Fasteners generally require surface treatment. The surface treatment of fasteners refers to the process of forming a covering layer on the surface of the fastener by certain methods, which can not only improve the corrosion resistance of the fastener itself, but also Makes the appearance of fasteners more beautified. Wanguan Hardware Machine Electric Co., Ltd. believes that there are mainly three common surface treatment methods for fasteners:

1. Mechanical plating of fasteners

The mechanical plating of fasteners refers to the use of specific physical and chemical means to impact the surface of the fastener with the powder of the coated metal, so that the coated metal forms a coating on the surface of the fastener through cold welding to reach the surface Treatment effect. The mechanical plating of fasteners is mainly applicable to spare parts such as screws, nuts and washers.

2. Electroplating of fasteners

Fastener electroplating refers to immersing the part of the fastener that needs to be electroplated into a specific aqueous solution. The aqueous solution will contain some deposited metal compounds, so that after the current passes through the aqueous solution, the metal substances in the solution will precipitate and adhere to On the immersed part of the fastener. Electroplating of fasteners generally includes zinc plating, copper, nickel, chromium, copper-nickel alloys, etc.

3. Hot dip galvanizing of fasteners

The hot-dip galvanizing of fasteners is to immerse the blow-molded abrasive fasteners of carbon steel composition into a molten zinc plating tank with a heat of about 510°C, so that the iron-zinc alloy on the surface of the fasteners will become blunt. Zinc to obtain the surface treatment effect. The price of hot-dip galvanizing of fasteners is higher than that of electroplating, about 1.5 to 2 yuan per kilogram.

Among them, electroplated fasteners occupies a large proportion in the actual use of fasteners. For threaded fasteners, not only a certain anti-corrosion ability is required in use, but also the interchangeability of threads must be guaranteed, that is, screw fit. In order to meet the dual-use performance of "anti-corrosion" and "interchangeability" required by threaded fasteners at the same time, it is necessary to formulate special plating standards.