Modeling of the High Temperature Creep and Rupture under the Complex Stress State

Abstract

A damage mechanics model linked to the creep strain and stress three-axiality has been adopted to predict the creep lifetime under the complex stress state. The model accounts for primary-secondary-tertiary creep laws. Constitutive equation parameters were determined using experimental data of smooth specimens. Finite element modeling of creep rupture in notched specimens is presented in this work. The calculated creep failure strain and time to rupture for notched specimens (semicircular with radius 4.0 mm and U-notched with radius 1.2 mm) have been compared with experimental data for the X10CrMoVNb-9-1 steel tested at 625 °C. The calculation results of creep rupture for smooth and notched specimens show notch strengthening or notch weakening depending on the tensile stresses level and notch geometry.

Resistance of Heterogeneous Metal Compositions to Fracture under Dynamic and Cyclic Loads

“…This is especially true if the base metal is steel with limited or low weldability [15]. The potential destruction of welded or clad composites is linked to the structural heterogeneity (interlayers) that forms near the fusion boundary [16]. For the fusion zone of 15Cr1Mo1V and 10CrMoVNb steels, the possibility of destruction depends primarily on the influence of the most dangerous soft layers (the cast seam structure and softening zones in the HAZ).…”