Creep Property of TMCP High-Strength Steel Q690CFD at Elevated Temperatures

Abstract

Creep effect becomes an important consideration in the design of high-strength steel structures subjected to a soaking period at elevated temperatures such as in stress-relieving post-weld heat treatment (PWHT) circumstances. However, very limited experimental data can be found for the creep property of the thermal-mechanical control process (TMCP) of high-strength steel (HSS) at different elevated temperatures and stress levels, which seriously restricts the numerical modelling for the creep effect and analysis of the mechanical behavior of TMCP HSS structural elements. To this end, the physical mechanisms underlying the creep in TMCP HSS were firstly discussed in this paper, after which the mechanical properties of Q690CFD at ambient and elevated temperatures were investigated. An experimental investigation on the creep properties of Q690CFD at elevated temperatures was organized in the current study. The effect of environmental temperature and stress level on the creep behavior of TMCP HSS was also studied. A constitutive model was proposed to describe the creep behavior of TMCP HSS under elevated temperatures. Finally, validation of the constitutive model shows good agreement with the test results.