect and materials plasticity. Therefore, the direct joining of 1 mm thick MgAZ31B and Al6061 alloy sheets can be obtained without improving the ultrasonic power. The effect of GTAW current on the microstructure and mechanical properties was investigated. The tensile shear strength of the joint increased with GTAW current up to a maximum strength and then decreased dramatically with higher GTAW current. The maximum lap shear strength was 1 kN at a GTAW current of 30 A, approximately 40% of AZ31B Mg alloy base metal. The failure occurred by interface fracture mode, and the fracture patterns exhibited brittle fracture mode with cleavage facet feature

  9. Electron microscopy and microanalysis of steel weld joints after long time exposures at high temperatures

    Science.gov (United States)

    Jandová, D.; Kasl, J.; Rek, A.

    2010-02-01

    The structural changes of three trial weld joints of creep resistant modified 9Cr-1Mo steels and low alloyed chromium steel after post-weld heat treatment and long-term creep tests were investigated. Smooth cross-weld specimens ruptured in different zones of the weld joints as a result of different structural changes taking place during creep exposures. The microstructure of the weld joint is heterogeneous and consequently microstructural development can be different in the weld metal, the heat affected zone, and the base material. Precipitation reactions, nucleation and growth of some particles and dissolution of others, affect the strengthening of the matrix, recovery at high temperatures, and the resulting creep resistance. Therefore, a detailed study of secondary phase's development in individual zones of weld joints can elucidate mechanism of cracks propagation in specific regions and the causes of creep failure. Type I and II fractures in the weld metal and Type IV fractures in the fine prior austenite grain heat affected zones occurred after creep tests at temperatures ranging from 525 to 625 °C and under stresses from 40 to 240 MPa. An extended metallographic study of the weld joints was carried out using scanning and transmission electron microscopy, energy-dispersive and wave-dispersive X-ray microanalysis. Carbon extraction replicas and thin foils were prepared from individual weld joint regions and quantitative evaluation of dislocation substructure and particles of secondary phases has been performed.

  10. Failure Behavior of Three-Steel Sheets Resistance Spot Welds: Effect of Joint Design

    Science.gov (United States)

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

    2012-08-01

    There is a lack of comprehensive understanding concerning failure characteristics of three-steel sheet resistance spot welds. In this article, macro/microstructural characteristics and failure behavior of 1.25/1.25/1.25 mm three-sheet low carbon steel resistance spot welds are investigated. To evaluate the mechanical properties of the joint, the tensile-shear test was performed in three different joint designs. Mechanical performance of the joint was described in terms of peak load, energy absorption, and failure mode. The critical weld nugget size required to insure pullout failure mode was obtained for each joint design. It was found that the joint design significantly affects the mechanical properties and the tendency to fail in the interfacial failure mode. It was also observed that stiffer joint types exhibit higher critical weld size. Fusion zone size along sheet/sheet interface proved to be the most important controlling factor of spot weld peak load and energy absorption.

  11. Camera Based Closed Loop Control for Partial Penetration Welding of Overlap Joints

    Science.gov (United States)

    Abt, F.; Heider, A.; Weber, R.; Graf, T.; Blug, A.; Carl, D.; Höfler, H.; Nicolosi, L.; Tetzlaff, R.

    Welding of overlap joints with partial penetration in automotive applications is a challenging process, since the laser power must be set very precisely to achieve a proper connection between the two joining partners without damaging the backside of the sheet stack. Even minor changes in welding conditions can lead to bad results. To overcome this problem a camera based closed loop control for partial penetration welding of overlap joints was developed. With this closed loop control it is possible to weld such configurations with a stable process result even under changing welding conditions.

  12. Carbon diffusion in friction welded joints of refractory metals in a liquid

    International Nuclear Information System (INIS)

    Research highlights: → The carbon from shielding liquid decomposition interacts with the metals being welded. This applies to the surface layers on the flash. → In vanadium-vanadium and vanadium-other metal joints a marked increase in microhardness in a narrow zone at the surface of the joint and carbide segregations in this zone on the vanadium side occur. → In titanium joints an increase in carbon content in the weld zone occurs. - Abstract: The effect of carbon on materials joined by friction welding in a liquid was studied. Titanium and tantalum specimens resistance-heated in a liquid and then specimens friction-welded in a liquid were tested. Same-metal (titanium, vanadium, tantalum) joints and dissimilar-metal joints were friction welded. The distribution of microhardness in the friction welded joints and their microstructure and linear concentration profiles were determined. The carbon from shielding liquid decomposition interacts with the metals being welded. This applies to the surface layers on the flash. In vanadium-vanadium and vanadium-other metal joints a marked increase in microhardness in a narrow zone at the surface of the joint and carbide segregations in this zone on the vanadium side occur. In titanium joints an increase in carbon content in the weld zone occurs.

  13. 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.

  14. Strength and microstructure of 2091 Al-Li alloy TIG welded joint

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The microstructure and tensile properties of TIG welding joints of 2091 Al-Li alloy were investigated both in as-welded and different postweld heat treatment condition. The results show that solution strengthening played an important role in the as-welded condition, though the precipitation strengthening δ' phase formed already in the as-welded weld metal, but its effect was not apparent due to the lower volume fraction of δ' phase. So the strength coefficient (φ) of the welded joint/base metal was 64%. After artificially aging heat treatment, the precipitation strengthening effect increased much due to the formation of more δ' phase and s' phase. Its φ value was increased up to 89%. The highest strength of the welded joints was obtained after solid solution and then artificially aged heat treatment. Due to the proper size of precipitation strengthening phases and their well distribution, the φ value was increased up to 98%.

  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. Operation reliability of plasma arc-welded joints for NPP pipings

    International Nuclear Information System (INIS)

    A technology has been developed of plasma-arc welding joints of pipe of steel 12Kh18N10T to replace the factory welding technology using the electrodes EA-400/10 t. It is established that the decisive influence of the formation and microcontinuity of the welded joint is produced by satisfying the optimum values of current and welding rate. Deviation from these values results in nonpenetrations and burnings. A study has been made of the welded joint strength properties at temperatures of 20, 200, 350 deg C and low-cycle fatigue at 350 deg C. The joints made by plasma-arc welding are shown to have higher cyclic strength and resistance to brittle fracture than those made by the former technology

  17. Interfacial characterization of resistance spot welded joint of steel and aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Zhang Weihua; Sun Daqian; Yin Shiqiang; Han Lijun; Qiu Xiaoming; Chen Qinglei

    2010-01-01

    The dissimilar material resistance spot welding of galvanized high strength steel and aluminum alloy had been conducted. The welded joint exhibited a thin reaction layer composed of Fe2Al5 and Fe4Al13 phases at steel/aluminum interface. The welded joint presented a tensile shear load of 3.3 kN with an aluminum alloy nugget diameter of 5.7 ram. The interfucial failure mode was observed for the tensile shear specimen and fracture occurred at reaction layer and aluminum alloy fusion zone beside the interface. The reaction layer with compounds was the main reason for reduction of the welded joint mechanical property.

  18. High-cycle Fatigue Properties of Alloy718 Base Metal and Electron Beam Welded Joint

    Science.gov (United States)

    Ono, Yoshinori; Yuri, Tetsumi; Nagashima, Nobuo; Sumiyoshi, Hideshi; Ogata, Toshio; Nagao, Naoki

    High-cycle fatigue properties of Alloy 718 plate and its electron beam (EB) welded joint were investigated at 293 K and 77 K under uniaxial loading. At 293 K, the high-cycle fatigue strength of the EB welded joint with the post heat treatment exhibited somewhat lower values than that of the base metal. The fatigue strengths of both samples basically increased at 77 K. However, in longer life region, the EB welded joint fractured from a blow hole formed in the welded zone, resulting in almost the same fatigue strength at 107 cycles as that at 293 K.

  19. A review on TIG welding for optimizing process parameters on dissimilar joints

    OpenAIRE

    Prashant Kumar Singh; Pankaj Kumar

    2015-01-01

    Tungsten Inert Gas Welding (TIG) is relatively high strength welding technique. This technique are mostly used in fabrication and other industries to join the either similar or dissimilar materials. In particular, it can be used to join high-quality strength of metal and alloys.In this paper we discuss abouttheTungsten Inert Gas welding of joining heat treatableof stainless steel and mild steel.These welded joints have higher tensile strength to weight ratio and finer micro struct...

  20. Fracture toughness of welded joints of a high strength low alloy steel

    International Nuclear Information System (INIS)

    The fracture toughness of the different regions of welded joints of a high strength low alloy steel, Niocor 2, was evaluated at different temperatures and compared with the toughness of the base metal. The studied regions were: the weld metal, fusion boundary and heat affected zone. The welding process used was the manual metal arc. It is shown that the weld metal region has the highest toughness values. (Author)

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Electron beam welding of tube-tube plate joints with a sectional chamber system

    International Nuclear Information System (INIS)

    The welding problem in a tube-tube plate and tube-lid joint of AlMgSi 1 is described, and conventional solutions and the progressive solution of electron beam welding with a newly developed machine with 'local' vacuum are presented. Set-up, functioning, machine characteristics and functions of the machine as well as fabrication difficulties and their solution are outlined. Furthermore, a progressive ultrasonic test method for the given welded joints is given. (orig./LH)

  6. The Cracking Induced by Oxidation-Hydriding in Welding Joints of Zircaloy-4 Plates

    Institute of Scientific and Technical Information of China (English)

    周邦新; 姚美意; 苗志; 李强; 刘文庆

    2003-01-01

    The welding joints of Zircaloy-4 plates obtained by diffusion welding at 800℃ under pressure in vacuum were cracked during autoclave tests at 400℃ superheated steam after exposure longer than 150 days. The section of specimens was examined by optical microscopy and the composition at the tips of cracking was analyzed by electron microprobe. The result shows that the combination of oxidation and hydriding induced cracking is responsible for this failure of the welding joints.

  7. Mechanical properties of austenitic stainless steel welded joints at high temperature

    International Nuclear Information System (INIS)

    Different test methods to define the characteristics of joints and their behavior in service are discussed, and various processes used in industrial projects are considered. The choice of process depends on many factors; thickness of the parts to be assembled, geometry of the joints etc... For construction designed to work at high temperature the reference process is manual welding. Electron welding and certain automatic welding methods are also examined

  8. Effect of Welding Current on the Structure and Properties of Resistance Spot Welded Dissimilar (Austenitic Stainless Steel and Low Carbon Steel) Metal Joints

    Science.gov (United States)

    Shawon, M. R. A.; Gulshan, F.; Kurny, A. S. W.

    2015-04-01

    1.5 mm thick sheet metal coupons of austenitic stainless steel and plain low carbon steel were welded by resistance spot welding technique. The effects of welding current in the range 3-9 kA on the structure and mechanical properties of welded joint were investigated. The structure was studied by macroscopic, microscopic and scanning electron microscopy techniques. Mechanical properties were determined by tensile testing and microhardness measurements. Asymmetrical shape weld nugget was found to have formed in the welded joint which increased in size with an increase in welding current. The fusion zone showed cast structure with coarse columnar grain and dendritic with excess delta ferrite in austenitic matrix. Microhardness of the weld nugget was maximum because of martensite formation. An increase in welding current also increased tensile strength of the weld coupon. An attempt has also been made to relate the mode of fracture with the welding current.

  9. Ultrasonic C-scanning imaging inspection of superplastic solid-state welded joint quality

    Institute of Scientific and Technical Information of China (English)

    张柯柯; 陈怀东; 杨蕴林; 薛锦

    2002-01-01

    Based on a large amount of dissection at welded interface and quantitative microscopic examination of welded rate, the suitable limit grey scale value was determined, and the welded rate of superplastic solid-state welding interface of heterogeneous steel was systematically studied by means of self-made ultrasonic C-scanning imaging inspection system. The experimental results show: the welded state of superplastic solid-state welding interface of heterogeneous steel can be conducted to be more accurately, reliably and quickly inspected by means of this system, and the ultrasonic testing results are good consistent with actual examination results of the interface defective distribution. Within the extent of the suitble welded rate,the welded rate in 40Cr/T10A superplastic welding process tested by this system is linear with its tensile strength of joint.

  10. Application of the local approach to the fatigue assessment for welded joints

    Institute of Scientific and Technical Information of China (English)

    王东坡; 张玉凤; 霍立兴; 陈俊梅; 王文先

    2003-01-01

    The fatigue behavior of welded structures is currently determined by means of recommendations defined in terms of S-N curve corresponding to the detail classes of welded joints without taking account of the actual geometry of the weld. A new fatigue strength assessment method based on Dang Van multiaxial fatigue limit criterion was introduced, which is named the local approach and presented by Institut de Soudure recently. The local approach has advantages in taking welding residual stresses and the geometry of the weld toe and weld root into consideration. The application of the local approach to the fatigue strength assessment of low carbon steel Q235B welded joints was studied. The fatigue tests and finite element analysis results show that the local approach parameters recommended by Institut de Soudure were incorrectly for low carbon steel Q235B welded joints. With aluminum alloy welded joints being used widely, the parameters of the local approach used for aluminum alloy welded joints were obtained and verified on bases of the fatigue tests and finite element analysis.

