Product Code: ICAL09_1804

High-power Fiber Laser Butt Welding of Thick High-strength Steel Plate using Sensing System with Hot Wire
Authors:
Terumasa Onishi, JWRI; Ibaraki City, Osaka Japan
Masami Mizutani, Jwri; Ibaraki City Japan
Yousuke Kawahito, Jwri; Ibaraki City Japan
Seiji Katayama, Jwri; Ibaraki City Japan
Presented at ICALEO 2009

Welding of thick high-strength steel plates without preheating or post-heating is expected in many industries. A high-power and high-brightness fiber laser is promising as one of the desirable heat sources for high-speed and deep-penetration welding. However, such a small beam spot has a low gap tolerance for butt welding. In this study, therefore, laser butt welding was performed on thick high-strength steel plates with several gaps with 10 kW fiber laser, using the sensing system with cold or hot wires. A laser-shooting point was feedback-controlled by the system. The effect of shielding gases on the weld penetration was investigated in order to produce sound high-quality butt welds. As a result, desirable full penetration welds without burn-through or underfilling could be formed in 12-mm thick plates in argon, air or carbon dioxide shielding gas. These welding phenomena were observed with high-speed video cameras under LD illumination to elucidate the formation mechanisms of welding defects and sound fully-penetrated welds. It was confirmed that oxygen should exert a great effect on melt flows and the consequent weld geometry.