Analysis of transient and tertiary creep behavior of Titanium modified 14Cr-15Ni stainless steel after cold working

Abstract

Characteristic of transient and tertiary creep behavior of ten, twenty, thirty, and forty percent cold worked indigenously developed Titanium modified 14Cr-15Ni stainless steel at 700 °C and various stress levels have been assessed. Small primary creep region followed by secondary creep and then substantial tertiary creep regions were exhibited by all steels. Creep parameters like transient strain and rate of exhaustion of transient creep in Garofalo equation and tertiary strain and rate of acceleration of tertiary creep in modified Dobes and Cadek equation have been extensively studied. The relationships among exhaustion rate of transient creep, acceleration rate of tertiary creep, and minimum creep rate revealed the prevailing theory of first order reaction rate during transient and tertiary creep deformation of the Titanium modified 14Cr-15Ni stainless steel. The exhaustion rate of transient creep decreased, whereas tertiary creep parameter decreased as the amount of cold work increased. Creep damage tolerance parameter indicated that necking, precipitate coarsening, and recovery of substructures are dominant creep damage mechanisms in the Titanium modified 14Cr-15Ni stainless steel.

Keywords

• transient creep
• garofalo equation
• creep damage
• tertiary creep