HIGH TEMPERATURE DAMAGE EVALUATION METHOD FOR TEMPER MARTENSITE STAINLESS STEEL

摘要

PROBLEM TO BE SOLVED: To provide a high temperature damage evaluation method for temper martensite stainless steel by which the high temperature damage of the machine parts which are used at a high temperature for a long time, and are made of temper martensite stainless steel, can be evaluated with high accuracy by a simple operation during the use of the same. SOLUTION: A surface of a part to be examined, having the mirror finished surface, is dipped into an electrolyte, the electric potential is applied to the same at a specific potential scanning speed, a peak value of the current value appeared in the almost constant potential on a dissolving current-potential curve obtained corresponding to the dissolution of a Laves phase as a specific deposit, is determined, the formation amount of the Laves phase is determined from an evaluation chart indicating the relationship between the peak current density and the formation amount of the Laves phase, formed by using a specimen on which the ageing treatment has 4 been performed in advance, and an impact value or the rupture strength of a material of the part to be examined, or the operating temperature of the material of the part to be examined, is evalurated on the basis of the relational chart of the Laves phase formation amount, and the impact value or rupture time obtained in advance on the basis of the obtained formation amount of Laves phase, or a relational expression of the Laves phase formation amount-temperature-retension time.