最新刊期
期 1 ， 2021
- 摘要：In this research,big data and visualization technologies were used to establishthe knowledge maps of research institutions,researchers,and research hotspots in the global welding field based on the papers indexed by the Web of Science（Wo S） database and the CNKI database,patents indexed by the Derwent Innovation Index（DII） database and the CNKI China Patent database,and projects funded by the National Natural Science Foundation of China from 2014 ～2018. The findings of this study pointed out that research institutions and scholars from China have contributed the most to the papers and patentsin global welding field. "Joint-microstructure-mechanical properties" is the main line of research in the global welding field. The study also found that compared with Japan,the United States and other welding manufacturing power countries,China is still weak in the transfer and transformation of science and technology achievements,and also the innovation ability of Chinese enterprises.关键词：welding;big data;knowledge map;research progress;research hotspot
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发布时间：2022-03-14 - 摘要：Laser additive manufacturing technology mainly includes powder bed melting（PBF） and directed energy deposition（DED）. In this paper,powder bed melting refers to laser selective melting（SLM）,and directed energy deposition refers to laser near-net shaping（LENS）. Along with these technologies came the corresponding laser additive manufacturing equipment.Taking the research and development of corresponding equip-ment in South China University of Technology as an example,this paper introduces the present situation of relevant technical equipment,and looks forward to the future development of laser additive manufacturing equipment.关键词：additive manufacturing;equipment;status;development
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发布时间：2022-03-14 - 摘要：The welding materials of 2.25 Cr-1 Mo-0.25 V steel used for hydrogenation reactor have been imported for a long time. 2.25 Cr-1 Mo-0.25 V electrode is developed in this paper. The main alloy elements of weld metal are transited from the welding core. The welding core is made of high purity alloy steel and elements of C,Si,Mn,Cr,Mo,V,Nb et al are all transferred from the core. The chemical compositions of weld metal are stable under different welding currents. Special formula with high basicity and low diffusible hydrogen is developed for the electrode coating,and the electrode has good welding usability. The diffusible hydrogen of electrode achieved H4 ultra-low hydrogen level,and cold crack can be prevented with a preheating temperature higher than 150 ℃. Welding procedure qualification is carried out and the results show that the elec-trode can satisfy the requirements for 2.25 Cr-1 Mo-0.25 V welding materials. Tests of room-temperature tensile, high-temperature tensile,charpy impact at-30 ℃,side bend,temper embrittlement are all qualified under different post heat treatment conditions,especially the charpy impact values are stable. Analysis show that alloying transition from the welding core is the key to achieve stable chemical composition and microstructure,which are the basis of stable mechanical properties.关键词：2.25Cr-1Mo-0.25V steel;welding electrode;welding core;impact value
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发布时间：2022-03-14 - 摘要：The research status of fusion welding of nickelbased superalloys and cobalt-based superalloys are reviewed.The mechanism of welding cracking and the effects of welding process and alloy compositions on weldability are described here. The weldability of nickel-based superalloys can be improved by adjusting alloy compositions,changing the morphology of precipitations and grain boundaries,and choosing reasonable welding process parameters. Compared with the precipitationstrengthened nickel-based superalloys,the solid-solution strengthening cobalt-based alloys have good weldability and exhibit superior welding fusion interface and high cracks resistance. In recent years,researchers have found that the lattice mismatch of γ and γ’ is positive in precipitation-strengthened cobalt-based superalloys,which would effectively reduce the sensitivity of welding strain aging cracks. The novel precipitation-strengthened cobalt-based superalloys have excellent mechanical properties and weldability,which are likely to become one of the most promising high-temperature materials.关键词：nickel-based superalloy;cobalt-based superalloy;fusion welding;weldability
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发布时间：2022-03-14 - 摘要：Tantalum plays an important role in the fields of weaponry,atomic energy,and aerospace,but the welding of tantalum is extremely difficult. Only a few countries at home and abroad have welding capabilities. This article reviews the main research institutions,research content,research status and development trends of tantalum welding allover the world. The survey results show that:the heat source of welding tantalum changed from arc welding to laser welding and electron-beam welding. The main research trend is to improve the welding process based on welding finite element simulation and material calculation results to obtain high-quality welds. Although welding techniques in China are relatively complete,the research depth is insufficient. In particular,there is almost no research on the formation mechanism,structure control method of welding joint,and finite element analysis. In-depth theoretical research is required to overcome the technical barriers.关键词：tantalum;tungsten argon arc welding;electron beam welding;laser welding;research development
