最新刊期
期 4 ， 2021
- 摘要：In this paper,the plate welding experiment of 304 stainless steel was carried out by using laser self-fusion welding technology,and the test results were analyzed from the microstructure and mechanical properties. Optimum process parameters as follow,laser power 2.6 kW,welding speed 1.8 m/min,defocus amount +2 mm. The composition of austenite and ferrite in welded joint was obtained by metallographic structure characterization,X-ray fluorescence diffraction and electron back scattering diffraction. According to the best process parameters,the large-scale general finite element simulation software ABAQUS is selected,and the combined heat source of Gaussian surface heat source and Gaussian rotating body is used to simulate the laser welding process. The cross-sectional morphology of the weld obtained by simulation and the cross-sectional morphology of the weld obtained by the experiment are compared,and the simulation model is optimized according to the comparison result. The simulation results show that in the front of the moving heat source,the concentration of isotherms is large,and the temperature gradient is large,while behind the moving heat source,the isotherms are sparse and the temperature gradient is also reduced.关键词：304 stainless steel;laser beaming welding;microstructure and property;numerical simulation
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发布时间：2022-03-14 - 摘要：This paper based on the finite element method,using ABAQUS software,referring to the groove shape of the actual pipe girth weld and the softening phenomenon of the heat-affected zone material,a nonlinear finite element analysis model of the pipe girth weld with pit defects is established.The stress of pipe girth welds with pit defects under different loads was analyzed. The influence of pit size,weld reinforce-ment and material properties of heat-affected zone on the stress distribution of circumferential welds of pipelines with pit defects was discussed. The results show that obvious stress concentration occurs around the pit,and the depth of the pit has a significant influence on the ultimate bearing capacity of the pipeline. As the depth of the pit increases,the maximum equivalent stress of the corroded pipeline increases significa-ntly,and the maximum stress is concentrated in the weld zone.When the pipeline is under extreme tensile load, the maximum equivalent stress of the pit defect in the weld reinforcement is concentrated in the heat-affected zone;when the depth of the pit is greater than the reinforcement,the maximum equivalent effect force is located at the edge of the pit in the center of the weld.关键词：pipe girth weld;pit defects;weld reinforcement;finite element analysis;safety assessment
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发布时间：2022-03-14 - 摘要：Aiming at the low welding efficiency and defects such as undercut and hump in the tungsten inert gas welding（TIG） of pure titanium TA2 thin walled pipe,the tandem TIG welding process is proposed,which can effectively increase the welding speed and improve the appearance of weld. The ABAQUS software is used to build welding thermal elastic-plastic finite element model for the two kinds of welding methods,and the welding temperature field and residual stress field are compared and analyzed. The microstructure analysis and mechanical properties test of welded joints are carried out. The results show that the weld contour sizes of the two simulated joints are similar to the actual joint and the weld center temperature of tandem TIG is lower than that of TIG. The width of Von Mises stress range above 200 MPa around tandem TIG is less than that of TIG,and the values of Von Mises stress in weld center are similar. The microstructure of the weld center and HAZ of tandem TIG is smaller than that of TIG,and the mechanical properties and corrosion resistance of the two joints meet the requirements of relevant standards.Under the conditions that the pure titanium TA2 pipe with a specification of Φ19 mm×0.7 mm obtains good appearance of weld,the welding speed by tandem TIG welding can reach 5 m/min. Comparing with TIG,the tandem TIG welding can highly improve production efficiency and basically accomplish no defect of straight weld.关键词：tandem tungsten inert gas welding（tandem TIG）;numerical simulation;welding temperature;welding residual stress;pure titanium TA2 thin-walled pipe
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发布时间：2022-03-14 - 摘要：CrNiMo duplex stainless steel surfacing layers with Co content of 0%,1%,2% and 3% are prepared on 304 austenitic stainless steel substrate by TIG powder surfacing.After solution treatment at 1100℃,the effect of Co content on the microstructures,hardness and corrosion resistance of CrNiMo duplex stainless steel is studied by metallographic observation,microhardness test,potentiodynamic polarization curve and electrochemical impedance spectroscopy（EIS）.The results show that with the increase of Co content,the proportion of austenite phase increases from 52% to 61% and then decreases to 41%,and the morphology of austenite phase changes from strip-like or island-like to grid-like;the solid solution of Co element in the matrix promotes the precipitation of Cr-rich and Mo-rich intermetallic phases,improves the hardness of the surfacing layer,destroys the stability of the passivation film,and weakens the corrosion resistance of the surfacing layer.关键词：TIG surfacing;duplex stainless steel;microhardness;corrosion resistance
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发布时间：2022-03-14 -
Safety evaluation of Hook defects in joints of friction stir butt-lap welded aluminum alloy profiles
