英文標題摘要及關鍵詞

MAIN TOPICS，ABSTRACTS & KEY WORDS

Researchprogressonweldingoftungstenalloywithsteel

Chen Guoqing1, Teng Xinyan1, Xing Ziqi1, Zhang Binggang1, Cao Hui2

(1. Harbin Institute of Technology, State Key Laboratory of Advanced Welding and Joining, Harbin 150001, China; 2. Beijing Aerospace Xinli Technology Co., Ltd., Beijing 100000, China).p1-6,20

AbstractBased on the weldability of tungsten and steel, the current research status of fusion welding, diffusion welding, brazing, and other welding technologies applied to tungsten and steel welding was summarized in this article, the key content and the trends of tungsten and steel welding research were discussed. In the brazing process, the low melting point amorphous solder and local heating were used to avoid the adverse effects of grain coarsening caused by the overall high-temperature heating. In the brazing and diffusion welding process, a suitable intermediate layer was used to relieve the residual stress and avoid the generation of intermetallic compounds and metal carbides. In the welding process, by adjusting the energy distribution, the effective molten pool was formed and a well-formed joint was obtained. Underwater explosive welding, chemical/physical vapor deposition, plasma spraying, magnetron sputtering, and other technologies could be connected with the low thickness of tungsten, as well as problems of large porosity, high residual stress and low connection strength.

Keywords:tungstenalloy,steel,fusionwelding,diffusionwelding,brazing

Researchprogressonadvanceddissimilarjoiningmethodsofaluminum/steel

Gao Chenkai1,2, Yang Jin1,2, Li Zhuguo1, Zhao Yixuan2, Liu Hongbing2, Zhang Lei3

(1. Shanghai Jiao Tong University, Shanghai 200240, China; 2. Shanghai University of Engineering Science, Shanghai 201620, China; 3. Jiangsu Yanxin Sci-Tech Co., Ltd., Jiangyin 214426, Jiangsu, China).p7-20

AbstractDifficulties of Al/Steel connection and the development of various connecting methods were introduced. Three mainly research directions of Al/Steel resistance spot welding, optimizing electrode, adding interlayer and thermal compensation gasket, to improve the joint performance and some advanced connecting methods were discussed. In addition, the monitoring and numerical simulation of resistance spot welding process was also briefly summarized. Finally, some existing problems of resistance spot welding of aluminum/steel were prospected.

Keywords:Al/Steelwelding,resistancespotwelding,welding-brazing,lightweight

MicrostructureandmechanicalpropertiesofweldedjointsofTi2AlNbandTC4bylaseroscillationscanning

Liu Jie1,2, Xie Meirong3, Wang Mengfei1,2, Liu Tianliang3, Wang Kehong1,2

(1. Nanjing University of Science and Technology, Nanjing 210094, China; 2. Key Laboratory of Controlled Arc Intelligent Additive Technology Ministry of Industry and Information Technology, Nanjing 210094, China; 3. Capital Aerospace Machinery Corporation, Beijing 100076, China).p21-26

AbstractLaser oscillation scanning welding technique was used to perform heterogeneous metal welding tests on 2 mm thick Ti-22Al-25Nb alloy and TC4 alloy. The microstructure evolution and mechanical properties of the laser oscillation scanning welded joints were studied. The results showed that the laser oscillation scanning welding technique can be used to obtain well formed welded joints without cracks, porosity and other defects. Microstructure of the weld was mainly composed of B2 phase and α’ martensite phase. The average tensile strength of the joint could reach 88.6% of that of the TC4 base material. When the laser scanning frequency reached 500 Hz, the grain was refined and the tensile strength and elongation after fracture of the weld were effectively improved.

Keywords:TC4,Ti2AlNb,heterogeneousmetalwelding,laserweldingwithoscillation,mechanicalproperties

Effectofweldingparametersonweldmorphologyandmechanicalpropertiesoflaserweldedaluminum/aluminum

Wu Yan1, 2, Li Zhaoyang1, Guo Lixin1, Xiao Lijun1, Sun Shixue3

(1. Shanghai Institute of Technology, Shanghai 201418, China; 2. Shanghai Physical Vapor Deposition (PVD) Superhard Coating and Equipment Engineering Technology Research Center, Shanghai 201418, China;3. Kunshan Shen Optoelectronic Machinery Factory, Suzhou 215321, Jiangsu, China).p27-30,47

