Experimental investigation on mechanical behaviours of TMCP high strength steel

• Published in: Construction & building materials 2019-03, Vol.200, p.664-680
• Main Authors: Jiang, Jin, Bao, W., Peng, Z.Y., Wang, Y.B., Liu, J., Dai, X.H.
• Format: Article
• Language: English
• Subjects: Cooling rate; Elevated temperature; High strength steel; TMCP; Welding heat input
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.12.130

•Mechanical properties of Q690CFD at elevated temperatures and post-fire condition are studied.•Effect of temperature, heat input and cooling rate on behavior of Q690CFD is studied.•The reduction factors of properties of Q690CFD at elevated temperatures are studied.•A series of predictive equations are proposed to evaluate the properties of TMCP HSS. The deterioration of mechanical behaviour of high strength steel (HSS) under elevated temperatures and post-fire condition would lead to reduction of load bearing capacity. To find out the effect of work temperature, welding heat input and cooling rate on the mechanical behaviour of thermal-mechanical control process (TMCP) HSS, a comprehensive experimental investigation on mechanical properties of Q690CFD at ambient and elevated temperatures and post-fire condition was organized in this study. Two types of studied objectives (basic material and welded specimens) were included. For ambient and elevated temperature condition, the elastic modulus, yield and ultimate strength were tested from different work temperatures and different welding heat inputs. For post-fire condition, the residual elastic modulus, residual yield and ultimate strength were tested under different heat inputs and cooling rates. The reduction factors of those mechanical properties were investigated. Finally, a series of predictive equation, which can be used to evaluate the ambient and elevated temperatures and post-fire performance of TMCP HSS, were proposed. The effects of welding heat input and cooling rate were incorporated in the proposed design equations.