最新刊期
期 2 ， 2021
- 摘要：Brazing is one of the key basic technologies in the manufacturing industry,and the wide application of composite brazing filler metals is an important method to realize green and automatic brazing. Comparing with the traditional filler metal,composite filler metal can achieve the precise flux reaction under the conditions of accurate positioning,constant temperature,timing and quantification. In this article,the classification and characteristics of brazing filler metals at home and abroad are reviewed,and the preparation technology,compo-sition design and typical applications of flux-cored brazing filler metals,flux-coated brazing filler metals,brazing filler metals prepared by powder are analyzed. The shortcomings of current research are pointed out,and suggestions for the future development of the composite filler metal are put forward. For example,with the aid of materials genome technology,developing low-Ag and Cd-free brazing filler metal with high activity and low emissions;continuously innovating the processing and preparation technology of composite brazing filler metals,such as friction stir processing and electromagnetic plastic technology; developing continuous plate-packed and barrel-packed flux-cored composite brazing filler metals with excellent surface quality to replace traditional manual strip brazing filler metals.关键词：composite brazing filler metal;flux-cored brazing filler metal;flux-coated brazing filler metal;brazing filler metal prepared by powder
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发布时间：2022-03-14 - 摘要：In establishing model process of three-dimensional heat source model of aluminum alloy friction stir welding,heat flux density range of shoulder,stir pin’s side and bottom generating heat quantity is uncertain,which needs certainty through verification,increases the difficulty and workload of modeling. For this problem,three-dimensional friction stir weld heat source model is established,and uncertain parameters in heat source model are determined. At the same time,effect of these parameters changing for welding temperature is resear-ched in the simulation. In addition,according to the effect law of parameters changing,library of parameters of friction stir welding heat source is established and inference rules are designed. Friction stir welding of aluminum alloy heat source model expert system of fast establishing model are achieved.Finally,temperature field results of friction stir welding experiment have validated expert system function. Expert system significantly reduce difficulty of numerical simulation of friction stir welding,and is beneficial to promote the popularization and application of numerical simulation technology of friction stir welding of aluminum alloy.关键词：friction stir welding;aluminum alloy;heat quantity;heat flux density;expert system
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发布时间：2022-03-14 - 摘要：Low temperature pressure vessel 08Ni3DR steel has a good strength and toughness at a very low temperature（-100 ℃）. In practical engineering application,it is one of the difficult problems to ensure the low temperature impact toug-hness of welded joints in the process of pressure vessel man-ufacturing. The determination of the weakest zone and the effects of the weakest zone are very important for the characterization of the actual welded joints. The microstructures and toughness of the welded joints of 08Ni3DR pressure vessel steel were systematically studied by preparing the Charpy V-notch on the base metal,weld metal and different locations of heat-affected zone. The results show that the weakest toughness zone of the welded joint is the coarse grain heat-affected zone,which is a composite microstructure composed of coarse granular bainite and lath bainite. As the proportion of the width of coarse grain heat affected zone in the front of the notch tip increases,the impact absorbed energy of the specimen decreases. When the proportion of the width of the coarse grain heat-affected zone reaches 100%,the impact absorbed energy is 27 J,and the impact toughness of the coarse grain heat-affected zone reduces by 90.7%. Above two aspects fully show that the weakest zone has a great effect on the impact toughness of the welded joint.关键词：08Ni3DR steel;the weakest zone;coarse grain heat affected zone;impact toughness
