Properties of HK40 Steel after Long Time Service

The HK40 steel tubes which served for 80 000 hours have been synthetically studied. The research involves surface flaw detection, metallographic examination, Charpy V impact test, creep rupture strength and creep crack growth rate, etc. On this base, the degradation on the properties of the HK40 steel after long time service has been discussed, and the residual life has been estimated. The estimation fits the actual result.