Author(s): LI Yu-kun, YOU Ze-guang, XIAO Ming, ZOU Xue-fei, College of Pipeline and Civil Engineering, China University of Petroleum, China Petroleum Pipeline Engineering Corporation, Petrochina Beijing Natural Gas Pipeline Co., Ltd.
Pages: 56-61
Year: 2016 Issue:  1
Journal: Materials for Mechanical Engineering
Keyword:  1.6220 cast steel; low temperature; mechanical property; ductile-brittle transition temperature;
Abstract: With 1.6220 cast steel for pressure regulating valve body of natural gas transportation as the research object,the change law of mechanical properties versus temperature of the hot rolled and quenched &tempered cast steels was studied by the low temperature tensile test and impact test,and then the ductile-brittle transition temperature was calculated.The fracture morphology at different temperatures was also observed.The results show that with the decrease of the temperature,the yield strength and tensile strength of the cast steel increased and the percentage reduction of area and elongation reduced.The quenching and tempering treatment significantly improved the low temperature mechanical properties of the cast steel.The yield strength,tensile strength and plasticity of the quenched & tempered cast steel were higher than those of hot rolled one,and the ductile-brittle transition temperature of the cast steel in quenching &tempering state decreased to-14.46 ℃from2.76 ℃in hot rolled state.With the temperature decrease,the fracture pattern of the cast steel changed from cleavage fracture into dimple fracture.