- A METHOD FOR MANUFACTURING Cr-Mo ADDED STEEL FOR HIGH TEMPERATURE APPLICATIONS WITH EXCELLENT IMPACT TOUGHNESS

摘要

PURPOSE: Provided is a process of preparing Cr-Mo steel having excellent strength and impact toughness by reducing a carbon content of steel and controlling the heat treatment suitably after hot rolling. Whereby, the steel can substitute a part of stainless or high-alloy heat resistant steel. CONSTITUTION: A steel slab consisting essentially of, in weight %, C: 0.03-0.13%, Si: 0.70% or less, Mn: 0.40-0.65%, Cr: 0.80-1.50%, Mo: 0.30-0.80%, P: 0.012% or less, S: 0.005% or less, Al: 0.030% and a balance of iron and unavoidable impurities is reheated, hot rolled, quenched or reheated at 850 to 950deg.C, directly quenched at 780 to 950deg.C and then tempered at 600 to 750deg.C for 10 to 30 min.