What to Determine the Quality of Plated Fasteners?

The fastener plating takes the corrosion resistance performance as the main quality measure, followed by the appearance. The test of corrosion resistance performance is to imitate the work environment, make corrosion test on the plated fasteners. Some aspects will affect the well performance of plated fasteners like the stainless steel rivet nut, or steel rivet nut.

1. Appearance

The surface of a flat head nut is not allowed to have no-plating, burnt, rough, dark, skinning, crusting and obvious stripes, as well as pinhole pits, black slag, passivation film loose, cracked, fall-off, and passivation marks.

2. Coating thickness

The life of the rivet nut in a corrosive work condition is proportional to its coating thickness. Generally the plating thickness is 0.00015in ~ 0.0005 in (4 ~ 12um). Hot dip galvanization: standard average thickness is 54 um, the minimum thickness is 43 um./p>.

3. Coating distribution

Using different deposition methods, the formation of the coating on the rivet nut surface is also different. Plating metal is not evenly deposited on the outer edge, the corner is often thick coating. In the threaded part of the fastener, the thickest coating is on the top of tooth, gradually becoming thinner along the thread side, the thinnest part is at the bottom of the tooth. However, the hot dip galvanization is on the contrary, the thicker coating is deposited on the inner corner and the bottom of the thread. The mechanical plating of the coating metal deposition is the same as the hot dip plating, but the surface is more smooth and the thickness of the entire surface will be much more uniform.