Martensitic stainless steel composition, method for making a mechanical part from said steel and resulting part

摘要

The invention concerns martensitic stainless steel, characterized in that its composition in weight percentages is as follows: 9%=Cr=13%; 1.5%=Mo=3%; 8%=Ni=14%; 1%=Al=2%; 0.5%=Ti=1.5% with AI+Ti=2.25%; traces=Co=2%; traces=W=1% with Mo+(W/2)=3%; traces=P=0.02%; traces=S=0.0050%; traces=N=0.0060%; traces=C=0.025%; traces=Cu=0.5%; traces=Mn=3%; traces=Si=0.25%; traces=O=0.0050%; and is such that: Ms (° C.)=1302 42 Cr 63 Ni 30 Mo+20AI-15W-33Mn-28Si-30Cu-13Co+10 Ti=50Cr eq/Ni eq=1.05 with Cr eq (%)=Cr+2Si+Mo+1.5 Ti+5.5 AI+0.6W Ni eq (%)=2Ni+0.5 Mn+3O C+25 N+Co+0.3 Cu. The invention also concerns a method for making a mechanical part using said steel, and the resulting part.