Novel measures for spatter prediction in laser welding of thin-gage zinc-coated steel. (March 2021)

• Record Type: Journal Article
• Authors: Wan, Zixuan; Wang, Hui-Ping; Li, Jingjing; Solomon, Joshua; Zhu, Yuanjing; Carlson, Blair
• Is Part Of: International journal of heat and mass transfer. Volume 167(2021)
• Publication Date: 2021-03
• Subjects: Remote laser welding -- Zigzag oscillation -- Zinc-coated steel -- Full penetration -- Spatter prediction -- Welding parameters; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2020.120830
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Spatter behaviors in laser welding of zinc-coated steels are classified into two types with spatter mechanism explained. Two measures Zout and Zp are proposed to predict the occurrence of two types of spatter. Numerical simulations of welding processes are used to calculate the two measures for spatter prediction and verified by the physical testing. Suggestions for spatter-free weld schedule design based on two measures are provided. Abstract: This paper studies full-penetration remote laser stitch welding of thin-gage zinc-coated steel sheets in a lap joint condition. The spatter was classified as either Type A or Type B based on their characteristics, corresponding to low and high linear energies, respectively. The Type A spatter was mainly affected by the zinc vapor outgassing through the keyhole openings, while Type B was more influenced by the vulnerability of the keyhole rear wall to the impact of the high-pressure zinc vapor jet originating from the faying interface. Two measures, Zout and Zp, are proposed to predict the occurrence of Type A and Type B spatter. A thermo-fluid numerical model was developed to investigate the physics in the remote laser welding of zinc-coated steels, such as molten pool dimensions, keyhole stability, and zinc coating evaporation and to calculate Zout and Zp in the welding process. The effects of welding parameters, such as laser power and feed speed, on spatter occurrence were studied numerically and verified against experimental observations. It was found that the laser linear energy could directly affect values of Zout and Zp . A medium linear energy, striking a balance between Zout and Zp, could generate welds with much less spatter compared to a relatively low or high linear energy.