MAIN TOPICS，ABSTRACTS & KEY WORDS

MAIN TOPICS，ABSTRACTS & KEY WORDS

Status of welding materials industry in China during the period of “12th five-year plan” and development trend during the period of “13th five-year pan”

Chen Jian，Su Jinhua, Zhang Huiwen

(Harbin Welding Institute, China Academy of Machinery Science and Technology, Harbin 150028, China).p1-6

Welding materials production in China has reached more than half of world output, and become the world's welding material production and consumption power. With the development of national economy, industry of welding materials is more and more playing an important role. Status of the welding materials industry in China during the period of “12th five-year plan” was analyzed, and the existing problems were points out. The development trend during the period of “13th five-year pan” were put forward.

welding material, welding technique, development trend

Cavitation erosion behavior of 316L steel weld joint in liquid lead-bismuth eutectic alloy

Lei Yucheng, Chang Hongxia, Guo Xiaokai

(School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China).p7-12,60

Abstract A high-power ultrasonic cavitation facility was used to investigate the cavitation erosion behavior of 316 L welded joints before and after PWHT in liquid LBE at 550 ℃. After different time of cavitation erosion test, SEM and AFM were used to analyze the surface topography, roughness and hardness. It is found that the roughness and the maximum erosion depth increase with the increase of erosion time, and work hardening is found on all the surface of welded joints with and without solution treatment. Plastic deformation appears on the surface of welded joint without solution treatment, and after solution treatment, the hardness of welded joint increases greatly but the plasticity is decreased. The results and analyses showed that the welded joint with solution treatment exhibits better cavitation erosion resistance.

Key words： cavitation erosion, 316L steel, weld joint, lead-bismuth eutectic alloy, solution treatment

Present situation of study on welding of Mo-Re alloys

Wu Lei1, Xia Chunzhi1, Liu Peng2

(1. School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, China; 2. School of Materials Science and Engineering, Shandong Jianzhu University, Jinan 250101, China).p13-16

Abstract Mo-Re alloys are one of promising materials for the future application. But Mo-Re alloys are sensitive to carbon, nitrogen and oxygen elements, which are easily oxidized. Pores and brittle compounds formed in joints cause serious drops in properties. Therefore, many scholars researched on the weldability of Mo-Re alloys. The research status of electron beam welding, laser welding, resistance spot welding, vacuum brazing and friction stir welding of Mo-Re alloys at home and abroad were summarized. The common problems in welding were analyzed and summarized, and reduction in brittle compounds, pores and cracks is the key to obtain good joints.

Key words： Mo-Re alloy, welding, property

Development of 690 nickel-alloy welding wire for GTAW in nuclear power industry

Gu Yu1,Zhang Junbao1,Zuo Bo1, Huang Yifeng1,Liu Weihua2

(1. Shanghai Nuclear Engineering Research & Design Institute, Shanghai 200233, China; 2. China Nuclear Industry Fifth Construction Co. Ltd., Shanghai 201500, China).p17-20

Abstract Aiming at the current situation that nuclear-grade 690 nickel-alloy welding wire depends on the imported products, its localization was studied. WHS690M welding wire meets the requirement of AP1000 and CAP1400 nuclear power plant, which has good welding performance. At different welding parameters, mechanical properties of the weld metal at room temperature and high temperature are relatively stable, and the tensile strength reaches 485 MPa at 350 ℃. Strain-to-fracture (STF) test based on Gleeble-3500 thermo-mechanical simulator was performed to evaluate the DDC susceptibility of Inconel 52M and WHS690M. Combined with OM, SEM and EBSD, the characteristics of grain orientation and precipitation were analyzed. According to the test results, the critical cracking strain is 2.1% for Inconel 52M, while 3.2% about for WHS690M at 1 050 ℃。

Key words： nuclear， 690 nickel-alloy welding wire， tensile strength， ductility dip cracking

Development of nickel base alloy covered electrode enicrmo-3 for all position welding

Chen Yan1,2, Zhang Xuegang1,2, Chen Peiyin1,2, Xu Kai1,2, Wang Qingjiang1,2，Hu Pengliang1,2

(1.Harbin Well Welding Co., Ltd., Harbin 150028, China; 2.Harbin Welding Institute, China Academy of Machinery Science and Technology, Harbin 150028, China).p21-24

Abstract Nickel base alloy covered electrode ENiCrMo-3 type Ni625 for all position welding was developed by reasonably adjusting ratio of carbonate, fluoride and oxide in the electrode and controlling alloying element content of deposited metal. The results showed that all performances of the developed electrode can meet the requirement and it exhibits good technological performances in all position welding, excellent intergranular corrosion resistance and hot cracking susceptibility.