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发布时间：2022-03-14 - 摘要：In this paper,experimental and simulation studies are conducted on the flow behavior and weld forming of304 stainless steel in the scanning laser welding process. In this study,the flow behavior of the molten pool is studied by using a three-dimensional transient model with keyhole effect and a high-speed camera platform. The results show that in the welding process,the holes will push the molten metal to flow perpendicular to the welding direction. When the molten metal hits the side wall of the molten pool,there will be overflow of the molten pool. When the scanning frequency is too high,the molten pool will splash. In addition,the morph-ologies of welding seams with different scanning frequencies and widths are compared and analyzed. The results show that when the scanning amplitude and other parameters are fixed,the lower scanning frequency has stronger effects on the base material. When the scanning frequency and other parameters are fixed,smaller scanning amplitude has stronger effects on the parent material.关键词：laser welding;beam oscillation;numerical simulation;molten pool flow;keyhole effect
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发布时间：2022-03-14 - 摘要：The time of enameled wire spot welding process is short,requiring quick response of spot welding power in control. The electrodes of this welding,with the characteristics of large difference in properties and constant loss during the use,need to be replaced frequently. It is difficult to make selfadaptive adjustment according to the difference of spot welding circuits,especially in electrodes,due to that the parameters of conventional PID control are constant. In this paper,an intell-igent control method of enameled wire spot welding based on pattern recognition PI self-tuning is proposed to solve this problem. The results show that compared with the conventional PID control method,the control parameters can be self-tuning for different electrodes,which improves the stability and rapi-dness of enameled wire spot welding control and obtains a good effect in application.关键词：enameled wire spot welding;PID self-tuning;pattern recognition;intelligent control
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发布时间：2022-03-14 - 摘要：This paper proposes a welding process resource and environment attribute evaluation method based on com-bination certificate and TOPSIS,aiming at the problems such as large amount of welding process raw materials,high energy consumption and serious environmental pollution. Firstly,based on the welding process framework,the comprehensive evalu-ation index system of welding process resources and enviro-nment attributes is constructed. Secondly,the subjective/obj-ective weight quantization method of evaluation index based on AHP-entropy method is proposed,and the final evaluation value and evaluation interval are calculated by TOPSIS method.Finally,the effectiveness and practicability of the above methods are verified through the case analysis of the evaluation of the process resources and environment properties of a workpiece for manual arc welding.关键词：welding technology;AHP-entropy method;evaluation index model;TOPSIS method;compreh-ensive evaluation
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发布时间：2022-03-14 - 摘要：The changes in the work requirements of gas welders in the new and old editions of the "（Welder） National Vocational Skills Standards" are elaborated and discussed,also the compilation principles and framework of the new edition of the "National Vocational Skills Qualification Training Course for Gas Welders" is introduced to facilitate relevant personnel can quickly adapt to the new gas welder training and assessment system,which can effectively promote gas welder vocational training and vocational skills verification,and make outstanding contributions to the transformation and upgrading of China’s welding industry.关键词：gas welding;welders;vocational skills training course;assessment
