SiMoV蠕墨铸铁高温变形行为研究OACSTPCD

The elevated deformation behavior of SiMoV vermicular graphite cast iron in the temperature range of 500℃to 800℃was studied through experimental methods of optical microscopy,scanning electron microscopy,and high-temperature mechanical properties testing.The results indicate that the strain range in the yield stage of the stress-strain curve does not show significant growth or change,while the length of the strain interval from the necking stage to the fracture process significantly increases,with the increasing of the temperature,leading to softening of the material.Meanwhile,the tensile strength and yield strength sharply decrease with increasing temperature,with a decrease of 740%and 935%in yield strength and tensile strength at 800℃compared to 500℃.However,the extension shows the opposite trend,increasing by 479%.The origin of the crack is the tip of vermicular graphite,and the decrease of high-temperature strength is not only affected by the microstructure characteristics of the ferrite matrix,but also related to the oxidation of vermicular graphite at high temperature,leading to forming of secondary crack propagation.