Ascometal

Gilles Pierson

Jacques Bellus

Claude Pichard

Steel for the manufacture of forgings having a bainitic structure and the mechanical properties of which are: R.sub.p0.2 .gtoreq.800 MPa, R.sub.m .gtoreq.1000 MPa, K.sub.cu .gtoreq.50 J/cm.sup.2 its chemical composition comprising, by weight: 0.05%.ltoreq.C.ltoreq.0.12%, 0.1%.ltoreq.Si.ltoreq.0.45%, 1.01%.ltoreq.Mn.ltoreq.1.8%, 0.15%.ltoreq.Cr .ltoreq.1.15%, 0.06%.ltoreq.Mo.ltoreq.0.12%, Cu.ltoreq.0.30%, Ni.ltoreq.0.30%, 0.01%.ltoreq.Ti.ltoreq.0.04%, 0.005%.ltoreq.Al.ltoreq.0.04%, 0.006%.ltoreq.N.ltoreq.0.013%, 0.0005% 5 B.ltoreq.0.004%, P.ltoreq.0.025%, 0.02%.ltoreq.S.ltoreq.0.1%, 0%.ltoreq.Pb.ltoreq.0.1%, 0%.ltoreq.Te.ltoreq.0.07%, optionally from 0.0002% to 0.002% of calcium, the balance being iron and impurities resulting from the smelting, the chemical composition furthermore satisfying the relationship: 0.2% .ltoreq.Ni+Mo+Cu.ltoreq.0.7%, the uncombined boron content not being less than 0.0005% above 950.degree. C. Process for the manufacture of a forging.

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Villers La Montagne, France

Gilles Pierson