Method for producing a hollow part made of a metal material and use of this method for producing a landing gear rod or beam

A method for producing a hollow part made of a metal material having given yield stresses at given temperatures, the method comprising:

• preparing a blank having two ends, made up of the metal material of the hollow part, and a sacrificial mandrel made of a material that, at all temperatures at which the various simultaneous deformations of the blank and the sacrificial mandrel, will take place, has a yield stress in the range at the temperatures between the yield stress of the material of the blank minus 30% and the yield stress of the material of the blank plus 20% at the temperatures;
• applying a punch on one of the ends of the blank in order to produce an expansion of at least a portion of the blank and to create an internal space inside the blank without any material removal, the expansion of at least the portion of the blank including radially expanding an outer surface of the blank;
• inserting the sacrificial mandrel in the internal space of the blank;
• then
• crimping the sacrificial mandrel in the blank;
• producing, by co-forging, a simultaneous deformation of the blank and the sacrificial mandrel, with a homothetic ratio (K);
• and
• performing a machining in order to remove the sacrificial mandrel and impart a final configuration to the internal space of the part.