最新刊期
期 7 ， 2021
- 摘要：Waveform control is beneficial to improve the quality of AC submerged arc welding,but it has very high requirements for polarity switching speed,zero-crossing arc stability and dynamic response speed of submerged arc welding power supply,especially in the condition of large current AC submerged arc welding pulse implementation is extremely difficult. Therefore,two optimal control strategies for high power AC pulse submerged arc welding power supply are proposed in this paper,including:the critical through strategy of secondary inverter,which can accelerate the polarity switching speed of AC output;PI separated control algorithm can improve the performance of dynamic waveform output of welding power source.The effectiveness of the proposed optimal control strategy is analyzed by modal analysis and SMIULINK model simulation method. Finally,the proposed optimization strategy is verified by experiments on the developed high-power AC pulse submerged arc welding power supply system. The results show that the proposed waveform control strategy can effectively improve the polarity switching speed of submerged arc welding power supply,and can well suppress the current overshoot,steady-state error and waveform oscillation of complex waveform.关键词：submerged arc welding;pulse-square waveform;polarity switching;PI separation algorithm
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发布时间：2022-03-14 - 摘要：The Cu/Cu-cored+SAC305/Cu and Cu/SAC305/Cu micro-solder joints were subjected to thermal aging tests with different length. The effects of thermal aging time on the interfacial microstructure and tensile properties of these two solder joints were analyzed by scanning electron microscope（SEM） and dynamic mechanical analyzer（DMA）. The results show that the grains in interfacial microstructures of solder joints gradually coarsen,the IMC layers become thicker and the tensile strength of solder joints reduce with increasing aging time. Compared with Cu/SAC305/Cu solder joints,under the same thermal aging time,adding Cu-cored can slow down the growth rate of IMC at solder joint interface and improve the tensile strength of solder joint,but has no significant effect on the microstructure morphologies of solder joints. Fracture analysis shows that the two kinds of solder joints are brittle fracture. However,there are a small number of dimples on the fracture surface of Cu/Cu-cored +SAC305/Cu solder joints,showing certain toughness.关键词：Cu-cored solder joint;thermal aging;intermetallic compound（IMC）;tensile strength
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发布时间：2022-03-14 - 摘要：The welding groove of ultra-narrow gap is deep and narrow,which is easy to cause the risk of arc climbing,resulting in poor fusion at the bottom side wall. Aiming at the problem that the fusion state of ultra-narrow gap welding with constrained arc by flux flake is difficult to be monitored on-line,a fusion state recognition method based on arc sound is proposed. The arc acoustic signal acquisition system for ultranarrow gap welding process is established,based on the analysis of arc acoustic generation mechanism and human ear identification behavior,the short-term energy,average amplitude,Moore loudness,Mel cepstrum coefficient and their first-order and second-order differences which effectively characterize the welding process are extracted. Based on particle swarm optimization least squares support vector machine（PSO-LSSVM）,the fusion state recognition model of ultra-narrow gap welding bottom sidewall is established. The results show that this method can realize the identification of three kinds of states:non fusion,critical fusion and good fusion,and the accuracy can reach 91.7%. It provides a new way for on-line monitoring of the fusion state of ultra-narrow gap welding.关键词：ultra-narrow gap welding;arc sound;ear recognition behavior;PSO-LSSVM;fusion state recognition
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发布时间：2022-03-14 - 摘要：The welded joint of rails will form a heat-affected zone after thermal cycling. In the heat affected zone,due to the existence of incomplete phase transformation affected zone,the hardness decreases and the softening occurs. Severely softened joints will produce saddle-shaped wear after service,resulting in uneven lines. In this paper,the variation of hardness in softening zone of high-strength wear-resistant steel rail gas pressure welding joints under different cooling conditions are studied. The results show that in the cooling process,the cooling rate is increased by jet-air and spraying,which has a significant effect on reducing the width of softening zone of the joint. The hardness of the softest point of the welded joint increases with the strength of the base metal,but the higher the strength of the rail,the lower the ratio of the softest point to the hardness of the base metal. When the rail is at the strength level of 1 280 MPa and above,the hardness standard requirement of the softening zone of the pressure welding joint(HJ1/HP≥0.8) is difficult to be stably met. It is recommended to modify or reduce the index requirement.关键词：rail;gas pressure welding;softening zone;hardness;cooling process
