MAIN TOPICS，ABSTRACTS & KEY WORDS



MAIN TOPICS，ABSTRACTS & KEY WORDS

Droplet transfer behavior in Pulsed Plasma-MIG welding

Chen Shujun1, Song Yaxiu1, Xiao Jun1, Bai Lilai1, Wang Xuping2

(1.College of Mechanical Engineering & Engineering Research Center of Advanced Manufacturing Technology for Automotive Components， Ministry of Education， Beijing 100124， China; 2.Capital Aerospace Machinery Company, Beijing 100076, China).p12-16

The coaxially compound pulsed plasma arc with MIG arc was proposed to utilize the high-speed plasma jet to impact the arc and weld pool. Thus both the metal transfer and weld depth can be promoted. A data acquisition system that synchronizing the high-speed camera and arc variables was developed to precisely analyze the droplet transfer of Pulsed Plasma-MIG hybrid welding. Experimental results indicated that the plasma arc current was adjusted to be pulse, which can be contributed to reduce the welding input and enhance the droplet transfer effectively. Furthermore, the effects of plasma peak current, width and droplet transfer position in the plasma arc on the droplet transfer were analyzed respectively, and the one droplet per pulse mode was obtained by adjusting the plasma arc parameters. The window of plasma pulse parameters for achieving one droplet per pulse transfer mode was thus determined.

Pulse Plasma-MIG hybrid, droplet transfer, plasma flow force, one droplet per pulse transfer

Cavitation erosion behavior of 304 austenitic stainless steel in Pb-Bi eutectic alloy

Lei Yucheng, Tang Dongmei, Li Tianqing, Zhu Qiang

(School of Materials Science and Engineering,Jiangsu University, Zhenjiang 212013, Jiangsu, China).p17-19

Abstract The cavitation erosion behaviors of 304 austenitic stainless steel base metal and welded joint had been investigated in Pb-Bi eutectic alloy at 550 ℃ with an ultrasonic vibratory instrument. The surface morphology of the base metal and welded joint after different cavitation erosion at different time was observed by a scanning electron microscopy (SEM), the surface roughness of the samples after cavitation erosion was analyzed by an atomic force microscopy (AFM).The results indicated that the cavitation damage on the surface of base metal and welded joint was more serious with cavitation time being increased. With characters of the structure inhomogeneity and composition segregation, welded joint had the weak zone in the structural material. During the cavitation erosion process, the surface roughness of the base metal increased from 0.098 μm to 0.460 μm, and the surface roughness of the welded joint increased from 0.117 μm to 0.599 μm.

Key words： 304 austenitic stainless steel, weld joint, Pb-Bi eutectic alloy, cavitation erosion

Influencing factors on weld-seam toughness and its discreteness of self shielded flux cored wire

Zhang Xuejie, Guo Chun ,Yao Rungang

(Luoyang Ship Material Research Institute, Luoyang 471023,Henan,China).p20-25

Abstract The toughening mechanism of the weld metal by self shielded flux cored wire was introduced, the influence of alloy elements, inclusion and rare earth element on weld-seam toughness were analyzed. And the results indicated that coarseM-Astructures in weld-seam caused the discreteness of weld toughness. The wire with proper chemical composition and appropriate thermal input were used,M-Astructures can be reduced and refined and the toughness will become stable.

Key words： self shielded flux cored wire, toughness, discreteness, influencing factor

Analysis of influence of swing welding parameters on weld appearance

Hou Yangqiang，Wang Tianqi， Li Liangyu， Li Tianxu，Liu Xiaohui

(Advanced Mechatronics Equipment Technology Tianjin Area Laboratory， Tianjin Polytechnic University， Tianjin 300387， China).p26-30,47

Abstract Swing welding technology was employed to weld ordinary low carbon steel with 3 mm in thickness, and the influence of swing welding parameters on weld appearance had been studied, and three sets of welds with different weld widths had been designed and implemented. Experimental results showed that, the influence of welding mode on weld shape was not obvious. As the length of the cycle increased, the gap in the horizontal direction of the weld increased gradually, an appropriate increasing in the width of the swing cycle would increase the width of the weld and the swing pause length should be controlled within 4 mm or less, otherwise there would be weld collapse phenomenon. There was no occurrence of weld collapse, layer fusion and undercut phenomenon on 3 group wide seam welding parameters, which met the requirements of wide welding seam welding.