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发布时间：2022-03-14 - 摘要：K-TIG welding method was used to carry out welding test on Q345/316 L dissimilar steel,and optical microscope,scanning electron microscope,universal testing machine,impact testing machine,microhardness tester,were used to study the microstructure and mechanical properties of welded joints. The results show that the weld microstructure close to316 L is austenite and skeletal ferrite with columnar crystal distribution,and the weld microstructure close to Q345 is lath martensite. On the 316 L side,a fusion zone about 45 ～50 m wide is formed,and the tiny vermicular ferrite is distributed on the austenite matrix without direction and discontinuously.The fusion zone on the Q345 side produces the Widmanstatten structure,the superheated zone has the formation of sorbite and the phase change recrystallization zone has the fine grain.The tensile fracture occurred at the base material of Q345 side. The joint welds have good impact toughness, and the fracture locations are all in the heat-affected zone of Q345.The fracture surface is ductile and brittle mixed quasi-cleavage fracture with dimples,river pattern and cleavage steps. The microhardness of weld is obviously higher than that of the heat-affected zone and base material on both sides.关键词：keyhole TIG;dissimilar steel welding;microstructure;mechanical properties
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发布时间：2022-03-14 - 摘要：Co Cr WSi high-temperature anti-oxidation coatings were prepared by high velocity oxygen fuel spraying technology,and the microstructures,micro-hardness,bonding strength and cracking toughness of coatings were analyzed. The long-term static oxidation and thermal shock tests were used to evaluate the high-temperature oxidation resistance of the coatings. Scanning electron microscopy（SEM） was used to analyze the changes of coating section morphology and chemical composition. The oxidation process and protection principle of anti-oxidation coating were discussed. The test results show that Co Cr WSi anti-oxidation coating is uniform and dense,porosity is less than 1%,microhardness is 543 ～743 HV0.3,and the average bonding strength is 81.75 MPa. Under the 200 h high temperature static oxidation and thermal shock conditions,the coating is only slightly oxidized,the coating and the substrate are not separated;the oxide is gradually coated and oxidized from the grain surface to the inside of the grain,and the surface of the substrate has been effectively protected,and new solu-tions have been provided for high-temperature anti-oxidation protection of steam turbine components at 630 ℃ and higher temperature classes.关键词：steam turbine;high velocity oxygen fuel spraying;high temperature anti-oxidation;coating;thermal shock
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发布时间：2022-03-14 - 摘要：Starting with the welding problems of UNS N08800 and A182 F11 CL.3 dissimilar steels in the construction of a large start-up furnace project,aiming at the contra-dictory welding characteristics of ferritic alloy steel and iron nickel alloy materials and the structural characteristics of these two materials in the equipment,the tungsten gas shielded welding process methods of these two materials are discussed,the welding and post welding heat treatment processes are formulated,and the welding performance test is carried out.According to the test results,a practical process scheme is developed,the key points of quality control in the welding process are clarified,and the construction problems are solved.关键词：dissimilar steel;buttering;weld process;PWHT
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发布时间：2022-03-14 - 摘要：The SAW with large heat input（50 k J/cm） is used for automatic welding of F460 Z high strength steel with CHW-S3 AB wire and CHF102 flux. The mechanical prope-rties,microstructures and fracture morphology of the welded joints are researched. The results show that when the welding parameters are wleding current of 750 A,welding voltage of 39 V,welding speed of 33.3 mm/min,and preheating temperature at 180 ℃,the optimal joint is obtained,and its tensile strength is 583 MPa. The impact absorption powers of weld,bond line and HAZ at-60 ℃ are 55 J,62 J and 71 J respectively. The weld microstructure is mainly composed of acicular ferrite,and all indexes of welded joint meet the standard requipments.This provides theoretical and experimental basis for the application of SAW with large heat input in ocean engineering.关键词：ocean engineering;large heat input;F460Z;SAW;low-temperature toughness
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发布时间：2022-03-14 - 摘要：In view of the complex characteristics of bogie frame,difficulties in weld shaping process are analyzed. Through the design analysis and experimental verification,a forming process for welds with specific shape or size is concluded.Through adopting the ceramic backing with the same shape as the specific shape weld,the direct forming of specific shape weld by MAG welding is realized,which decreases the welding filler,significantly reduce the polishing workload after welding,and avoids frequently striking arc and extinguishing arc in srufacing of specific shape weld,so as to improve the quality of weld and significantly increase the welding production effi-ciency of bogie frame. This technology has been applied and popularized in some bogie frame production,which is of great significance.关键词：bogie;MAG;ceramic backing;forming process
