最新刊期
期 4 ， 2022
- 摘要：By means of "Arc Welding Information Analysis Platform", the current progress in the research and application of arc welding process information analysis methods is introduced. It proposes how to use data to find problems and obtain new cognition in data; how to locate problems and find analytical "blind spots" according to data; and provides a way to realize the understanding of key information in the arc welding process through analysis data with multiple testing examples in welding production. That is, taking the robot production line of the digital welding production workshop as an example, the output characteristics of different welding machines can intuitively produce quality differences in the weld seam and the "short boards" in the implementation of data supervision standards; taking the process design of multilayer welding of aluminum alloy plates as an example, the detection of the transition time of the droplets in pulsed current welding, as well as the regulation of the transition amount of the droplets are discussed; the fluctuation information of the contact resistance between the welding wire and the conductive nozzle and its influence on the arc voltage drop are revealed, which reveals the corresponding arc characteristics generated by the oxidation of the surface of the aluminum alloy welding wire, which also provides a new analysis method for the surface state of the aluminum alloy welding wire and the arc stability of the welding process. The article specially introduces the mapping of "visual" information from image to data, laying the foundation for deep learning of data information and intelligent recognition of images.关键词：arc welding;data information;analysis method
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发布时间：2022-05-12 - 摘要：The microstructure and texture distribution in weld zone of IN718+FGH96 inertial friction welding joint were analyzed by means of SEM and EBSD. The results show that the γ', γ"and δ enhanced phases disappear in base material, and the weld zone transforms into a single equiaaxial γ phase grains. The size of weld zone grain on IN718 and FGH96 sides is about 10 μm and 15 μm, respectively. The orientation of the recrystallized crystal in weld zone is disorderly, resulting in weak crystal texture and can be ignored. The large Angle grain boundary is mainly between the adjacent crystals in the weld zone after dynamic recrystallization, and the large Angle grain boundary accounts for 65.1%. The Schmidt factor of {111}<11-1> slip system of γ phase in weld zone is close to 0.5 under the X-axis load.Thus, the {111}<11-1> slip system of γ phase crystal is easier to start and gradually form a large number of dislocations under the action of axial force. Five tensile specimens are all fractured in weld zone. The average tensile strength and yield strength of the specimens are 1126.3 MPa and 998.9 MPa respectively.关键词：high temperature alloy;inertia friction welding;EBSD;high tamperature tensile property;texture distribution
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发布时间：2022-05-12 - 摘要：Transverse and longitudinal TC4 titanium alloy samples were prepared by laser metal deposition, including room temperature tensile samples, room temperature impact samples, metallographic samples. The relationship between microstructure and anisotropy of mechanical properties was studied. The results show that the different plane structures are composed of typical net basket structure α+β for annealed laser metal deposition of TC4 titanium alloy, but compared with XOZ plane and YOZ plane, the XOY plane has the finer microstructure, the α phase is interlaced with a woven network, the overall size is 2~3 times smaller, there are more α grain boundaries (αGB) in coarse columnar β; the transverse specimen has high strength and low plasticity, and the longitudinal specimen has low strength and high plasticity; the reasons for the anisotropy of mechanical properties in transverse (Y direction) and longitudinal (Z direction) directions are as follows: grain boundary strengthening plays a crucial role, the more grain boundaries, the higher strength and the lower plasticity.关键词：laser metal deposition;TC4 titanium alloy;mechanical properties;anisotropy;grain boundary
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发布时间：2022-05-12 - 摘要：With the development of brazing technology, a variety of alloy brazing materialshave also come into being. Compared with silver-based brazing,copper-based brazing has the advantages of high strength, low cost, good brazing performance, moderate hardness, good performance of brazing head, good fluidity of brazing, etc., and can bewidely used in aerospace, machinery manufacturing, energy and petrochemical industries, etc.,to meet the requirements of green environmental protection and increase economic benefits. It is highly valued by scholars and researchers at home and abroad. However, the melting temperature of copper is too high, and alloying is usually used to add some elements to reduce the melting point. This paper mainly reviews several types of copper-based alloy fillers that have received widespread attention in recent years - copper-tin fillers, copper-zinc fillers, copper-phosphorus fillers, combined with some examples of copper-based brazing research and development at home and abroad, reviews the research reports on copper-based brazings,discusses the influence of process parameters on the structure and properties of the butts. And finally, the current problems and difficulties in the preparation and brazing process of brazing have been sorted out, and the prospects for future development and research have been put forward.关键词：copper-based alloy;Cu-Sn brazing filler metal;Cu-P brazing filler metal;Cu-Zn brazing filler metal
