MAIN TOPICS，ABSTRACTS & KEY WORDS

GenerationofweldingpathaboutshapedworkpiecewithuniversalapproximationNURBScurvefitting

Zhang Tie，Zhou Renyi，Zou Yanbiao

(School of Mechanical & Automobile Engineering, South China University of Technology, Guangzhou 510641, China).p1-6

During automatic welding for small batch, the generating process of welding path is complex. Aiming to solve this problem, the automatic welding equipment with the workpiece whose welding seam is in plane was developed, and a method was proposed that the welding path of shaped workpiece was generated on-line based on machine vision system. The contour figure of the shaped workpiece could be extracted through image recognition algorithms, and the welding path would be generated on-line after least square method applied to NURBS curve fitting. The results show that the algorithm can generate online the smooth welding path for any shaped workpiece quickly with high degree of precision and efficiency, and the welding jitter can be avoided and the welding quality can be ensured.

machinevision,imagerecognition,curvefitting

Researchprogressandanalysisofaluminumalloywelding

Chen Guoqing,Liu Junpeng, Shu Xi, Zhang Binggang, Feng Jicai

(State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China).p7-12

As an important light metal material, aluminum alloy has unique performance advantages and is widely used in all kinds of fields. With the development of science and technology, more and more welding methods can be used to weld aluminum alloys. In view of the present research situation of aluminum alloy welding methods, the tungsten inert gas welding, metal inert gas welding, friction stir welding, laser welding and electron beam welding were introduced, the weld formation, microstructure evolution and the defects were discussed, and the improvement measures were proposed. The improvement of welding technologies were used to improve the performance of Aluminum Alloy. At last, the welding of Aluminum alloy was prospected.

aluminumalloy,weldingtechnology,property,prospect

ResearchonfillingweldingtechnologyofV-shapedgrooverobotforthickplate

Li Tianxu1,Wang Tianqi1,Yang huaqing2,Hou Yangqiang1

(1. Tianjin Area Laboratory of Advanced Mechatronics Equipment Technology, Tianjin Polytechnic University, Tianjin 300387, China;2. China Petroleum Corporation Institute of Engineering and Technology, Tianjin 300450,China).p13-17,67

The weld width, the thickness of base metal, the curve of seam track and the weld center line of the work piece to be welded are inconsistent in welding of thick plate with V groove, so a set of swing welding program was designed. In the off-line programming software of robot, the modeling of workstation, off-line programming and trajectory simulation were carried out, and the simulation results meet the test requirements. The test system was built with six axis robot and Fronius welding machine. By using the classical single variable control theory, the optimum welding parameters were determined. The low carbon steel plate of 18 mm in thickness was used as the base metal, multipass filling welding and cover welding in V groove were carried out. The test results show that there is good fusion on both sides of V groove, and it is free of weld collapse, interlayer fusion, undercut and gap between weld passes, and weld appearance is shaped like a fish scale.

Vgroove,offlineprogramming,weldingparameter,weldingtechnology

Researchonlaserweldingtechnologyofexplosion-proofvalvesbasedonsimulationoftemperaturefield

Geng Libo1, Yang Yatao2, Fu Hongya1

(1. School of Mechatronics Engineering,Harbin Institute of Technology, Harbin 150001, China; 2. Shenzhen Dade Laser Technologies Ltd., Shenzhen 518055, Guangdong, China).p18-21

In order to analyze the effect of laser welding heat input on explosion-proof force of car battery covers, finite element method (FEM) was used to simulate the temperature field of explosion-proof valves during laser welding. According to the effect of recrystallization annealing and homogenization annealing on crystal segregation of Al3003 and microstructures of explosion zone, the variation law of explosion-proof force was analyzed at different welding heat inputs. Meanwhile, the laser welding process parameters were optimized according to the explosion-proof force target range of 0.9±0.05 MPa. It is showed that the explosion-proof force presents a parabola trend with the increase of laser powers. Explosion-proof force is closer to the target value of 0.9 MPa when the laser welding process parameters are laser power of 1 050 W, z-value of +161 mm, and welding speed of 50 mm/s.

