Fasteners generally need to be surface treated. There are many types of fastener surface treatments. Electroplating, oxidation, phosphating, and non-electrolytic zinc coating treatments are commonly used. However, electroplated fasteners account for a large proportion of the actual use of fasteners. Especially in the automotive, tractor, home appliances, instrumentation, aerospace, communications and other industries and fields are more widely used. However, for threads

 

For fasteners, it is not only required to have a certain degree of corrosion resistance, but also to ensure the interchangeability of the threads, which can also be referred to herein as the screwing property. In order to meet the "preservative" and "interchangeable" dual-use properties required for the use of threaded fasteners, it is necessary to develop special plating standards.