First, to enhance appearance texture. Unplated nuts have a natural material surface, which is dull and has poor aesthetics. In contrast, electrogalvanized nuts have a smooth and bright surface. They can also be plated with different coating colors such as white zinc, blue-white zinc, and colored zinc according to requirements, adapting to various scenario needs.

Second, to improve rust resistance. Unplated nuts may rust after two to three months of use in humid environments. However, under conventional indoor dry conditions, electrogalvanized nuts can usually be used for more than five years without rusting, showing significant rust prevention effects.

Third, to facilitate installation and operation. Many people may not understand the connection between nut galvanization and installation. When installing most nuts, you need to manually screw on a few threads first, then tighten them with tools. If unplated, the nut surface may have residual oil stains that easily dirty hands; wearing gloves during operation will affect flexibility. In addition, the surface of unplated nuts may have processing burrs that could scratch hands. Therefore, installing unplated nuts is time-consuming and laborious, while electrogalvanized nuts can be directly screwed by hand, making the installation process convenient and efficient.

Standard Requirements for Electrogalvanized Nuts

Although electrogalvanizing of nuts is a conventional process, the threaded part after electroplating must pass go-no-go gauge inspection. Relevant technical requirements are implemented in accordance with GB/T 5267 "Fasteners - Electroplated Coatings". This standard specifies the thickness range of the zinc coating and corrosion resistance requirements.

Since nuts have internal thread structures, to avoid ineffective zinc plating in the thread grooves, the upper limit of the zinc coating thickness is usually controlled at around 15 microns (local thickness not less than 5 microns). In contrast, the standard thickness of the electrogalvanized layer for bolts is approximately 7-10 microns. The higher upper limit for nuts is to ensure uniform zinc coating coverage across the entire internal thread.

In actual inspection, there may occasionally be cases where electrogalvanized nuts are difficult to pass the go gauge. If the deviation is within the allowable range of GB/T 5267 and does not affect normal matching with corresponding bolts, it can be accepted through negotiation. This is not a product quality issue but a normal phenomenon caused by zinc layer accumulation in the internal threads, not a quality defect.

Measuring the zinc coating thickness of nuts is very simple. Early methods such as the drop test and timed flow test have been gradually phased out. Nowadays, you only need to use a handheld coating thickness gauge, place the probe close to the nut surface, and quickly read accurate zinc coating thickness data.

Currently, the processing cost of electrogalvanizing has increased slightly. From the industry trend, this upward trend may continue for a period of time. Electrogalvanized nuts are available in a wide range of specifications. Fan'ao Company provides spot supply of electrogalvanized nuts starting from M2, with a large inventory up to M64. Among them, the M2 specification has few application scenarios, and most users' procurement demand is concentrated on specifications M3 and above.