Key words： nickel base alloy covered electrode, all position welding, intergranular corrosion resistance, hot cracking susceptibility

Automatic feeding and welding equipment of reinforcing plate

Shen Xiaoqin, Li Huanhuan, Guo Haizhi,Yu Fusheng

(School of Mechanical and Electrical Engineering, Shandong Jianzhu University, Jinan 250101,China).p25-28

Abstract To solve the welding questions of reinforcing plate for large diameter percussive drill bit and tapered steel pipe, an automatic feeding and welding equipment of reinforcing plate is developed. The automatic feeding device and the control system were designed. This whole equipment consists of frame, feeding device, clamping and distance measuring device, welding gun moving device, welding machine, control cabinet etc. The control system includes detection part and control part. The former was used to detect the rotation of the tapered steel pipe to determining the weld position of the reinforcing plates. The later controls the motion of the welding gun to realize the welding of the reinforcing plates. This equipment can improve the welding automation level of reinforcing plate, reduce the labour strength of worker and increase the welding efficiency.

Key words： tapered steel pipe, large diameter percussive drill bit, automatic feeding, welding equipment, reinforcing plate

Study on weldability of NiCrFe corrosion resistant alloy

Wang Baosen1, Zhu Shuangchun2

(1. Baosteel Research Institute，Baosteel Iron&steel Co.， Shanghai 201900, China; 2 School of Materials Science and Engineering, Tongji University, Shanghai 200092, China).p28-30

Abstract NiCrFe corrosion resistant alloy is one of the preferred materials for high temperature and corrosion resistant equipment manufacturing in the future. In this paper, the characteristics and weldability of UNS N08800 corrosion resistant alloy were analyzed, and the method of shielding arc welding was used for butt joint. Welded joint properties under the corresponding process condition were studied through OM observation and performance testing methods. The results showed that the domestic N08800 steel has good weldability, its welding performance is equivalent to the similar foreign product under certain welding process conditions. Heat affected zone in welded joint has no significant grain coarsening and has single austenite, and the width of heat affected zone is narrow. The studied provide a reference for the application of this kind of steel.

Key words： corrosion resistant alloy, N08800, weldability

Effect of rare earth elements on brazing process performance of Al-Si-Zn-Cu filler metal

Xuan Qingqing，Long Weimin，Zhang Qingke，Lu Quanbin

(State Key Laboratory of Advanced Brazing Filler Metals & Technology, Zhengzhou Research Institute of Mechanical Engineering, Zhengzhou 450000, China).p31-36

Abstract In order to investigate the influence of Ce-La mischmetal on Al-Si-Zn-Cu brazing filler metal, the microstructure, mechanical properties and wettability of brazing filler metal with varying dosage of mischmetal addition were studied. Result shows that in Al-Si-3Zn-15Cu alloy, both tensile strength and wettability increase with the content of rare earth elements. The fundamental phase of Al-Si-3Zn-15Cu areα-Al/Al-Si/Al-Si-Cu/Si, the addition of La and Ce reduces the grain boundary segregation of impurity elements, decreases the crystallization rate and refines the grainsize. Besides, the strength and ductility are improved because of the modification effect of rare earth elements on the net structure of second phase particles.

Key words： Al-Si-Zn-Cu brazing filler metals, rare earths, mechanical properties, microstructure

The effect of several welding methods to the quality of gas tungsten arc weld (GTAW) for pipelines

Zhang Xiaodong, Wang Xinghua

(MCC Baosteel Technology Service Co.,Ltd，Shanghai 200999,China).p36-39

Abstract Gas Tungsten Arc Weld (GTAW), which was characterized as flexible operation, high welding quality, is widely used in critical welding production, especially in the backing welding of pressure pipelines, boilers and pressure Vessels. In the process of GTAW, the use of different welding methods has large influence on the welding quality. In this paper, we take the GTAW of small-diameter pipeline as an example to analyze the effect of three welding methods on the appearance forming of weld pass and the welding quality, and to summarize an appropriate method during the site-welding of pipelines. Therefore, the pass rate of site-welding of pressure pipelines was increased.

Key words： GTAW, welding technique, weld defects, pipelines

Standardized width of tensile and fatigue specimens of laser lap welded joints considering residual stress

Zhao Ruirong1, Kan Ying2, Jiang Yunlu2, Chen Huaining2, Han Xiaohui1

(1. CRRC Qingdao Sifang Co., Ltd., Qingdao 266111, Shandong, China; 2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China).p40-43

Abstract The shear strength and fatigue strength are important mechanical properties of the laser lap welded joints. However, no standard has regulated the dimensions of the tensile and fatigue specimens. In this paper, the reasonable widths of the laser lap welded specimens were determined by taking account of the residual stress. The shear strengths of specimens with residual stress and without residual stress were studied. It was found that the residual stress reduced the shear strength of the laser lap welded joints by change the stress state and micro-deformation uniformity.

