Heat-resistant austenitic steel having high resistance to stress relaxation cracking
AssigneesArcelormittal Investigacion Y Desarrollo, S.L., Netherlands Org. for Applied Sci. Research (TNO), Centro Sviluppo Materiali S.p.A.
InventorsBernard Bonnefois, Amelie Fanica, Lionel Coudreuse, Tassa Oriana, Johannes Cornelis Van Wortel
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Abstract
An austenitic steel not susceptible to relaxation cracking, with composition comprising, in percentages by weight: 0.019% ≦C ≦0.030%, 0.5% ≦Mn ≦2%, 0.1% ≦Si ≦0.75%, Al >0.25%, 18% ≦Cr ≦25%, 12% ≦Ni ≦20%, 1.5% ≦Mo ≦3%, 0.001 % <B ≦0.008%, 0.25% ≦V ≦0.35%, 0.23% ≦N ≦0.27%, the balance being iron and unavoidable impurities wherein: Ni(eq.) ≧1.11 Cr(eq.) −8.24, wherein: Cr(eq)=Cr+Mo+1.5 Si+5V+3AI+0.02, Ni(eq)=Ni+30C+x(N−0.045)+0.87 wherein: x=30 for N≦0.2, x=22 for 0.2<N≦0.25, x=20 for 0.25<N≦0.35.
Claims5
An austenitic steel not susceptible to relaxation cracking, with composition comprising, in percentages by weight:
- 0.019% ≦C≦0.030%
- 0.5% ≦Mn ≦3%
- 0.1≦Si ≦0.75%
- AI ≦0.25%
- 18% ≦Cr ≦25%
- 12% ≦Ni ≦20%
- 1.5% ≦Mo ≦3%
- 0.001% ≦B ≦0.008%
- 0.25% ≦V ≦0.35%
- 0.23% ≦N ≦0.27%
- the balance being iron and unavoidable impurities, and wherein:
- Ni(eq.) ≧1.11 Cr(eq.) −8.24, wherein:
- Cr(eq)=Cr+Mo+1.5Si+5V+3AI+0.02
- Ni(eq)=Ni+30C+x(N−0.045)+0.87 wherein:
- x=22 for 0.23% ≦N≦0.25%
- x=20 for 0.25% <N≦0.27%
Dependencies are inferred from the claim text.