最新刊期
期 8 ， 2023
- 摘要：In view of the lack of functional, practical and effective online detection methods for welding energy consumption in the industry, an online detection system was proposed and constructed, and a set of practical energy consumption detection system was developed to achieve the acquisition of key energy consumption parameters of titanium alloy plate-fin heat exchanger shell in the process of laser wire filling welding. The effectiveness of the detection system and method was verified through experiments. The results show that it can be widely used in energy consumption monitoring, analysis management and energy saving optimization of parts in welding process. This will help to evaluate the welding industry in a reasonable and effective way, and provide technical support for the future establishment of welding energy consumption detection standards and green factory evaluation.关键词：titanium alloy;plate-fin heat exchanger;welding processing;energy consumption detection
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发布时间：2023-09-08 - 摘要：A comparative study was conducted focusing on the microstructural inhomogeneities and their effect on the mechanical behavior of magnetically controlled narrow gap TIG welding (MCNG-TIG) and vacuum electron beam welding (EBW) of large-thickness TC4 titanium alloy joints. The microstructure of different regions, including the weld zone and heat affected zone, in the middle of the two joints was characterized using scanning electron microscopy. Moreover, the micro-hardness distribution and room temperature tensile properties of the joint sections were measured. The results showed that the weld zone of both joints had a basketweave structure. But the α lath width in the MCNG-TIG weld was finer than that of the EBW weld. The heat-affected zone is a mixture of primary α phase + β-transformed structure. The content of β-transformed structure decreases with increasing distance from weld seam center. β-transformed structure in the MCNG-TIG heat affected zone is finer than that in the EBW heat affected zone. The average hardness distribution of the MCNG-TIG joints is: heat affected zone > base metal > weld seam; the average hardness value distribution of the EBW joints is: weld seam > heat affected zone > base metal. The room temperature tensile strength coefficients of both joints were above 0.9, and the strength and elongation of EBW joints were slightly higher than those of MCNG-TIG joints. The room tensile fracture location of MCNG-TIG joints was located in the heat-affected zone near the base metal, while the fracture location of EBW joints was in the weld seam center. The tensile strain evolution results showed that in the early stage of tensile testing, the MCNG-TIG joints showed both peak strain regions in the weld and in the heat affected zone near the base material. As the tensile proceeds, the double strain peak region feature disappears and the plastic strain is mainly concentrated in the heat-affected zone near the base metal.关键词：titanium alloy;large-thickness plate;narrow gap welding;EBW;microstructure inhomogeneity;mechanical properties
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发布时间：2023-09-08 - 摘要：The Al/Cu dissimilar metals were welded using the external heating assisted magnetic pulse welding technique, and a comparative analysis was conducted on the macroscopic morphology, interface structure, and mechanical properties of the welded joints under different external heating temperatures, namely room temperature, 100 ℃, and 200 ℃. The results demonstrate that the external heating assisted electromagnetic pulse welding technique can achieve high-quality welding of Al/Cu dissimilar metals. With increasing external heating temperature, the size of the effective bonding area of the welded joint increases. The wavy interface morphology exhibits different forms depending on the external heating temperature: at room temperature, the interface shows a mixed waveform of sine waves and shear waves; at 100 ℃, an irregular embedded waveform morphology is formed; at 200 ℃, the morphology is similar to that at room temperature, but the thickness of the interface reaction layer is maximum. Al-Cu compounds were detected in the interface reaction zones under all three conditions. The mechanical property test results indicate that as the external heating temperature increases, the mechanical performance of the welded joint gradually improves. When the heating temperature is 200 ℃, the tensile-shear strength of the welded joint reaches 4 076 N. All specimens fractured at the joint interface, exhibiting a mixed fracture morphology of "river-like" and ductile dimples, suggesting a ductile-brittle mixed fracture as the failure mode of the welded joint. Under the influence of the external heating, the increase in the effective bonding area of the welded joint and the changes in the interface waveform structure effectively enhance the mechanical properties of the joint.关键词：magnetic pulse welding;external heating-assisted;Al/Cu dissimilar metals;microstructure;mechanical properties
