Research on Underwater Laser Welding with Filler Wire Process of TC4 Titanium Alloy

doi:10.3901/JME.2020.06.118

Abstract

Abstract: Laser welding with filler wire of the TC4 titanium alloy has been successfully applied in underwater field. The underwater laser welding with filler wire of TC4 titanium alloy was researched by adjusting welding speed and wire feed speed to obtain high quality underwater weld metal. After welding, the welding surface appearance and micro forming, as well as the microstructure and mechanical properties of the weld metal under different process parameters are analyzed. The results show that when the welding speed and wire feed speed are 20 mm/s and 60 mm/s respectively, a well-formed and continuously stable weld metal can be obtained. The center of the weld metal is scattered acicular martensite, besides, the heat affected zone can be divided into two parts, they are mainly near the weld metal zone and the close to base metal zone, the α' phase of the close to the base metal zone is less than that of the near the weld metal zone, because the temperature of the close to base metal zone is higher, more β phase change to α'phase. With the increase of welding speed (or wire feed speed), both yield strength and impact toughness of the welded joints show a trend of increasing firstly and then decreasing. When the welding speed is 20 mm/s and wire feeding speed is 60 mm/s, both of them reach the maximum value, the yielding strength is 813.42 MPa and impact toughness is 39.07 J/cm². Larger aspect ratio and cross-sectional area of weld metal can improve the mechanical properties of joints The fractures are surveyed to obtain the surfaces traits by the scanning electron microscope, it can be found that they are mixed fractures of cleavage fracture and dimple fracture.

Key words: underwater laser beam welding, local dry cavity, welding surface appearance, micro forming, microstructure, mechanical properties

CLC Number:

TG156

GUO Ning, CHENG Qi, FU Yunlong, ZHANG Xin, XU Changsheng, HUANG Lu. Research on Underwater Laser Welding with Filler Wire Process of TC4 Titanium Alloy[J]. Journal of Mechanical Engineering, 2020, 56(6): 118-124.

References

[1] ZHAO Jingwei,DING Hua,ZHAO Wenjuan,et al. Modelling of the hot deformation behaviour of a titanium alloy using constitutive equations and artificial neural network[J]. Computational Materials Science,2014,92:47-56.
[2] 朱晓亮,欧梅桂,张松,等. TC4钛合金热变形行为研究[J].现代机械,2019(2):88-92. ZHU Xiaoliang,OU Meijia,ZHANG Song,et al. Thermal deformation behavior of TC4 titanium alloy[J]. Modern Machinery,2019(2):88-92.
[3] 王振民,谢芳祥,冯允樑,等.水下机器人局部干法焊接系统[J].焊接学报,2017,38(1):5-8. WANG Zhenmin,XIE Fangxiang,FENG Yunliang,et al. Underwater robot local dry welding system[J]. Transactions of the China Welding Institution,2017,38(1):5-8.
[4] 李兰,薛龙,黄军芬,等.水下局部干法焊接圆形排水罩的流体仿真分析[J].焊接学报,2016,37(2):43-46. LI Lan,XUE Long,HUANG Junfen,et al. Simulation of fluid in cylindrical drainage cover for underwater local dry welding[J]. Transactions of the China Welding Institution,2016,37(2):43-46.
[5] GUO Depeng,PU Chenghao,LI Maolin,et al. Application and study of 3D visualization model on nuclear power plant construction[J]. IOP Conference Series:Earth and Environmental Science,2017,61:012023.
[6] ZHU Jialei,JIAO Xiangdong,ZHOU Canfeng,et al. Applications of underwater laser peening in nuclear power plant maintenance[J]. Energy Procedia,2012,16:153-158.
[7] 蒋力培,王中辉,焦向东,等.水下焊接高压空气环境下GTAW电弧特性[J].焊接学报,2007,28(6):1-4. JIANG Lipei,WANG Zhonghui,JIAO Xiangdong,et al. Characteristics of GTAW arc in underwater welding under high pressure air environment[J]. Transactions of the China Welding Institution,2007,28(6):1-4.
[8] 吴磊,宋红伟.水下焊接技术的现状及发展趋势[J].管道技术与设备,2013(2):37-39. WU Lei,SONG Hongwei. The current situation and development trend of underwater welding[J]. Pipeling Technique and Equipment,2012(2):37-39.
[9] GUO Ning,HUANG Lu,DU Yongpeng,et al. Control of droplet transition in underwater welding using pulsating wire feeding[J]. Materials,2019,12:1715.
[10] GUO Ning,DU Yongpeng,FENG Jicai,et al. Study of underwater wet welding stability using an X-ray transmission method[J]. J. Mater. Process. Technol.,2015,225:133-138.
[11] GUO Ning,XU Changsheng,GUO Wei,et al. Characterization of spatter in underwater wet welding by X-ray transmission method[J]. Mater. Des.,2015,85:156-161.
[12] GUO Ning,FU Yunlong,XING Xiao,et al. Underwater local dry cavity laser welding of 304 stainless steel[J]. J. Mater. Process. Technol.,2018,260:146-155.
[13] SHANNON G J,MCNAUGHT W,DEANS W F,et al. High power laser welding in hyperbaric gas and water environments[J]. J. Laser. Appl.,1997,9:129.
[14] SHI Yonghua,SUN Kun,CUI Shuwan,et al. Microstructure evolution and mechanical properties of underwater dry and local dry cavity welded joints of 690 MPa grade high strength steel[J]. Materials,2018,11:167.
[15] 徐虎.变形镁合金的CO2激光填丝焊研究[D].哈尔滨:哈尔滨工业大学,2006. XU Hu. Study on CO2 laser wire filler welding of deformed magnesium alloys[D]. Harbin:Harbin Institute of Technology,2006.
[16] 王文政,张永康,姜福银,等. 20钢光纤激光填丝焊工艺与焊缝组织的研究[J].热加工工艺,2013,42(19):26-28,32. WANG Wenzheng,ZHANG Yongkang,JIANG Fuyin,et al. Study on fiber laser wire filling welding process and weld microstructure of 20 steel[J]. Hot Working Technology,2013,42(19):26-28,32.
[17] 刘建华,胡伦骥,骆红,等.薄板激光填丝焊工艺研究[J].汽车技术,1997(3):40-44. LIU Jianhua,HU Lunji,LUO Hong,et al. Research on thin plate laser wire filling welding process[J]. Automotive Engineering,1997(3):40-44.
[18] ZHANG Xudong,CHEN Wuzhu,ASHIDA E,et al. Metallurgical and mechanical properties of underwater laser welds of stainless steel[J]. J. Mater. Sci. Technol.,2003,19:479-483.