Study on Tensile Behaviour under Low Temperture and Stess Relaxation of 60Si2Mn Steel
|School||Harbin Institute of Technology|
|Keywords||60Si2Mn steel Extrude Hypothermia Stress relaxation Organization|
In this paper, electronic tensile testing machine , respectively, in 50 ° C , -50 ° C , -100 ° C and -196 ℃ temperature test 60Si2Mn steel tensile properties . Tensile fracture morphology and deformation microstructure and low temperature scanning electron microscope (SEM) and transmission electron microscopy (TEM) analysis . Stress relaxation device test 60Si2Mn steel at 100 ° C for 200 and 300 ℃ temperature stress relaxation properties , and stress relaxation curve . The tensile test results show that as the temperature decreases , 60Si2Mn steel yield strength and tensile strength have a clear upward trend . Compared with the room temperature , -196 ℃ yield limit increased by 25.5% ; same time , the tensile strength of a rise of 20.2% ; the elongation decreased 11.9 % . Tensile fracture surface analysis showed that the type of tensile fracture surfaces as the temperature is lowered , the transition from ductile fracture to brittle fracture . As the temperature decreases , the carbon in the ferrite matrix tend to be saturated, the tensile deformation of the TEM observation of the microstructure found in the precipitation of carbides . The original tissue 60Si2Mn steel and -100 ℃ tensile deformation Organization XPS analysis and comparison results indicate that low - temperature stretching process , content of α - Fe - matrix of Fe3C increase . The stress relaxation test results show that the stress relaxation curve of 60Si2Mn steel presents the stress relaxation characteristics of a typical two-phase , the stress relaxation process is mainly affected by the two factors of the temperature and stress , when both changes , the influence of the temperature on the stress relaxation strength greater than the impact of the initial stress .