Theoretical Analysis for Solidification Cracking Susceptibility in Type 316FR Stainless Steel Laser Welds

Abstract

For quantitative evaluation of solidification cracking susceptibility in two kinds of ty pe 316FR stainless steel (316FR-A and 3 16FR-B) laser welds, laser beam welding (LBW) transverse-Varestraint test was performed. As the welding speed increased from 1.67 to 40 .0 mm/s, enlargement range of solidification brittle temperature range (BTR ) for 316FR-B (from 14 to 40 K) wa s larger than that for 316F R-A (from 37 to 46 K), respectively. Based on theoretical calculations fo r solid/liquid coexistence temperat ure range by using Kurz-Giova nola-Trivedi and solidification segregation models, the reason for larger increm ent of the BTR for 316FR-B could be regarded as larger decre ment of δ -ferrite amount during the welding solidifi cation than that for 316FR-A, affecting se vere increment of the impurities’ segregat ion (S and P), thereby more enlarging the solid/liqui d coexistence temperature range as compared with that of 316FR-A.