Localized creep characterization of 316LN stainless steel weld joint using Small Punch Creep test

Type 316LN stainless steel (SS) weld joints are widely used in several high temperature applications. The variations of creep properties across the microstructurally heterogeneous regions of 316LN SS weld joint such as base metal, weld metal and heat affected zone (HAZ) have been evaluated using Small Punch Creep (SPC) technique at 923 K. Both the SPC rupture and deformation behaviors were investigated. The creep strength gradient across 316LN SS weld joint showed a smooth increasing trend from base metal to weld metal. However, the trend of the rupture life for weld metal shifted with change in load level. The SPC deformations of various regions of weld joint have been analyzed according to the equation,δ=δ0+δT(1−e−κt)+δ̇st+δ3e[ϕ(t−tr)]. The variations of transient, secondary and tertiary creep parameters were determined across the weld joint. The master curve for transient creep deflection was obtained for various regions of weld joint.