explosion-proofforce,laserwelding,temperaturefieldsimulation,microstructures

Microstructuresofstainlesssteelcladsteelcompositematerialsweldedbyexothermicwelding

Geng Jinfeng1, Shen Yuanxun2, Wang Zhongqiang3, Xu Jiangxiao1, Wang Yi1, Nie Jingkai4, Long Weimin2

(1. State Grid Henan Electric Power Research Institute, Zhengzhou 450052, China; 2. State Key Laboratory of Advanced Brazing Filler Metals & Technology, Zhengzhou Research Institute of Mechanical Engineering, Zhengzhou 450001, China; 3. State Grid Henan Electric Power Company, Zhengzhou 450018, China; 4. Global Energy Interconnection Research Institute, Beijing 102211, China).p22-25

Three kinds of exothermic welding powders such as commercial powders, imported powders and self-developed powders were used to join the stainless steel clad steel materials which have broad application prospects in grounding grid. The microstructure of the joint and its formation mechanism were studied. The results showed that the stainless steel clad steel joints welded by the three kinds of exothermic welding powders show the similar microstructure characteristics. The obvious diffusion zone was found at Cu/steel interface. The typical interfacial structures in welded joint are Cu(s,s)/Cu(s,s) + Fe(s,s)/Fe(s,s) and the granular Fe-rich phase discretely distributes in the Cu(s,s) matrix. The formation of joint microstructure attributes to the dissolving and diffusing of steel into the molten copper after the exothermic chemical reaction. The results also revealed that the addition of active agents into exothermic powders plays an important role in purifying the joints and improves the followability of molted copper, which leads to the sound joint without pores and defects. On other hand, the addition of fluorite and SiGaBa powders can obviously enhance the slag removal function during chemical reaction process.

stainlesssteelcladsteelmaterials,exothermicwelding,powders,jointmicrostructure

StudyofelectrodeforT/P92steelanditsperformancetest

Lü Tianmin1, Li Liansheng1,Gong Maotao2

(1. Harbin Welding Institute, China Academy of Machinery Science and Technology, Harbin 150028, China; 2. Shanghai Power and Equipment Manufacture Corporation Limited, Shanghai 201316, China).p25-28

A number of performance tests and welding procedure assessment which in accordance with relevant standards had been done about the electrode for T/P92 steel. Physicochemical parameters of slag reflect the desirable usability of the electrode. The test results show that the mechanical properties of the deposited metal by PP-R727 electrode can meet the requirements, and its diffusible hydrogen content is 2.1 mm/100 g which achieve ultra-low hydrogen electrode level. Under the experimental conditions,AC1of the deposited metal is 795 ℃. The results of the slit type cracking test indicate that the cold crack can be stopped at the preheating temperature of 150 ℃. The results of SEM show that the welding electrode has good plasticity and oxidation resistance.

T/P92steel,electrode,propertytest

Establishmentandapplicationofprocesssupportinweldingnumericalsimulation

Fang Yuanbin1, Zong Xuemei2,Yun Zhengwen2,Meng Qingyu2, Chen Bing3

(1.Jiangsu Xuzhou Engineering Machinery Research Institute, Xuzhou 211104, Jiangsu, China; 2.State Key Laboratory of Intelligent Manufacturing of Advanced Construction Machinery, XCMG Construction Machinery Co., Ltd, Xuzhou 211104, Jiangsu, China;3.XCMG Road Machinery Corporation, Xuzhou 221004,Jiangsu, China).p29-31

Through numerical simulation analysis of the boom welding process, the welding deformation was obtained and verified. Based on the simulated deformation, the support was designed, and its effect on deformation was verified by experiments. The results show that the deformation trend of the boom shows the inwards contraction. Peak value of 2.532mm appears at the free end of weld seam. Simulation results are in good agreement with experimental results, which can meet the requirements of engineering application. It proves accuracy of simulation results. The support is designed in a simple double helix. Welding deformation decreases and is more than 25% with the process support.

