FRACTURE AND TOUGHNESS TETS STUDY OF HIGH PERFORMANCE STEEL HPS 485W FOR BRIDGE ENGINEERING

To study the fracture behavior of high performance steel for bridge engineering, a series of fracture toughness tests were conducted for high performance steel HPS 485W, which was produced by Wuyang Steel Company in China. The toughness at different temperature was obtained from HPS 485W Charpy V notch toughness test, and the ductile to a brittle curve was fitted using a Boltzmann function. Charpy V notch toughness test shows that HPS 485W, compared with traditional steel, is characterized with higher toughness and lower brittle-ductile transition temperature. After the ductility fracture toughness (J_IC ) test, the calculated Jvalues were obtained for 18mm and 28mm thick specimens, which shows good fracture toughness of HPS 485W. Crack tip opening displacement (CTOD) tests were conducted for 8mm and 14mm HPS485W specimens. CTOD test results show the good plasticity and toughness of HPS485W. Based on the stress and strain curve obtained from a tensile test for HPS485W, a failure assessment diagram was used for evaluation. The evaluation results show that the CTOD test result belonges to an acceptable field. Fracture toughness tests proposed in this paper are helpful in the safety assessment and fracture control of HPS bridges.