文献类型：期刊文献

英文题名：Mechanisms for Improvement of Weld Appearance in Autogenous Fiber Laser Welding of Thick Stainless Steels

作者：Zhang, Mingjun Chen, Shun Zhang, Yingzhe Chen, Genyu Bi, Zhuming

第一作者：Zhang, Mingjun

通信作者：Zhang, MJ[1];Zhang, MJ[2]

机构：[1]Changsha Univ Sci & Technol, Educ Dept Hunan Prov, Key Lab Lightweight & Reliabil Technol Engn Vehic, Changsha 410114, Hunan, Peoples R China;[2]Guizhou Inst Technol, Coll Mat & Met Engn, Guiyang 550003, Guizhou, Peoples R China;[3]Hunan Univ, State Key Lab Adv Design & Mfg Vehicle Body, Changsha 410082, Hunan, Peoples R China;[4]Purdue Univ, Dept Civil & Mech Engn, Ft Wayne, IN 46805 USA

第一机构：Changsha Univ Sci & Technol, Educ Dept Hunan Prov, Key Lab Lightweight & Reliabil Technol Engn Vehic, Changsha 410114, Hunan, Peoples R China

通信机构：corresponding author), Changsha Univ Sci & Technol, Educ Dept Hunan Prov, Key Lab Lightweight & Reliabil Technol Engn Vehic, Changsha 410114, Hunan, Peoples R China;corresponding author), Guizhou Inst Technol, Coll Mat & Met Engn, Guiyang 550003, Guizhou, Peoples R China.|贵州理工学院材料与冶金工程学院;贵州理工学院;

年份：2018

卷号：8

期号：8

外文期刊名：METALS

收录：;Scopus(收录号：2-s2.0-85051522931);WOS:【SCI-EXPANDED(收录号:WOS:000443616400061)】；

基金：National Natural Science Foundation of China (no. 51605045, 51641502), the Natural Science Foundation of Hunan Province of China (no. 2018JJ2437, 2015JJ3003).

语种：英文

外文关键词：fiber laser welding; keyhole; thick plate welding; deep penetration; weld appearance; high-speed imaging

摘要：High-power fiber laser welding is an efficient and effective way to produce heavy section structures. However, there is a significant challenge in producing the welds with free of imperfections such as nail-head-shaped welds, spatters, and root sagging. This is partially due to a lack of understanding of the welding mechanism of high-power fiber laser. In this paper, we were especially interested in the mechanism to improve the appearance of welds, and we focused on the autogenous laser welding on thick stainless steel plates by a 10 kW fiber laser. To look into the relations of process parameters and the quality of welds, a high-speed imaging system was applied to observe the molten pool flow and vapor plume during the welding process. The appearances of welds subjected to different welding conditions were analyzed. The results showed that (1) nail-head-shaped welds were suppressed by using a gas jet during laser welding process. (2) In the forward welding, a gentle upwelling molten metal flow on the rear keyhole wall, a deeper weld pool and a weaker vapor plume resulted in no spatter. (3) The gravity affected the formation of underfills and root sagging significantly during autogenous laser welding of thick plates. (4) When the workpiece was placed vertically in the transverse position, the welding process was stable without an aggregation of molten melt at the back surface. Moreover, the mechanisms of forming root sagging and humps were different at the top surface.