Key words： wide weld, swing welding, weld shape, welding parameter

Influence of steady-state thermal loading modes on deformation and stress of tubular structure

Fang Yuanbin1, Lu Yongneng2, Zhang Linjie3, Kong Xiangyi4

(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. Xi’an Jiaotong University, Xi’an 710049, China; 4. XCMG Road Machinery Corporation, Xuzhou 211104,Jiangsu, China).p31-34

Abstract Two kinds of steady-state thermal loading of double ellipsoid heat source and entire weld seam were used to obtain the deformation and stress distribution of tubular structure, and verified by experiments. The results show that welding deformation and stress with the two kinds of loading mode have the same trend. The peak of welding deformation at entire seam loading is located in the middle of the seal plate. The peak value is 4.931 mm. Welding deformation at entire seam loading is close to experimental results. The peak of stress is similar, and the peak value is about 339 MPa, and close to experimental results. The simulation results meet the requirement of engineering application. It proved accuracy of the simulation results. The calculation time of double ellipsoid heat source loading is 27.2 times of entire seam loading. Considering engineering applications, entire seam loading has great use value in numerical simulation.

Key words： steady-state thermal loading, tubular structure, stress, computational efficiency

Microstructure and mechanical properties of bobbin tool friction stir welded joints of 6063 aluminum alloy

Zhao Yunqiang, Deng Jun, Wang Chungui, Dong Chunlin

(Guangdong Welding Institute (China-Ukraine E.O.Paton Institute of Welding), Guangzhou 510651, China).p35-39

Abstract Bobbin tool friction stir welding was applied to join 3 mm thick 6063-T4 aluminum alloy. When the tool rotation speed was 600 rpm and the welding speed was in range of 100 to 300 mm/min, the sound weld with good formation and without defects can be obtained. In the stir zone of the joint, the hardness is distributed uniformly. In the thermal-mechanically affected zone and thermal affected zone, the hardness at the upper and lower layers was higher than that at the middle layer. The location which was in the thermal-mechanically affected zone and near the stir zone, and the boundary between the thermal-mechanically affected zone and the thermal affected zone were the two weak areas of the joint. With the increase of welding speed, the hardness and the tensile strength of the joint firstly increased and then decreased. The tensile strength of the optimal joint was 174 MPa and the joint efficiency was up to 87%. The fracture location was in the heat affected zone.

Key words： 6063 aluminum alloy, bobbin tool friction stir welding, microstructure, mechanical property

Effects of different welding processes on mechanical properties and corrosion resistantance of duplex stainless steel

Yuan Shidong

(Shanghai Morimatsu Pressure Vessel Co,Ltd., Shanghai 201323, China).p39-42

Abstract Three different welding processes of duplex stainless steel S31803 were used to welding test coupon, based on the analysis of micro-structures, tests of mechanical properties, oxygen content and corrosion resistance, the optimal welding parameters were determined, and the effect of different welding process on welding joint were analyzed. The results show that, compared with the joints of GTAW and SMAW, the impact toughness and corrosion resistance of GTAW+SAW welded joint can meet the manufacturing requirements of duplex stainless steel. It can be used widely in manufacturing of pressure vessel.

Key words： duplex stainless steel, submerge arc welding, oxygen content, impact toughness, corrosion resistance

Effect of sintering temperature on microstructure and properties of FeCu-based matrix

Du Quanbin, Long Weimin, Zhong Sujuan, Sun Huawei, Ma Jia

(State Key Laboratory of Advanced Brazing Filler Metals, Zhengzhou Research Institute of Mechanical Engineering, Zhengzhou 450001, China).p43-47

Abstract To reduce the sintering temperature of Fe-based powder, CuZnSnMnSi powder binder was added in Fe-based powder, and the microstructure and properties of sintered matrix at different sintering temperatures were studied. Experimental results and analysis show that the sintered matrix is mainly composed of Cu-based solid solution, Fe-based solid solution and (Mn,Si)x·Oycomposite phase. With the increasing of sintering temperature, the relative density of sintered matrix first increases and then decreases, the banded (Mn,Si)x·Oycomposite phase gradually gather and grow into spherical shapes. With the increasing of sintering temperature, bending strength of sintered matrix decreases after rising first, and the maximum average bending strength is 683.6 MPa at the sintering temperature of 750 ℃. Bending strength of sintered matrix depends mainly on the relative density and banded (Mn,Si)x·Oycomposite phase. The presence of interfacial pores and banded or large-sized spherulitic (Mn,Si)x·Oycomposite phase is the main reason for decrease of bending strength.

Key words： sintering temperature, sintered matrix, microstructure, bending strength

Analysis of amount of lap in temper bead welding of SA508-3 steel

Qin Jian1，Li Shiqian1，Zhang Huiwen2，Lü Xiaochun2，Du Bing2

(1. Luoyang Ship Material Research Institute，Luoyang 471000，Henan,China; 2. Harbin Welding Institute，Harbin 150028，China).p48-51

Abstract Temper bead TIG welding of SA508-3 steel with weld overlap was studied. The result shows that there were obvious scallops between the adjacent welds when the overlap arrange from 0 to 30%, which was easy to form the lack of fusion problem. When the overlap excess 70%, the weld surface turns to tumor which was bad to deposit subsequent welds, which resulted in that the temper bead welding technique cannot be carried out. Welds surface was relatively flat when the overlap arrange from 40% to 60%, the micro hardness and hardening microstructures distribute uniformly.