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发布时间：2022-03-14 - 摘要：In the case of abnormal displacement of the main steam pipeline and the furnace top pipe section of reheat steam pipeline in a certain power plant,the abnormal displacement of the pipe section was treated and the structural stress of the pipe and weld was optimized based on the non-destructive test of the weld on site and the indication state of the hanger.Finite element analysis method,pipe load perfor-mance test,elevation measurement and other comprehensive measurement techniques are combined to assist the non-destructive test methods of welds. The primary stress and secondary stress of the pipe system reduce by more than 15%,and the stress concentration of the weld at the cracking position also reduces.Through this pipe section settlement management and optimization of structural stress,it is suggested that a new production unit should master the stress level and displacement deviation status of pipe system as soon as possible within two years.Combining with the comprehensive pipeline measurement technology and the supports and hangers adjustment technology,the pipeline structure optimization and systematic treatment are carried out to prolong the service life of the pipeline and realize the safe and stable operation of the unit.关键词：abnormal displacement;structural stress;support and hanger adjustment;service life
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发布时间：2022-03-14 - 摘要：During the fabrication of deep-sea floating FPSO project,austenitic stainless steel has been widely used for oil and gas pipelines in the inner turret single point mooring system. It is impractical to apply RT inspection due to the narrow inspection space. PAUT is one of the best methods in lieu of RT and highly developed in recent years,the coarser grain of austenitic stainless steel weld is the difficulty to be overcome,and the small diameter and thin wall increase multiple difficulties such as large emission loss. In this paper,the feasibility of testing the material pipeline by phased array technology is analyzed through a large number of experiments,and the phased array scanning process for some specific specifications of austenitic stainless steel is formulated.关键词：austenitic stainless steel;PAUT;scan plan;small diameter;thin wall
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发布时间：2022-03-14 -
Study on mechanical properties and microstructure of extrusion weld of 6005A aluminum alloy profiles
摘要：In this paper,the mechanical properties of 6005A aluminum alloy profiles are tested and the microstructure of extruded weld and base material is observed to determine the weak position of aluminum alloy profiles and discuss the difference between the mechanical properties and microstructure in the weak position and its causes. The results show that the microstructure of the extruded weld and the base material is Mg2Si evenly distributed in the aluminum matrix,but the Mg2Si in the extruded weld is thicker and more disorderly. The grain shape of the extruded weld is mainly strip grain and fine equiaxed grain,and the average grain size is 15.5 μm.In the process of hot extrusion,the non-uniformity of grain size in the extruded weld increases,and the coordination between grains becomes worse during deformation. Cracks are easy to occur in tensile process,which makes the material strength decrease and becomes the weak position of aluminum alloy profile. The average hardness of 6005A aluminum alloy profile is88.176 HBW,the minimum value is 81.7 HBW,and the minimum value appears in the extruded weld. The sample position 6 has the minimum elongation after fracture（4.5%）,and it is judged that the sample position 6 is the weakest position of the profile.关键词：6005A;extruded weld;mechanical properties;microstructure;EBSD- 29
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发布时间：2022-03-14 - 摘要：The multi-pass welding within the groove butt of ERNiCrMo-3 was operated by the gas tungsten arc welding（GTAW）,and the deposited metal was obtained for microstru-cture observation and mechanical properties analysis. The microstructure of deposited metal is dominated by dendrite crystals. The precipitates which are Laves phase,NbC/TiN and δphase are mainly located in the interdendritic core. From the bottom to the top in the deposition direction,the hardness gradually decreases. Various precipitates in the deposited metal have no adverse effect on impact and tensile properties.关键词：ERNiCrMo-3;deposited metal;hardness;impact properties;tensile properties
