PURPOSE: To improve the corrosion fatigue strength and impact value of a product material by pouring the stainless steel molten metal contg. C, Si, Mn, Cr, Ni, Mo and Nb in specified wt.% and rapidly cooling a casting in the specified temp. range.

CONSTITUTION: In the component of a stainless steel molten metal ≤0.08% C, 0.1W1.5% Si, 0.1W3% Mn, 16W19% Cr, 4.5W7.5% Ni, 0.5W2% Mo, and 0.1W0.8% Nb in wt.% are contained and the balance Fe with impurities. This molten stainless steel is poured in a mold and rapidly cooled with an air cooling, etc., prior to the casting temp. becoming at less than 900°C. With this component configuration the strength and corrosion resistance of a product casting are improved and the formation of a carbide is prevented due to the rapid cooling from more than 900°C. Consequently, the corrosion fatigue strength and stiffness of a casting material are improved.