Electroplating Process Of Bolts And Screws

Electroplating bolts and screws is a common surface treatment process, which can not only improve the surface brightness of bolts and screws but also improve their performance. Electroplating on the bolt surface can enhance corrosion resistance, but different types of electroplating can produce different corrosion resistance. If you need to know how corrosion-resistant it is, you can test its corrosion resistance through a salt spray test.

Electro galvanizing is the most commonly used surface treatment method for screw fasteners. It not only costs less but also the appearance of screw fasteners after frequent galvanizing treatment is more beautiful. It can be electroplated into the black and military green. However, there is one bad thing about galvanizing, that is, its anti-corrosion performance is general, and its anti-corrosion performance is the lowest in the electroplating (coating) layer. Screws after galvanizing can pass the neutral salt spray test within 72 hours, and the special sealer is used to make the salt spray test after galvanizing reach more than 200 hours, but its price is expensive, 5-8 times that of general galvanizing.

Cadmium electroplating for screw fasteners has very good resistance to corrosion, especially in the Marine atmosphere where it is Xeromorphous. However, the waste liquid treatment cost in the process of cadmium plating is large and the cost is high. Its price is about 15-20 times that of galvanizing. So it's not used in the general industry, it's only used in some specific environments.

The chrome coating of screw fasteners is stable in the atmosphere, not easy to discolor and lose luster, has high hardness, and good wear resistance. Chrome coating on fasteners is generally used as decoration, and rarely used in the industrial field with high anti-corrosion performance. Because good chrome plating fasteners are as expensive as stainless steel, only when stainless steel is not strong enough, are chrome plating fasteners used instead. In order to improve the corrosion resistance of chromium plating, copper and nickel should be plated before chromium plating. Chromium plating can withstand the high temperature of 1200 degrees Fahrenheit (650 degrees Celsius), but it also has the same problem of hydrogen emittance as electro galvanizing.

The silver coating of screw fasteners can not only prevent corrosion but also be used as a solid lubricant. For cost reasons, silver plating is generally used for nuts, not bolts, and sometimes for small bolts. Silver loses its luster in the air, but it can operate at 1600 degrees Fahrenheit. Therefore, people make use of its high-temperature resistance and lubrication characteristics for fasteners working at high temperatures to prevent the oxidation of bolts and nuts.

Nickel plating on bolts is mainly used in places where corrosion protection and good electrical conductivity are required. For example, the leading terminal of a vehicle battery.

The above is a detailed introduction to the surface treatment of fasteners. we hope it will be helpful to you. If you need to purchase bolts and screws, you need to choose the right type according to the actual use to avoid unnecessary losses caused by the wrong selection. If you want to learn more about fasteners, pls continue to focus on AYA FASTENERS.

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