A Study of Laser Welding on 304 Stainless Steel Vessel Fabrication

Abstract

The purpose of this study is to weld long 304 stainless steel vacuum chambers without deformation. The requested accuracy is less than 1 mm per 4, 700 mm. To achieve this high accuracy welding, the authors compared suitable welding method among EBW, LBW and GTAW. According to this study, they decided that the LBW is the most appropriate method because of its highest welding speed and deep penetration ability that leads lower deformation. As there is less information of laser welding deformation, the present authors conducted some basic experiments on laser welding deformations of 304 stainless steel. In this report, following test results were obtained on the long chamber fabrication.
1. An equation of maximum deflection for 304 stainless steel laser welding is derived as δ=0.04[α·Q/(c·ρ)][L²·Z/I]
2. The maximum deflection has linear relationship to heat input Q (J/mm) and to the welding distance from neutral axis.
3. The compressed area of laser welding is fairy large compared to weld bead area and it expands almost all 10mm-plate thickness close to weld bead.
4. According to the information above, the authors could weld 4, 700 mm long vacuum chambers within the requested accuracy.