摘要：In this paper,based on the theory of fracture mechanics,the safety evaluation of Hook defects in joints of friction stir butt-lap welded aluminum alloy profiles is carried out, and the fatigue test is used to verify it. The metallography shows that the essence of the Hook defect is the result of the upward migration of the overlapping surface under the vigorous stirring action of the stirring head,which appears as a crack.The Hook defect is normalized to a unilateral crack extending into the inside of the weld. The linear fitting of crack growth rate test shows that the threshold value of the stress intensity factor amplitude ΔKth is 2.509 MPa·m1/2. According to the crack growth conditions,the defect size-stress amplitude relationship curve for evaluating the fatigue growth of Hook defects is obtained.There is a certain error between the fatigue test results and the theoretical Hook defect critical growth stress amplitude. The average error is 9.4%. The overall trend is in good agreement with the theoretical curve. The theoretical formula can be applied to the prediction of the critical stress amplitude of Hook defect fatigue growth,then it can be used to evaluate the safety of hook defects in joints under different working stress amplitudes.关键词：aluminum alloy;friction stir butt-lap welding;Hook defects;threshold;critical stress amplitude- 27
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发布时间：2022-03-14 - 摘要：According to NB/T 47014 standard,the paper designed a general procedure qualification system for pressure equipment. In order to solve the problems of long development cycle and high cost of the previous related systems,on the basis of the management of basic procedure documents（PWPS,PQR,WPS）,the paper realized the auxiliary proposal of welding procedure qualification project,the intelligent judgement of the necessity of welding procedure qualification and the autogeneration of welding procedure specification. Compared with the pre vious custom welding procedure qualification system,the general system can meet the needs of most pressure equipment enterprises. There is no need for repeated development,which avoids a lot of repetitive work and reduces the cost of system development.关键词：NB/T 47014-2011;pressure equipment;general system;procedure qualification
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发布时间：2022-03-14 - 摘要：This paper discusses the current situation of the training of domestic brazers and analyzes the deficiency of the current vocational skill training for brazers. Combined with national vocational skills standard "welder" and the upcoming release of form a complete set of teaching material "welder national vocational qualification training tutorial-brazer",overall summarizes the classification,brazer professional skill level teaching training system content and specific skills to master requirement,so that the relevant personnel can quickly adapt to the new brazer training and examination system,and then quickly regulate domestic brazer forensics work,so as to overall improve the technology level of domestic brazing operators;finally,some suggestions on the future work of domestic brazer vocational skill training are put forward.关键词：braze;brazer;vocational skills training;qualification test
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发布时间：2022-03-14 - 摘要：In the design of pulse welding digital control system,in view of the different requirements of the control system during the control of the base current and peak current,as well as the possible instantaneous transition of the digital PI operation results when the base value and peak value are switched instantaneously,this paper designs a digital double PI algorithm to control the base value and peak value respectively,and compares it with the case that only one PI regulator is used to control the base value and peak value. It is found that the control effect of double PI algorithm is good and the system is stable.According to the characteristics of variable speed integral PI control, the transition time of the pulse peak after the arc striking can be reduced by using the double PI algorithm. The process test shows that this method can effectively improve the primary arc striking rate.关键词：pulse welding power supply;double PI control algorithm;process test;arc striking
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发布时间：2022-03-14 - 摘要：In this article,an automatic welding production line is designed for the body bolster of the railway wagons.Different work stations and logistics measures are set according to the welding manufacturing technology to achieve the assembly line operation mode,to manage and control a series of technological processes such as materials feeding,grouping,welding and cutting through the automatic and digital controlling system,to collect the working condition of the field equipment and welding process data in real-time through the control system,and to upload to the central control system through the bus mode,display the process status digitally,and the centralized monitoring of production line and process is realized by interface with MES system.关键词：sleeper beam;digitalize;welding production line
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发布时间：2022-03-14 - 摘要：The material properties of stainless steel rail vehicle are analyzed,which is suitable for the process analysis of resistance spot welding technology.The composition and application of each system of resistance spot welding equipment are analyzed from the working principle,overall structure,welding system,running system,control system,welding monitoring system,lubrication system,cooling system,electrode holder structure,spot welding electrode,welding ability and auxiliary device of equipment,etc.The basic composition,application characteristics and requirements of the resistance spot welding equipment for the production of stainless steel rail vehicles are studied.关键词：stainless steel vehicle;resistance spot welding;equipment;performance