  11. Mechanical properties of type 316L stainless steel welded joint for ITER vacuum vessel (1). Experiment of unirradiated welded joint

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Shigeru; Fukaya, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishiyama, Shintaro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Takahashi, Hiroyuki; Koizumi, Kouichi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2001-01-01

    In design activity of ITER, the vacuum vessel (VV) is ranked as one of the most important components in core reactor from the view point of first barrier to tritium release from the reactor. The VV of ITER is designed as double walled structure so that some parts of them are not qualified in the conventional design standards. So it is necessary to prepare the new design standards to be applied them. JAERI has executed the preparation activity of the new design standards and the technical data to support them. In this study, the results of metallographic observation and mechanical properties of unirradiated type 316L stainless steel welded joint were reported. (author)

  12. 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

  13. Effect of Scandium on Corrosion Resistance of Welded Joint of Al-6Mg-Zr Alloy

    Institute of Scientific and Technical Information of China (English)

    Tao Binwu; Li Songmei; Liu Jianhua

    2005-01-01

    The corrosion resistance of welded joints of Al-6Mg-Sc-Zr alloy was studied by neutral salt spray and exfoliation corrosion methods. The microstructure of welded joints was investigated by using optical microscope and transmission electron micrograph (TEM). It is demonstrated that the welded joints of Al-6Mg-Sc-Zr alloy are more corrosion resistance, comparing with Al-6Mg-Zr alloy. The addition of scandium in the alloy results in (Al3Sc, Zr) particles, potently refined grains and restrained recrystallization process. The formation of homogeneous, discontinuous distribution of β-phase in welded joints improves the corrosion resistance of welded joints of Al-Mg-Zr alloy with high level content of magnesium.

  14. Application of welding simulation to block joints in shipbuilding and assessment of welding-induced residual stresses and distortions

    Directory of Open Access Journals (Sweden)

    Fricke Wolfgang

    2014-06-01

    Full Text Available During ship design, welding-induced distortions are roughly estimated as a function of the size of the component as well as the welding process and residual stresses are assumed to be locally in the range of the yield stress. Existing welding simulation methods are very complex and time-consuming and therefore not applicable to large structures like ships. Simplified methods for the estimation of welding effects were and still are subject of several research projects, but mostly concerning smaller structures. The main goal of this paper is the application of a multi-layer welding simulation to the block joint of a ship structure. When welding block joints, high constraints occur due to the ship structure which are assumed to result in accordingly high residual stresses. Constraints measured during construction were realized in a test plant for small-scale welding specimens in order to investigate their and other effects on the residual stresses. Associated welding simulations were successfully performed with fine-mesh finite element models. Further analyses showed that a courser mesh was also able to reproduce the welding-induced reaction forces and hence the residual stresses after some calibration. Based on the coarse modeling it was possible to perform the welding simulation at a block joint in order to investigate the influence of the resulting residual stresses on the behavior of the real structure, showing quite interesting stress distributions. Finally it is discussed whether smaller and idealized models of definite areas of the block joint can be used to achieve the same results offering possibilities to consider residual stresses in the design process.

  15. Effects of welding speed on the microstructures and mechanical properties of laser welded AZ61 magnesium alloy joints

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Jun, E-mail: shenjun@cqu.edu.cn; Wen, Libiao; Li, Yang; Min, Dong

    2013-08-20

    In this paper, the effects of welding speed on the microstructures and mechanical properties of laser welded AZ61 magnesium alloy plates were investigated by microstructural observations, microhardness tests and tensile tests. The results show that the microstructure in the fusion zone consisted of fine α-Mg equiaxed dendrite crystals and dispersed β-Mg{sub 17}Al{sub 12} particles. With an increase in welding speed, the sizes of α-Mg grains and β-Mg{sub 17}Al{sub 12} particles in the fusion zone decreased and the volume fraction of β-Mg{sub 17}Al{sub 12} particles increased. The ultimate tensile strength, yield strength and elongation of welded joint increased when the welding speed increased from 1800 mm min{sup −1} to 2800 mm min{sup −1}. In addition, the average hardness value of fusion zone and heat-affected zone increased with the increase in welding speed.

  16. Effects of welding speed on the microstructures and mechanical properties of laser welded AZ61 magnesium alloy joints

    International Nuclear Information System (INIS)

    In this paper, the effects of welding speed on the microstructures and mechanical properties of laser welded AZ61 magnesium alloy plates were investigated by microstructural observations, microhardness tests and tensile tests. The results show that the microstructure in the fusion zone consisted of fine α-Mg equiaxed dendrite crystals and dispersed β-Mg17Al12 particles. With an increase in welding speed, the sizes of α-Mg grains and β-Mg17Al12 particles in the fusion zone decreased and the volume fraction of β-Mg17Al12 particles increased. The ultimate tensile strength, yield strength and elongation of welded joint increased when the welding speed increased from 1800 mm min−1 to 2800 mm min−1. In addition, the average hardness value of fusion zone and heat-affected zone increased with the increase in welding speed

  17. Metallurgical characterization of pulsed current gas tungsten arc, friction stir and laser beam welded AZ31B magnesium alloy joints

    International Nuclear Information System (INIS)

    This paper reports the influences of welding processes such as friction stir welding (FSW), laser beam welding (LBW) and pulsed current gas tungsten arc welding (PCGTAW) on mechanical and metallurgical properties of AZ31B magnesium alloy. Optical microscopy, scanning electron microscopy, transmission electron microscopy and X-Ray diffraction technique were used to evaluate the metallurgical characteristics of welded joints. LBW joints exhibited superior tensile properties compared to FSW and PCGTAW joints due to the formation of finer grains in weld region, higher fusion zone hardness, the absence of heat affected zone, presence of uniformly distributed finer precipitates in weld region.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Ultrasonic Nondestructive Testing of Superplastic Solid-State Welding Joint for Different Steels

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on quantitative microscopic examinations of welds and welding rate for different steels (40Cr and T10A) joint, which possess the ultra-fine microstructure after high frequency hardening (HFH) and salt-bath cyclic quenching (SCQ), the suitable defect grey scale threshold value was determined, and the welding rate of superplastic solid-state welding of different steels (40Cr and T10A steel) was systematically inspected and analyzed by means of self-made ultrasonic imaging inspection system. The experimental results showed that the superplastic solid-state weld of different steels can be inspected more accurately, reliably and quickly by this system, and the results were in good accordance with that of metallographic observation. The welding rate of superplastic welding is in linear relation with tensile strength of joint.

  3. Microstructure and properties of 7A52 Al alloy welded joint

    Institute of Scientific and Technical Information of China (English)

    HUANG Ji-wu; YIN Zhi-min; LEI Xue-feng

    2008-01-01

    7A52 Al alloy plate aged at 105 ℃ for 8 h and then at 130 ℃ for 24 h was welded by means of TIG using Al- 6.3Mg-0.35Sc-0.1Zr-0.1Cr solder wire. Mechanical properties and microstructures of welded joint were studied. There are two obviously soft areas in the welded joint, welding seam and over-aging zone. The mechanical properties of welded joint are that σb is 358 MPa, σ0.2 is 238 MPa and δ5 is 6.6%. 75.6% of welding coefficient can be achieved. The addition of scandium leads to very significant grain refinement in the fusion zone, which results in a reduction in solidification cracking tendency. The solidification cracking isn't observed.

  4. Joint performance of CO2 laser beam welding 5083-H321 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Qi Junfeng; Zhang Dongyun; Xiao Rongshi; Chen Kai; Zuo Tiechuan

    2007-01-01

    Laser beam welding of aluminum alloys is expected to offer good mechanical properties of welded joints. In this experimental work reported, CO2 laser beam autogenous welding and wire feed welding are conducted on 4mm thick 5083-H321 aluminum alloy sheets at different welding variables. The mechanical properties and microstructure characteristics of the welds are evaluated through tensile tests, micro-hardness tests, optical microscopy and scanning electron microscopy (SEM). Experimental results indicate that both the tensile strength and hardness of laser beam welds are affected by the constitution of filler material, except the yield strength. The soften region of laser beam welds is not in the heat-affected zone (HAZ). The tensile fracture of laser beam welded specimens takes place in the weld zone and close to the weld boundary because of different filler materials. Some pores are found on the fracture face, including hydrogen porosities and blow holes, but these pores have no influence on the tensile strength of laser beam welds. Tensile strength values of laser beam welds with filler wire are up to 345.57MPa, 93% of base material values, and yield strengths of laser beam welds are equivalent to those of base metal (264.50MPa).

  5. 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.)

  6. 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

  7. 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

  8. 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...

  9. Microstructure and mechanical properties of laser-arc hybrid welding joint of GH909 alloy

    Science.gov (United States)

    Liu, Ting; Yan, Fei; Liu, Sang; Li, Ruoyang; Wang, Chunming; Hu, Xiyuan

    2016-06-01

    In this paper, laser-arc hybrid welding of 10 mm thick low-thermal-expansion superalloy GH909 components was carried out to obtain a joint with good performance. This investigation was conducted using an optical microscope, scanning electron microscope, energy diffraction spectrum and other methodologies. The results showed that weld joints with a desirable wineglass-shaped weld profile can be obtained employing appropriate process parameters. The different grains in between the upper central seam and the bottom seam were associated with the temperature gradient, the pool's flow and the welding thermal cycle. MC-type carbides and eutectic phases (γ+Laves) were produced at grain boundaries due to the component segregation during the welding process. In addition, γ‧ strengthening phase presented in the interior of grains, which kept a coherent relationship with the matrix. The lowest hardness value occurred in the weld center, which indicated that it was the weakest section in the whole joint. The average tensile strength of the joints reached to 632.90 MPa, nearly 76.84% of the base metal. The fracture analysis revealed that the fracture mode of the joint was ductile fracture and the main reason for joint failure was as a result of the occurrence of porosities produced in the weld during the welding process.

  10. Improving the fatigue performance of longitudinal welded joints by low transformation temperature electrodes

    Institute of Scientific and Technical Information of China (English)

    王文先; 霍立兴; 王东坡; 张玉凤; 荆洪阳; 杨新岐

    2003-01-01

    For a longitudinal welded joint, the tensile residual stresses are as high as the yield stress of the metal, so that the weld toes are sensitive to fatigue load. In this case a low transformation temperature electrode (LTTE) is one of the most useful methods used to improve the fatigue strength of the longitudinal welded joint, because the tensile residual stress is reduced or changed into compressive stress. Three kinds of longitudinal welded joints were selected to conduct fatigue tests. The tests results show that the fatigue strengths at 2×106 cycles of the joints welded with LTTE were improved by 41%, 47% and 59% respectively compared with those of the joints welded with E5015, and the fatigue lives at 162 MPa were improved by 9.9 times, 9.6 times and 46.8 times respectively. Furthermore, the LTTE method is not necessary to add process after welding and so that it can be valuable method to improve the fatigue performance of longitudinal welded joints.

  11. 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....

  12. Structure and properties of welded joints produced by pulsating and stationary arcs

    International Nuclear Information System (INIS)

    Comparison studies of the structure and properties of welded joints were carried out for the 245x45 mm pipeline made of the 15Kh1M1F steel and produced by manual welding with pulsating and stationary arcs. Service behaviour of welded joints was evaluated from the metal structure, cold resistance, fracture toughness and heat resistance. The manual welding by pulsating arc is shown to provide formation of 15Kh1M1F steel tube joints with more favourable structure and properties and also with higher cold resistance, deformability and heat resistance. High tempering (710-740 deg C, 3 h) is required for the welded joints produced both by pulsating and stationary arcs

  13. The Effect of Ultrasonic Peening Treatment on Fatigue Performance of Welded Joints

    Directory of Open Access Journals (Sweden)

    Xiaohui Zhao

    2016-06-01

    Full Text Available Ultrasonic peening treatment (UPT as a method of severe plastic deformation was used to treat cruciform welded joints of Q345 steel. The application of UPT achieves material surface nanocrystallization of the peening zone, reduces stress concentration, and produces residual compressive stresses at the welded toe. Micro-structure, hardness, stress relief, S-N curve, and the fatigue fracture mechanism of cruciform welded joint of Q345 steel, both before and after UPT, were analyzed in detail. The main results show that: stress concentration and residual tensile stress are the main reasons to reduce fatigue strength of cruciform welded joints. The fatigue life of cruciform welded joints is improved for surface hardening, compressive stress, and grain refinement by UPT. Residual compressive stress caused by UPT is released with the increase of fatigue life. A very significant fatigue strength improvement happens when UPT is replenished repeatedly after a certain number of cycles.

  14. Creep Rupture of Mismatched Welded Joints of Steels with Dissimilar Creep Strengths

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The finite element analysis of mismatched welded joints with a 30°groove angle was performed to study the mechanical behavior of DMWJs (dissimilar metal welded joints). It is concluded that the distribution of stress triaxiality in the DMWJs is uneven, especially near the fusion lines. The degree of creep strength mismatch has remarkable effect on the distribution. The higher the level of mismatch is, the more uneven the distribution is and the easier for premature failure to occur in the joint.

  15. Influences of post weld heat treatment on tensile properties of friction stir welded AA2519-T87 aluminium alloy joints

    Science.gov (United States)

    Sabari, S. Sree; Balasubramanian, V.; Malarvizhi, S.; Reddy, G. Madusudhan

    2015-12-01

    AA 2519-T87 is an aluminium alloy that principally contains Cu as an alloying element and is a new grade of Al-Cu alloy system. This material is a potential candidate for light combat military vehicles. Fusion welding of this alloy leads to hot cracking, porosity and alloy segregation in the weld metal region. Friction stir welding (FSW) is a solid state joining process which can overcome the above mentioned problems. However, the FSW of age hardenable aluminium alloys results in poor tensile properties in the as-welded condition (AW). Hence, post weld heat treatment (PWHT) is used to enhance deteriorated tensile properties of FSW joints. In this work, the effect of PWHT, namely artificial ageing (AA) and solution treatment (ST) followed by ageing (STA) on the microstructure, tensile properties and microhardness were systematically investigated. The microstructural features of the weld joints were characterised using an optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The tensile strength and microhardness of the joints were correlated with the grain size, precipitate size, shape and its distribution. From the investigation, it was found that STA treatment is beneficial in enhancing the tensile strength of the FSW joints of AA2519-T87 alloy and this is mainly due to the presence of fine and densely distributed precipitates in the stir zone.