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发布时间：2022-05-12 - 摘要：At present, there is no effective mathematical model for the welding parameters of automobile sheet resistance spot welding, which can only be confirmed through experience and many tests. Moreover, it requires more work force and material resources, and wastes more time. In this paper, the resistance spot welding of body-in-white steel plate is taken as the research object, and the key welding parameters that affect the spot welding quality are deeply studied. Based on the concept of equivalent plate thickness, the mathematical models of welding current, welding pressure, welding time and electrode cap life were established through a lot of test verification and production practice. The establishment of the model provides a systematic and scientific solution for body-in-white steel plate welding, which has high theoretical and practical application value and provides a fast and reliable solution for the process design of body-in-white welding.关键词：body-in-white;steel plate;resistance spot welding;welding parameters;model
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发布时间：2022-05-12
Important Issuse
- 摘要：Friction stir welding was applied on 6005A-T6 aluminum alloy side wall profiles with a wall thickness of 4.0 mm. The microstructure and fatigue properties of the joints after welding were analyzed, and the feasibility of different fatigue test schemes was discussed. By means of the research method combining equivalent structural stress calculation method and Abaqus finite element analysis, the fatigue performance of the friction stir welded joint of aluminum alloy profiles based on the main S-N curve method is studied. The results show that the L-shape fixture loading scheme is feasible and the test fixture is loaded with different methods have a certain influence on the fatigue performance of the joint.The short bolt L-shape fixture-assisted bending fatigue test can well avoid the influence of the bolted connection, and can achieve the expected cracking failure mode at the welding root position of the joint. The fatigue life of the lap joint is seriously reduced when the lap joint is subjected to a relatively harsh load environment, especially when there is a high stress concentration at the position of the weld root notch. According to the fracture analysis of the fatigue specimen, the cold lap position does not have the connection strength.关键词：aluminium alloy profile;friction stir welding;the main S-N curve method;loading form of fixture;properties
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发布时间：2022-05-12 - 摘要：It is easy for the intermediate case to deform during welding, thus affecting the quality of parts and assembly process. Electron beam welding is usually used to join the intermediate case to reduce the welding deformation, but the conventional single electron beam welding still can not solve the problem of large deformation, which affects the manufacturing of the whole aero engine. In this paper, the temperature fields, stress fields and deformations of aero-engine case welded by single electron beam with 180 ° apart, double electron beams with 180° apart and double electron beams with 90 ° apart respectively are simulated by using SYSWELD. Finally, the influence of these methods on the welding deformation of thin-walled complex structures is studied. The results show that the non-uniform temperature field of single electron beam welding results in large welding deformation. The temperature field of double electron beam welding is more symmetrical than that of single electron beam welding and has less welding distortion. Therefore, double-electron beam welding is more suitable for welding thin-walled structure which is easily deformed. The research results provide theoretical basis for equipment upgrade and double-electron beam welding research in domestic enterprises.关键词：intermediate case;TC4 titanium alloy;electron beam welding;numerical simulation;welding deformation
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发布时间：2022-05-12 - 摘要：Oil and gas pipelines are often used in harsh environments, and their welded joints are facing serious corrosion problems and great potential safety hazards. Laser-arc hybrid welding has become a promising welding method in the field of pipeline construction welding due to its high welding efficiency and small deformation. Hence, corrosion resistance of hybrid laser-MIG welded metal of X80 pipeline steel under different laser powers was investigated. Microstructure distribution in different zones in the welded joints was analyzed. Polarization curves, electrochemical impedance spectroscopy and SEM corrosion morphology of base metal and weld metal with different laser powers were also investigated. Influence of laser power on electrochemical corrosion properties was obtained. The results show that microstructures in hybrid laser-MIG welded metal are mainly composed of acicular ferrite, granular bainite and proeutectoid ferrite. Less granular bainite and more acicular ferrite/proeutectoid ferrite formed in the hybrid laser-MIG welded metal with increasing laser power. The polarization curves of both base metal and hybrid laser-MIG welded metal show no obvious passivation region. The base metal exhibits a higher corrosion current density and a lower charge transfer resistance compared with that of the hybrid laser-MIG welded metal. With increasing laser power, the corrosion resistance increases first and then decreases. The hybrid laser-MIG welded metal with a laser power of 3.0 kW shows the best corrosion resistance.关键词：hybrid laser arc welding;X80 pipeline steel;laser power;microstructure;corrosion resistance
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发布时间：2022-05-12 - 摘要：In order to realize the laser non-destructive removal of bird droppings on the surface of clay sculpture relics, a high-speed camera optical filter amplification acquisition system was built, the dynamic removal process of organic pollutants on the surface of clay sculpture relics by laser was collected, and the energy threshold of different removal modes and the damage behavior of the substrate were studied. The results show that: under the action of different laser energy densities, the organic dirt layer on the surface of clay sculpture relics will appear ablation effect and vibration effect, the combustion phenomenon will appear in the process of ablation effect removal, accompanied by a large number of white smoke, and the organic dirt layer cracking and granular splash phenomenon will appear in the process of vibration effect removal, the main damage forms of the substrate after removing the organic dirt layer are burning damage and pit damage.关键词：laser cleaning;clay sculpture;organic pollutants;removal mode