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发布时间：2022-03-14 - 摘要：The construction of liquefied natural gas（LNG）storage tanks is complicated and the technical requirements are very strict. Currently,9Ni steel is commonly used in the manufacturing of LNG storage tanks. 9Ni steel is a low-carbon martensitic ultra-low temperature steel with a Ni content of 9%.It has excellent strength and toughness at -196 ℃. The welding materials and welding technology of 9Ni steel are difficult and key points in the construction of LNG low temperature storage tanks. A few developed countries in the world have been mastering these technologies. The localization of 9Ni steel welding has become the focus of the industry. Based on the research on 9Ni steel and its welding materials in recent years,this paper summarizes the development and technical chara-cteristics of 9Ni steel,and discusses the development of its welding materials,welding methods and welding processes.关键词：9Ni steel;welding material;welding process;ENiCrMo-6
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发布时间：2022-03-14 - 摘要：With the continuous increase of domestic electricity consumption,the construction of high head and large capacity pumped storage power station is also increasing.In this paper,the weldability test of domestic B950CF steel plate is carried out with self developed submerged arc welding wire and flux.After the test,the tensile strength is 979 MPa,yield strength is 812 MPa,the impact energy value at -40 ℃ is above 90 J and at-60 ℃ is above 60 J. It also has excellent performance in butt joint welding.The pass rate of bending test with thickness of 70 mm is 100%. A good match between high strength and high toughness is achieved,which lays the foundation for engineering application of domestic 1 000 MPa hydropower steel.
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发布时间：2022-03-14 - 摘要：Electron beam welding of 30CrMnSi alloy steel and TC4 titanium alloy was realized by Cu/V interlayer.Microstructure and mechanical properties of the joint were investigated. The results show that by adding Cu/V transition layer metal, the direct mixing of Ti-Fe elements and the brittle intermetallic compounds can be avoided. Characteristic phases of different components and properties are distributed in different areas of the weld. The weld near the steel side is a mixture of Fe-rich phase and Cu-rich phase. The weld near the titanium side forms Ti-V solid solution and also forms a small amount of Ti-Cu intermetallic compounds. The maximum tensile strength of the joint is 418 MPa,and the joint fails at the interface between the weld and 30CrMnSi base metal.关键词：TC4 titanium alloy;30CrMnSi alloy;electron beam welding;microstructure
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发布时间：2022-03-14 - 摘要：Based on the thermal elastoplastic finite element theory and Abaqus analysis software,the residual stress and deformation of fillet joint after welding are analyzed. The segmented moving heat source model is adopted and the heat source subroutine is developed by using Fortran language. The numerical simulation analysis of the welding temperature field,residual stress and deformation of the fillet joint is carried out by means of straight through welding and backstep welding respectively. The results show that the transverse deformation is the main deformation of the fillet joint;the residual stress at the weld end of the fillet joint is compressive stress,while the residual stress in the middle part is tensile stress;the transv-erse residual stress is obviously weakened by backstep welding,which can effectively reduce the deformation and stress after welding.关键词：fillet joints;backstep welding;temperature field;residual stress;deformation
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发布时间：2022-03-14 - 摘要：Combined with the structural dimensions,construction methods and the requirements for post-weld heat treatment（PWHT）of steel containment vessel（CV）,the heating methods suitable for PWHT of CV are analyzed and compared.The feasibility of local PWHT is proved by application. According to the engineering experience,it’s suggested that the exemption of PWHT for SA-738 Gr.B steel plates with thickness less than 60 mm should be promoted and ultrasonic impact treatment should be used instead of PWHT for CV.关键词：steel containment vessel;SA-738 Gr.B;local post weld heat treatment;exemption of post-weld heat treatment;ultrasonic impact treatment
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发布时间：2022-03-14 - 摘要：In this paper,the resistance brazing of pure copper plates with different overlapping areas made under different electrode pressures was studied by ultrasonic testing and metallographic testing. The magnitude and the uniformity of the applied electrode pressure are the key factors for the brazing rate to meet the requirements and the welding quality to be stable. Under proper electrode pressure,the resistance brazing of pure copper plates with different overlapping areas can obtain ideal brazing rate. The results of ultrasonic inspection and metallographic examination of the brazing seam show that the unfused defects with small local weld gap are the main defects in the brazing seam whose average width is less than 78 μm,while in the brazed seam whose average width is over 78 μm,the main defects are looseness and round holes formed by the unfilled solder. The ultrasonic flaw detection is consistent with the metallographic testing, so the ultrasonic flaw detection can be used to effectively detect the brazing rate of large-area overlapping resistance brazing.关键词：resistance brazing;ultrasonic flaw detection;brazing rate;electrode pressure
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发布时间：2022-03-14 - 摘要：The microstructure and mechanical properties of 20Mn23AlV non-magnetic steel plate with thickness of 12 mm are compared by welding with different shielding gases.The results show that the appearance of weld surface of the test plate welded with 97.5% Ar+2.5% CO2 shielding gas is better,and there are few pores in the weld.The welded joints with two kinds of shielding gases have good plasticity,toughness and tensile strength.The microstructure of the weld is white austenite matrix+δ ferrite. Using 97.5%Ar+2.5%CO2 shielding gas is reasonable and can meet the non-magnetic steel welding production requirements.
