Importance

Loading Importance Indicators...

Abstract

The invention concerns steel building components whereof the chemical composition comprises, by weight: 0.40 %=C=0.50%, 0.50%=Si=1.50%, 0%=Mn=3%, 0%=Ni=5%, 0%=Cr=4%, 0%=Cu=1%, 0%=Mo+W/2=1.5%, 0.0005%=B=0.010%, N=0.025 %, Al≤0.9%, Si+Al=2.0%, optionally at least one element selected among V, Nb, Ta, S and Ca, in contents less than 0.3%, and among Ti and Zr in contents not more than 0.5%, the rest being iron and impurities resulting from the preparation, the aluminium, boron, titanium and nitrogen contents, expressed in thousandths of %, of said composition further satisfying the following relationship: B=⅓×K+0.5, (1) with K=Min (1*; J*), I*=Max (0;1) and J*=Max(0;J), I=Min(N; N−0.29(Ti−5)), J=Min {N; 0.5 (N−0.52 Al+v(N−0.52 Al)²+283)}, and whereof the structure is bainitic, martensitic or martensitic/bainitic and additionally comprises 3 to 20% of residual austenite. The invention also concerns a method for making said components.

Loading the Abstract Image...

First Claim