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发布时间：2022-03-14 - 摘要：By studying welding technology of full penet-ration X-shped weld in butt joint between cast steels G20 Mn5 and S355 J2 W for the braking hanging bracket in boige in the double-decker train for Sydney project,the macro metallo-graphy and mechanical properties of welded joint are analyzed,such as tensile, bending, impact and hardness. By formulating a reasonable welding process,comparing and analyzing the exp-erimental results of symmetric and asymmetric welding tech-nologies,a set of welding technology method is summarized,which meets the quality requirment,has short auxiliary time and strong operability,and improves the quality and efficiency. This method relaizes the full penetration butt welding of dissimilar materials of cast steel and weathering resistant steel,and provides basis and experience for bogie production.关键词：bogie;cast steel;butt welding;welding technology
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发布时间：2022-03-14 - 摘要：Ni-based high-temperature ally have excellent high temperature mechanical properties and corrosion resista-nce,which are often used in nuclear power equipment. However,recent studies have found that this kind of material has obvious ductility dip cracking tendency,which will lead to the existence of great security risk of the key components in service. Aiming at this problem,this paper selects Inconel 690 welding deposited metal,Using STF method to explore the ductility dip cracking temperature range and high temperature strain threshold value,further reveals themechanism of ductility dip cracking of Ni-based high-temperature ally.关键词：Ni-based high-temperature ally;ductility dip cracking;STF
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发布时间：2022-03-14 - 摘要：In this paper,the butt welded joints of 10 mm AH36 steel under different welding parameters were obtained by laser arc hybrid welding,and the forming characteristics,microstructure and mechanical properties of weld under different welding parameters were analyzed. Based on the finite element software,the typical temperature field distribution of laser hybrid welding was obtained,and the welding deformation of 6 m×6 m×6 mm large panel was simulated. The results show that the laser power can significantly change the welding penetration,and also has a certain impact on the weld morp-hology;the influence of welding current on the penetration is less than that of the laser power,and the welding current has a great impact on the weld width and morphology;the weld zone of laser hybrid welding is mainly acicular ferrite and granular bainite,the microstructure of coarse grained zone is mainly granular bainite,ferrite and martensite;the change of laser power has little effect on the hardness of arc zone,but has certain effect on laser zone. The hardness of weld improves as the laser power increases,the increase of welding current makes the hardness of weld zone and heat affected zone decrease as a whole;The constraint position has an important effect on welding deformation,the closer the constraint position is to the weld center,the smaller the postweld deformation.关键词：weld forming;process parameters;microstructure and mechanical properties;numerical simulation;welding deformation
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发布时间：2022-03-14 - 摘要：Aiming at the problem of high strength and low plasticity in selective laser melting（SLM） test sample of TA17 titanium alloy,the annealing heat treatment process under with different temperatures and cooling modes was studied,By studying the test results of mechanical properties of the test sample before and after annealing heat treatment,the influence of annealing heat treatment process on the mechanical pro-perties of the SLM test sample of TA17 titanium alloy was analyzed. The results show that by annealing heat treatment of air cooling after vacuum heat preservation at 900～950℃ for 2 hours,the strength of the SLM test sample reduces,the plasticity and the toughness obviously improve,the overall mechanical properties are balanced and meet the technical requirements.关键词：TA17 titanium alloy;selective laser melting;annealing heat treatment;mechanical properties
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发布时间：2022-03-14 - 摘要：In this paper,a overlaying procedure of nickel base alloy Inconel 625 on the surface of marine high strength steel E36 is analyzed. Manual GTAW is used,and the welding current,arc voltage and welding speed are strictly controlled to ensure low heat input in overlaying process. Meanwhile,the low interpass temperature is maintained in welding process. The GTAW with clean welding materials in a clean welding environment is required to obtain high quality nickel base alloy layer. In order to ensure the welding quality,the welding process control of alloy overlaying is clearly required. According to the test,this reliable overlaying procedure of nickel base alloy is confirmed,and is provided as a guideline for the production.关键词：marine high-strength steel;nickel base alloy Inconel 625;GTAW;overlaying;welding procedure
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发布时间：2022-03-14
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