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发布时间：2022-03-14 - 摘要：The requirement of stress-relief heat treatment for Nuclear Power Plant steel containment vessel（CV） is demonstrated,and the advantages and feasibility of replacing heat treatment with ultrasonic regulation are analyzed theoretically. The mechanical properties and residual stress distribution on weld state,heat treatment state and ultrasonic regulation state are compared and analyzed. The results show that the residual stress of the joint can be effectively reduced by ultrasonic,and the average stress relief rate reaches 24.4%. The stress reduction effect of ultrasonic regulation for 2 hours is similar to that of heat treatment for 10 hours. At the same time,there is no obviously deterioration in tensile strength,elongation and impact properties of the joint under ultrasonic regulation. It is considered that the ultrasonic regulation technique could replace the stress-relief heat treatment,and the direction of further research is given.关键词：containment vessel;stress-relief heat treatment;ultrasonic regulation;residual stress;mechanical property
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发布时间：2022-03-14 - 摘要：Aiming at the corrosion of the heat-affected zone（HAZ） of the weld of stainless steel close packed pipe joint,the test pieces are prepared with the same base metal,welding structure and welding procedure and are removed the oxide layer generated in the welding process by different surface treatment methods,and the simulated corrosion test is carried out to compare and observe the surface corrosion resistance status of the material surface after removing the oxide layer. The reason of rust in the heat-affected zone of the weld is determined by intergranular corrosion test,electrolytic corrosion test and metallographic microscope observation,and on this basis,the solution is put forward combining with the verification test.关键词：stainless steel;weld;heat-affected zone;corr osion
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发布时间：2022-03-14 - 摘要：Friction stir welding（FSW） is used to conduct different welding process contrast experiment of 3 mm thick 6005A alloy plate. Through the mechanical tensile,hardness,forward bending,macro metallographic and micro metallogra-phic analysis of the weld position,the optimal welding process is finally determined. Research shows that when the rotational speed of the friction head is 1 200 r·min-1 and the welding speed is 700 mm ·min-1,the mechanical tensile fracture occurs near the heat affected zone and the fracture surface shows "necking" phenomenon,the Vickers hardness distribu-tion is W-shaped,and there are small S-lines in the micro-structure. The mechanical value is higher than the standard and better than the other three welding parameters,which meets the production process requirements and provides technical support for the production process.关键词：6005A aluminum alloy;friction stir welding;mechanics;hardness;macro metallographic;micro metallographic;bending test
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发布时间：2022-03-14 - 摘要：Taking the welding technology research and development of nickel base alloy heat exchange tube（SB-163 N06690,size φ19 mm ×2.5 mm） as an example,the develop-ment process of this welding technology is comprehensively introdu-ced,including the selection of welding equipment suitable for actual working conditions,design,test and optim-ization of welding groove,development of welding parameters,necessary tooling design,inspection and destructive test of welded joints. Through the technology development,the high quality welded joints are effectively obtained,the indexes are verified to meet the use requirements,and a lot of engineering manufacturing costs are saved. It is hoped that this welding technology can be popularized and applied in similar welding joints.关键词：civil nuclear equipment;nickel base alloy heat exchange tube;welded joint;welding technology
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发布时间：2022-03-14 - 摘要：The microstructure and mechanical properties of P355NL1 steel MAG welded joints before and after stress relief annealing treatment were compared. The results show that a welded joint with good appearance could be obtained by the MAG welding method. The stress relieving annealing treatment has no obvious effect on the microstructure of the weld,heat-affected zone and base metal of the welded joints.The stress relief annealing treatment has little effect on the tensile properties,breaking elongation and bending properties of the welded joints,but the hardness of the joint reduces to a certain extent. The impact absorption energy of the stress relief annealing joint weld has little change,while the impact absorption energies of the base material and heat-affected zone have a certain degree of improvement. On the whole,the stress-relieving annealing treatment has no significant influence on the microstructure and mechanical properties of the P355NL1 steel MAG welded joints,which can ensure the good service performance of welded joints.关键词：stress relief annealing;P355NL1 steel;welded joint;microstructure;mechanical properties