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发布时间：2022-05-12 - 摘要：In order to realize the compact layout of the reactor, several complex annular components with composite functions are designed in the reactor pressure vessel. This structural form appears in the reactor pressure vessel design for the first time. It belongs to the structural type of large thickness and high restraint weld, which makes the residual stress of the welded joint between the annular component and the inner wall of the reactor pressure vessel show the characteristics of high amplitude and complex distribution. This kind of structure has been in service under high temperature, high pressure and strong irradiation environment for a long time and bears alternating load for a long time, which has high requirements for structural safety and reliability. Therefore, it is necessary to carefully study and analyze the non-uniformity of welding residual stress between the ring part in the reactor pressure vessel and the large thickness welded structure on the inner wall of the vessel, so as to lay a technical foundation for the performance evaluation of the welded joint of the ring specimen of the reactor pressure vessel. The mechanical distribution of butt welded joints of 16MND5 low alloy steel ring members of reactor pressure vessel is tested by micro punching shear and micro hardness methods. The results show that the transverse distribution of tensile strength of butt welded joints is uneven, showing an M-shaped distribution, and the peak strength appears in the heat affected area. The tensile strength of the welded joint is unevenly distributed in the thickness direction, and the wave amplitude in the base metal area is 35 MPa, the wave amplitude in the weld area is 77 MPa, and the wave amplitude in the heat affected area is 80 MPa. The distribution trend of Vickers hardness of welded joints is consistent with the test results of micro punching shear, which confirms the rationality of the test results of micro punching shear.关键词：large thickness low alloy steel;butt joint;tensile strength;micro punching shear method;mechanical heterogeneity
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发布时间：2022-05-12 - 摘要：Aiming at the possible defects of the nozzle fillet weld and buttering of the main pipeline of a nuclear power plant, the research and development of OVERLAY welding repair technology was carried out, and the study of welding technology was carried out by numerical simulation. First, the overlay welding repair structure design was completed; secondly, a finite element analysis model was established by Abaqus, combined with the method of birth-death element and welding thermal cycle curve, the process of multi-layer and multi-pass welding was researched by numerical simulation, and the temperature field and stress field distribution characteristics of the overlay welding process was studied; finally, the stress comparison under different overlay welding thickness and line energy was carried out. The calculation results show that there is a stress concentration area at the weld toe, the original fillet weld and the buttering surface are dominated by compressive stress after overlay welding, and the tensile stress of the overlay weld gradually increases from the inside to the outside. With the increase of the surfacing thickness, the stress level shows a downward trend, however, the deformation shows an increasing trend, and the increasing range of inward shrinkage is more obvious than that of axial shrinkage；and with the increase of the line energy, the stress level and post-weld deformation have an increasing trend, but the increase is not obvious. The above research results are able to provide data support for the formulation of on-site surfacing maintenance programs.关键词：nozzle fillet welds;overlay welding;numerical simulation;residual stress;thermal cycle curve
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发布时间：2022-05-12 - 摘要：In order to improve the wear resistance and corrosion resistance of Q235 plain carbon structural steel, the flux cored wire was deposited on the surface of Q235 plain carbon structural steel by CO2 gas metal arc welding technology, the macro-morphology, microstructure, micro-hardness, friction and wear resistance and corrosion resistance of the surfacing layer were studied, by using Zeiss's advanced metalloscope, micro hardness tester, friction and wear tester, and electrochemical workstation. The results show that when the welding current is 200 A, the microstructure of the surfacing layer is uniform, the carbide is evenly distributed in the microstructure, the microhardness is 500 HV, the wear resistance is the best, the wear loss weight is 26 mg, and the wear mechanism is abrasive wear. When the welding current is 230 A, the heat input is the highest, and the amount of alloy elements dissolved in austenite matrix increases, which increases its stability and corrosion resistance.关键词：CO2 gas metal arc welding;microstructure;wear resistance;corrosion resistance
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发布时间：2022-05-12 - 摘要：The influences of welding parameters including welding current, welding duration and electrode force on the shearing strength of resistance spot-welded joints of hot-dipped galvanized low carbon steel sheets were studied by using orthogonal tests, and the microstructure, hardness distribution and shearing strength of welded joints produced by optimal welding parameters were also investigated. The results showe that the welding current has the most significant influences on the shearing strength of welded joints. The optimal welding parameters are welding current of 13 kA, welding duration of 80 ms and electrode force of 4 kN. The microstructure of welding zone is mainly lath martensite with hardness of 320 HV, the microstructure of substrate is mainly ferrite with hardness of 102 HV, the microstructure of heat affected zone is martensite and ferrite with the medium hardness.关键词：resistance spot welding;galvanized low-carbon steel sheets;welding parameters;shearing strength
