2021年, 第30卷, 第4期　
刊出日期：2021-12-28

  

• 全选
  |

• Select
  Numerical simulation of thermal field of FSW 2219 aluminum alloy thick plate

  卢晓红, 孙旭东, 孙世煊, 钱俊瑜, Steven Y. Liang

  中国焊接. 2021, 30(4): 1-8. https://doi.org/10.12073/j.cw.20211103001

  摘要 ( ) PDF全文 ( )   可视化   收藏

  To investigate the influence of temperature field of friction stir welding (FSW) 2219 aluminum alloy thick plate, and to achieve effective prediction of temperature field, the authors establish a three-dimensional numerical simulation model of FSW 18 mm thick 2219 aluminum alloy based on ABAQUS/CEL, considering the morphological characteristics of the tool pin. The simulations of plunging, dwelling, and welding stages are achieved. The distribution of temperature and temperature cycle curve of characteristic points in welding process are obtained. The validity of the simulation results is verified by experiments. The influence of the tool-rotational speed and welding speed on temperature field is explored. The work lays a foundation for the prediction and control of temperature field in FSW medium thickness 2219 aluminum alloy, and provides reference for selection of welding parameters to ensure high quality welding of fuel tank of heavy-lift rocket.
• Select
  Investigation of C276 alloy and 316L SS TIG welded joints with ERNiCrMo-4 and ER304 welding wires

  徐涛, 王子顺, 石永华

  中国焊接. 2021, 30(4): 9-16. https://doi.org/10.12073/j.cw.20211010001

  摘要 ( ) PDF全文 ( )   可视化   收藏

  To evaluate themetallurgical properties of ERNiCrMo-4 and ER304 welding wires in the Hastelloy C276 and 316L stainless steel lap-welded joints, the analyses of microstructure, hardness, element distribution and mechanical properties were conducted. The results indicate that the Fe-rich zone was found at joint which added ER304 wire. The weld metals (WM) in two types of joints both consist of dendritic crystal and center equiaxed crystal. Besides, a large number of inter-dendrite precipitates were confirmed as p phase and μ phase. A transition zone was found at the interface between WM and 316L base metal as a result of dilution. The WM near the interface has the highest hardness due to the fine crystals here. In the joint added with ERNiCrMo-4, a large quantity of carbides causes a stress concentration and becomes the source of cracks, resulting in a reduction in shear strength.The fracture mode in all shear samples is ductile fracture.
• Select
  Influence of shielding gas and non-consumable electrode configuration on weld formation

  中国焊接. 2021, 30(4): 17-24. https://doi.org/10.12073/j.cw.20210609003

  摘要 ( ) PDF全文 ( )   可视化   收藏

  The effect of the shielding gas composition and the cathode processing history on the weld formation quality during welding with a non-consumable electrode at high current was studied. The major reasons for pores, “waists” and undercuts formation during welding at high currents and speed are discrete melt movement to the solidification front due to the arc decline from the cathode axis and significant melt overhanging in the pool tail part caused by excessive peak pressure on the discharge axis. Cathode flow dispersion causes the lack of displacement of the molten metal which results in its laminar flow in the weld pool, uniform flow of the metal to the crystallization front and sound weld formation. The melt movement in the weld pool and eventually the welded joint quality is determined by the pressure distribution pattern on the welded metal surface and the anode spot lag from the electrode. It was demonstrated that non-consumable electrode configurations that provide arcing with a diffuse cathode spot and increased helium concentration in the inert atmosphere during welding with a conical electrode allow sound weld formation.
• Select
  Thermal fatigue behavior of copper/stainless steel explosive welding joint

  姜超, 龙伟民, 冯健, 张雷, 孙华为, 程战

  中国焊接. 2021, 30(4): 25-29. https://doi.org/10.12073/j.cw.20210921001

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Thermal fatigue performance of copper/stainless steel explosive welding joint was investigated by using a highly effective thermal fatigue test device. The testing device adopted induction coil to heat and carry out two groups of thermal fatigue test at the same time. Metallurgical microscope and scanning electron microscope were used to respectively measure the surface crack and cross-section crack propagation morphology of the explosive welding joint specimen that were conducted thermal cycling for different upper limit temperatures and different cycle time.Experimental results indicated that the cyclic thermal stress and oxidation corrosion was the major factors for fatigue damage behavior of explosive welding joints, where the oxidation corrosion of the interface has become more serious with the increasing the upper limit temperature or the number of cycles rising. Thermal fatigue cracks initiation was mainly beginning from the wavy interface between copper and stainless steel, the vortex-like cast microstructure formed by explosive welding can prevent the crack from propagating along the interface edge and change the direction of crack propagation.The initiation and expansionof thermal fatigue cracks were observed in the copper matrix.
• Select
  Research progress of nickel based filler for development of diamond tools

