PART MADE OF NIOBIUM-CONTAINING LOW ALLOY HEAT RESISTANT STEEL, AND PRODUCTION METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a heat resistant steel part in which cracks on forging frequently occurring in the production of a part made of niobium-containing low alloy heat resistant steel are eliminated, and the occurrence of cracks in a working process including forging is prevented, and to provide a production method therefor.;SOLUTION: When, with niobium-containing low alloy heat resistant steel containing 0.01 to 0.10% Nb as an object, at least a part of crystallized NbC is made to form a solid solution in a matrix by soaking, and next and forging and required mechanical working are performed, ≥60% of the crystallized NbC is allowed to form the solid solution. The progress rate into the solid solution is estimated by the formula, S=1-exp[{-2.72×10¹⁶exp(-6.41×10⁵/RT)}×t] (wherein S is the progress rate into the solid solution; T is the temperature (K) of a steel ingot; t is the time (s), and R is a gas constant of 8.3114), and the heating temperature and time are decided, so that the soaking is efficiently performed.;COPYRIGHT: (C)2004,JPO