Surface treatment of high strength blackened bolt

As the name implies, the surface of high-strength blackened bolt is blackened, and its strength is relatively high, which can reach 8.8 level. It is widely used, especially in machinery, bridge, power facilities, petrochemical and other industries.

The principle of high-strength blackened bolt processing is to produce a layer of oxide film on the bolt surface, which can play the role of air insulation, avoid bolt rust corrosion, and improve the wear resistance of the product.

For those cases where the appearance requirements are not too high, the surface is generally blackened or some are called bluing. Although the product surface has changed, the internal structure of the product will not change.

How to blacken the high-strength blackened bolt? In fact, the blackening process is to heat the product by acid pickling and degreasing, so that a layer of black or blue oxide film will be formed on the surface of the bolt. It should be noted that the heating temperature should not be too high to avoid deformation of the bolt.