Key words： SA508-3 steel, temper bead welding, weld overlap, weld appearance

Preparation of TiCp/Ag-Cu-Ti composite filler film and its application to SiC joining

Zhao Jing1, Xu Jiayue1, Liu Yan2, Wu Xishi2, Zhang Hui2, Huang Zhengren2

(1. Shanghai Institute of Technology , Shanghai 201418, China; 2. Shanghai Institute of Ceramics, Shanghai 201800, China).p52-56

Abstract Rheological property caused by dispersant and its content, binder content and solid loading was studied through General Rheometer. The microstructure and phase composition of SiC joint were studied by SEM and EDS and factors affecting the connection strength were also discussed. Results showed that the rheological property of the slurry was better at 5wt.% castor oil phosphate of dispersant, 2.6wt.% PVB of binder and 26vol.% solid loading, the composite filler film toughness is perfect, and the reinforcement is homogeneously distributed. The microstructure of the SiC joint using the composite filler film as filler indicated that the interface is dense and no defects between the SiC joint, its the thickness is 1.0～1.5 μm and the reinforcements TiC are uniformly dispersed in the metal filler matrix with no chemical reaction. TiC addition can improve the connection strength. However, the main factors affecting the strength is the thickness of the reaction layer. The maximum four-point flexural strength of the brazed joints is 92 MPa when the thickness of the reaction layer was 1.5 μm.

Key words： composite filler, TiC ceramic powder, tape casting, microstructure, mechanical property

Design of argon-arc welding system for circular silicon steel sheet

Li Kunquan,Shao Fengxiang

(Henan Institute of Engineering, Zhengzhou 451191, China).p57-60

Abstract The automatic argon-arc welding system was designed for welding of multilayer circular silicon steel sheets. The system consisted of cabinet, functional components, control system and welding system, in which the functional components consisted of positioning components, pressing components, lifting mechanism of welding torch, rotating structure and the corresponding mechanical plus. The system realized positioning, pressing, welding, feeding and blanking for the silicon steel sheet, and improved the production efficiency, meanwhile, the pressing mechanism realized that the compression force of axial was larger than 4 000 N, the welding torch lifting mechanism done 100 slice of silicon steel sheets at one time, ensured the stability of welding quality.

Key words： silicon steel sheet, argon-arc welding, system designed, functional components

Study on welding process of DP-TIG

Liu Zigang, Qu Huaiyu, Cao Ruichang, Sun Wei

(Tangshan Kaiyuan Welding Institute of Automation Technology，Tangshan 063000，Hebei,China).p61-65

Abstract The method of the Deep Penetration Tungsten Inert Gas Welding is obtain the arc with the characteristic of high energy density and high arc degree based on the efficient cooling of tungsten , compression of arc, and to realize the types of perforation welding, with deep penetration. Base materials of low carbon steel and stainless steel were used, the stable keyhole welding was achieved by adjusting the process parameters, which can realize one-side butt welding with back formation without grove for the low carbon steel plate with the thickness thinner than 10 mm and stainless steel plate with the thickness thinner than 12 mm, respectively, and the TIG welding efficiency was greatly improved.

Key words： deep penetration argon arc welding, process test, low carbon steel, stainless steel

IGBT short circuiting protection in digital submerged arc welding inverter

Fu Weiliang1,Gou Rong1, Tian Songya2

(1. Changzhou Technician College of Jiangsu Union Technical Institute，Changzhou 213022,Jiangsu,China; 2. College of Mechanical & Electrical Engineering，Hehai University，Changzhou 213022,Jiangsu, China).p66-71

Abstract In order to improve the veracity of IGBT short circuiting protection in full bridge inverter main circuit of high power digital submerged arc welding power source, and the reliability of the welding machine. The IGBT short circuiting mode was analyzed in the main circuit of full bridge inverter, and an IGBT driver with the short circuiting protection function was designed. The IGBT short circuiting protection was tested accurately and reliably by an anti-jamming measuring method. Compared with the 2SC0106T driver of Concept Company, the experimental results show that the IGBT driver has high performances in the short circuiting protection, such as short time of protection, lower short circuiting voltage spike and strong anti-interference capacity. It can be applied to practical engineering.

Key words： submerged arc welding inverter, IGBT driver, short circuit protection, common mode interference

编辑 韩 柯