Prediction of the remaining life of high temperature-pressure reactors made of Cr-Mo steels

The Cr-Mo steels widely used for pressure vessels have a potential for temper embrittlement. Therefore, embrittlement during long-time service is expected, and it leads to the decrease of the critical flaw size to a brittle fracture and/or to the reduction of the remaining life of a pressure vessel. In this paper, the concept of a remaining life prediction model is presented. And also, experimental data on the temper embrittlement and fracture toughness after long-term exposure and subcritical crack growth rate such as creep crack growth rate were collected, and the data were analyzed for the use with the remaining life prediction model. Examples of the remaining life prediction of a 2 1/4Cr-1Mo steel hydrogenation reactor and a 1 1/4Cr-1/2Mo steel catalytic reforming reactor were calculated from the statistical data base