processsupport,numericalsimulation,boom,weldingdeformation

InfluenceofshieldinggasonmicrostructureandpropertiesofK-TIGwelded304Nstainlesssteel

Liu Yang，Wang Qiuping

(State Key Laboratory of Advanced Stainless Steel Materials TISCO, Taiyuan 030003, China).p32-35

304N stainless steel plate with 13.5 mm in thickness was butt welded by K-TIG without groove. The chemical components, microstructures and properties of butt welded joint were studied by SEM, XRD, 3D measuring laser microscope, hardness tester. The experimental results indicate that the N-content in the weld metal reduces by 18%, the ferrite content of weld metal increases by 20 times, and the hardness of weld decreases by 15%, compared with that of base material when pure Ar gas is used as the shielding gas. The N-content in weld metal increases by 90%, the ferrite content of weld metal reduces by 84%, and the hardness of weld increases by 14% at least when the shielding gas is the mixture of Ar+3%N2.

nitrogen-containingstainlesssteels,keyholeTIG,ferritecontent

Arplasweldingapplicationandqualitycontrol

Song Hongwei， Wang Zichen， Zhang Qiuhua

(Beijing Benz Automotive Co., Ltd., Beijing 100176, China).p36-39

By taking the application of Arplas welding in BBAC for example, the welding process and quality control method were introduced, the factors which affect the drop force were analyzed. The defects were analyzed and the prevention measures were taken. The results show that with the proper parameters and quality monitoring, Arplas welding is a good method to replace laser welding. Pre-force, drop force and welding energy are important parameters for Arplas welding, and the drop force is the most one. Dimple, perforce, electrode tip, background noise and guiding block can affect drop force. The proper prevention method and measures can avoid factors that affect the drop force to obtain the real results.

door,arplaswelding,qualitycontrol,dropforce

ApplicationofGMAW-Pautomaticweldingprocesstosteelcontainmentofnuclearpowerplant

Liu Fei

(State Nuclear Power Demonstration Plant Corp., Ltd., Rongcheng 264312, Shandong, China).p40-44

The characteristics and application status of GMAW process were briefly introduced, and the implementation difficulties and guarantee measures of GMAW-P in manufacturing the steel containment vessel in nuclear power plants were discussed. The studies has important engineering significance in domestic nuclear power automation welding manufacturing and quality assurance.

nuclearpowerengineering,steelcontainmentvessel,GMAW-P,automaticweldingprocess

Statusanddevelopmentofthermalcuttingindustry

Jing Wen, Wang Zhixin, Yu Haonan, Lin Si

(Harbin Welding Institute, China Academy of Machinery Science and Technology, Harbin 150028, China).p45-48

The thermal cutting industry status in China was introduced and its development tendency was analyzed from four different kinds of cutting process of oxygen cutting, plasma arc cutting, laser cutting and water-jet cutting. The problems at the present stage were summarized and it is suggested that domestic thermal cutting industry quality upgrading can be realized by focusing on the original innovation, intensifying basic subject construction and basic research, enhancing protection of intellectual property rights, increasing R&D investment in core foundation components and strengthening the product quality supervision. By taking “made in China 2025” as the gripper to promote industry upgrade, resolutely eliminating outmoded products and technology, and speeding up the old and new kinetic energy transformation, the high-end development of domestic thermal cutting industry can be promoted.

thermalcutting,industrystatus,developmenttendency,qualityupgrading

Variablepolarityplasmaarcweldingbasedonkeyholecharacteristics

Yu Yixi, Wang Jifeng

(Shanghai Institute of Special Equipment Inspection and Technical Research, Shanghai 200062, China).p48-51

Variable polarity plasma arc welding(VP-PAW) is a high efficient method for aluminum alloy, while it is sensitive to welding parameters. The effect of VP-PAW parameters on keyhole characteristics and weld appearance were studied. The results show that the welding process can be controlled by combining the suitable welding parameters and keyhole characteristics.