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发布时间：2023-09-08 - 摘要：The effects of aging time on microstructure, thickness and composition of intermetallic compounds (IMC) were studied by means of SEM and EDS.The results show that the interfacial structure of SnInBi brazing metal is significantly affected by the aging time under load.With the increase of load aging time, the continuity of IMC layer becomes better, the bulges near the matrix disappear, and the small bulges on the near low temperature filler metal side merge and extend to the low temperature filler metal side. The thickness and growth rate of interfacial IMC layer increased with the increase of loading aging time (the thickness increased by 5 times at 720 h, and the average growth rate reached 0.021 4 μm/h). There is no obvious segregation of Bi element distribution with aging time. The diffusion of Cu into the IMC layer is obvious, accompanied by the growth of bulges on one side of the directional low temperature filler metal. In elements have uneven distribution and uniform distribution changes. The distribution trend of Sn element is opposite to that of In element. When the load time reaches 480 h, the rich in layer and rich Sn layer appear on the brazed interface, and the rich Sn layer thickness reaches 41.43 μm.关键词：IMC;on-load aging;SnInBi solder;soldering interface
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发布时间：2023-09-08 - 摘要：In order to explore the laser welding characteristics of thick-walled titanium alloy under different ambient pressures, the non-penetration welding test of Ti6Al4V alloy was carried out by low vacuum laser welding technology. The influence of sub-atmosphere ambient pressure on the weld formation, welding porosity, plasma plume, molten pool and keyhole of laser welding of titanium alloy was analyzed, and the possible reasons why sub-atmosphere environment can improve the quality of laser welding of ten thousand watts were discussed. The results show that there is a critical range of 104 Pa for the influence of ambient pressure on weld penetration, weld pool width and keyhole upper surface opening diameter. After reaching the critical range, the weld penetration will increase significantly, and the weld pool width and orifice diameter will decrease significantly. One of the possible reasons for this phenomenon is the sudden change of plasma plume. The plasma plume of laser welding in sub-atmosphere environment is obviously suppressed, and the interference effect on laser beam energy transmission is reduced.关键词：thick-walled titanium alloy;low vacuum laser welding;welding characteristics;plasma plume
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发布时间：2023-09-08 - 摘要：The problems of cracking, coarse microstructure, residual stress and deformation in the welding process of aluminum alloy have been restricting the development of this field. Ultrasonic impact treatment (UIT), as one of the strengthening means to assist in strengthening welded joints, can effectively refine the microstructure, improve the stress state, surface roughness, the tensile properties, fatigue properties and corrosion resistance of welded joints. This paper aims to better understand the role and effect of ultrasonic impact treatment on aluminum alloy welded joints and promote the technology in the field of aluminum alloy welding more widely used. It bases on the working principle of ultrasonic impact treatment to elaborate the effect on microstructure morphology, stress distribution, surface roughness, comprehensive performance and internal defects in different types of aluminum alloy welded joints. It is expected to provide help for ultrasonic impact treatment assisted aluminum alloy welding process. Finally, the issues and development directions that need to be further investigated in the field of aluminum alloy welding using ultrasonic impact treatment were prospected.关键词：aluminum alloy;ultrasonic impact treatment;welding joint;microstructure and properties
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发布时间：2023-09-08 - 摘要：This article used ER5356 aluminum alloy welding wire to conduct MIG welding experiments on 6mm thick 5083-H111 aluminum alloy. The welding quality analysis platform and high-speed camera were used to collect and analyze the arc droplet morphology and electrical signals with four different shielding gases: 100% Ar, 75% Ar+25% He, 50% Ar+50% He, and 100% He. The results show that as the proportion of He gas in the shielding gas increases, the arc morphology changes from bell shaped to flat bundle shaped, and there is a trend of contraction at the bottom of the arc. The area of the bright arc column area decreases; As the arc voltage increases, the welding current increases, leading to arc shrinkage and an increase in arc density, which affects the melting rate of the welding wire and increases the frequency of droplet transfer. The welding current probability density curve does not change much, while the arc voltage probability density curve diverges significantly. The droplet transfer tends to be unstable, transitioning from short circuit transfer to sub jet transfer, but the uniformity of droplet size decreases and the droplet particles are uneven. Overall, with the increase of He, the stability of the arc is poor. However, the droplet transfer mode is improved to some extent.关键词：shielding gases;aluminum alloy wire;arc stability;droplet transfer
