HOT DUCTILITY AND HOT CRACKING BEHAVIOR OF MODIFIED 316 STAINLESS-STEELS DESIGNED FOR HIGH-TEMPERATURE SERVICE

The weldability of the modified 316 stainless steel was evaluated by t he Gleeble hot ductility test and two hot cracking test methods (Vares traint and Sigmajig). The fusion zone and weld metal heat-affected zon e (HAZ) hot cracking susceptibilities of the modified 316 stainless st eel are similar to conventional fully austenitic 316 stainless steels and greater than the conventional 316 materials that have a primary fe rritic solidification mode. The Gleeble hot ductility test results cor relate with the base metal HAZ hot cracking results from the Varestrai nt test and indicate that the modified 316 materials show a considerab ly higher base metal HAZ hot cracking susceptibility as contrasted to nuclear grade 316 stainless steels. Varestraint test results and Sigma jig test results for the tested materials showed good correlations. Th e sensitivity of the base metal to HAZ liquation cracking has been suc cessfully predicted by using a newly developed hot ductility criterion , the ratio of ductility recovery (RDR). An excellent correlation betw een the Gleeble Test criterion RDR and the Varestraint Test criteria ( TCL, MCL and CHL) has been found.