Nitrogen Content of 316L Weld Metal and Its Fine Particle by Means of High-pressure MIG Arc Welding

摘要

The suitability of the high nitrogen pressure Metal Inert Gas (MIG) ARC welding process (constant arc length condition) for high nitrogen containing stainless steel was investigated. The formation of the stainless steel fine particles by the high nitrogen pressure MIG arc welding process was examined. The welding atmosphere consisted of pressurized N_2 gas. Nitrogen absorption of 316L stainless steel weld metal and its fine particle in the high nitrogen pressure MIG process was studied. The effect of nitrogen contents in remelted weld metal and changes in the microstructure of the weld metal were observed. The nitrogen content of weld metal and the number of fine particles increased with increasing pressure of N_2. Approximately 0.6 and 2.4 mass% nitrogen was absorbed in the weld metal and fine particles at pressure of N_2 6 Mpa and 3 Ma nitrogen respectively. Nitrogen content of the weld metal was lower than that representing equilibrium solubility of 316L stainless steel at close to the melting point.