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发布时间：2023-09-08 - 摘要：Laser welding technology, as a typical representative of current efficient and high-quality welding new technologies, has advantages such as high quality, high efficiency, high stability, and low deformation, and has a wide range of application fields. The influence of welding parameters on weld formation during laser welding , laser welding with filler wire and laser-arc hybrid welding of TC4 (Ti-6Al-4V) titanium alloy at home and abroad is summarized. Analyzed the mechanism of action of metal vapor plasma in laser-arc hybrid welding, the interaction mode of composite heat sources, and the dynamics of droplet transfer and melt pool，and the typical microstructure and transformation process of weld and Heat-affected zone are emphatically discussed, which provides theoretical support for the application and popularization of laser welding technology in practical engineering of TC4 titanium alloy.关键词：TC4 titanium alloy;laser welding;weld formation;microstructure
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发布时间：2023-09-08 - 摘要：Tungsten and its alloys are indispensable materials for manufacturing various Electron optics materials, special alloys, new functional materials and organometallic compounds. They are connected with dissimilar materials such as steel and copper to form new components that can meet the different requirements for materials under different working conditions and give play to the performance advantages of different materials. Therefore, the realization of high-quality and reliable connection of tungsten/steel, tungsten/copper and other heterogeneous materials will expand the application of tungsten and its alloys in metallurgy, national defense The applications in fields such as electronics and nuclear power are of great significance. However, the limited mutual solubility and significant differences in physical and chemical properties between tungsten and steel, copper, etc. result in poor weldability. This article summarizes the current research status of tungsten/steel and tungsten/copper bonding technology both domestically and internationally, and looks forward to the technical direction and development prospects of tungsten bonding with dissimilar materials.关键词：tungsten;dissimilar materials;brazing;diffusion bonding
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发布时间：2023-09-08 - 摘要：The connection of TA1 titanium alloy was successfully realized by using Ti-Zr-Cu-Ni-Ag filler. The interfacial microstructure and Fracture morphology of joints brazed at different temperature were analyzed by optical microscope (OM)，scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results showed that the typical interfacial microstructure of TA1/Ti-Zr-Cu-Ni-Ag/TA1 joint was α-Ti/α-Ti+β-Ti+(α-Ti+γ)/α-Ti. With the increase of temperature, the width of the brazing seam increases first and then decreases, the eutectoid structure is more dispersed, α- Ti tissue gradually increases，and the lamellar structure of α-Ti and (α-Ti+γ) is gradually obvious The shear test indicated that the joint brazed at 900 ℃ for 20 min exhibited the average highest shear strength of 172.04 MPa, and the fracture mode of the joint is ductile brittle mixed fracture. The average tensile strength of the joint is 260.04 MPa, which is 65% of the base metal.关键词：TA1 titanium alloy;Ti-Zr-Cu-Ni-Ag filler;brazing;interfacial microstructure
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发布时间：2023-09-08 - 摘要：In response to technical challenges such as uncontrollable joint diameter, softening of nickel based pin wires resulting in low solder joint strength, incomplete connection of multi stranded wires, and unstable process in the connection of aviation sensing component wires and multi stranded high-temperature wires of different materials with different diameters, This article proposes to use laser micro-welding technology to study the connection problem between platinum resistance leads (0.2 mm nickel wire or 0.2 mm silver wire) and wires (0.5 mm nickel wire or copper silver plated multi-strand high-temperature wires), and conduct a series of process experiments. The results show that laser micro-welding technology can achieve good welding between 0.2 mm nickel wire and 0.5 mm nickel wire, with no defects such as pores and cracks in the joint. When the laser power percentage is 14%, the frequency is 4 Hz, and the pulse width is 4 ms, the tensile shear force of the welded joint is the highest, reaching 22.75 N (85.5% of the 0.2 mm nickel wire base material); When the input energy of laser welding is below 2.9 J, reliable joints cannot be formed. When the input energy increases to 3.2 J or above, the joint size is significantly too large, with a large number of fine wires melting or even welding collapse, and severe softening; Laser energy fluctuations, welding assembly, and other factors can significantly lead to softening fluctuations, resulting in poor stability of joint tensile and shear forces; Pre coating solder to braze multiple wires into one strand and then perform laser micro-welding is not suitable for the welding of this type of part, as the quality of the welded joint is difficult to control and the diameter exceeds the requirements; Using a square pressing machine, multiple high-temperature wires are first pressed, and then laser micro welded with 0.2 mm nickel (silver) wire. The tensile shear force of the welded joint is low, and the tensile joint fractures at the weld seam. Through the above basic research, the feasibility of laser micro-welding method for the connection of such products was explored, and the feasibility of welding process and performance data of welded joints were obtained. It is expected to provide guidance for improving existing process methods and enhancing the load-bearing capacity of welded joints.关键词：aviation sensing components;laser micro-welding;dissimilar metal;microfilament
