Characteristics Of Powder Sherardizing Process

①The coating thickness has good uniformity and can be accurately controlled. The thickness of the coating depends only on the process, and has nothing to do with the shape and different positions of the fasteners. For shape and complex fasteners such as internal thread, blind hole, inner wall or groove, etc., through the control specification, the layer can be changed between 20 and 110 μm, and the thickness is almost the same.

②The coating has high hardness, strong abrasion resistance and scratch resistance. The microhardness of powder zinc-coated zinc-iron alloy is generally 220～420HV0.2, which is the hardest zinc coating at present.

③The bonding strength between the coating and the base metal is high. The sherardizing coating is a diffusion zinc-iron alloy, the coating is difficult to peel off, and can only be removed by chemical methods. The tensile strength of the interface between the coating and the base material is 600-700MPa; the tensile strength of the surface layer is 300-350MPa.

④The coating has strong corrosion resistance. In particular, it is suitable for various environments such as marine atmosphere and harsh industrial atmosphere, and its corrosion resistance is better than hot-dip galvanizing and electro-galvanizing. It can resist high temperature oxidation corrosion less than 1000℃.

⑤ Good coating performance. The sherardizing coating has good adhesion strength with various paints and polymer coating materials.

⑥The sherardizing coating does not have the hazard of hydrogen embrittlement of the original wood. The processing temperature is low and does not affect the mechanical properties of fastener components. The powder sherardizing temperature is 320～500℃, which will not affect the mechanical properties of high-strength fasteners. In addition, the sherardizing technology is a green and clean technology, with a price of powder sherardizing, and there is no "three wastes" emissions during the production process, which saves raw materials.