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发布时间：2022-03-14 - 摘要：The main pipeline of the nuclear power plant connects the pressure vessel,steam generator and main pump,and is the aorta of the nuclear power plant. At present,automatic all-position welding technology is used,and welding deformation is used for installation and adjustment of equipment during the welding process;aiming at the problem of excessive pump casing levelness and clearance of support leg gaskets caused in the repair process of the main pipeline of a nuclear power project,by adjusting the shrinkage and deformation during the automatic welding process of the main pipeline,the levelness of the pump casing,the support leg gasket,and the center position are finally adjusted to the requirements of the design standard, which ensures that the subsequent water conservancy components are installed in place,and provides reference and reference for follow-up similar issues.关键词：nuclear power plant;automatic welding of main pipeline;shrinkage and deformation;pump casing adjustment
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发布时间：2022-03-14 - 摘要：Pressurizer is one of the main equipment in the primary loop of PWR nuclear power plant. As the key element of pressurizer,the electric heater is welded by automatic TIG welding. In this paper,a case of incomplete penetration of the joint of electric heating element according to the original mature automatic TIG welding process is introduced. The analysis shows that that too low content of S element in the base metal changes the flow and heat transfer direction of the molten pool,and causes more welding heat to flow to the two sides of the weld,as a result,the depth of penetration becomes shallow and incomplete penetration of joint can not be solved. According to the characteristics of the existing low S base metal,the new welding parameters are adjusted through the process experiment.The two-step welding method can not only guarantee complete penetration,but also ensure that the surface depression of the final joint does not exceed the standard. Furthermore,the improvement suggestions are put forward for the welding of the electric heating element of the follow-up project and the replacement process of the electric heaters of the pressurizer in service.关键词：pressurizer;electric heating element;automatic TIG;incomplete penetration;low S base metal
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发布时间：2022-03-14 - 摘要：According to EEMUA 158 standard,the welding procedure qualification is required when the repair welding procedure is different from the original weld. In this paper,for S355 grade structural steel,the original weld is welded with automatic submerged arc welding procedure. After welding,the visual and non-destructive tests are carried out. Then carbon arc gouging and grinding are performed on the original weld.The repair depth is half of the wall thickness of the base metal.The repair area includes the original weld and base material.The flux cored arc welding procedure is used for the repair welding. After the repair,the visual and non-destructive tests are carried out. The related mechanical tests,such as transverse tensile test,full weld tensile test,impact test,macro-corrosion examination and hardness test are carried out on the repaired weld. The test results meet the requirements of EEMUA 158 standard and obtain the approval of DNV GL.关键词：EEMUA 158;SAW;FCAW-G repair;welding procedure
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发布时间：2022-03-14 - 摘要：In order to avoid the influence of jack accessory welding on the size and roundness of inner hole of the cylinder after finish machining,the welding production technology suitable for the finished cylinder accessories was studied from the point of view of increasing rigid restraints,reserving reverse deformation and controlling welding heat input. The research shows that the product quality cannot be guaranteed only by using the small specification MAG welding process of I =140 ～160 A,U=20～22 V and v=210～230 mm/min,and the maximum welding deformation of 0.3 mm will still appear in the inner hole of cylinder. The welding deformation can be effectively controlled by using small specification welding and prefabricating 0.8 ～1.2 mm transverse reverse deformation with restricted tooling,so as to ensure that the size and roundness of inner hole of the cylinder meet the design requirements.关键词：hydraulic support;cylinder accessory;welding;reverse deformation;size and roundness of inner hole
