Abstract: A piston for an internal combustion engine is formed from a metal part cast in one piece. Heating of a billet is carried out so as to bring it to an intermediate temperature between its solidus temperature and its liquidus temperature, and shaping thereof by thixoforging is carried out.

Abstract: The invention relates to a steel for mechanical construction, wherein its composition in percentages by weight is: 0.35%?C?1.2%; 0.10%?Mn?2.0%; 0.10%?Si?3.0%; traces?Cr?4.5%; traces?Mo?2.0%; traces?Ni?4.5%; traces?V?0.5%; traces?Cu?3.5% with Cu?Ni %+0.6 Si % if Cu?0.5%; traces?P?0.200%, traces?Bi?0.200%, traces?Sn?0.150%, traces?As?0.100%, traces?Sb?0.150%, with 0.050%?P %+Bi %+Sn %+As %+Sb %?0.200%, 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.

Abstract: 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. The invention also relates to a method of hot-shaping a steel part, wherein a billet of steel of the preceding composition is obtained, it is heated to a temperature between the solidus and the liquidus so as to obtain a liquid phase and a globular solid phase, shaping of the said billet is carried out by thixoforging so as to obtain the said part, and cooling of the said part is carried out. Finally, the invention relates to a steel part thus obtained.

Abstract: The invention relates to a steel for mechanical construction, wherein its composition in percentages by weight is: 0.35%<C<1.2%; 0.10%<Mn<2.0%; 0.10%<Si<3.0%; traces<Cr<4.5%; traces<Mo<2.0%; traces<Ni<4.5%; traces<V<0.5%; traces<Cu<3.5% with Cu<Ni %+0.6 Si % if Cu>0.5%; traces<P<0.200%, traces<Bi<0.200%, traces<Sn<0.150%, traces<As<0.100%, traces<Sb<0.150%, with 0.050%<P %+Bi %+Sn %+As %+Sb %<0.200%, traces<Al<0.060%; traces<Ca<0.050%; traces<B<0.01%; traces<S<0.0200%; 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.

Abstract: 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.

Abstract: The invention relates to a method of manufacture of a piston for an internal combustion engine, the said piston being formed from a metal part cast in one piece, wherein heating of a billet is carried out so as to bring it to an intermediate temperature between its solidus temperature and its liquidus temperature, and that shaping thereof by thixoforging is carried out.

Abstract: A process for manufacturing a forged connecting rod of the type including a big end, a shank and a small end. A connecting rod rough forging, free of lateral flash and including at least one bore initiator on the big end and on the small end, is manufactured by forging. The connecting rod rough forging is sized, content-wise, by plating the connecting rod rough forging between two inserts inside a die in order to obtain a sized connecting rod rough forging.

Abstract: Steel useful for the manufacture of a separable mechanical component, whose chemical composition preferably comprises, by weight: 0.25%.ltoreq.C.ltoreq.0.75%, 0.2%.ltoreq.Si.ltoreq.1.5%, 0.1%.ltoreq.Mn.ltoreq.2%, 0%.ltoreq.Ni.ltoreq.1%, 0%.ltoreq.Cr.ltoreq.1%, 0%.ltoreq.Mo.ltoreq.1%, 0%.ltoreq.Cu.ltoreq.1%, 0%.ltoreq.V.ltoreq.0.2%, 0.02%.ltoreq.S.ltoreq.0.35%, 0.04%.ltoreq.P.ltoreq.0.2%, 0%.ltoreq.Al.ltoreq.0.005%, 0.005%.ltoreq.N.ltoreq.0.02%; optionally at least one element taken from lead, tellurium and selenium in contents of less than 0.1%, the balance being iron and impurities resulting from the smelting, the steel being optionally treated with calcium. Use of the steel for the manufacture of a separable component and component obtained.

Abstract: A process for reducing the coefficient of friction and the wear between a metal part and an organic polymer- or copolymer-based part, in an aqueous medium containing chlorides, characterized in that the organic polymer- or copolymer-based part is submitted to a surface treatment by ionic implantation of elements selected from nitrogen, argon, oxygen and carbon.