What are the surface treatments of thread inserts?

Thread insert surface treatment refers to the process of forming a covering layer on the surface of the workpiece through a certain method. After surface treatment, thread inserts can present a more beautiful appearance, and the corrosion resistance of the thread insert itself will also be improved. The more important purpose is to make the thread insert itself anti-corrosion, so as to increase the reliability and adaptability of the fastener. Electroplating, hot-dip galvanizing, and mechanical plating are the three most commonly used methods for surface treatment of thread inserts.

1. Electroplating
The electroplating of thread inserts refers to immersing the parts of the thread inserts that need to be plated into a specific aqueous solution. The aqueous solution will contain some deposited metal compounds. In this way, after the current passes through the aqueous solution, the metal substances in the solution precipitate and adhere to the thread inserts. on the immersed portion of the firmware. The electroplating of fasteners generally includes zinc plating, copper, nickel, chromium, copper-nickel alloy, etc. Sometimes boiling black (blue), phosphating, etc. are also included.

2. Hot dip galvanizing
Hot-dip galvanizing of fasteners is to immerse carbon steel thread inserts into a molten zinc plating bath with a temperature of about 510°C, so that the iron-zinc alloy on the surface of the fastener will be converted into passivated zinc. To obtain surface treatment effect (similar to hot dip aluminum plating)

3. Mechanical plating
Mechanical plating of thread inserts refers to using specific physical and chemical means to impact the surface of the thread inserts with coated metal powder, so that the coated metal forms a coating on the surface of the fastener through cold welding to achieve Surface treatment effect. Mechanical plating of fasteners is mainly suitable for spare parts such as screws, nuts and washers.

To judge the quality of thread insert surface treatment, it is mainly to check whether the anti-corrosion ability of the thread insert is effectively increased and whether the increase meets the expected requirements. The inspection method is to simulate the working environment of the product, set test conditions, and perform corrosion tests on it. The second step is to check the appearance.