How are fasteners generally surface treated?

Fasteners generally require surface treatment, fastener surface treatment of many types, generally commonly used electroplating, oxidation, phosphating, non-electrolytic zinc flake coating treatment, etc.. However, electroplated fasteners occupy a large proportion in 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 threaded fasteners, not only is a certain degree of corrosion resistance required in use, but also the interchangeability of threads must be ensured, which can also be called spinability in this case. In order to meet both the "corrosion protection" and "interchangeability" requirements of threaded fasteners, it is necessary to establish a special plating standard.