The surface treatment of fasteners is a process that forms a protective coating on the surface of the workpiece to enhance its corrosion resistance, aesthetics, and functionality. The main methods include electroplating, hot-dip galvanizing, mechanical plating, phosphating, and Dacromet coating, etc. Electroplating deposits metal coatings (such as zinc and nickel) through electrolysis, which is cost-effective and widely used, but the coating thickness (4-12 micrometers) needs to be controlled and the risk of hydrogen embrittlement eliminated; hot-dip galvanizing forms a protective layer in a molten zinc bath, the coating is uniform and has a long lifespan, and is mostly used in power facilities; mechanical plating avoids hydrogen embrittlement through cold welding and is suitable for high-strength fasteners.
The development of this process focuses on standardization and quality control. China has formulated standards such as GB/T 5267.1-2002 and GB/T 3099.3-2017 based on international standards, clearly defining the classification of coatings, detection indicators, and process flows. Process improvements focus on hydrogen embrittlement prevention (such as baking after plating) and the optimization of coating uniformity, promoting the application of new technologies such as mechanical plating and non-electrolytic zinc sheet coating. The technological iterations of hot-dip galvanizing and electroplating further adapt to the performance requirements of fasteners in industries such as automobiles and aviation.
Post time: 2025-11-26 17:40:29