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发布时间：2023-09-08 - 摘要：In this paper, 3 mm thick titanium alloy was welded by laser-MIG hybrid welding technology. The microstructure, microhardness, tensile properties and corrosion resistance of the welded joints were studied. The results indicated that laser-MIG hybrid welding could realize high quality welding for TC4 titanium alloy with well weldrd formation and no obvious defects. The coarse β phase columnar crystals existed in the weld center, and the fine acicular α' martensite existed inside the crystals. The heat affected zone mainly consisted of equiaxed α phase+β phase+α' martensite, with finer grain and less martensitic α' martensite as the distance from the fusion line increased. The hardness of welded seam was the highest, followed by the heat-affected zone, and the base metal was the lowest, and the hardness of the coarse-grained zones was higher than that of the fine-grained zone in heat-affected zone. The average tensile strength of welded joints was 1 069 MPa, and the average elongation was 5.3%. The specimens fractured in the base metal close to the heat affected zone, and the fracture characteristics were plastic fracture. The corrosion resistance of the welded joints were slightly higher than that of the base metal.关键词：titanium alloy;laser-MIG hybrid welding;microstructure;mechanical properties;electrochemical corrosion
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发布时间：2023-09-08 - 摘要：The welding process determines the microstructure of the welded joint, which in turn determines the performance of the entire welded structure. The conventional experimental methods can only obtain the microstructure of the welded joint, and cannot dynamically understand the formation process of the joint in situ. With the help of advanced numerical simulation methods, the evolution process of the joint microstructure can be studied, the welding process parameters can be optimized, and the joint performance can be improved. The phase field method has been widely used to simulate the microstructure evolution of materials. The phase field simulation of microstructure evolution in welding process has also become a research hotspot. Firstly, the phase field method is briefly introduced. Aiming at the three main research objects of dendrite growth in molten pool, dynamic recrystallization in friction stir welding stirring zone, formation and microstructure evolution of brazed joints, the research progress of phase field simulation in welding process at home and abroad is summarized. The challenges faced by the application of phase field simulation in welding field are put forward and the future development direction is prospected.关键词：welding;phase field method;numerical simulation;microstructure
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发布时间：2023-09-08 - 摘要：Through the comparison test of 5059 Al-Mg alloy 4 mm automatic TIG welding, it is concluded that when the heat input is 13.8 kJ/cm, the weld microstructure is a large equiaxed crystal structure with dendritic growth within the crystal, and the average grain size is about 2.56. The second phase contains 7.78%Mg and 9.20%Mn, according to the energy spectrum (EDS) in the weld zone. The tensile strength of the joint is less than 330 MPa. When the heat input is reduced to 12.5 kJ/cm, by adjusting the working state of the welding pressure frame tool, the welding test plate can be effectively pressed and the weld cooling rate can be improved. The weld microstructure is small equiaxed crystal structure, which is arranged in a regular strip, and the average grain size is about 4.91. It was found that the second phase contained 11.10%Mg and 8.86%Mn, and the joint formed a metal compound strengthening phase containing Mg and Mn, dispersed in the aluminum matrix, and the content of Mg and Mn was high. The microhardness of the weld zone could reach more than 90% of the microhardness of the substrate, and the tensile strength of the joint could meet 330 MPa.关键词：Al-Mg alloy;TIG welding;heat input;grain size number;room temperature tensile property
