Studies on temperature induced creep in high strength Q460 steel

Significant levels of creep deformation in structural steel members exposed to high temperatures have been widely observed in experiments; however inclusion of creep effects in numerical simulations has been limited due to lack of reliable experimental data and corresponding constitutive creep models for structural steel, especially for high strength steel. This paper presents an experimental investigation into temperature induced creep in high strength Q460 steel which is commonly used in structural member. A set of creep tests is carried out at various stress levels in 300-900 degrees C temperature range. Data from these creep tests indicate that temperature has significant influence on the level of creep deformations in Q460 steel, especially when the temperature in steel exceeds 400 degrees C. The creep strain at a given temperature increases with stress level and the creep strain at a given stress level increases with temperature. Results from creep tests are utilized to develop relations for expressing creep as a function of temperature and stress. These relations, which are based on creep power law and unified theory on plasticity and creep phenomenon, can be utilized in modeling the response of steel structures made of Q460 steel exposed to fire.