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发布时间：2022-03-14 - 摘要：In this paper,6061-T6 aluminum alloy and pure copper are welded by friction stir welding and the effect of rotation speed on the microstructure and mechanical properties of dissimilar joints is studied. When the welding speed is 30 mm/min and the rotation speed is in the range of 1 200 r/min to1 800 r/min,sound joints without defects can be obtained. The complex structures are formed in the nugget zone where a large number of broken Cu particles are stirred into. Al2Cu,Al4Cu9 and AlCu intermetallic compounds are found in the nugget zone.The intermetallic compound layer is formed by mutual diffusion between aluminum and copper at the interface. With the increase of rotation speed,the compounds layer gradually becomes thicker. Due to the grain refinement,solid solution strengthening and the appearance of the IMCs,the average microhardness of the nugget zone is higher than that of aluminum and copper sides,and the microhardness peak appears in the nugget zone.Meanwhile,the tensile strength of the joint firstly increases and then decreases. The tensile strength of the optimal joint is 183 MPa and the joint efficiency is up to 71.8% of Cu BM. The fracture occurs in the heat affected zone of Al side,and the fracture mode is a ductile fracture.关键词：6061 aluminum alloy;pure copper;friction stir welding;microstructure;mechanical properties
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发布时间：2022-03-14 - 摘要：S355 steel is a low alloy steel,which is accompanied by solid phase transformation during welding. Based on the solid phase transformation effect of S355 steel,a thermal-stress finite element model of welding process was established.The microstructure evolution law in the weld and heat affected zone was analyzed. The results show that under the effect of solid phase transformation,the Mises stress of the weld decreased. The residual stress and deformation evolution curves of the heat affected zone with and without phase transformation were compared. The calculated residual stress was in good agreement with the measured value.关键词：S355 steel;solid state transformation;microstructure;residual stress
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发布时间：2022-03-14 - 摘要：In order to explore the effect of different welding inputs on the microstructure and impact properties of coarse grain heat-affected zone（CGHAZ） of ultra-low carbon bainitic steel welded joint,Gleeble-3500 thermal simulation machine was used to simulate different inputs to study the effects of different heat inputs on the microstructure and impact toughness of CGHAZ of Q420 qEN steel joint. And the CGHAZ was characterized. The results show that as the welding heat input increases,the mic-rostructure of CGHAZ becomes coarser,the lath bainite decreases and granular bainite increases;meanwhile,when the welding heat input increases from 18 kJ/cm to 30 kJ/cm,the impact toughness of CGHAZ at-20℃ increases first and then decreases.关键词：ultra-low carbon bainitic steel;thermal simulation;heat-affected zone;microstructure;impact property
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发布时间：2022-03-14 - 摘要：In this paper,the effect of heat treatment on microstructure of high chromium cast iron was analyzed by metallographic microscope and scanning electron microscope.The effect of heat treatment on mechanical properties of high chromium cast iron was studied by hardness test and wear resistance test. The results show that when the solution temperature is below 920 ℃,the microstructure after quenching and tempering is as as-cast. When the solution treatment temperature is 920 ℃ or above,the as-cast microstructure disappears after quenching+tempering,and the quenching microstructure appears.As the solution temperature increases,the hardness and wear resistance of high chromium cast iron first increases and then decreases. At 870 ℃,the hardness reaches the maximum value and the wear resistance is the best. Cryogenic treatment can not improve the wear resistance of high chromium cast iron in ascast microstructure,but can improve the wear resistance of quenched high chromium cast iron.关键词：high chromium cast iron;heat treatment;wear resistance;cryogenic treatment;microstructure
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发布时间：2022-03-14 - 摘要：This paper discusses the installation and welding technology of the reactor coolant system surge tube in nuclear power plant,and describes in detail the plan before the inst-allation of the surge tube,the preparation requirements for welding procedure qualification,the installation procedure and specific implementation process and key points,the welding technical requirements and welding parameter control,the welding quality inspection method and the control of welding deformation,etc.,and the welding work of the surge tube is also discussed The key points of the experience are summarized and feedback,which can be used for reference in the installation,welding and quality control of the reactor coolant system surge tube in nuclear power plant.关键词：nuclear power plant;reactor coolant system;surge piping;installation and welding