  16. Single-sided laser beam welding of a dissimilar AA2024–AA7050 T-joint

    International Nuclear Information System (INIS)

    Highlights: • Single-sided laser beam welding of a dissimilar AA2024–AA7050 T-joint was realised. • For this purpose a fibre laser with high power and a large beam diameter was used. • Porosity-free weld seams with low penetration into the skin material were achieved. • The mechanical properties are comparable to that of double-sided welded T-joints. - Abstract: In the aircraft industry double-sided laser beam welding of skin–stringer joints is an approved method for producing defect-free welds. But due to limited accessibility – as for the welding of skin–clip joints – the applicability of this method is limited. Therefore single-sided laser beam welding of T-joints becomes necessary. This also implies a reduction of the manufacturing effort. However, the main obstacle for the use of single-sided welding of T-joints is the occurrence of weld defects. An additional complexity represents the combination of dissimilar and hard-to-weld aluminium alloys – like Al–Cu and Al–Zn alloys. These alloys offer a high strength-to-density ratio, but are also associated with distinct weldability problems especially for fusion welding techniques like laser beam welding. The present study demonstrates how to overcome the weldability problems during single-sided laser beam welding of a dissimilar T-joint made of AA2024 and AA7050. For this purpose a high-power fibre laser with a large beam diameter is used. Important welding parameters are identified and adjusted for achieving defect-free welds. The obtained joints are compared to double-sided welded joints made of typical aircraft aluminium alloys. In this regard single-sided welded joints showed the expected differing weld seam appearance, but comparable mechanical properties

  17. 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.

  18. Ultrasonic inspection of the brazed joint and explosive welds used to repair the PFR evaporators

    International Nuclear Information System (INIS)

    A small number of in-service failures associated with the steam-tube to tube-plate welds of the PFR evaporators led to the decision to protect the welds by sleeving. The philosophy was to insert a sleeve through the tube-plate and into the steam tube, thus bridging the existing weld. The top portion of the sleeve was to be explosively welded to the zone adjacent to the top face of the tube-plate and the lower portion brazed into the steam tube. This paper deals with the development and use of ultrasonics to test both the brazed and explosively welded joints

  19. Low-cycle fatigue of welded joints of alloy AMg5

    International Nuclear Information System (INIS)

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

  20. Crack propagation analysis of welded thin-walled joints using boundary element method

    Science.gov (United States)

    Mashiri, F. R.; Zhao, Xiao-Ling; Grundy, P.

    Tube-to-plate nodal joints under cyclic bending are widely used in the road transport and agricultural industry. The square hollow sections (SHS) used in these constructions are thin-walled and cold formed, and they have thicknesses of less than 4mm. Some fatigue failures have been observed. The weld undercut may affect the fatigue life of welded tubular joints especially for thin-walled sections. The undercut dimensions were measured using the silicon imprint technique. Modelling of thin-walled cruciform joints, as a simplification of welded tubular joints, is described in this paper to determine the effect of weld undercut on fatigue propagation life. The Boundary Element Analysis System Software (BEASY) is used. The results of the effect of weld toe undercut from this analysis are compared with results from previous research to determine the comparative reduction in fatigue life between thin-walled joints (T=3mm) and those made of thicker sections (T=20mm). The loss in fatigue strength of the thin-walled joints is found to be relatively more than that for thicker walled joints. A 3D model of a tube to plate T-joint is also modelled using the boundary element software, BEASY. The nodal joint consists of a square hollow section, 50×50×3 SHS, fillet welded to a 10-mm thick plate, and subjected to cyclic bending stress. Fatigue analyses are carried out and the results are compared with the only available S-N design curve.

  1. Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

    Science.gov (United States)

    Wang, Jing; Lu, Min-xu; Zhang, Lei; Chang, Wei; Xu, Li-ning; Hu, Li-hua

    2012-06-01

    To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by energy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corrosion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG welding. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints produced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.

  2. Microstructures and Plane Energy Spectra of X80 Pipeline Steel Welded Joints by Submerged Arc Automatic Welding

    Institute of Scientific and Technical Information of China (English)

    KONG Dejun; YE Cundong; GUO Wei; WU Yongzhong; LONG Dan

    2014-01-01

    X80 pipeline steel was welded with submerged arc automatic welding, the microstructures, cavity sizes, fusion depths and plane scanning of chemical elements in the welded zone, fusion zone, heat affected zone and base steel were observed with OM (optical microscope) and SEM (scanning electron microscope), respectively. The experimental results show that there is main acicular ferrite in the base steel and welded zone, the microscopic structure of fusion zone is a blocked bainite, and the heat affected zone is composed of multilateral ferrite and pearlite. M-A unit of the welded zone is the main factor to strengthen the welded zone, composed of acicular ferrites. The percentage of cavities in the welded joint is less than that in the base steel, which is beneficial to increasing its mechanical performance and corrosion resistance. The fusion depth in the fusion zone and welded zone is 101.13μm and 115.85μm, respectively, and the distribution of chemical elements in the welded zone is uniform, no enrichment phenomena.

  3. Effects of Sealing Run Welding with Defocused Laser Beam on the Quality of T-joint Fillet Weld

    Science.gov (United States)

    Unt, Anna; Poutiainen, Ilkka; Salminen, Antti

    Fillet weld is the predominant weld type used for connecting different elements e.g. in shipbuilding, offshore and bridge structures. One of prevalent research questions is the structural integrity of the welded joint. Post weld improvement techniques are being actively researched, as high stress areas like an incomplete penetration on the root side or fluctuations in penetration depth cannot be avoided. Development of laser and laser-arc hybrid welding processes have greatly contributed to increase of production capacity and reduction of heat-induced distortions by producing single pass full penetration welds in thin- and medium thickness structural steel parts. Present study addresses the issue of how to improve the quality of the fillet welds by welding the sealing run on the root side with defocused laser beam. Welds having incomplete or excessive penetration were produced with several beam angles and laser beam spot sizes on surface. As a conclusion, significant decrease or even complete elimination of the seam irregularities, which act as the failure starting points during service, is achieved.

  4. 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 and the pipe, which includes the welded joint, and preparing an austenitic stainless steel tubular section for substitution; the 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 PWR pressurizer tube and the expansion pipe of the pressurizer. (authors). 7 refs., 3 figs

  5. 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.

  6. THE INFLUENCE OF CURRANT MMA WELDING ON THE TENSILE STRENGHT OF JOINT

    Directory of Open Access Journals (Sweden)

    Piotr Penkała

    2014-03-01

    Full Text Available Welding with coated electrodes is still growing method of joining metals in construction machinery. If the electrodes are properly selected and current welding can weld materials in a wide range of geometric dimensions and species. With carefully selected ingredients one can introduce additional elements to the welded material and the joint during welding. An important issue in the electric welding is a welding current selection, depending on the thickness of the electrode and material thickness. The use of too low operating current cause instability and inadequate mechanical properties of the weld, resulting from insufficient melting of the material combined. Too high operating current results in the weld metal spraying and thermal overload of the electrode. For welding samples that were used to test the strength of the electrode used ESAB OK. 46.00 a diameter of 3.2 mm. Product of the company will provide a range of welding current ranging from 80 A to 150 A. The samples were welded currents amounting to 90 A, 115 A and 150 A. Due to problems with arc ignition and its instability is not made ​​of welded samples current of 80 A.

  7. Qualification of electron-beam welded joints between copper and stainless steel for cryogenic application

    Science.gov (United States)

    Lusch, C.; Borsch, M.; Heidt, C.; Magginetti, N.; Sas, J.; Weiss, K.-P.; Grohmann, S.

    2015-12-01

    Joints between copper and stainless steel are commonly applied in cryogenic systems. A relatively new and increasingly important method to combine these materials is electron-beam (EB) welding. Typically, welds in cryogenic applications need to withstand a temperature range from 300K down to 4K, and pressures of several MPa. However, few data are available for classifying EB welds between OFHC copper and 316L stainless steel. A broad test program was conducted in order to qualify this kind of weld. The experiments started with the measurement of the hardness in the weld area. To verify the leak-tightness of the joints, integral helium leak tests at operating pressures of 16 MPa were carried out at room- and at liquid nitrogen temperature. The tests were followed by destructive tensile tests at room temperature, at liquid nitrogen and at liquid helium temperatures, yielding information on the yield strength and the ultimate tensile strength of the welds at these temperatures. Moreover, nondestructive tensile tests up to the yield strength, i.e. the range in which the weld can be stressed during operation, were performed. Also, the behavior of the weld upon temperature fluctuations between room- and liquid nitrogen temperature was tested. The results of the qualification indicate that EB welded joints between OFHC copper and 316L stainless steel are reliable and present an interesting alternative to other technologies such as vacuum brazing or friction welding.

  8. Characterization of laser weld joints in ASTM A387 grade 91 steel

    International Nuclear Information System (INIS)

    Laser welding is a high power - density joining process; well known for its deep penetration, narrow heat affected zone and negligible joint distortion and therefore, it facilitates fabrication of complex structures. ASTM A387 Grade 91 steel is a ferritic/martensitic steel (FMS), which is widely used in super critical thermal power plants as steam generator material. This is also a potential candidate for fast breeder reactor clad material and also forms the basis for development of reduced activation ferritic/martensitic steel (RAFMS), which is an accepted material for fabrication of Test Blanket Material (TBM) for International Thermonuclear Experimental Reactor (ITER). Joining of this material for fabrication of steam generator is routinely done using conventional welding techniques like TIG, SMAW etc. However, there are many limitations associated with conventional welding techniques due to martensitic transformation of this material while cooling, multiple pass requirements, higher heat input, distortion and soft inter-critical microstructure. Besides, there are geometrical constraints associated with conventional welding processes when it comes to fabricate complex structures with limited access to the joint line. Laser welding is a potential solution to overcome most of these limitations; however, not much work has been reported on laser welding of this material. This paper presents detailed analysis and discussion of the microstructural evolution during laser welding and PWHT of the weld joint and also correlates the same with the experimentally measured mechanical properties of the weld joints

  9. Integrity of Polymethylmethacrylate (PMMA) Chemically Welded Joints Examined

    Science.gov (United States)

    Lerch, Bradley A.; Thesken, John C.; Bunnell, Charles T.; Kurta, Carol E.; Sydenstricker, Mike

    2005-01-01

    NASA Glenn Research Center s Capillary Flow Experiments (CFE) program is developing experiment payloads to explore fluid interfaces in microgravity on the International Space Station. The information to be gained from the CFE is relevant to the design of fluid-bearing systems in which capillary forces predominate, for example in the passive positioning of liquids in spacecraft fuel tanks. To achieve the science goals of CFE, Glenn researchers constructed several types of experiment vessels. One type of vessel, known as the interior corner flow (ICF), will be used to determine important transients for low-gravity liquid management in a two-phase system. Each vessel has a cylindrical fluid reservoir connected to each end of the test chamber by internal transport tubes, each with a quarter-turn shutoff valve (see the following photograph). These multipiece vessels are made from polymethylmethacrylate (PMMA) because of its excellent optical properties (i.e., the fluids can be observed easily in the vessel). Because of the complexity of certain vessels, the test chamber had to be manufactured in pieces and welded chemically. Some past experience with adhesive bonded plastic showed that the experiment fluid degraded the adhesive to the point of failure. Therefore, it was necessary to see if the fluid also degraded the chemically welded PMMA joints.

  10. Ultrasonic testing of pressure contact welded joints of heterogeneous tubes

    International Nuclear Information System (INIS)

    A method of ultrasonic testing of welded joints of tubes of heterogeneous 12Kh1MF and 1Kh18N12T steels is described. The tubes are 32 to 57 mm in diameter with the walls 4 to 6 mm thick. A prism of a serial inclined converter rated at 5 MHz has been used for testing. The testing has been conducted by a singly - and doubly reflected beam at the incident angle of 50 deg. The sensitivity margin of the converter is 35 dB at a 6 to 9 dB signal/noise ratio. 25 specimens have been tested. The test results have shown that amplide of echosignal in a defective sample is by 2 dB higher as compared with the reference signal. Criteria according to which a sample is considered to be defective are given

  11. Surrogate modeling for initial rotational stiffness of welded tubular joints

    Directory of Open Access Journals (Sweden)

    M.R. Garifullin

    2016-10-01

    Full Text Available Recently, buildings and structures erected in Russia and abroad have to comply with stringent economic requirements. Buildings should not only be reliable and safe, have a beautiful architectural design, but also meet the criteria of rationality and energy efficiency. In practice, this usually means the need for additional comparative analysis in order to determine the optimal solution to the engineering task. Usually such an analysis is time-consuming and requires huge computational efforts. In this regard, surrogate modeling can be an effective tool for solving such problems. This article provides a brief description of surrogate models and the basic techniques of their construction, describes the construction process of a surrogate model to calculate initial rotational stiffness of welded RHS joints made of high strength steel (HSS.

  12. Macrostructural and microstructural features of 1 000 MPa grade TRIP steel joint by CO2 laser welding

    Institute of Scientific and Technical Information of China (English)

    Wang Wenquan; Sun Daqian; Kang Chungyun

    2008-01-01

    Bead-on-plate CO2 laser welding of 1 000 MPa grade transformation induced plasticity (TRIP) steel was conducted under different welding powers, welding speeds and shield gases. The macrostructural and microstructural features of the welded joint were investigated. The increase of welding speed reduced the width of the weld bead and the porosities in the weld bead resulting from the different flow mode of melted metal in weld pool. The decrease of welding power or use of shield gas of helium also contributed to the reduction of porosity in the weld bead due to the alleviation of induced plasma formation, thus stabilizing the keyhole. The porosity formation intimately correlated with the evaporation of alloy element Mn in the base metal. The laser welded metal had same martensite microstructure as that of water-quenched base metal. The welding parameters which increased cooling rate all led to fine microstructures of the weld bead.

