Steel for mechanical construction, method of hot-shaping of a part from this steel, and part thus obtained

摘要

The invention relates to a steel for mechanical construction, wherein its composition in percentages by weight is: 0.35%<=C<=2.5%; 0.10%<=Mn<=2.5%; 0.60%<=Si<=3.0%; traces<=Cr<=4.5%; traces<=Mo<=2.0%; traces<=Ni<=4.5%; traces<=V<=0.5%; traces<=Cu<=4% with Cu<=Ni %+0.6 Si % if Cu>=0.5%; traces<=Al<=0.060%; traces<=Ca<=0.050%; traces<=B<=0.01%; traces<=S<=0.200%; traces<=Te<=0.020%; traces<=Se<=0.040%; traces<=Pb<=0.070%; traces<=Nb<=0.050%; traces<=Ti<=0.050%; the remainder being iron and impurities resulting from the manufacture.