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发布时间：2022-03-14 - 摘要：The residual stress and welding deformation of metal structure may occur after welding. Taking a butt welded steel beam as an example,the residual stress and deformation caused by submerged arc welding was simulated by the finite element method. Taking the welding results as the initial condition,the influence of residual stress on the stress distribution of corrected steel beam is analyzed. The results show that large welding residual stress still exists in corrected weld and can not be ignored.关键词：submerged arc welding;residual stress;deformation correction;stress distribution;finite element method
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发布时间：2022-03-14 - 摘要：This article introduces a kind of pipeline used in nuclear power plants closed since all-position automatic welding,through the early market research,equipment selec-tion,process development and engineering application,research a set of mature closed since the all-position automatic wel-ding method for field welding of pipe,replacing the traditional manual welding method;effectively saving cost,ensuring welding quality and improving construction efficiency. It provides a reference for the application of automatic welding in the field of nuclear power plant pipeline.关键词：nuclear power plant;pipe;all-position automatic welding;equipment selection;welding technology
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发布时间：2022-03-14 - 摘要：The S355 J2 + N thick plate commonly used in EMU bogies is taken as the research object,aiming at the defects of the base metal of the thick plate after the completion of bogie frame manufacturing,the performance research after welding repair is carried out. The simulated repair joints are made and the tensile test,bending test,impact test and hardness test are carried out on these joints,and the static strength and fatigue strength test verification are also carried out on the repaired bogie parts. The results show that the performance of the bogie parts after welding repair can fully meet the requirements of the standards,providing theoretical basis for the welding repair operation in actual production.关键词：bogie;defect repair;strength verification
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发布时间：2022-03-14 - 摘要：In this paper,aluminum alloy（A6061） and carbon fiber reinforced thermal plastic（CFRTP） were joined by laser direct joining technology. Taking the tensile strength of joint as the evaluation index,the influence law of joining parameters and the optimal joining process were determined.The aging treatment method was adopted to improve the joint strength,the influence of aging treatment parameters on the tensile strength was studied,and the joining mechanism of the joint under the optimal process parameters was revealed. The results showed that oxygen element was found in the joining interface and there was element diffusion. The strength of the joint between CFRTP and A6061 could be significantly improved by aging treatment,which was about two times as much as that without aging treatment. The interface was closely joined after aging treatment.关键词：aluminum alloy;carbon fiber reinforced thermoplastic plastic;laser joining;aging treatment
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发布时间：2022-03-14 - 摘要：This paper introduces the TIG welding process of duplex stainless steel 2205 under the type of 1.2 mm thin plate end joint. Starting from the characteristics and appli-cation of 2205,the weldability of materials,welding process parameters and operation essentials,it emphatically analyzes the problems（uneven metallographic structure） that are easy to occur in the process of thin plate end welding,and the relevant process measures and measures to solve the defects.关键词：duplex stainless steel 2205;edge joint;welding process;metallographic structure
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发布时间：2022-03-14 - 摘要：In the related equipment of the third generation nuclear power unit,the CVS mixed bed and cation bed are high pressure vessels made of austenitic stainless steel. The wall thickness of the cylinder reaches 122 mm,and there is no manhole design. The circumferential weld between the head and the cylinder can only be welded from one side,which puts forward higher requirements for the welding process and welding quality control. Any weld defect is difficult to repair,and it has great influence on weld quality. In this paper,the control measures of welding process,welding quality control and welding shrinkage are established. The final weld quality of the product meets the design requirements,which provides reference for the welding of similar thick wall stainless steel vessels.关键词：austenitic stainless steel;high pressure vessel;thick walled vessel;welding repair
