THE EFFECT OF RESTORATION-HEAT-TREATMENT ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF 15CrMo STEAM PIPE STEEL

摘要

1. The deviation of experiment results caused by the unhomogeneity of creep cavities distribution in different position of the pipe can be avoided by using the small and thin specimens cut from identical position of the pipe. 2. After restoration-heat-treatment, the strength of aged steel at room temperature and high temperature had increased by 10～20% and 30%, the long-term rupture strength had increased greatly. 3. After restoration-heat-treatment, the microstructure of aged steel can been restored as normal state, smaller creep cavities can been removed from the grain boundries and larger creep cavities may been leaved within the grain. 4. The creep cavities of aged steel can not be removed completely ,but a little of cavities leaved within the grain will not deteriorate the mechnical properties of steel obviously.