Patent ID: 6994758

Claim:
A method of hot-shaping a steel part, which comprises obtaining a billet of steel with the following composition: 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% optionally: traces≦P %≦0.200%, traces≦Bi≦0.200%, traces≦Sn≦0.200%, traces≦As≦0.200%, traces≦Sb≦0.200%, with P %+Bi %+Sn %+As %+Sb %≦0.200%, the remainder being iron and impurities resulting from the manufacture; heating the billet to an intermediate temperature between its solidus temperature and its liguidus temperature under conditions such that the solid fraction of the billet has a globular structure; thixoforging the billet so as to obtain the said part; and cooling the said part.