  13. Tensile Properties and Work Hardening Behavior of Laser-Welded Dual-Phase Steel Joints

    Science.gov (United States)

    Farabi, N.; Chen, D. L.; Zhou, Y.

    2012-02-01

    The aim of this investigation was to evaluate the microstructural change after laser welding and its effect on the tensile properties and strain hardening behavior of DP600 and DP980 dual-phase steels. Laser welding led to the formation of martensite and significant hardness rise in the fusion zone because of the fast cooling, but the presence of a soft zone in the heat-affected zone was caused by partial vanishing and tempering of the pre-existing martensite. The extent of softening was much larger in the DP980-welded joints than in the DP600-welded joints. Despite the reduction in ductility, the ultimate tensile strength (UTS) remained almost unchanged, and the yield strength (YS) indeed increased stemming from the appearance of yield point phenomena after welding in the DP600 steel. The DP980-welded joints showed lower YS and UTS than the base metal owing to the appearance of severe soft zone. The YS, UTS, and strain hardening exponent increased slightly with increasing strain rate. While the base metals had multi-stage strain hardening, the welded joints showed only stage III hardening. All the welded joints failed in the soft zone, and the fracture surfaces exhibited characteristic dimple fracture.

  14. Fracture toughness of welded joints of a high strenghth low alloy steel

    International Nuclear Information System (INIS)

    The fracture toughness of welded joints of a high strength low alloy atmospheric corrosion resistant steel was investigated. The welded joints were produced using the manual metal arc welding process and fracture toughness was evaluated by the COD method. An effort was made in order to correlate the microstructure of the different regions of the welded joints and their critical COD values. The results appear to indicate that when the structure of the heat affected zone is formed mainly by bainite and ferritic grains the fracture toughness tends to increase. Also, an increase on the amount of acicular ferrite on the weld metal tends to improve its fracture toughness. The fusion boundary showed a structure formed mainly by bainite and ferrite grains and its fracture toughness was higher than that of the parent metal at room temperature whereas it was lower at 00C. Both at 00C and room temperature the fracture toughness of the weld metal was better than those of the other regions of the welded joints. The correlations between critical values of COD and the microstructures of the different regions of the welded joints were very difficult. (Author)

  15. Distortion and residual stresses in laser beam weld shaft-hub joints

    Science.gov (United States)

    Buschenhenke, F.; Hofmann, M.; Seefeld, T.; Vollertsen, F.

    In laser beam welding, a serious challenge is to control the distortion during the process. Understanding the whole process chain in view of different distortion potentials applied in each processing step provides the ability to control the distortion of the welded components. Every manufacturing step induces residual stresses in the component which can be released by the heat of the welding process, while further residual stresses are introduced into the welded parts upon cooling. The laser beam sources of the new generation permit a high power welding process and high beam quality at the same time. These laser beams are capable of producing deep and narrow seams. Thus the thermal strains of the joined parts are expected to be minimized. Especially axial welded shaft-hub joints show an irregular distribution of bending deformation, which is caused by the self-influencing welding gap. This work deals with the investigation of different laser beam sources and their effect on the welding distortion in axial welded shafthub joints made of steel (20MnCr5). The aim of the work done was to achieve minimal distortion after the welding process. To characterize the influences on the distortion behaviour of the welded parts, residual stresses have been determined by neutron diffraction.

  16. Laser spot welding of cobalt-based amorphous foils dependence of the quality of the joint on the welding regime

    International Nuclear Information System (INIS)

    The intensity of the shear strength was chosen as an indicator for the quality of the joint performed by laser spot welding of cobalt-based amorphous foils. The shearing force is defined as depending of the most important laser welding parameters: U, tp and Def, The modeling of the dependence was performed by a regressive analysis of the achieved results of one planned three factors central composition orthogonal plan of second degree. (Author)

  17. 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.

  18. 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...

  19. Welding technology R and D on port joint of JT-60SA vacuum vessel

    International Nuclear Information System (INIS)

    Highlights: ► Mock-up of the upper vertical, most difficult port, is successfully weld-jointed. ► Quality as the product joint and the controllability of the manipulator are assured. ► Perspectives to the other ordinary port joints are discussed through this R and D. -- Abstract: This paper focuses on one of the JT-60SA vacuum vessel manufacturing R and D, onsite welding technology of the port joint. The work space is limited inside the vessel, and manipulator application is examined through the simulation and the mock-up trial. As a result, the most difficult port of the upper vertical is successfully weld-jointed. The quality as the product joint and the controllability of the manipulator are assured and perspectives to the other ordinary port joints are discussed with issues gained from this R and D

  20. Evaluation of High Temperature Properties and Microstructural Characterization of Resistance Spot Welded Steel Lap Shear Joints

    Science.gov (United States)

    Gupta, R. K.; Anil Kumar, V.; Panicker, Paul G.

    2016-02-01

    Joining of thin sheets (0.5 mm) of stainless steel 304 and 17-4PH through resistance spot welding is highly challenging especially when joint is used for high temperature applications. Various combinations of stainless steel sheets of thickness 0.5 mm are spot welded and tested at room temperature as well as at high temperatures (800 K, 1,000 K, 1,200 K). Parent metal as well as spot welded joints are tested and characterized. It is observed that joint strength of 17-4PH steel is highest and then dissimilar steel joint of 17-4PH with SS-304 is moderate and of SS-304 is lowest at all the temperatures. Joint strength of 17-4PH steel is found to be >80% of parent metal properties up to 1,000 K then drastic reduction in strength is noted at 1,200 K. Gradual reduction in strength of SS-304 joint with increase in temperature from 800 to 1,200 K is noted. At 1,200 K, joint strength of all combinations of joints is found to be nearly same. Microstructural evaluation of weld nugget after testing at different temperatures shows presence of tempered martensite in 17-4PH containing welds and homogenized structure in stainless steel 304 weld.

  1. Precipitation of Niobium Boride Phases at the Base Metal/Weld Metal Interface in Dissimilar Weld Joints

    Science.gov (United States)

    Výrostková, Anna; Kepič, Ján; Homolová, Viera; Falat, Ladislav

    2015-07-01

    In this work, the analysis of failure mechanism in the heat affected zone is described in dissimilar weld joints between advanced martensitic steel T92 and Ni-base weld metal. The joints were treated with two different post-weld heat treatments and tested. For the creep, tensile, and Charpy impact tests, the samples with interfacially located notch were used. Moreover long term aging at 625 °C was applied before the tensile and notch toughness tests. Decohesion fractures ran along carbides at the T92 BM/WM interfaces in case of the modified PWHT, whereas type IV cracking was the prevailing failure mechanism after the classical PWHT in the creep test. In the notch tensile and Charpy impact tests, with the notch at T92 base metal/weld metal interface, fractures ran along the interface with a hard phase on the fracture surface along with the ductile dimple and brittle quasi-cleavage fracture. The phase identified as niobium boride (either NbB and/or Nb3B2) was produced during welding at the end of the solidification process. It was found in the welds regardless of the post-weld heat treatment and long-term aging.

  2. 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.

  3. 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...

  4. SIMULATION ON TEMPERATURE FIELD OF FRICTION STIR WELDED JOINTS OF 2024-T4 Al

    Institute of Scientific and Technical Information of China (English)

    S.X. Lü; J.C. Yan; W.G. Li; S.Q. Yang

    2005-01-01

    e thermal model of FSW based on the thermal elastic-plastic finite element method, and the transient temperature distribution of FS welded joints of 2024-T4 Al was simulated by using this model, which provides useful information for the investigation of FSW process. Simulation results show that the temperature distribution of the weld gradually decreases toward periphery in a radiate format, whose center is the probe, and the highest temperature in the weld can reach about 400℃. The initial terminal of the weld is a zone, in which the temperature gradient is great, and defects of the welding are easily produced in this zone. Temperature change at the end of the welded joint is as layer variation, the local serious defects are not easy to produce in this zone.

  5. 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.

  6. Different types of cracking of P91 steel weld joints after long-term creep tests

    Energy Technology Data Exchange (ETDEWEB)

    Jandova, D.; Kasl, J.; Chvostova, E. (SKODA VYZKUM s.r.o., Plzen (Czech Republic))

    2010-05-15

    This paper deals with creep testing and microstructural investigation of trial weld joints prepared of wrought and cast 9Cr-1Mo-V steels using GTAW & SMAW method. Creep testing was carried out at temperature range from 525 degC to 625 degC, the longest time to rupture of 45 811 hrs was achieved. The creep strengths of weld joints for 100 000 hrs were calculated. Different types of cracking were observed in dependency on conditions of creep test and the type of weld joint. Type 1 and Type 2 fractures occurred at high applied stress at relatively low temperatures in the tube weld joint and also in two speciments of the cast plate weld joint after creep test at the lowest temperature and the highest temperature. All other fractures were of the Type 4. Causes of different fracture location in tested weld joints were elucidated on the base of substructure evolution in individual zones - the weld metal, the heat affected zone and the base material. Two processes occur simultaneously, which result in the creep damage: (i) softening of solid solution as a result of Laves phase precipitation and (ii) formation and coalescence of cavities in the soft fine grained parts of heat affected zone. (orig.)

  7. Corrosion Behavior of Welded Joints of Al-6Mg Alloy with Trace Scandium Addition

    Institute of Scientific and Technical Information of China (English)

    Wang Yue

    2004-01-01

    Al-6Mg alloy with trace Sc addition was prepared by means of melting-casting.The samples of the welded joints of Al-6Mg alloy with trace Sc addition were made by method of manual argon-arc welding.Neutral salt spray test was carried out by referring to GB/T10125-1997 and GB6384-1986 practice.Exfoliation testing was carried out in accordance with the method of Al-Mg alloy exfoliation corrosion test.The corrosion behaviors of the welded joints of AlMg alloy with high level of Mg and trace Sc addition were studied.The microstructures of the welded joints were observed by using optical microscope and transmission electron microscope.The corrosion resistance mechanism of the alloy was also involved.This work intended to determine if the welded joints of Al-6Mgalloy with trace Sc addition can have excellent corrosion resistance, when their strength are clearly improved.The results show that trace content of Sc refines the grains of alloys effectively, raises remarkably the corrosion resistance of the welded joints of Al-6Mg alloy with trace Sc addition.The corrosion resistance mechanisms are that there is free of continuous grain boundary precipitation or network which could be susceptible to corrosion in the microstructure of welded joints.

  8. Ultrasonic Impact Treatment to Improve Stress Corrosion Cracking Resistance of Welded Joints of Aluminum Alloy

    Science.gov (United States)

    Yu, J.; Gou, G.; Zhang, L.; Zhang, W.; Chen, H.; Yang, Y. P.

    2016-07-01

    Stress corrosion cracking is one of the major issues for welded joints of 6005A-T6 aluminum alloy in high-speed trains. High residual stress in the welded joints under corrosion results in stress corrosion cracking. Ultrasonic impact treatment was used to control the residual stress of the welded joints of 6005A-T6 aluminum alloy. Experimental tests show that ultrasonic impact treatment can induce compressive longitudinal and transverse residual stress in the welded joint, harden the surface, and increase the tensile strength of welded joints. Salt-fog corrosion tests were conducted for both an as-welded sample and an ultrasonic impact-treated sample. The surface of the treated sample had far fewer corrosion pits than that of the untreated sample. The treated sample has higher strength and lower tensile residual stress than the untreated sample during corrosion. Therefore, ultrasonic impact treatment is an effective technique to improve the stress corrosion cracking resistance of the welded joints of 6005A-T6 aluminum alloy.

  9. Characterization on strength and toughness of welded joint for Q550 steel

    Indian Academy of Sciences (India)

    Jiang Qinglei; Li Yajiang; Wang Juan; Zhang Lei

    2011-02-01

    Q550 high strength steel was welded using gas shielded arc welding and three different welding wires without pre- or post-heat treatments. The paper investigates the influence of welding wire on the microstructure, tensile strength and impact toughness of Q550 steel weld joints. Results showed that the microstructure of the weld metal of joints produced using ER50-6 wire was a mixture of acicular ferrite and grain boundary ferrite including pro-eutectoid ferrite and ferrite side plate. Acicular ferrite was mainly obtained in the weld metal of the joints produced using MK.G60-1 wire. Pro-eutectoid ferrite was present along the boundary of prior austenite. Crack initiation occurred easily at pro-eutectoid ferrite when the joint was subjected to tensile. Tensile strength and impact toughness were promoted with increasing acicular ferrite. Tensile strength of the joint fabricated using MK.G60-1 wire was close to that of base metal. And tensile samples fractured at location of the fusion zone, which had lower toughness and thus became the weak region in the joint. Impact absorbing energy was the highest in the heat affected zone. Fibrous region in fracture surfaces of impact specimens was characterized as transgranular fracture with the mechanism of micro-void coalescence. Acicular ferrite microstructure region corresponded to relatively large dimples while boundary ferrite microstructure corresponded to small dimples.

  10. Fatigue Behavior of Friction Stir-Welded Joints Repaired by Grinding

    Science.gov (United States)

    Vidal, C.; Infante, V.

