METHOD AND APPARATUS FOR MEASURING CARBURIZATION DEPTH OF STEEL MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a method of non-destructively and accurately measuring the carburization depth on the inner surface of a steel pipe.;SOLUTION: This method of measuring the carburization depth of the steel material having front and back surfaces (hereinafter, respective surfaces are called "first surface" and "second surface") comprises a process 1 of measuring carbon concentration C_o on the first surface of the steel material, a process 2 of measuring total carbon content A_Ct from the second surface to the first surface of the steel material, and a process 3 of determining the carburization depth d_i of the second surface of the steel material based on the expression: d_i²=2{A_Ct-(C_o-C_b)²/(2×K_o)+C_b×t}/K_i. In this expression, d_i is carburization depth (mm) of the second surface of the steel material, A_Ct is total carbon content (g) from the second surface to the first surface of the steel material obtained by measurement, C_o is carbon concentration (mass%) on the first surface of the steel material obtained by measurement, C_b is carbon concentration (mass%) of base material, K_o is constant about the carburization of the first surface of the steel material, K_i is constant about the carburization of the second surface of the steel material, and t is thickness (mm) of the steel material.;COPYRIGHT: (C)2009,JPO&INPIT