variablepolarityplasmaarcwelding,keyholecharacteristics,weldingparameters

MAGweldingprocessofQ690EHSLAsteel

Liu Junhua

(Jiangsu Maritime Institute, Nanjing 211170, China).p52-56

By using KOBELCO robot off-line programming method and remote control single wire welding system, Q690E low-alloy high-strength steels were welded by MAG welding with MG-S88A welding wire. Based on the analysis of Q690E weldability, by properly designing welding procedure and strictly controlling welding factors. The problem of the low impact property of the joint was solved. The results show that KOBELCO robotic MAG welding method is suitable for Q690E steel. According to marine standards, the mechanical properties of welded joints were tested. The tensile and bending properties of the welded joint meet the requirement of testing standards. The impact toughness at the welding center, fusion area, fusion zone +2 mm, fusion zone +5 mm can be assured to be higher than 69 J at -40 ℃.

HSLAsteel,roboticwelding,mediumplatewelding,mechanicalproperties

Submergedarcwelding(SAW)ofhighpressureheat-resistantsteel(A335-P91)pipeforsiteoperation

Tang Yuansheng1, Li Chang’an2

(1.Sinopec Tenth Construction Co., Ltd., Qingdao 266555, Shandong, China; 2. Institute of Advanced Welding Technology, Shandong University, Jinan 250061, China).p56-59

In recent years, martensitic heat-resistant steel (A335-P91) imported from the United States and Japan was applied to the main steam pipelines in the construction of large-scale power station units in China. The steel has high strength at high temperature, oxidation resistance and creep resistance with a relatively high thermal conductivity and low thermal expansion and so on. A335-P91 pipelines of 7600 inches or so in length were used in the syngas purification device for a coal chemical group’s coal indirect liquefaction project. The A335-P91 pipelines with design pressure of 13.5 MPa and design temperature of 545 ℃ have the largest specifications forΦ610×46 mm. According to its weldability, the welding process of A335-P91 steel pipeline was determined by taking GTAW with filler metal as backing welding, and SAW as filling welding and cover welding. The welding task was accomplished with high quality and efficiency.

martensiticheat-resistantsteel,submergedarcwelding,heattreatment

Effectofultralowvacuumdegreeonelectronbeamshapeandweldingprocess

Zhang Yimei, Wang Kai, Su Jinhua,Chen Jian

(Harbin Welding Institute, China Academy of Machinery Science and Technology, Harbin 150028, China).p60-63

Te influence of working chamber pressure(1 333.22-133.32 Pa) with the accelerating voltage of 100 kV and the beam current of 80 MA on the electron beam shape and welding process was investigated to solve the severe problem of electron beam scattering in the low vacuum welding and local vacuum electron beam welding process. The method of electron beam welding with coaxial helium protection was proposed. The effect of vacuum degree on the shape of the electron beam was studied under the condition of no protection and helium protection, respectively. Sound welded joints were obtained by electron beam welding with coaxial helium protection.

electronbeam,weldingprocess,lowvacuum,heliumprotection

TIGweldingprocessof2205duplexstainlesssteelplate

Chen Anzhong, Wang Junwei, Li Yufeng

(Department of Stainless Steel, Jiuquan Iron and Steel(Group)Co.,Ltd., Jiayuguan 735100, Gansu, China).p64-67

16 mm thick 2205 duplex stainless steel was welded with multipass at different welding parameters. The results showed that the welded joint of 2205 duplex stainless steel consists of austenite and ferrite, and multi pass welding results in moreγ2. The content of ferrite in weld metal and heat affected zone were inversely proportional to the heat input. The impact test of the welded joints at -40 ℃ was carried out, the fracture appearances of low and high impact fracture toughness of welded joint were quasi cleavage fracture and ductile fracture, respectively. The toughness of welded joints was inversely proportional to the ferrite content.

2205duplexstainlesssteel,gastungstenarcwelding,microstructure,fracturemorphology