    2014-04-01

    Fatigue is undoubtedly the most important design criterion in aeronautic structures. Although friction stir-welded joints are characterized by a high mechanical performance, they can enclose some defects, especially in their root. These defects along with the relatively low residual stresses of the friction stir-welding thermomechanical cycle can turn into primary sources of crack initiation. In this context, this article deals with the fatigue behavior of friction stir-welded joints subjected to surface smoothing by grinding improvement technique. The 4-mm-thick aluminum alloy 2024-T351 was used in this study. The fatigue strength of the base material, joints in the as-welded condition, and the sound and defective friction stir-welded joints improved by grinding were investigated in detail. The tests were carried out with a constant amplitude loading and with a stress ratio of R = 0. The fatigue results show that an improvement in fatigue behavior was obtained in the joints repaired by superficial grinding technique. The weld grinding technique is better especially for lower loads and increases the high cycle fatigue strength. The fatigue strength of the improved welded joints was higher than that of the base material.

  11. Effect of welding parameters on the mechanical and microstructural properties of friction stir welded AA- 2014 joints

    Science.gov (United States)

    Khan, R.; Bhatty, M. B.; Iqbal, F.; Zaigham, H.; Salam, I.

    2016-08-01

    In this study, the effect of processing parameters on the mechanical and microstructural properties of aluminum AA2014-T6 joints produced by friction stir welding was analyzed. Friction stir welding was carried out on a milling machine. Different samples were produced by varying the tool rotational rates (700, 1000 rpm) and travel speeds (45-105 mm/min). Tensile tests performed at room temperature were used to evaluate the mechanical properties of the joints. In order to analyze the microstructural evolution of the material, the welds’ cross-sections were observed under optical microscope. The results shows that the resulting microstructure is free of defects and tensile strength of the welded joints is upto 75% of the base metal strength.

  12. Ultrasonic depth-sizing errors of crack-like defects in saddle-shaped weld joints

    International Nuclear Information System (INIS)

    In order to determine crack depth in primarily loop recirculation (PLR) piping of boiling water reactors, ultrasonic angle beam testing using time of flight measurement of the diffracted signal from the crack tip, is employed. There are some power stations in Japan having saddle-shaped weld joints at branch connections in PLR piping. If the angle beam testing is applied without considering curvature of saddle-shaped weld joints, unlike weld joints of straight piping, it can be predicted that determined depth by the typical technique mentioned above contains a geometrical error due to the curvature. This issue has never been discussed in welds of branch connections. This paper deals with this issue with a mockup and phased array inspection system. As a result, the geometrical error is negligibly small in comparison to underlying depth-sizing errors of stress corrosion cracks in authentic stainless steel welds. (author)

  13. Process of friction-stir welding high-strength aluminum alloy and mechanical properties of joint

    Institute of Scientific and Technical Information of China (English)

    王大勇; 冯吉才; 郭德伦; 孙成彬; 栾国红; 郭和平

    2004-01-01

    The process of friction-stir welding 2A12CZ alloy has been studied. And strength and elongation tests have been performed, which demonstrated that the opportunity existed to manipulate friction-stir welding parameters in order to improve a range of material properties. The results showed that the joint strength and elongation arrived at their parameters changing, joint tensile strength and elongation had similar development. Hardness measurement indicated that the weld was softened. However, there was considerable difference in softening degree for different joint zone. The weld top had lower hardness and wider softening zone than other zone of the weld. And softening zone at advancing side was wider than that at retreating side.

  14. 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.

  15. Microstructure of Aluminum/Glass Joint Bonded by Ultrasonic Wire Welding

    Science.gov (United States)

    Iwamoto, Chihiro

    2013-11-01

    An Al/glass joint created by using ultrasonic welding was analyzed by means of multiscale observation techniques. A cross-sectional analysis of the microstructure revealed that a directly joined interface without reaction phases formed at the periphery of a round joined region. The size of Al grains markedly decreased after ultrasonic welding and some subgrains were observed along the interface. The finer Al grains observed around the periphery of the joined interface showed active plastic flow that promoted welding.

  16. Modelling of ultrasonic impact treatment (UIT) of welded joints and its effect on fatigue strength

    OpenAIRE

    K.L. Yuan; Sumi, Y.

    2015-01-01

    Ultrasonic impact treatment (UIT) is a remarkable post-weld technique applying mechanical impacts in combination with ultrasound into the welded joints. In the present work, a 3D simulation method including welding simulation, numerical modelling of UIT-process and an evaluation of fatigue crack growth has been developed. In the FE model, the actual treatment conditions and local mechanical characteristics due to acoustic softening are set as input parameters. The plastic deformat...

  17. Friction Stir Spot Welding: A Review on Joint Macro- and Microstructure, Property, and Process Modelling

    OpenAIRE

    Yang, X.W.; Fu, T; Li, W. Y.

    2014-01-01

    Friction stir spot welding (FSSW) is a very useful variant of the conventional friction stir welding (FSW), which shows great potential to be a replacement of single-point joining processes like resistance spot welding and riveting. There have been many reports and some industrial applications about FSSW. Based on the open literatures, the process features and variants, macro- and microstructural characteristics, and mechanical properties of the resultant joints and numerical simulations of t...

  18. Structural, chemical and deformation changes in friction welded joint of dissimilar steels

    OpenAIRE

    Ratković, N.; R. Nikolić; I. Samardžić

    2014-01-01

    Fundamental principles of friction welding of dissimilar steels (high speed and tempering steel) from the aspect of metallurgical and chemical processes occurring in the joint zone are presented in this paper. Considering that phenomena accompanying the friction welding are interdependent, it was necessary to experimentally determine the process variable parameters, to establish the optimal welding regime. The experiments were set and realized so that all the variables were analyzed as a func...

  19. Numerical simulation of temperature fields for T-joint during TIG welding of titanium alloy

    Institute of Scientific and Technical Information of China (English)

    Wang Min; Dong Zhibo; Yu Lan; Wei Yanhong

    2008-01-01

    Three-dimensional finite element model was established to simulate temperature fields of T-joint titanium sheets during TIG welding with finite element method (FEM) software. Temperature dependent material properties and the effect of latent heat were considered. A technique of element birth and death was used to simulate the process of welded metal filling. Dynamic variation process of temperature fields during TIG welding was achieved. The simulated results agreed well with the measured results.

  20. USING TEMPERATURE TRACES IN NON-DESTRUCTIVE DIAGNOSTICS OF RESIDUAL STRESSES OF WELDED JOINTS

    OpenAIRE

    Popov Aleksandr Leonidovich; Kurov Dmitriy Andreevich

    2012-01-01

    Diagnostics of residual welding stresses based on the layout of temperature traces that (i) characterize isothermals of maximal temperatures within a thermal cycle of welding and (ii) are retained on the metal surface of a welded joint represents a prospective trend of non-destructive methods of control of residual stresses. The traces to be examined include both natural (temper colours and fusion boundaries) and artificial traces formed on the metal surface in the course of fusio...

  1. Increase of the Reproducibility of Joints Welded with Magnetic Pulse Technology Using Graded Surface Topographies

    OpenAIRE

    Rebensdorf, A.; Boehm, S

    2016-01-01

    The reproducibility of individual welding methods depends to large extents on the material properties. This is especially the case for impact welding as tests have shown that the surface properties influence the joint formation. With the aim to influence the formation and position of the lower curve of the welding process window, this paper focuses on how the surface topography influences an asymmetrical impact. Additionally, relevant process parameters (e.g. collision speed, c...

  2. Tensile Fracture Location Characterizations of Friction Stir Welded Joints of Different Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Huijie LIU; Hidetoshi FUJII; Masakatsu MAEDA; Kiyoshi NOGI

    2004-01-01

    The tensile fracture location characterizations of the friction stir welded joints of the AA1050-H24 and AA6061-T6Al alloys were evaluated in this study. The experimental results show that the fracture locations of the joints are different for the different Al alloys, and they are affected by the FSW parameters. When the joints are free of welding defects, the AA1050-H24 joints are fractured in the HAZ and TMAZ on the AS and the fracture parts undergo a large amount of plastic deformation, while the AA6061-T6 joints are fractured in the HAZ on the RS and the fracture surfaces are inclined a certain degree to the bottom surfaces of the joints. When some welding defects exist in the joints, the AA1050-H24 joints are fractured on the RS or AS, the AA6061-T6 joints are fractured on the RS, and all the fracture locations are near to the weld center. The fracture locations of the joints are dependent on the internal structures of the joints and can be explained by the microhardness profiles and defect morphologies of the joints.

  3. 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.

  4. Joint performance of laser-TIG double-side welded 5A06 aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    CHEN Yan-bin; MIAO Yu-gang; LI Li-qun; WU Lin

    2009-01-01

    The influence of welding parameters on mechanical properties and microstructure of the welds of laser-TIG double-side welded 5A06 aluminum alloy was investigated. The results show that the weld cross-sectional shape has an intimate relation with the mechanical properties and microstructure of the welds. The symmetrical "X" cross-section possesses a relatively higher tensile strength and elongation than the others, about 91% and 58% of those of base metal, respectively. The good weld profiles and free defects are responsible for the improvement of tensile properties. Due to low hardness of the fusion zone, this region is the weakest area in the tensile test and much easier to fracture. The loss of Mg element is responsible for the decrease of mechanical properties of the joints. The microstructure of "X" cross-section has an obvious difference along the direction of weld depth, and that of the "H" cross-section is consistent and coarse.

  5. Optimization of parameters and study of joint microstructure of resistance spot welding of magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    Wang Yarong; Zhang Zhongdian; Li Dongqing

    2006-01-01

    Experimental investigations on the DC spot welding of Mg alloy AZ31B are presented. Experiments are carried out to study the influence of spot welding parameters (electrode force, welding heat input and welding time) on the tensile shear load and the diameter of nugget, based on an orthogonal test and analysis method. The optimum parameters are as follows:electrode force is 2 000 N, welding heat input is 80% and welding time is 6 cycles. The microstructure of spot weld is single fine equiaxed crystals in the nugget, of which the structure is β-Mg17Al12 precipitated on α-Mg boundaries induced by nonequilibrium freezing. And the surface condition of the workpiece has great influence on the joint quality.

  6. Influence of temperature on strength and failure mechanisms of resistance welded thermoplastic composites joints

    NARCIS (Netherlands)

    Koutras, N.; Fernandez Villegas, I.; Benedictus, R.

    2015-01-01

    In this work, the effect of temperature exposure on the strength of resistance welded joints is analysed. Glass fibre polyphenylene sulphide (GF/PPS) laminates were joined using the resistance welding technique and a stainless steel metal mesh as the heating element. Single lap shear tests at temper

  7. Crack initiation and propagation in welded joints of turbine and boiler steels during low cycle fatigue

    International Nuclear Information System (INIS)

    Low cycle fatigue (LCF) tests have been performed at 300 and 565 degrees C on welded joints and on microstructures to be found in or near welded joints in a low alloy ferritic steel 0.5 Cr, 0.5 Mo, 0.25 V. The difference in lifetimes between the 300 degrees C and 565 degrees C tests was small comparing the same microstructures and strain ranges, although the stress amplitude was greater at 300 degrees C. Under constant stress conditions the fatigue life depended on the fatigue life of the parent metal but under constant strain conditions the lifetime was governed by that of the bainitic structures. Strain controlled LCF tests have been performed at 750 degrees C on welded joints in the austenitic steel AISI 316 and on different parent and weld metals used in these joints. In continuously cycled samples all cracks were transgranular and initiated at the surface; hold-time samples displayed internally initiated intergranular cracking in the weld metal. Under constant strain conditions the 316 parent and weld metals exhibited similar lifetimes. When considering a constant stress situation the strength of the microsturctures decreased in the following order: Sanicro weld metal, cold deformed parent metal, undeformed parent metal and weld metal (K.A.E.)

  8. Ultrasonic inspection of austenitic welded joints of equipment of nuclear power plant

    International Nuclear Information System (INIS)

    The ultrasonic control technique has been checked according to main provisions of the instruction during experimental-production control of welded joints of austenitic pipeline of 560x34 mm of 12Kh18NKh12T steel welded by electrode of austenite-ferrite class. The weld seam root of the above pipeline has been welded by means of argon-arc welding. Alpha-phase content in a melt metal has been at 3-4% level. Real and artificial defects in a form of slag inclusions, pores, asbestos pieces have been in the seam metal. It is shown that longitudinal ultrasonic vibrations in a clad austenitic metal have less damping than transverse vibrations at the same wave length and may be recommended for control by the direct beam of austenitic welded joints of 12Kh18N12T steel. The recommended by normalyzing materials control sensitivity level ensures revealing dangerous defects of planar type in a welded joint root not always found by radiation control methods. A rejected sensitivity level which does not lead to re-evaluation of items as a result of ultrasonic longitudinal wave reflection from dendrite welded joint structure is chosen

  9. Effects of activating fluxes on the weld penetration and corrosion resistant property of laser welded joint of ferritic stainless steel

    Science.gov (United States)

    Wang, Yonghui; Hu, Shengsun; Shen, Junqi

    2015-10-01

    This study was based on the ferritic stainless steel SUS430. Under the parallel welding conditions, the critical penetration power values (CPPV) of 3mm steel plates with different surface-coating activating fluxes were tested. Results showed that, after coating with activating fluxes, such as ZrO2, CaCO3, CaF2 and CaO, the CPPV could reduce 100~250 W, which indicating the increases of the weld penetrations (WP). Nevertheless, the variation range of WP with or without activating fluxes was less than 16.7%. Compared with single-component ones, a multi-component activating flux composed of 50% ZrO2, 12.09% CaCO3, 10.43% CaO, and 27.49% MgO was testified to be much more efficient, the WP of which was about 2.3-fold of that without any activating fluxes. Furthermore, a FeCl3 spot corrosion experiment was carried out with samples cut from weld zone to test the effects of different activating fluxes on the corrosion resistant (CR) property of the laser welded joints. It was found that all kinds of activating fluxes could improve the CR of the welded joints. And, it was interesting to find that the effect of the mixed activating fluxes was inferior to those single-component ones. Among all the activating fluxes, the single-component of CaCO3 seemed to be the best in resisting corrosion. By means of Energy Dispersive Spectrometer (EDS) testing, it was found that the use of activating fluxes could effectively restrain the loss of Cr element of weld zone in the process of laser welding, thus greatly improving the CR of welded joints.