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发布时间：2022-03-14 - 摘要：The composite steel plate is widely used in the railway industry due to its excellent mechanical properties and corrosion resistance. However,since the materials of the base layer and top layer of composite steel plate are different,various problems will occur if they are directly welded,therefore a welding transition layer is added and it becomes a key part of the welded joint. The microstructure and properties of the postweld transition layer of 16MnR-0Cr18Ni9 composite steel plate with large thickness are analyzed and thus this kind of process is evaluated.关键词：composite steel plate;transition layer;microstructure;properties
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发布时间：2022-03-14 - 摘要：The material of VVER-1000 MCL（main coolant line in nuclear power plant connects with reactor pressure vessel,steam generator and reactor coolant pump,thus constituting the primary loop pressure boundary） is the composite pipe with large thickness and dissimilar metal. Welding procedure of VVER-1000 MCL is complex,and the welding shrinkage is difficult to control. In this article,starting from the selection of welding material,formulation of welding parameters and other aspects,an effective and reasonable welding procedure is analyzed scientifically and formulated to ensure the welding quality.关键词：main coolant line;weldability;cold crack;postweld heat treatment
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发布时间：2022-03-14 - 摘要：Ultrasonic diffraction time difference method was applied to 304/Q345R stainless steel composite plate atmospheric storage tank. Firstly,the surface blind zone with butt weld was measured by direct wave method. Secondly,the welding simulation test block of composite plate was tested,and the difference of detection effect based on cladding side and base side was analyzed and compared. Finally,the developed detection process was applied to a 25 000 m3 stainless steel composite plate atmospheric pressure storage tank,and one buried crack was detected and verified by anatomy. The results show that the TOFD detection technology based on cladding side can be applied to open tank inspection of composite plate atmospheric tank.关键词：stainless steel composite plate;atmospheric storage tank;TOFD detection;process verification
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发布时间：2022-03-14 - 摘要：This study was based on the collections and analyses of the latest research reports by using method o comparative analysis,to systematically compare the difference between the current standard of occupational exposure limits（OELs） domestic and overseas maximum workplace concentration in the aspects of content,technical terms,position of law,establishing method and the revision of standards of occupational exposure limits. Additionally,discussed the diversity and significance of the occupational exposure limits.This study aims to try to give a clear and more particular knowledge of the current standard of occupational exposure limits dom-estic and overseas,and provide a reference for the formulation and revision of harmful chemical factors for welding fume standards of occupational exposure limits（OELs） in China.关键词：welding fume;limit value;occupational exposure;standard
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发布时间：2022-03-14 - 摘要：Intelligent arc welding is to intelligentize all aspects of arc welding. The traditional teaching and reappearance welding robot can not meet the requirements,so it is necessary to build an intelligent arc welding robot system. The industrial robot control,robot vision,six dimensional torque sensing,laser 2 D/3 D welding seam sensing,high frequency inverter arc welding power source,robot arc voltage adjustment technology and robot arc welding technology are studied.关键词：intelligent arc welding;welding robot;seam tracking;arc voltage adjustment
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发布时间：2022-03-14 - 摘要：In this paper,the self-developed Cu based fluxcored wire is used for the fusion welding butt joint test of Ti/X65 layered composite plate,and the coverage of V powder in the welding wire is 15%,20% and 25%. The results show that the addition of V element can significantly reduce the formation of Ti-Cu intermetallic compound and further refine the microst-ructure of the welded joint,and V can form a continuous solid solution with Ti,diluting the Ti element in the weld. When the V content is 25%,the tensile strength and bending strength of the welded joint reach a maximum. From the aspect of hardness,the hardness of the transition layer of Cu flux-cored wire is about 500 HV0.1.关键词：Ti/X65 layered composite plate;Cu based fluxcored wire;microstructure;tensile properties;bending strength
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发布时间：2022-03-14 - 摘要：<正>专题从焊接自动化、智能化、综合集成技术、适应于机器人和智能化焊接新工艺等方面,展开先进技术及其应用的深度讨论。征文时间:2021年1月1日～2021年3月31日重点关注内容:制造领域中的先进焊接与切割设备,突出智能、高效;与自动化、智能化相适应的焊接工艺、焊接设备、焊接材料、母材以及焊接辅助配套等的有机匹配思路;实现高品质焊接的高端焊接机器人;焊接过程中的智能传感;焊接动态的建模与仿真;人工智能技术在焊接领域的应用;
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发布时间：2022-03-14
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