| 摘要 |
PROBLEM TO BE SOLVED: To provide martensitic stainless steel grains which have hardness conforming to that of high-speed steel or cast steel, further, even when used as a fine-grained projection material in peening treatment, suppresses deterioration in corrosion resistance in the surface of the material to be projected, further has satisfactory toughness, and is hardly cracked. SOLUTION: As the composition of the martensitic stainless steel grains, the following conditions are satisfied: Fe is contained as the main component, and 0.35 to 0.8 mass% C and 8 to 20 mass% Cr are contained. Further, provided that the content of C is defined as WC (mass%), Cr as WCr (mass%), Mo as WMo (mass%), Si as WSi (mass%), Mn as WMn (mass%) and Ni as WNi (mass%), and M=538-317WC-33WMn-28WCr-17WNi-11WSi-11WMo, and P=WCr+3.3WMo are defined, the value of M is >=15, and also, the value of P is >=8. The above composition is adopted, and, by a gas atomizing method, the spherical martensitic stainless steel grains are obtained.
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