  10. Improvements in welding parameters for a new design of zircaloy-4 tube-end plug joints

    International Nuclear Information System (INIS)

    This work presents the experimental results for the characterization of welds using a new design for zircaloy-4 tube-end plug joints, applicable to the production of fuel elements for the Atucha I Nuclear Plant. Test specimens were prepared following the new joint design and were welded using orbital welding equipment. Hydrogen content was measured in the different welding areas, and corrosion tests, and mechanical and microstructural descriptions were carried out, obtaining values that meet the current production standards. We reported previously that test samples welded in equipment with a smaller camera showed some relatively high hydrogen levels, together with alterations in the welded zone in the corrosion tests. Given these results, new tests were undertaken to optimize the welding parameters, being very careful with the purity of the welding atmosphere and in the handling of the samples. The intensity of the welding current was increased slightly to obtain better penetration of the material, without significantly increasing the heat input. The traction resistance values improved, reducing the hydrogen content to well below the maximum allowed by the standards (25 ppm) in all the welding zones and obtaining satisfactory results in the corrosion tests

  11. Microstructures and properties of laser welding joint of super-eutectic ZA alloy

    International Nuclear Information System (INIS)

    Highlights: ► It is a new process for the forming of ZA alloy via laser welding. ► A good joint by pulsed laser welding has been achieved successfully. ► It may be applied other non-ferrous alloys in various engineering applications. -- Abstract: In this paper, we describe the experimental laser welding of ZA alloy. The formation of the weld demonstrated that pulsed laser welding for ZA alloy was more effective than continuous laser welding. The characteristics of microstructures and properties of the ZA alloy’s bond area welded by pulsed laser were investigated using an optical microscope, X-Ray Diffractometer (referred to as XRD) and other methodologies. The applicable technological parameters include welding speed of 0.9 m/min, pulsed laser power of 1.8 kW, impulse period of 3 ms and duty cycle of 3:4. The average micro-hardness of the laser welding seam zone is higher than that of the ZA alloy substrate, which is as high as 183HV. The microstructures in the weld consist of primary η phase (the white dendritic structure), β phase (the black block distribution around η phase), and eutectic phases (β + η) (platy layer). The average strength of the joints is 119 MPa, 70% of that of the base metal.

  12. 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...

  13. Experiments and simulation for 6061-T6 aluminum alloy resistance spot welded lap joints

    Science.gov (United States)

    Florea, Radu Stefanel

    This comprehensive study is the first to quantify the fatigue performance, failure loads, and microstructure of resistance spot welding (RSW) in 6061-T6 aluminum (Al) alloy according to welding parameters and process sensitivity. The extensive experimental, theoretical and simulated analyses will provide a framework to optimize the welding of lightweight structures for more fuel-efficient automotive and military applications. The research was executed in four primary components. The first section involved using electron back scatter diffraction (EBSD) scanning, tensile testing, laser beam profilometry (LBP) measurements, and optical microscopy(OM) images to experimentally investigate failure loads and deformation of the Al-alloy resistance spot welded joints. Three welding conditions, as well as nugget and microstructure characteristics, were quantified according to predefined process parameters. Quasi-static tensile tests were used to characterize the failure loads in specimens based upon these same process parameters. Profilometer results showed that increasing the applied welding current deepened the weld imprints. The EBSD scans revealed the strong dependency between the grain sizes and orientation function on the process parameters. For the second section, the fatigue behavior of the RSW'ed joints was experimentally investigated. The process optimization included consideration of the forces, currents, and times for both the main weld and post-heating. Load control cyclic tests were conducted on single weld lap-shear joint coupons to characterize the fatigue behavior in spot welded specimens. Results demonstrate that welding parameters do indeed significantly affect the microstructure and fatigue performance for these welds. The third section comprised residual strains of resistance spot welded joints measured in three different directions, denoted as in-plane longitudinal, in-plane transversal, and normal, and captured on the fusion zone, heat affected zone

  14. 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...

  15. Structural, chemical and deformation changes in friction welded joint of dissimilar steels

    Directory of Open Access Journals (Sweden)

    N. Ratković

    2014-10-01

    Full Text Available Fundamental principles of friction welding of dissimilar steels (high speed and tempering steel from the aspect of metallurgical and chemical processes occurring in the joint zone are presented in this paper. Considering that phenomena accompanying the friction welding are interdependent, it was necessary to experimentally determine the process variable parameters, to establish the optimal welding regime. The experiments were set and realized so that all the variables were analyzed as a function of the friction time. The metallographic investigations included analysis of the joint zone microstructure through structural phases and hardness changes, due to influence of the heat treatment - annealing. The experimental work included analysis of the geometry changes, the joint zone structure and the basic mechanical characteristics of the joint realized by the friction welding.

  16. Fatigue crack propagation in welded joint of austenitic steel for nuclear power engineering

    International Nuclear Information System (INIS)

    The crack propagation characteristics were obtained for Cr-Ni type austenitic steel 08Kh18N10T under variable stress in the individual zones of a welded joint on a pipe. Measurements of the threshold deviation of the stress intensity factor, ΔKp, showed that the root zone of the pipe welded joint was the weakest point as concerns crack propagation. The threshold values obtained for the filler metal on the pipe outer surface were considerably greater than those for the root zone of the welded joint and slightly greater than those for the base material and for the transition between the joint and the base material. The measured propagation response showed that the rate of fatigue crack propagation was for the base material higher by up to one order for low ΔK than for the filler joint and the root zone of the joint. (J.B.). 5 figs., 3 tabs., 6 refs

  17. Strength Investigation of Thick Welded T-Joint using Finite Element Modelling

    Directory of Open Access Journals (Sweden)

    Aidy Ali

    2010-01-01

    Full Text Available The paper discusses the computation of finite element modelling (FEM of a thick welded joint as a high load transfer joint. The FEM utilises MSC PATRAN/NASTRAN software programs to predict and simulate the critical area of a welded joint. The elasticity limit for the specimen was determined and stress distribution was achieved in the joint to indicate critical parts of a welded T-joint and predict the critical locations for crack initiation in this kind of joint. Simulation and experimental results show good in agreement and the sources of some differences in these results are discussed.Defence Science Journal, 2010, 60(1, pp.112-118, DOI:http://dx.doi.org/10.14429/dsj.60.118

  18. 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.

  19. High-quality MOVPE butt-joint integration of InP/AlGaInAs/InGaAsP-based all-active optical components

    DEFF Research Database (Denmark)

    Kulkova, Irina; Kadkhodazadeh, Shima; Kuznetsova, Nadezda;

    2014-01-01

    In this paper, we demonstrate the applicability of MOVPE butt-joint regrowth for integration of all-active InP/AlGaAs/InGaAsP optical components and the realization of high-functionality compact photonic devices. Planar high-quality integration of semiconductor optical amplifiers of various epi......-structures with a multi-quantum well electro-absorption modulator has been successfully performed and their optical and crystalline quality was experimentally investigated. The regrown multi-quantum well material exhibits a slight bandgap blue-shift of less than 20 meV, when moving away from the regrowth interface...

  20. Liquid-Phase-Impacting Diffusion Welding Mechanism and Microstructure of Welded Joint of Al Matrix Composite SiCp/101A

    Institute of Scientific and Technical Information of China (English)

    Jitai NIU; Wei GUO; Qingchang MENG; Xinmei ZHANG; Xingqiu LIU; Guangtao ZHOU

    2003-01-01

    The liquid-phase-impacting (LPI) diffusion welding mechanism and microstructure of welded joint of aluminum matrixcomposite SiCp/101A have been studied. It shows that by LPl diffusion welding, the interface state between SiCparticle and matrix is prominen

  1. Numerical analysis of thermal stresses in welded joint smade of steels X20 and X22

    OpenAIRE

    Mladenović Saša M.; Šijački-Zeravčić Vera M.; Bakić Gordana M.; Lozanović-Šajić Jasmina V.; Rakin Marko P.; Đurđević Andrijana A.; Đukić Miloš B.

    2014-01-01

    Stress calculation of steam pipeline is presented, focused on the welded joint. Numerical calculation was performed using the finite element method to obtain stress distribution in the welded joint made while replacing the valve chamber. Dissimilar materials were used, namely steel 10CrMoV9-10 according to EN 10216-2 for the valve chamber, the rest of steam pipeline was steel X20, whereas the transition piece material was steel X22. Residual stresses were c...

  2. Static and repeated-strength static f stud joints made by percussion capacitor-type welding

    International Nuclear Information System (INIS)

    Results of the experimental study of static and repeated-static strength of stud joints, made by percussion capacitoA-type welding, are presented. Under conditions of stretching, cut and bend the effect of loading type, cycle asymmetry, sublayer material and oxide layer on its surface, as well as defects of welding in the form of undercuttings and caverns on the resistance of the joints to repeated-alternating loading on the basis of 5000 cycles, has been studied

  3. Re-analysis of fatigue data for welded joints using the notch stress approach

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Mouritsen, Ole Ø.; Hansen, Michael Rygaard;

    2010-01-01

    Experimental fatigue data for welded joints have been collected and subjected to re-analysis using the notch stress approach according to IIW recommendations. This leads to an overview regarding the reliability of the approach, based on a large number of results (767 specimens). Evidently, there......-welded joints agree quite well with the FAT 225 curve; however a reduction to FAT 200 is suggested in order to achieve approximately the same safety as observed in the nominal stress approach....

  4. Analysis of quality control efficiency for NPP pipeline welded joints using nondestructive methods

    International Nuclear Information System (INIS)

    The problems of improving the quality of nondestructive examination for welded joints of NPP cooling system pipelines are considered. The data of ultrasonic testing and radiography of the welded joints of pipelines 800 mm in-diameter at the Smolensk and Kursk NPPs are analyzed. The conclusion on the necessity of accurate fulfilment of the existing PN AEh G-7-010-89 Rules of testing during NPP contruction and operation is made

  5. Tension fracture behaviors of welded joints in X70 steel pipeline

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The surface of welded joints in X70 steel pipeline was processed by laser shock wave, its mechanical behaviors of tension fracture were analyzed with tension test,and the fracture morphologies and the distributions of chemical element were observed with scanning electron microscope and energy dispersive spectrum,respectively.The experimental results show that the phenomenon of grain refinement occurs in the surface of welded joints in X70 steel pipeline after the laser shock processing,and compressive re...

  6. Influence of Welding With Two-Jet Gas Shielding On the Shaping of a Welding Joint

    Science.gov (United States)

    Chinakhov, D. A.; Chinakhova, E. D.; Grichin, S. V.; Gotovschik, Y. M.

    2016-04-01

    The author considers gas-dynamic influence upon microhardness and weld configuration of single-pass welds from steel 30HGSA when welding with consumable electrode under double-jet shielding. The relations to the chosen controlled welding parameters (Q, L, I) are developed and the controlling influence of the gas-dynamic affect of dynamic shield gas jet over formation of welds from alloy-treated steel 30HGSA is determined.

  7. 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)

  8. Study of mechanical joint strength of aluminum alloy 7075-T6 and dual phase steel 980 welded by friction bit joining and weld-bonding under corrosion medium

    International Nuclear Information System (INIS)

    Highlights: • Friction bit joining (FBJ) and weld-bonding (adhesive + FBJ) processes. • FBJ to spot weld high-strength Al alloy to high-strength steel. • Lap shear strength of ∼10 kN for high-strength Al alloy to high-strength steel. • Effective corrosion mitigation by combining FBJ with adhesive. - Abstract: In this work, we have employed a unique solid-sate joining process, called friction bit joining (FBJ), to spot weld aluminum alloy (AA) 7075-T6 and dual phase (DP) 980 steel. Static joint strength was studied in the lap shear tension configuration. In addition, weld-bonding (adhesive + FBJ) joints were studied in order to evaluate the ability of adhesive to mitigate the impact of corrosion on joint properties. Accelerated laboratory cyclic corrosion tests were carried out for both FBJ only and weld-bonding joints. The FBJ only joints that emerged from corrosion testing had lap shear failure loads that were significantly lower than freshly prepared joints. However, weld-bonding specimens retained more than 80% of the lap shear failure load of the freshly prepared weld-bonding specimens. Examination of joint cross sections confirmed that the presence of adhesive in the weld-bonding joints mitigated the effect of the corrosion environment, compared to FBJ only joints

  9. Study on improving properties of welded joints of 400 MPa ultra fine grained steel by mechanical surface hardening

    Institute of Scientific and Technical Information of China (English)

    Zhao Hongyun; Han Fei; Xia Long; Liu Xueyun

    2006-01-01

    The welded joints of 400 MPa ultra fine grained steel in manual arc welding were treated by mechanical surface hardening. Microstructure and mechanical properties of the treated joints were compared with those of the untreated joints,based on which, primary study on the process and principle of mechanical surface hardening was carried out. The results shows that: Grain size of HAZ increases greatly and mechanical properties of welded joint decrease obviously compared with those of base material, but grain size in the surface layer of HAZ can be refined ( the grain size is about 100 nm or so) and mechanical properties of welded joints can be improved greatly by mechanical surface hardening.

