Various composition powders are duly mixed, and the cold-pressed in hard press-forging dies, in order to obtain the required shape and size. The obtained metal parts are sintered in controlled atmosphere special furnaces allowing the powder sparkers to get soldered without melting, and thus obtaining a single-body structure. If tolerance limits are very narrow, calibration must be performed by an additional compression operation. By a vacuum process, the porosity of the sintered parts can be satured with oil. By the same system, metal parts are protected from corrosion. The obtained parts can be protected with galvanic, steam-oxidized and heat-treaded coatings and can also be worked with machine tools.