  崔冰, 刘正未, 丁梓超

  中国焊接. 2021, 30(4): 30-41. https://doi.org/10.12073/j.cw.20211009001

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Owing to diamond excellent physical and chemical properties, so synthetic diamond abrasives are extensively used in manufacturing diamond tools are utilized in machining hard and brittle materials. The brazing technology is exploited with strong bonding force between the diamond and substrate, which can realize metallurgical and chemical bonding between the filler metals and diamond abrasives. In this paper, the research reports on nickel-based fillers for brazing diamond grains at home and abroad in recent years are reviewed systematically, with emphasis on the influence of alloying elements and active elements on the properties of nickel-based fillers. The advantages and disadvantages of Cr, B, Si, P, Mn, Fe, Cu, W, C in nickel-based fillers and the negative effects of impurity elements were summarized. The shortcomings in the research and application of nickel-based fillers were pointed out, which provided theoretical guidance for further systematic research and development of related technologies.
• Select
  Bonding interface morphology of keyholeless friction stir spot welded joint of AZ31B Mg alloy and DP600 galvanized steel

  刘骁, 赵凤玲, 牛红伟, 陈阳, 王晨阳, 李小平

  中国焊接. 2021, 30(4): 42-50. https://doi.org/10.12073/j.cw.20210911001

  摘要 ( ) PDF全文 ( )   可视化   收藏

  Because the bonding interface of dissimilar metal joint between AZ31B Mg alloy and DP600 galvanized steel by keyholeless friction stir spot welding (KFSSW) is permanent bonding, the interface morphology cannot be directly observed. If the joint is separated by external force, the original features of bonding interface of joint will be destroyed, which has influence on the accuracy for observation and analysis of the result. In this paper, the coordinates of the key point at the interface of every cross-section at intervals of 0.2 mm were measured and connected into an outline. The outline of all interfaces makes up the three-dimensional morphologies of bonding interface between AZ31B Mg alloy and DP600 steel by KFSSW, which was constructed by Solidworks software to restore the real mechanical bonding state of joint. Combined with the microhardness analysis of cross-section and results of in-situ tensile test, the unique bonding state and morphology of Mg and steel in the welded joint were confirmed.
• Select
  Microstructure and properties of composites gun drill bit/drill pipe interface produced by 3D printing method

  赵菲, 王康, 段宣政, 张亮

  中国焊接. 2021, 30(4): 51-57. https://doi.org/10.12073/j.cw.20210811003

  摘要 ( ) PDF全文 ( )   可视化   收藏

  In this paper,the rapid and integrated manufacture method of 3D printing gun drill is put forward. The 3D printing process test of the composites gun drill composed of medium carbon steel drill shank, low alloy steel drill pipe and tungsten cobalt hard alloy drill bit is conducted. Microstructure and morphology of the composites gun drill interface between low alloy steel and tungsten cobalt hard alloy is analyzed using SEM. Element distribution and Phase composition of the interface between low alloy steel and tungsten cobalt hard alloy were tested and analyzed by EDS and XRD respectively. The oxidation resistance, micro hardness and corrosion resistance of the interface between low alloy steel and tungsten cobalt hard alloy were analyzed.The results show that the interface performance of 3D printing composite gun drill is better than that of the welding gun drill. The rapid and integrated 3D printing method is feasible for gun drill manufacture.
• Select
  Microstructure and property research on welded joints of 7xxx aluminum alloy welding wire TIG for 7075 aluminum alloy

  李小平, 刘骁, 李润洲, 王壮壮, 郭立祥, 雷卫宁

  中国焊接. 2021, 30(4): 58-64. https://doi.org/10.12073/j.cw.20211030001

  摘要 ( ) PDF全文 ( )   可视化   收藏

  7xxx welding wire was self-made by spray forming ingots drawn to series welding wires products, and then TIG butt welding test is used for 5 mm thick 7075 high-strength aluminium alloy. After welding, the stress relief + solid-solution aging heat treatment (T6) were performed to joints, and the mechanical properties and microstructure of the joints before and after heat treatment were comparative analyzed. The results show that the properties of the heat-affected zone (HAZ) of the joint before heat treatment decreas, and the joint is softened. The welded joints tensile strength is 271.8MPa, the elongation is 5.6%, and the average hardness of the weld is 118. 4HV. The second phase particles such as η(MgZn₂), S(Al₂CuMg), Al₁₃Fe₄ are distributed in a network layer, with no apparent element segregation. After heat treatment, the structure of each area of the joint is coarsened, and a small amount of Fe-containing impurity phases are distributed. The η and S phases are dissolved in the matrix. The hardness of each area of the joint is increased to 155 HV, and the softening zone is disappeared, this leads the joint elongation close to 16.9%. The tensile strength is increased to 511.8 MPa, reaching 94% of the base metal tensile strength.