  10. The influence of pieces thickness on metallographic structure of welded joints

    OpenAIRE

    D. Dobrotă; G. Iacobescu; I. Ghionea; Ionescu, N

    2016-01-01

    The main objective of this paper was to establish how the thickness of welded pieces influences the metallographic structure of welded joints. Thus were made a total of 6 samples, and from each sample were taken test specimens for metallographic analysis of the base material, the filler material respective heat affected zone (HAZ). The samples were carried out by welding process: metal active gases (MAG) using a steel E 36-4, and the welded pieces had a thickness between 10 and 24 mm. The wel...

  11. A review on TIG welding for optimizing process parameters on dissimilar joints

    Directory of Open Access Journals (Sweden)

    Prashant Kumar Singh

    2015-02-01

    Full Text Available Tungsten Inert Gas Welding (TIG is relatively high strength welding technique. This technique are mostly used in fabrication and other industries to join the either similar or dissimilar materials. In particular, it can be used to join high-quality strength of metal and alloys.In this paper we discuss abouttheTungsten Inert Gas welding of joining heat treatableof stainless steel and mild steel.These welded joints have higher tensile strength to weight ratio and finer micro structure. Tungsten Inert Gas Weldingofdissimilar material such as stainless steel and mild steel have the potential to hold good mechanical and metallurgical properties.

  12. Multi-Response Optimization of Friction-Stir-Welded AA1100 Aluminum Alloy Joints

    Science.gov (United States)

    Rajakumar, S.; Balasubramanian, V.

    2012-06-01

    AA1100 aluminum alloy has gathered wide acceptance in the fabrication of light weight structures. Friction stir welding process (FSW) is an emerging solid state joining process in which the material that is being welded does not melt and recast. The process and tool parameters of FSW play a major role in deciding the joint characteristics. In this research, the relationships between the FSW parameters (rotational speed, welding speed, axial force, shoulder diameter, pin diameter, and tool hardness) and the responses (tensile strength, hardness, and corrosion rate) were established. The optimal welding conditions to maximize the tensile strength and minimize the corrosion rate were identified for AA1100 aluminum alloy and reported here.

  13. JOINTING PROCESS OF THE SAE 1020 WITH MAG WELD'S REGION HAVE BEEN INVESTIGATED AND FACTOR OF MISMATCH DETERMINED

    Directory of Open Access Journals (Sweden)

    Cevdet MERİÇ

    1997-03-01

    Full Text Available In this study, the jointing process of the SAE 1020 low carbon steel, generally used in the industry, has been done by the MAG weld method. The aim of this study is to examine the mismatch between base and weld metal. After the jointing process, mechanical and metalographical properties of the weld region, HAZ, and the weld metal of the samples considered here were searched, and CTOD (Crack Tip Opening Displacement was identified.

  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. 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)

  16. Hydrogen Embrittlement of Welded Joint Made of Supermartensitic Stainless Steel in Environment Containing Sulfane

    Directory of Open Access Journals (Sweden)

    Jonšta P.

    2016-06-01

    Full Text Available The work is focused on evaluation of resistance of the welded joint made of supermartensitic 13Cr6Ni2.5Mo stainless steel to sulfide stress cracking. Testing method A and solution B in accordance with NACE TM 0177 were used. All the testing samples were ruptured in a very short time interval but welded joint samples were fractured primarily in the weld metal or in heat affected zone and not in the basic material. Material analysis of samples were made with use of a ZEISS NEOPHOT 32 light microscope and a JEOL 6490LV scanning electron microscope.

  17. Structure and mechanical properties of the welded joints of large-diameter pipes

    Science.gov (United States)

    Khotinov, V. A.; Arabei, A. B.; Pyshmintsev, I. Yu.; Farber, V. M.

    2013-05-01

    The structure and mechanical properties of the technological welded joints of large-diameter pipes of strength class K60 produced by two companies are studied. Along with standard mechanical properties (σ0.2, σu, δ, ψ), specific work of deformation a (tensile toughness) and true rupture strength S f are estimated from an analysis of the stress-strain diagrams constructed in true coordinates. The mechanical behavior is found to be different for samples cut from different zones of a welded joint (central weld, heat-affected zone, and base metal). The mutual correlation between parameters a, S f, and impact toughness KCV is considered.

  18. Ultrasonic test procedure for evaluating fuel clad endcap weld joints of PHWRs

    International Nuclear Information System (INIS)

    This paper describes the application of ultrasonic test method and digital signal analysis techniques for the detection of fine defects of ≅10 percent of wall thickness in resistance welded endcap-clad tube joints of fuel elements used in pressurized heavy water reactors (PHWRs). Standardization of test methodology was carried out using reference defects made on inner an outer surface of the weld region and subsequently, testing wa carried out on a number of endcap weld joint suspected to have natural defects which were rejected in the helium leak testing. The results obtained were further validated by destructive metallography, thereby confirming the sensitivity and reliability of the developed test methodology

  19. The effects of dynamic load on behaviour of welded joint A-387 Gr. 11 alloyed steel

    Directory of Open Access Journals (Sweden)

    O. Popović

    2013-01-01

    Full Text Available The in-service behaviour of alloyed steel A-387 Gr. 11 Class 1, for pressure vessels, used for high temperature applications, depends on the properties of its welded joint, with parent metal (BM, heat-affected-zone (HAZ and weld metal (WM, as constituents. Charpy testing of BM, WM and HAZ, together with, determination of the parameters of fatigue-crack growth and fatigue threshold ΔKth was used, in order to understand, how heterogeneity of structure and different mechanical properties of welded joint constituents affect on crack initiation and propagation.

  20. Numerical analysis of thermal stresses in welded joint smade of steels X20 and X22

    Directory of Open Access Journals (Sweden)

    Mladenović Saša M.

    2014-01-01

    Full Text Available Stress calculation of steam pipeline is presented, focused on the welded joint. Numerical calculation was performed using the finite element method to obtain stress distribution in the welded joint made while replacing the valve chamber. Dissimilar materials were used, namely steel 10CrMoV9-10 according to EN 10216-2 for the valve chamber, the rest of steam pipeline was steel X20, whereas the transition piece material was steel X22. Residual stresses were calculated, in addition to design stresses, indicating critical regions and necessity for post-weld heat treatment.

  1. Microstructural Characteristics and Mechanical Properties of 7050-T7451 Aluminum Alloy Friction Stir-Welded Joints

    Science.gov (United States)

    Zhou, L.; Wang, T.; Zhou, W. L.; Li, Z. Y.; Huang, Y. X.; Feng, J. C.

    2016-06-01

    The ultra-high-strength Al-Zn-Mg-Cu alloy, 7050-T7451, was friction stir welded at a constant tool rotation speed of 600 rpm. Defect-free welds were successfully obtained at a welding speed of 100 mm/min, but lack-of-penetration defect was formed at a welding speed of 400 mm/min. The as-received material was mainly composed of coarse-deformed grains with some fine recrystallized grains. Fine equiaxed, dynamic, recrystallized grains were developed in the stir zone, and elongated grains were formed in the thermomechanically affected zone with dynamic recovered subgrains. Grain sizes in different regions of friction stir-welded joints varied depending on the welding speed. The sizes and distributions of precipitates changed in different regions of the joint, and wider precipitation free zone was developed in the heat-affected zone compared to that in the base material. Hardness of the heat-affected zone was obviously lower than that of the base material, and the softening region width was related to the welding speed. The tensile strength of the defect-free joints increased with the increasing welding speed, while the lack-of-penetration defect greatly reduced the tensile strength. The tensile fracture path was significantly influenced by the position and orientation of lack-of-penetration defect.

  2. Joint strength in high speed friction stir spot welded DP 980 steel

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, Nathan; Miles, Michael; Hartman, Trent; Hovanski, Yuri; Hong, Sung Tae; Steel, Russell

    2014-05-01

    High speed friction stir spot welding was applied to 1.2 mm thick DP 980 steel sheets under different welding conditions, using PCBN tools. The range of vertical feed rates used during welding was 2.5 mm – 102 mm per minute, while the range of spindle speeds was 2500 – 6000 rpm. Extended testing was carried out for five different sets of welding conditions, until tool failure. These welding conditions resulted in vertical welding loads of 3.6 – 8.2 kN and lap shear tension failure loads of 8.9 – 11.1 kN. PCBN tools were shown, in the best case, to provide lap shear tension fracture loads at or above 9 kN for 900 spot welds, after which tool failure caused a rapid drop in joint strength. Joint strength was shown to be strongly correlated to bond area, which was measured from weld cross sections. Failure modes of the tested joints were a function of bond area and softening that occurred in the heat-affected zone.

  3. Numerical Analysis of Welding Residual Stress and Distortion in Laser+GMAW Hybrid Welding of Aluminum Alloy T-Joint

    Institute of Scientific and Technical Information of China (English)

    Guoxiang XU; Chuansong WU; Xuezhou MA; Xuyou WANG

    2013-01-01

    A 3-D finite element model is developed to predict the temperature field and thermally induced residual stress and distortion in laser+GMAW hybrid welding of 6061-T6 aluminum alloy T-joint.And the characteristics of residual stress distribution and deformation are numerically investigated.In the simulation,the heat source model takes into account the effect of joint geometric shape and welding torch slant on the heat flux distribution and a sequentially coupled thermo-mechanical method is used.The calculated results show that higher residual stress is distributed in and surround the weld zone.Its peak value is very close to the yield strength of base metal.Besides,a large deformation appears in the middle and rear part of the weldment.

  4. On Post-Weld Heat Treatment of a Single Crystal Nickel-Based Superalloy Joint by Linear Friction Welding

    Directory of Open Access Journals (Sweden)

    T. J. Ma

    2015-09-01

    Full Text Available Three types of post-weld heat treatment (PWHT, i.e. solution treatment + primary aging + secondary aging (I, secondary aging (II, and primary aging + secondary aging (III, were applied to a single crystal nickel-based superalloy joint made with linear friction welding (LFW. The results show that the grains in the thermomechanically affected zone (TMAZ coarsen seriously and the primary γ' phase in the TMAZ precipitates unevenly after PWHT I. The primary γ' phase in the TMAZ and weld zone (WZ precipitates insufficiently and fine granular secondary γ' phase is observed in the matrix after PWHT II. After PWHT III, the primary γ' phase precipitates more sufficiently and evenly compared to PWHTs I and II. Moreover, the grains in the TMAZ have not coarsened seriously and fine granular secondary γ' phase is not found after PWHT III. PWHT III seems more suitable to the LFWed single crystal nickel-based superalloy joints when performing PWHT.

  5. Evaluation of Laser Braze-welded Dissimilar Al-Cu Joints

    Science.gov (United States)

    Schmalen, Pascal; Plapper, Peter

    The thermal joining of Aluminum and Copper is a promising technology towards automotive battery manufacturing. The dissimilar metals Al-Cu are difficult to weld due to their different physicochemical characteristics and the formation of intermetallic compounds (IMC), which have reduced mechanical and electric properties. There is a critical thickness of the IMCs where the favored mechanical properties of the base material can be preserved. The laser braze welding principle uses a position and power oscillated laser-beam to reduce the energy input and the intermixture of both materials and therefore achieves minimized IMCs thickness. The evaluation of the weld seam is important to improve the joint performance and enhance the welding process. This paper is focused on the characterization and quantification of the IMCs. Mechanical, electrical and metallurgical methods are presented and performed on Al1050 and SF-Cu joints and precise weld criteria are developed.

  6. Acoustic emission detection of 316L stainless steel welded joints during intergranular corrosion

    Institute of Scientific and Technical Information of China (English)

    Meng-yu Chai; Quan Duan; Wen-jie Bai; Zao-xiao Zhang; Xu-meng Xie

    2015-01-01

    This study analyzes acoustic emission (AE) signals during the intergranular corrosion (IGC) process of 316L stainless steel welded joints under different welding currents in boiling nitric acid. IGC generates several AE signals with high AE activity. The AE tech-nique could hardly distinguish IGC in stainless steel welded joints with different welding heat inputs. However, AE signals can effectively distinguish IGC characteristics in different corrosion stages. The IGC resistance of a heat-affected zone is lower than that of a weld zone. The initiation and rapid corrosion stages can be distinguished using AE results and microstructural analysis. Moreover, energy count rate and am-plitude are considered to be ideal parameters for characterizing different IGC processes. Two types of signals are detected in the rapid corro-sion stage. It can be concluded that grain boundary corrosion and grain separation are the AE sources of type 1 and type 2, respectively.

  7. Optimization of friction stir welding parameters for improved corrosion resistance of AA2219 aluminum alloy joints

    Directory of Open Access Journals (Sweden)

    G. Rambabu

    2015-12-01

    Full Text Available The aluminium alloy AA2219 (Al–Cu–Mg alloy is widely used in the fabrication of lightweight structures with high strength-to-weight ratio and good corrosion resistance. Welding is main fabrication method of AA2219 alloy for manufacturing various engineering components. Friction stir welding (FSW is a recently developed solid state welding process to overcome the problems encountered in fusion welding. This process uses a non-consumable tool to generate frictional heat on the abutting surfaces. The welding parameters, such as tool pin profile, rotational speed, welding speed and axial force, play major role in determining the microstructure and corrosion resistance of welded joint. The main objective of this work is to develop a mathematical model to predict the corrosion resistance of friction stir welded AA2219 aluminium alloy by incorporating FSW process parameters. In this work a central composite design with four factors and five levels has been used to minimize the experimental conditions. Dynamic polarization testing was carried out to determine critical pitting potential in millivolt, which is a criteria for measuring corrosion resistance and the data was used in model. Further the response surface method (RSM was used to develop the model. The developed mathematical model was optimized using the simulated annealing algorithm optimizing technique to maximize the corrosion resistance of the friction stir welded AA2219 aluminium alloy joints.