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发布时间：2022-03-14 - 摘要：Aiming at the problem that the background of welding seam on the inner wall of tank truck affects the defect segmentation,a method based on edge detection is proposed to extract the welding seam area. Firstly,the image of tank car inner wall is preprocessed by grayscale and Gaussian filtering.Then,Canny operator is used to obtain the edge details of the weld. A series of morphological processing methods are used to connect the edge of the weld into a region. The maximum area method is used to remove the surrounding noise and preliminarily extract the weld area. Then,the minimum outer rectangle of the weld area was obtained,and the four vertex coordinates of the minimum outer rectangle were applied to the original weld image of tank truck to extract the complete weld area. Finally,the "rotary method" is used to solve the extraction problem of inclined weld.关键词：tank truck;edge detection;weld extraction;minimum circumscribed rectangle
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发布时间：2022-03-14 - 摘要：In order to investigate the characteristics of the distribution of the temperature field and stress field of single-wire and double-wire GMAW welding of T-joint of bogie frame,based on ABAQUS finite element analysis software,a method of combining numerical simulation with actual measurement is used to study the T-joints of bogie sleeper beam SMA490 BW weathering steel. The heat source models of single-wire and double-wire welding are established respectively,and the welding temperature field and postweld residual stress field are simulated correspondingly,and the simulation results are verified by experiments. The results show that the relative error between the simulated sizes of the welds and the measured results of single-wire and double-wire welding does not exceed5%. Compared with single-wire welding,in double-wire welding the peak temperature and length of the molten pool increase,the thickness of the weld improves significantly,the size of leg also increases slightly,the postweld residual tensile stress distribution shrinks,and the maximum weld residual tensile stress reduces by 8.5%.关键词：bogie;double-wire welding;temperature field;numerical simulation;residual stress
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发布时间：2022-03-14 - 摘要：According to the mechanism of the crack produced by the joint action of the three elements of the cold crack in the welding of high strength steel,the technical connotation of the crack is analyzed in detail,and the mechanism of the delayed crack is mainly analyzed. The application project is illustrated. The special type of "transverse crack" in the cold crack is also described in detail. At the same time,the treatment scheme of welding cold crack in a project of high strength steel is put forward. On the basis of successful treatment,the method to prevent welding cold cracks is proposed;and the viewpoints that are easily misunderstood are demonstrated;therefore,it is valuable to prevent cold crack in high strength steel.关键词：high-strength steel welding;transverse crack;treatment and prevention
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发布时间：2022-03-14 - 摘要：Oriented by the training of students’ capability,this paper analyzes the common problems in the current welding training and teaching. Relying on the welding technology training project of Guizhou Minzu University,combined with the students’ capability objective training system,a modern practical teaching system has been constructed from four aspects:the construction of "cloud engineering training" platform,the "seven step cycle" practical teaching method, the evaluation scheme of capability objectives and the implementation of "7S" management system,which formed a more scientific and distinct talent training plan,and the achievement of talent training goals,quality assurance effectiveness and satisfactory results degree have been improved.关键词：welding training;modern teaching system;evaluationof capability objective;cloud engineering training
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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 - 摘要：<正>一、征文主题:先进技术与生产工艺应用论文侧重于先进焊接技术、优化焊接工艺和可靠检测手段等在实际生产中的应用,是对提高产品质量、提升生产效率、解决实际生产中的技术难题而得到先进经验的总结。二、征文内容焊接材料制备技术及工艺应用;新型焊接、切割设备的技术突破或数字化、智能化、柔性化技术及工艺应用;基于5G+工业互联网相关技术的焊接、切割及大数据系统的推广和应用;
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发布时间：2022-03-14 - 摘要：<正>为进一步提升《电焊机》杂志期刊质量,加强稿件编审水准,提高杂志学术水平,搭建与焊割及相关领域专家的互动交流平台,逐步实现《电焊机》杂志中长期规划目标,现特面向行业内广大专家、学者招募审稿专家,诚邀热心参与办刊和帮助期刊发展的专家加入《电焊机》杂志审稿专家队伍。审稿专家为兼职,主要工作内容为对论文研究内容的创新性、学术性、科学性、发表价值、
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