Key words： residual stress, laser lap welding, fatigue specimen, tensile specimen, width of specimen

Analysis on microstructure and mechanical properties of 960 MPa deposited metal

Li Danhui1, Xu Yinan1, Xu Hao1,Zhang Huiwen2

(1. Harbin Well Welding Co., Ltd., Harbin 150060, China; 2. Harbin Welding Institute, China Academy of Machinery Science & Technology, Harbin 150028, China).p44-47

Abstract The solid wire of high strength and toughness was successfully developed by vacuum melting technique. The microstructure and mechanical properties of deposited metal were analyzed in detail by means of optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), instrumented impact tests. Results showed that the highest tensile strength and toughness of deposited metal can reached to 920 MPa and 66.7 J (-60 ℃), respectively, for the alloying systems of Mn-Ni-Cr-Mo-Ti. With the content of alloying elements being increased, the microstructure transformed from bainite to the mixture of granular bainite and low carbon martensite. However, the higher content of alloying elements in deposited metal can promote the formation of martensite, and its appearance is adverse to toughness. The existence of the film-like residual austenite which can improve the impact toughness was found between the lath-like bainite ferrites.

Key words： high strength steel, solid wire, microstructure, mechanical properties

CRC automatic welding technology of X100 grade high strength pipeline steel

Le Wei

(China Jiangxi Oil Products Company of Sinopec，Nanchang 330046, China).p48-53

Abstract Based on the analysis of the chemical composition and mechanical properties, the tensile strength, low temperature impact toughness, hardness, CTOD and HIC of welded joints had been studied on X100 pipeline steel with the selected welding process, welding filler metal and technical parameter. The results show that the welding performance of X100 pipeline steel is good, and the welding process put forward in this paper can meet the working and application requirements.

Key words： CRC automatic welding， X100 pipeline steel， welding process， mechanical properties

Analysis and repair of welding crack in 304 stainless steel flange

Zhao Qiang1，Xiao Weibao2，Wang Daqiang2，Sun Zhanghao2，Xiong Xuping2

(1.Engineering and Technology Department ，Technology Center of State Grid Xinyuan Co. Ltd.，Beijing 100161， China；2. East China Langyashan Pumped Storage Co. Ltd.，Chuzhou 239000, Anhui, China).p54-57

Abstract The cracks in 304 stainless steel welds and base metal were analyzed during the overhaul, it was found that welding slag in the weld and lack of penetration were the reasons of cracking of welded joint. Metallographic analysis of base metal showed that carbides precipitate in grain boundary of 304 stainless steel, which likely results in the intergranular corrosion that could cause the cracking of base metal. During the welding process, the multi-pass welding easily caused the intergranular corrosion of heat affected zone, which can lead to cracking. During the cooling process after manufacturing of 304 stainless steel forging flange, it should be avoided remaining at sensitization temperature for too long time, and fast cooling after solution should be taken to avoid intergranular corrosion. The welded joint of 304 stainless steel was qualified by welding inspection after repairing by strictly controlling interpass temperature and low heat input during and fast welding.

Key words： 304 stainless steel, weld, crack, intergranular corrosion

Design of key structure of automatic all-direction tube-sheet argon-arc welding machine

Li Min

(School of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056, China).p57-60

Abstract According to the functional requirements, the design principle of automatic all-direction tube-sheet argon-arc welding machine was put forward in this paper. Then the key problems of this machine were described, such as reliable wire feeding, accurate positioning, flexible water and gas supplying. Finally, a tube-plate welding head with high performance was designed. This welding head with the conductive ring and static positioning, dual water and gas supply, has the advantages of compact structure, reliable operation, strong applicability etc. The production practice shows that the welding head can effectively ensure the quality of the welded joint, and significantly improves the production efficiency.

Key words： automatic tube-sheet welding machine, static positioning, dual water supply, dual gas supply

Design of laser welding and testing system for shift and gear shaft

Shan Lan

(Zhejiang Tongji Science and technology Career Academy, Hangzhou 311231,China).p61-64

Abstract The laser welding system and testing machine was designed to joint the shift and gear shaft. The machine realized the function of automatic loading the shift, positioning the gear shaft, position adjusting after assembly, automatic welding, testing after welding and automatic unloading. Through the gripper of the pressing components to position and clamp for the sample, then automatic welding was realized. The eddy flaw detector was used to test the welded products.

Key words： gear shaft, laser welding, position and clamp, testing

Preparation of comparison specimens of typical brazed structures for ultrasonic testing

Sha Zhongyu1, Wang Tao2

(1. Jilin Railway Technology College, Jilin 132200, Jilin, China; 2. State Key Lab of Science and Technology on Reactor Fuel and Materials, Nuclear Power Institute of China, Chengdu 610213, China).p65-68

Abstract Comparison specimens of brazed structures such as honeycomb structure, panel structure and radar array antenna surface structure used for ultrasonic C-scan test were designed and fabricated. A series of presetting artificial defects methods were tested by ultrasonic C-scan inspection to select the proper comparison specimen for specific brazed structure. The result shows that the proper comparison specimen for panel brazed structure should be made by drilling a through hole before brazing. The best way to make a comparison specimen for brazed structure of honeycomb should be as follows: the curing agent was injected to the honeycomb after brazing, machining a flat bottom hole and then using heating or chemical method to remove curing agent. For the antenna surface brazed structure comparison specimen, the best way to make it is milling strip defects in lower plate near the rib plate position after brazing.

Key words： ultrasonic C-scan, artificial defects, fabrication of comparison specimen

编辑 常 青