  8. Reliability assessment and prediction of a fatigue design criterion for the gas-welded joints

    International Nuclear Information System (INIS)

    Gas metal arc welding is a very important and useful technology in the fabrication of railroad cars and commercial vehicle structures. However, since the fatigue strength of the joints welded by gas metal arc welding is considerably lower than that of the parent material due to stress concentration and metallurgical changes at the weld, the fatigue-strength assessment of welded joints is very important for the reliability and durability of railroad cars and the establishment of a criterion for long-life fatigue design. In this paper, in order to save time and cost for the fatigue design, an accelerated life-prediction method that is based on the theory of statistical reliability was investigated. Its usefulness was verified by comparing the (Δσa)R-Nf relationship that was obtained from actual fatigue test results with the (Δσa)R-(Nf)ALP relationship that was derived from accelerated life testing. And the reliability of the predicted life was evaluated. The reliability of the accelerated life-prediction on the base of actual test data was analyzed to be 80% for the plug-type gas-welded joints and 95% for the ring-type gas-welded joints

  9. Microstructural Characteristics of a Stainless Steel/Copper Dissimilar Joint Made by Laser Welding

    Science.gov (United States)

    Chen, Shuhai; Huang, Jihua; Xia, Jun; Zhang, Hua; Zhao, Xingke

    2013-08-01

    The microstructures and its formation mechanism of a stainless steel/copper dissimilar joint by laser welding were investigated. It was found that the two modes of joining, i.e., welding-brazing and fusion welding, depend on different processing parameters. In the welding-brazing mode, the interface between copper and the fusion zone has scraggy morphology because the molten pool is frozen by solid copper with high thermal conductivity. The interdiffusion of elements occurs in the neighborhood of the interface, which leads to the metallurgy bond of the mode. In the fusion welding mode, the liquid phase in the fusion zone undergoes not only primary but also secondary liquid separation due to the high cooling rate and high supercooling level of laser welding. Some microcracks generated in the fusion zone by thermal stress mismatch are healed by liquid copper filling.

  10. Measurement and Analysis of the Diffusible Hydrogen in Underwater Wet Welding Joint

    Directory of Open Access Journals (Sweden)

    Kong Xiangfeng

    2016-01-01

    Full Text Available The diffusible hydrogen in steel weldments is one of the main reasons that led to hydrogen assisted cracking. In this paper, the results of literatures survey and preliminary tests of the diffusible hydrogen in underwater wet welding joint were presented. A fluid-discharge method of for measuring the diffusible hydrogen in weldment was introduced in detail. Two kinds of underwater welding electrode diffusible hydrogen are 26.5 mL/100g and 35.5 mL/100g by fluid-discharge method, which are high levels. The diffusible hydrogen of underwater welding is higher than atmospheric welding, and the result is closely related to welding material. The best way to control the diffusible hydrogen is adjusting welding material and improving fluidity of slag.

  11. 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.

  12. Comparison of joint designs for laser welding of cast metal plates and wrought wires.

    Science.gov (United States)

    Takayama, Yasuko; Nomoto, Rie; Nakajima, Hiroyuki; Ohkubo, Chikahiro

    2013-01-01

    The purpose of the present study was to compare joint designs for the laser welding of cast metal plates and wrought wire, and to evaluate the welded area internally using X-ray micro-focus computerized tomography (micro-CT). Cast metal plates (Ti, Co-Cr) and wrought wires (Ti, Co-Cr) were welded using similar metals. The specimens were welded using four joint designs in which the wrought wires and the parent metals were welded directly (two designs) or the wrought wires were welded to the groove of the parent metal from one or both sides (n = 5). The porosity and gap in the welded area were evaluated by micro-CT, and the maximum tensile load of the welded specimens was measured with a universal testing machine. An element analysis was conducted using an electron probe X-ray microanalyzer. The statistical analysis of the results was performed using Bonferroni's multiple comparisons (α = 0.05). The results included that all the specimens fractured at the wrought wire when subjected to tensile testing, although there were specimens that exhibited gaps due to the joint design. The wrought wires were affected by laser irradiation and observed to melt together and onto the filler metal. Both Mo and Sn elements found in the wrought wire were detected in the filler metal of the Ti specimens, and Ni was detected in the filler metal of the Co-Cr specimens. The four joint designs simulating the designs used clinically were confirmed to have adequate joint strength provided by laser welding. PMID:22080283

  13. Effects of molten state of ultrasonic welded joints of plastics on their strength

    Institute of Scientific and Technical Information of China (English)

    YAN Jiuchun; LIU Jingquan; ZHOU Yusheng; YANG Shiqin; ZHOU Fuhong

    2001-01-01

    Effects of molten state of ultrasonic welded joints of plastics on their strength were investigated. Physical parameters such as temperature, viscosity and thickness of melting layers of plastic material joints were measured and analyzed. Results show that when the welding vibration amplitude and pressure increase, the temperature increases, the viscosity decreases, and the thickness of molten layer decreases. The microstructure of weld fusion zone was observed by using an optical microscope. It was found that there is strong orientation along transverse direction in the microstructure of fusion zone. Testing results show that the mechanics performance of welded joints are obviously anisotropic, and strongly affected by the thickness of molten layer and the extent of orientation.

  14. Microstructure of friction stir welded joints of 2017A aluminium alloy sheets.

    Science.gov (United States)

    Mroczka, K; Dutkiewicz, J; Pietras, A

    2010-03-01

    The present study examines a friction stir welded 2017A aluminium alloy. Transmission electron microscope investigations of the weld nugget revealed the average grain size of 5 microm, moderate density of dislocations as well as the presence of nanometric precipitates located mostly in grains interiors. Scanning electron microscope observations of fractures showed the presence of ductile fracture in the region of the weld nugget with brittle precipitates in the lower part. The microhardness analysis performed on the cross-section of the joints showed fairly small changes; however, after the artificial ageing process an increase in hardness was observed. The change of the joint hardness subject to the ageing process indicates partial supersaturation in the material during friction stir welding and higher precipitation hardening of the joint.

  15. Pinless Friction Stir Welding of AA2024-T3 Joint and Its Failure Modes

    Institute of Scientific and Technical Information of China (English)

    李文亚; 李锦锋; 张志函; 高大路; 王卫兵; 栾国红

    2014-01-01

    The joining of aluminum alloy sheets with thickness less than 2.0 mm is difficult via conventional friction stir welding owing to the defects in the joint, such as root flaw, keyhole and lazy S. In the present research, a newly designed pinless tool with involute grooves on its shoulder surface was applied to weld 1.5 mm thick AA2024-T3. The effects of the rotating speed and welding speed on the microstructure and mechanical properties of the joints were ana-lyzed. The experimental results showed that the root flaw and keyhole were successfully eliminated. The lazy S was also eliminated under the optimized welding parameters. The maximum tensile strength of the joints was 326 MPa, which is about 74.1% that of the base material. Moreover, all the tensile samples fractured from the retreating side. Two fracture modes were observed during the tensile tests, which are related with the lazy S.

  16. Hydrogen embrittlement of welded joints for the heat-treatable XABO 960 steel heavy plates

    Directory of Open Access Journals (Sweden)

    M. Opiela

    2010-01-01

    Full Text Available Purpose: In the paper, influence of hydrogen on mechanical properties of welded joints from heat-treatable structural XABO 960 steel plates was investigated.Design/methodology/approach: The heat treatment of welded plate specimens was performed, and then the specimens were charged with hydrogen electrolytically generated from 1 N H2SO4 solution. The following studies were carried out: static tensile test, hardness investigations, macroscopic metallographic investigations as well as investigations with the use of a scanning microscope.Findings: Hydrogen embrittlement of welded joints from XABO 960 steel plates was revealed by a distinct decrease of ductility and a slight decrease of strength. On the basis of metallographic investigations, it was found that in a fracture region there are fine pores created by the presence of hydrogen and its displacement due to formed stresses and plastic deformation. It was shown that welded joints are susceptible to hydrogen cracking in the heat affected zone and in the fusion zone.Research limitations/implications: TEM investigations on structure of the steel were predicted.Practical implications: The obtained results can be used for searching the appropriate way of improving the hydrogen embrittlement resistance of welded joints of the heat-treatable structural XABO 960 steel plates.Originality/value: The hydrogen embrittlement of welded joints of the heat-treatable XABO 960 steel plates was investigated.

  17. Experimental analysis of dissimilar metal weld joint: Ferritic to austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Rathod, Dinesh W., E-mail: dineshvrathod@gmail.com [Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi 110016 (India); Pandey, Sunil [Department of Mechanical Engineering, Indian Institute of Technology Delhi, New Delhi 110016 (India); Singh, P.K. [Bhabha Atomic Research Centre, Mumbai 400085 (India); Prasad, Rajesh [Department of Applied Mechanics, Indian Institute of Technology Delhi, New Delhi 110016 (India)

    2015-07-15

    The dissimilar metal weld (DMW) joint between SA508Gr.3Cl.1 ferritic steel and SS304LN using Inconel 82/182 consumables was required in the nuclear power plants. The joint integrity assessment of these welds requires mechanical and metallurgical properties evaluation in weldment regions. The joint was subjected to 100% radiography test and bend test and transverse tensile test. Welding and testing were carried out as per the requirements of ASME Sec-IX and acceptance criteria as per ASME Sec-III. The transverse tensile test results indicated the failure from the weld metal although it satisfies the minimum strength requirement of the ASME requirements; therefore, the DMW joint was analyzed in detail. Straight bead deposition technique, fine slag inclusion, less reliable radiograph technique, plastic instability stress, yield strength ratio and metallurgical deteriorations have been contributed to failure of the DMW joint from the weld region. In the present work, the factors contributing to the fracture from weld metal have been discussed and analyzed.

  18. Numerical and microstructural evaluation of 9%Cr welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Sawada, K. [National Institute for Materials Science (Japan); Bauer, M.; Kauffmann, F.; Klenk, A. [Stuttgart Univ. (Germany). MPA

    2008-07-01

    Microstructural changes after creep at 600 C were investigated on E911 welded joints, focusing on the influence of multiaxiality of stress on microstructure of the fine-grained heat-affected zone (FGHAZ). In FGHAZ, more creep voids were observed in the interior portion of the specimen, compared with the outer surface. This is due to the higher multiaxiality of stress in the interior portion. There was no significant growth of VX particles during creep because of their higher thermal stability in base metal and FGHAZ. For M{sub 23}C{sub 6}, the growth during creep in FGHAZ was faster than in the base metal. There was no large difference in the growth rate of M{sub 23}C{sub 6} between the interior portion and near the outer surface. The number of Z-phase particles after creep in the base metal was higher than that in the FGHAZ. For FGHAZ, the number of Z-phase particles was higher in the interior portion of the specimen in contrast with near the outer surface. Increase in subgrain size and decrease in dislocation density were observed after creep in the base metal and the FGHAZ. For FGHAZ, the subgrain size and dislocation density after creep in the interior portion were almost the same as near the outer surface. (orig.)

  19. Adaptive control of penetration and joint following for robotic GTA welding

    International Nuclear Information System (INIS)

    A statistical-based method for adaptive control of weld pool penetration and joint following in Tungsten Inert Gas Welding as an approach to process and trajectory control of robotic GTA welding has been designed and simulated. Welding process parameters such as: base current and time, pulse current and time, electrode tip to work piece distance, filler travelling speed, torch speed and work piece thickness were used for finding the equations which describe the interrelationship between the aforementioned variables and penetration depth as well as bead width. The calculation of these equations was developed from the statistical regression analysis of 80 welds deposited using various combinations of welding parameters. For monitoring of the work piece thickness variations, an ultrasonic device was used. In order to control the weld trajectory, a CCD camera was also used. The results showed that the misalignment of the progressive heat affected zone which is adjacent to the weld puddle can be detected, and used for control of the weld trajectory. Also, it was found that scanning of a certain region of the captured image in front of the weld puddle decreases the data processing time drastically

  20. Design of a welded joint for robotic, on-orbit assembly of space trusses

    Science.gov (United States)

    Rule, William K.

    1992-12-01

    In the future, some spacecraft will be so large that they must be assembled on-orbit. These spacecraft will be used for such tasks as manned missions to Mars or used as orbiting platforms for monitoring the Earth or observing the universe. Some large spacecraft will probably consist of planar truss structures to which will be attached special purpose, self-contained modules. The modules will most likely be taken to orbit fully outfitted and ready for use in heavy-lift launch vehicles. The truss members will also similarly be taken to orbit, but most unassembled. The truss structures will need to be assembled robotically because of the high costs and risks of extra-vehicular activities. Some missions will involve very large loads. To date, very few structures of any kind have been constructed in space. Two relatively simple trusses were assembled in the Space Shuttle bay in late 1985. Here the development of a design of a welded joint for on-orbit, robotic truss assembly is described. Mechanical joints for this application have been considered previously. Welded joints have the advantage of allowing the truss members to carry fluids for active cooling or other purposes. In addition, welded joints can be made more efficient structurally than mechanical joints. Also, welded joints require little maintenance (will not shake loose), and have no slop which would cause the structure to shudder under load reversal. The disadvantages of welded joints are that a more sophisticated assembly robot is required, weld flaws may be difficult to detect on-orbit, the welding process is hazardous, and welding introduces contamination to the environment. In addition, welded joints provide less structural damping than do mechanical joints. Welding on-orbit was first investigated aboard a Soyuz-6 mission in 1969 and then during a Skylab electron beam welding experiment in 1973. A hand held electron beam welding apparatus is currently being prepared for use on the MIR space station