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发布时间：2022-03-14 - 摘要：By the experimental study on electron beam welding（EBW） process of Niobium alloy Nb521,the welding parameters are optimized,and the appearance of weld surface and the microstructure of welded joint are analyzed. The results show that Nb521 alloy is well compatible with EBW. The tensile strength and yield strength of the weld can reach more than 95% of the base metal at normal temperature,and the elongation percentage of the weld reaches 86.7% of the base metal.The weld performance is good below 1 600 ℃.关键词：Niobium alloy Nb521;electron beam welding;tensile strength
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发布时间：2022-03-14 - 摘要：Automatic welding of long-distance pipeline has many advantages such as good welding quality,high efficiency and low labor intensity,which can better solve the problems of high-grade steel welding quality and pipeline operation safety.However,for the pipeline construction unit,using pipeline automatic welding technology and process,the investment of personnel and equipment is huge and the construction cost increases exponentially.And for most construction units, the actual construction efficiency of automatic welding is far lower than the theoretical efficiency,which cases the construction unit to have big investment and little output, and affects the promotion and use of the pipeline automatic welding technology.In view of this situation,it is necessary to analyze the construction resource allocation,technology and process,construction management and economy of the automatic welding,in order to find methods and ways to reduce the automatic welding construction cost,obtain reasonable construction profits,improve the market competitiv-eness of construction unit,better drive the application of auto-matic welding technology and process,and promote the sustai-nable development of pipeline automatic welding.关键词：long-distance pipeline;automatic welding;resource allocation;economy analysis
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发布时间：2022-03-14 - 摘要：Clamps are widely used in airplanes and are often used to fix various gas cylinders. The quality of the clamp affects the safety of flight. The fixing clamps for air-conditioning cylinders in a certain type of aircraft often suffer from fracture of the clamp body. Spot welding is used to weld the fractured location.Through stereo observation,fracture met-allographic observation,section composition analysis,low power test,and tensile test analysis,it is found that the clamp fracture is a corrosion fatigue fracture;the source of fatigue is at the junction of the clamp welding point and the heat-affected zone.When analyzing the welding quality,the metallographic insp-ection finds that there are small cracks at the junction of the clamp welding point and the heat-affected zone. The phenom-enon and causes of clamp fracture are studied and preventive measures are proposed.关键词：failure analysis;corrosion fatigue;welding defect;1Cr11Ni20Ti2B welding
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发布时间：2022-03-14 - 摘要：<正>2020年12月,经过多项学术指标综合评定及同行专家评议推荐,《电焊机》杂志被中国科学技术信息研究所收录为"中国科技核心期刊"（中国科技论文统计源期刊）。《电焊机》杂志多年来一直被收录为"中国科技核心期刊",在此感谢行业专家、学者、广大读者、作者长期以来的关注与支持,《电焊机》杂志将继续努力,进一步提高出版质量和办刊水平,不断增强影响力、传播力和竞争力,争创优秀精品期刊。
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发布时间：2022-03-14 - 摘要：<正>近日,由中国学术期刊（光盘版）电子杂志社有限公司、中国科学文献计量评价研究中心编制出版的《中国学术期刊影响因子年报（2020版）》正式发布,《电焊机》杂志再次入选《中国学术期刊影响因子年报》统计源期刊,在此感谢行业专家、学者、广大读者、作者长期以来的关注与支持,《电焊机》杂志将继续努力,进一步提高出版质量和办刊水平,不断增强影响力、传播力和竞争力,争创优秀精品期刊。
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发布时间：2022-03-14 - 摘要：<正>随着数字时代的到来和新媒体的出现,数字阅读已成为一种新的生活方式,期刊的数字化发行已成为转型发展重要举措。为促进学术传播和交流,扩大期刊传播范围、提高影响力,推进学术资源的公益使用和开放共享,《电焊机》杂志积极与多家数字期刊发行平台合作,以数字化方式进行互联网和移动互联网的发行与传播,竭力为读者提供优质服务。欢迎搜索阅读!
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发布时间：2022-03-14
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