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发布时间：2023-09-08 - 摘要：This article mainly uses inertial friction welding technology to connect Ti60/TC17 alloy, and analyzes the microstructure and properties of the welded/heat treated joints; During the weld process, there was viscous flow of metal droplets, and the metal materials on both sides fused well. The morphology at the welded joints presented an irregular curve shape, with a reduction of 4.2 mm and an axial misalignment of less than 0.3 mm; Dynamic recrystallization occurred on both sides of the weld interface, resulted in a higher microhardness values in the weld zone, and a lower microhardness value was further away from the weld; In the welded state, the structure of the weld was composed of acicular α slats and equiaxed grains, the heat engine affected zone on both sides had obvious streamline morphology; After heat treatment, the weld was needle shaped α flat noodles refinement, secondary α the phase increases, the recrystallization grain boundaries was obvious, and the streamline morphology of the heat affected zone on both sides disappeared; Through joint tensile performance test, the tensile fracture positions of the welded/heat treated specimens at room temperature occurred on the TC17 side, and the fracture morphology showed typical cleavage fracture. In the welded state, the average tensile strength was 978.5 MPa, reaching 92.06% of the base metal. After heat treatment, the average tensile strength was 1 076.5 MPa, an increase of 98 MPa, exceeding the tensile strength of the base metal. This indicates that heat treatment was beneficial for releasing residual stress in the organization and was easy to precipitate needle like structures α Phase, thereby improving the mechanical properties of the welded joint.关键词：titanium alloy;inertia friction welded;dissimilar material;dissimilar joints;mechanical properties
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发布时间：2023-09-08 - 摘要：Nickel-based superalloy is an important material in the aerospace field, which has been widely used in engine turbine blades, combustion chambers and other components. Its connection structure is the key part that affects the overall performance, and brazing is the most common connection process in the manufacturing of nickel-based superalloy parts. In this paper, the current situation of brazing of nickel-based superalloy GH4099 was introduced, from the aspects of common brazing filler metal, brazing joint interface and mechanical properties.The future research direction and development trend of brazing connection of GH4099 alloy were prospected.关键词：nickel-based superalloy;GH4099;brazing;interfacial microstructure;mechanical properties
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发布时间：2023-09-08 - 摘要：According to the urgent demand of aluminum alloy complex thick wall structural parts for spatial three-dimensional curve friction stir welding technology, combined with the disadvantage that the traditional friction stir welding head mechanism has poor flexibility and can only complete the welding of two-dimensional linear welds in the plane, this paper takes the three-dimensional parallel friction stir welding head as the research object, and combines the orthogonal parallel mechanism with Combining the advantages of load-bearing capacity and flexibility with friction stir welding technology, and applying the means of design, calculation and simulation, the developed high rigid three-dimensional parallel friction stir welding head has extremely important scientific significance and engineering practical value.关键词：parallel mechanism;friction stir welding;head mechanism design;light alloy large components
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发布时间：2023-09-08 - 摘要：The quality of spot welding determines the strength and safety of the vehicle body. Ultrasonic non-destructive testing methods are commonly used for spot inspection after welding. But many welding points of the structure are difficult to reach and cannot be detected when the welding is completed. In order to address the problem, ultrasonic testing technology is applied to the monitoring of welding process. Based on pulse-echo ultrasonic probe and characteristic signal analysis technology, the transient distribution of ultrasonic field inside the workpiece during spot welding process is studied. A new type of built-in ultrasonic probe electrode structure is designed. The ultrasonic probe is embedded in the water-cooled cavity of the electrode boom, and the ultrasonic on-line monitoring test of pulse resistance spot welding is carried out. The characteristics of ultrasonic time history and ultrasonic echo diagram during welding process are analyzed. The melting and solidification process of the nugget is recorded in real time by using acoustic signals, and the characteristics of the ultrasonic echo diagram of the virtual welding of the typical spot welding defects are studied, and the identification method of the virtual welding spot based on the echo diagram is analyzed. The results show that the heat affected zone, fusion zone, nugget zone and welding defects of spot welded joints can be well divided by observing the characteristics of C-scan images and A-scan signals. The virtual welding spot can be quickly identified by the characteristics of the display diagram, and then the spot welding defect detection and nugget size measurement can be realized.关键词：ultrasonic non-destructive testing;resistance spot welding;welding core melting;monitoring
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发布时间：2023-09-08
Welding of Non-Ferrous Light Metal
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