Weldability examination of ASTM A 240 S41500 martensitic stainless steel by thermal cycles simulation testings

The weldability assets of ASTM A 240 S41500 (ASTM A 240/A 240M) martensitic stainless steel are presented through the study of the effects of single and double thermal weld cycles on mechanical properties and microstructure of base metal (BM) and the artificial heat affected zone (HAZ) created by thermal weld simulations. For single cycles, separate peak temperatures of 1000 ºC/12 s and 1350 ºC/12 s (cooling times: 12 s in both cases) were evaluated, whilst two combinations of peak temperatures: (1350 ºC/5 s + 1000 ºC/5 s) ºC and (1350 ºC/12 s + 1000 ºC/12 s) ºC (cooling times: 5 s and 12 s), were applied for double cycles. Post weld heat treatment (PWHT) with short and long holding times were applied and Vickers hardness, impact toughness and metallographic examinations were used in order to assess mechanical and metallographic properties in the as-simulated (no heat treated) and postweld heat treated conditions. Best properties of the welded joint for double thermal weld cycles with long holding times were reached, which reveals the good weldability and applicability of the tested material in post weld heat treated conditions