AbstractAiming at the welding problem of automobile power battery tabs, the single control variable method was used to study the influence of laser power and welding speed on the surface morphology and cross-sectional topography of the weld of automotive power battery aluminum tabs and aluminum busbars. The hardness and shear resistance under different welding parameters were measured to study the influence of welding parameters on mechanical properties and the optimal welding parameters were determined. The research results showed that the increase of laser power and welding speed caused the gradual blurring of fish scales, the size and number of cross-section pores and the shear resistance reduced after rising. A positive association was discovered between hardness and welding speed, while laser power was negatively correlated with hardness. When the laser power was 650 W and the welding speed was 55 mm/s, the weld quality was the best, the fish scale phenomenon was obvious, the center hardness of the weld was about 36 HV, and the shear resistance was 765.41 N. This research had practical guiding significance for the optimization of the welding process of aluminum tabs and aluminum busbars of automotive power batteries.

Keywords:aluminum/aluminumwelding,weldingparameters,weldquality,mechanicalproperties

Influenceofweldingparametersonmorphologyandmechanicalpropertiesoflaserscannerweldedjoints

Li Luyu1,2, Luo Ziyi2, Yi Yaoyong2, Hu Yongjun1, Hao Jiahui1

(1. Guangdong University of Technology, Guangzhou 511436, China; 2.China-Ukraine Institute of Welding, Guangdong Academy of Sciences, Guangzhou 510650, China).p31-37

AbstractIn order to obtain high quality welded joints of galvanized sheets, laser scanner welding method was used for lap welding of 1.5 mm thick DP 780 galvanized sheets, and effects of laser power and welding speed on weld formation, microstructure and mechanical properties of welded joints were studied. The results showed that full penetration welds were obtained when laser power and welding speed were in the range of 2.5～3.0 kW and 25～55 mm/s, respectively. Increasing welding power was beneficial to eliminate the undercut on the weld surface, while it caused serious recession on the back of the weld. In full penetration welding, increasing the welding speed reduced the degree of weld recession. The center of the weld was mainly composed of coarse lath martensite and the heat-affected zone was mainly made up of martensite and ferrite. Reducing welding power or increasing welding speed reduced the martensite content and size, and made ferrite content increased. The microhardness test showed that welded joints appeared a softened zone, it was explained that the tensile properties of joints increased in the range of 55-75 mm/s welding speed. The combination of welding parameters, 3 kW welding power and 35 mm/s welding speed, was the most suitable.

Keywords:laserscanningwelding,DP780galvanizedsheet,microstructure,tensileproperties

Human-machineinteractiondesignofweldingcentralizedcontrollerbasedonheterogeneousmulticore

Zeng Min, Yuan Song, Shi Yonghua, Hu Zixin, Wang Zhuoran

(South China University of Technology, Guangzhou 510641,China).p38-41,47

AbstractAccording to the fact that the human-machine interaction interface of traditional welding centralized controller affected the real-time performance of welding task, and that the communication speed between multi controllers was low and unstable, a human-machine interaction design of welding centralized controller based on heterogeneous multi-core controller was proposed. Through running Linux and FreeRTOS systems on different cores at the same time, the main welding task and human-computer interaction task were run on different cores respectively. The data transmission between the two cores was carried out through inter-core communication task to complete the welding process control, and the decoupling of real-time task and non-real-time task was realized. The experimental results showed that the communication rate of heterogeneous multicore reached 6 675.78 kB/s, which ensured the real-time control of welding process, and displayed and controlled the slave computers in real time through human-machine interaction interface.

Keywords:heterogeneousmulticore,humancomputerinteraction,welding,centralizedcontroller,inter-corecommunication

Influenceofcrackandporosityonimpacttoughnessofmulti-wireSAWweld

Liu Bin1,2, Liu Yun1,2, Niu Hui1,2, Wei Feng1,2, Li Xiao3

(1. Steel Pipe Research Institute, Baoji Petroleum Steel Pipe Co., Ltd., Baoji 721008, Shaanxi, China; 2. National Engineering Technology Research Center for Petroleum and Natural Gas Tubular Goods, Baoji 721008, Shaanxi, China; 3. Xi’an Shiyou University, Xi’an 710065, China).p42-47