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发布时间：2022-05-12 - 摘要：In order to achieve effective joining of aluminum and steel dissimilar materials, laser welding-brazing is used for lap joint test on galvanized steel/5052 aluminum alloy with thickness of 2 mm ( aluminium on top and steel on the bottom). As the laser power increases (2 400 to 2 800 W), the shear strength of the weld first increases and then decreases; when the laser power is 2 400 W and 2 500 W, there are defects such as non-penetration and non-fusion; when the laser power is 2 600 W, the shear strength reaches the maximum value of 164.4 MPa, and the weld has no surface defects and is well formed; when the laser power is 2800 W, the test plate is burnt through. The microstructure, SEM, EDS and mechanical properties of 2 600 W lap joint were analyzed. Studies show that the obtained lap joints have no obvious defects such as pores, slag inclusions, cracks, etc. and an effective joining of aluminum and steel is realized; the weld area is mainly Zn solid solution ,and there are intermetallic compounds such as Fe2Al5 and FeAl at the joint interface, the thickness of which is less than 10 μm. The fracture morphology of the joint has a large area of river-like and step-like tearing edges, which are brittle fractures.关键词：aluminum and steel dissimilar materials;laser welding-brazing;intermetallic compounds;shear strength
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发布时间：2022-05-12 - 摘要：Friction stir welding is used for butt lap welding of 6005A-T6 aluminum alloy. Through a series of metallographic analysis, hardness, tensile, bending, and fatigue tests, the mechanical properties and fatigue properties of 6005A-T6 aluminum alloy welded joints are studied. Through the metallographic analysis of the welded joints, it can be seen that the structure of the weld nugget zone is fine equiaxed dendrites; the grains in the heat-mechanical affected zone are relatively coarse and have a certain directionality and accompanied by great deformation; the structure of the heat-affected zone Compared with the base material, the grains have obvious growth but no deformation, the tensile and bending tests show that the tensile and bending resistance of the welded joint is good. The fatigue test shows that the welded joint has a certain strength, which has certain data reference value for actual production.关键词：6005A-T6 aluminum alloy;friction stir welding;structure;mechanical properties;fatigue properties
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发布时间：2022-05-12 - 摘要：The casting molding process is widely used in the production of large gear seat in the domestic product, because of the case-structural reasons, the problem of the process is complicated, the casting defect is large, the product quality rate is low and the production cost is higher. After the construction of "casting change to welding", the technology is relatively simple, the welding quality is easy to guarantee, the highly product qualification rate and highly efficiency of the material can greatly reduce the manufacturing cost, so the application prospect of the welding in the case gear is broad. However, it is difficult to ensure the processing size of welding, because the material plate is thick and large, the weld is dense, the welding stress is large, it is easy to produce the crack, and the welding deformation is large, and the processing size is difficult to guarantee.This paper mainly studies the welding process of the lower box of large gear seat. On the basis of process analysis, a reasonable welding process is developed and implemented. The results show that the welding method combined with CO2 shielded welding and argon shielded welding can fully meet the design requirements of the structure by choosing the right welding size, welding sequence, welding parameters, groove form and corresponding welding processes such as pre-welding, in-welding and post-welding heat treatment关键词：lower Box of gear seat;welding stress and deformation;analysis of welding process;process measures
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发布时间：2022-05-12
Welding Technology
- 摘要：The speed of foreign high-speed electroslag surfacing with band electrode has reached more than 40 cm/min and the welding process performance is good, while the domestic supporting flux for high-speed electroslag surfacing with band electrode is prone to defects such as undercut, poor weld bead forming and unstable product quality. This kind of welding material mainly relies on import, which restricts the development of China's manufacturing industry to a certain extent. A kind of sintered flux CHF25B for strip electroslag surfacing of austenitic stainless steel is developed. The slag system is CaF2-Al2O3-SiO2 and its alkalinity is from 3.8 to 4.0. In the welding test of 15CrMoR steel with this flux combined with welding strips EQ309LMo and EQ316L, the welding speed can reach 40cm/min, and the electroslag process is stable, the welding spatter is small, the slag removal is easy, the weld bead surface is flat and smooth, and the lap joint between weld beads is well fused. The content of impurity elements of the surfacing metal such as S and P is low and burning loss of alloy elements is less. The chemical composition and performance of surfacing metal meet the requirements of NB/T 47018.5-2017 and design technical conditions.关键词：high speed electroslag surfacing with band electrode;welding material;localization;process evaluation
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发布时间：2022-05-12
Welding Material
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