Stress strain relationship of Tempcore steel after heating up to 650°C and cooling

Reinforcing bars of 12 mm and 25 mm have been tested, at room temperature, at elevated temperatures (steady state and transient conditions), and after cooling from elevated temperatures. No decrease of the residual strength was observed as long as the elevated temperature has not exceeded 600°C. A slight decrease seems to appear for elevated temperatures beyond 600°C. Additional test for elevated temperatures higher than 680°C should ideally be performed to confirm this trend.