Making corrosion-protected, surface-hardened steel components, e.g. vehicle suspension springs or screws, ball-peens with metallic anti-corrosion agent causing mechanical surface-alloying

摘要

The component is given a metallic anti-corrosion layer based on zinc or zinc alloys. It is coated during the surface-hardening ball-peening stage. Coating results from mechanical action of the jet-blasted balls at the component surface. This causes mechanical alloying between the steel and the layer, at the boundary layer between them. The balls used, carry a surface layer or coating of the metallic anti-corrosion agent. Ball-peening takes place in the presence of particles of the metallic anti-corrosion agent. The jetted medium comprises coarser balls of steel, carbide and/or hard alloys, together with finer particles of the metallic corrosion protection agent. Steel or tungsten carbide balls are used. The mechanical anti-corrosion agent comprises metallic zinc, a zinc alloy, zinc/aluminum alloy and/or zinc/aluminum mixtures. The ratio of zinc to aluminum is 6 : 4 to 9.5 : 0.5. Organic auxiliary materials are added to the metallic anti-corrosion agent. These comprise thermoplastic polymers or thermally-hardening resins. To fire-on or stove the anti-corrosion layer after ball-peening, the component is heated to between 100[deg] C and 250[deg] C. After ball-peening or heating, the component is painted for stoving. The steel component treated, has been hardened and tempered. It is a spring, vehicle suspension spring or a screw.