HEAT RESISTANT LOW ALLOY STEEL HAVING HIGH CORROSION RESISTANCE AND EXCELLENT IN HIGH TEMPERATURE STRENGTH AND WELDABILITY, AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To provide a heat resistant low alloy steel containing 5% Cr, capable of sufficiently meeting the increase in the temperature and pressure of steam condition while keeping oxidation resistance, and excellent in weldability as well as in high temperature strength, and its manufacturing method.;SOLUTION: The heat resistant low alloy steel has a composition consisting of, by weight, 0.02 to 0.10% C, 0.05 to 0.40% Si, 0.1 to 1.0% Mn, 4.5 to 5.5% Cr, 0.1 to 1.0% Mo, 0.5 to 2.0% W, 0.10 to 0.40% Ti, 0.0010 to 0.0060% B, and the balance Fe with inevitable impurities and satisfying (Mo %+W %)=0.6 to 2.5%. The heat resistant low alloy steel can be manufactured by subjecting a steel with the above composition to normalizing at 1000 to 1150%oC and then to tempering at a temperature between 700°C and the Ac1 point.;COPYRIGHT: (C)2001,JPO