AbstractInfluence of porosity and crack defects on impact toughness of X80 steel pipeline steel weld by multi-wire submerged arc welding with inner four wires and outer five wires was studied. Due to the limitation of crack preparation technology, 1/4 specimen was used as impact toughness specimen. By comparing with full-scale specimen, it was found that the proportional coefficient of impact absorbing energy between 1/4 specimen and full-scale specimen was 0.17 at -10 ℃. The results of study on the interaction between crack and porosity showed that porosities with diameters of 0.5 mm and 1 mm reduced the impact toughness without crack arresting effect. For the pre-made cracks perpendicular to the crack propagation path, as long as its position was in the zone 1 mm far from the impact location, the plastic deformation could improve crack propagation resistance, curve the crack propagation path and increase impact absorbing energy. The effect of transverse pre-made crack was equivalent to that of large-diameter air hole. A large amount of plastic deformation could occur on the lower crack surface, which had a certain crack arresting effect and improved impact absorbing energy of samples. The impact absorbing energy of X80 pipeline steel weld was changed by the existence of defects in the weld, while the microscopic fracture analysis results showed that fracture behavior was not changed, and microtopography was still dimple type, which was consistent with the defect-free samples.

Keywords:X80pipelinesteel,weld,porosity,crack,impacttoughness

RootdefectcontrolofFSWjointofaluminumalloy

Zhou Ping

(Jiangxi University of Engineering, Xinyu 338000, Jiangxi, China).p48-51

AbstractBased on analysis of root defects formation mechanism of aluminum alloy FSW joints, optimization of mixing head and welding parameters was put forward to subdue root defects of FSW joints, avoid the mechanical properties of joints such as bending properties and tensile properties decline caused by root defects, while the strength coefficient of joints was increased from 71% to 81% above.

Keywords:FSW,defectcontrol,jointroot,aluminumalloy

Influenceofweldingpositiononpropertiesof5083aluminumalloyT-jointsbyfrictionstirwelding

Fang Yuanfang, Zhang Lina, Mi Yanlong, Zhang Xin, Li Yue

(Capital Aerospace Machinery Co., Ltd., Beijing 100076, China).p52-56

AbstractFriction stir welding butt test of 5083 aluminum alloy T-joint was carried out by adjusting the welding position of tool and adding pre-welding procedure. The metallographic structure of the cross section of the weld was observed, the tensile and bending of the joint were detected, and the fracture was detected by scanning electron microscopy. The results showed that the traditional welded T-joints were prone to crack at the root, which could be eliminated by adjusting the welding position and increasing the welding depth, but it also caused the root to deform slightly, which could be eliminated by adding a pre-welding procedure. The tensile strength, yield strength and elongation at fracture of joints increased by 32.5%, 32.1% and 71.4% respectively after "adjusting welding position + pre-welding". After process improvement, the bending degree of specimen after bending detection flattened, the size of fracture dimple increased, and the fracture mechanism developed to the direction of ductile fracture.

Keywords:frictionstirwelding,T-joints, 5083aluminumalloy,mechanicalproperties

Pipelinebrazedjointstructureandbrazingleakage

Liu Ao1, Xu Guilin2, Wang Dairong3, Tang Yao1, Zhou Haiyu4, Zhao Yue1

(1. Ocean University of China, Qingdao 266100, Shandong, China; 2. Qingdao Haier Joint Stock Co., Ltd., Qingdao 266000, Shandong, China; 3. Qingdao Haier Special Refrigeration Appliance Co., Ltd., Qingdao 266000, Shandong, China; 4. Qingdao Haier Special Refrigerator Co., Ltd., Qingdao 266000, Shandong, China).p57-61

AbstractBy designing a new type of refrigeration pipe brazed joint, uniform gap brazed joint, to solve the problem of high leakage rate caused by uneven gap of brazed joint. The uniform gap brazed joint consisted of a brazing section and a positioning section, and the brazed seam structure was distributed in a stepped structure. During the brazing process, brazing filler metal flowed into the brazing section of uniform gap by capillary action to play the role of connection. The positioning section controlled the fit gap to ensure that the axis of the intubation tube and the sleeve overlap and play a positioning role, thereby preventing the quality problem of brazing caused by the skew of the insertion tube. By X-ray inspection and cross section morphology, the quality of brazed joints could be accurately judged. A comparative experiment on the uniform gap brazed joints and the existing brazed joints showed that the former had almost no gap unevenness, while 80% of the samples in the latter had uneven gaps, and the brazing quality of the former was greatly superior than that of the latter. Uniform gap brazed joint was an effective brazed joint structure that could prevent the leaking of brazed joint.

Keywords:refrigerationpipeline,brazedjoint,X-raynon-destructivetesting,brazingclearance,assemblyclearance