| 摘要 |
The present invention relates to the production of metal parts whose core and surface must have different characteristics. Its subject comprises firstly a process for the production of a composite metal part by coating or hard-surfacing a metal core of low-alloy structural steel with a harder metal layer composed of a high-speed chromium-tungsten or chromium-molybdenum steel or a high-speed steel containing chromium associated at the same time with a plurality of elements such as tungsten, molybdenum, vanadium, and cobalt, this process being at the same time characterized in that this high-speed steel has a hardness higher than 57 Rockwell C, in that the low-alloy steel which constitutes the metal core is selected to be compatible with the said high-speed steel, in that the said high-speed steel is applied exclusively in the form of a prealloyed powder, and in that the coating or hard-surfacing of the core with this powder is effected with the aid of one of the welding processes of the follow-group: welding by means of a transferred or semi-transferred arc plasma torch, or welding by means of a laser torch, the operation of coating or hard-surfacing by welding being followed by heat treatment. Another subject of the invention comprises the products obtained by the abovedescribed process. It is particularly applicable to the production of rolls for cold rolling mills, rolling or forming rollers, shear blades, wear plates, and armor plates. |
