Creep damage evaluation method for ferritic heat-resistant steel

摘要

PURPOSE:To provide a method by which creep damage can be evaluated accurately without cutting a mechanical part on which the creep damage is evaluated. CONSTITUTION:Ferrite type heat resistant steel changes the carbide distributed condition due to creep damage. That is, when it is manufactured, the carbide 3 distributed condition was as shown in the drawing (1), but when it is used in a heated condition and the creep damage is caused, the carbide 3 becomes bulky, and an inter-particle distance is increased. Thereby, when the carbide distributed condition is observed on a supply sample material, a coefficent of a creep curve can be recognized. Since the creep curve changes due to a working temperature and working stress of the material, the creep curve can be estimated from these working condition and coefficent. When time corresponding to creep distortion is found from the creep curve estimated in this way, the residual service life of the material can be evaluated.