Hex Nut Wholesaler introduced that high-strength hexagon socket bolts are generally treated before they leave the factory. The bluing process is one of them. The so-called bluing treatment is to blacken the surface of the bolt.
The more commonly used methods now are: the traditional alkaline blackening and room temperature blackening, and the normal temperature blackening method is not good for the treatment of low-carbon steel. As for the bolts produced with A3 steel materials, alkaline blackening is generally used: That is, blackened once and blackened twice.
During the blackening process, the blackening liquid must be prepared first, and its main components are sodium hydroxide and sodium nitrite. In practice, it is necessary to pay attention to the degreasing and rust removal work before the bolts become black, so that the passivation and oil immersion can be carried out after the detonation. These processes have a lot to do with the quality of the blackening treatment.
The most commonly used method is alkaline oxidation or acid oxidation to form an oxide film on the surface of the metal to avoid corrosion of the metal surface. This treatment method is called "bluing".
After the "bluish" treatment, an oxide film will be formed on the black metal surface. The inner layer is ferrous oxide and the outer layer is ferroferric oxide.
When using alkaline oxidation "blueing" chemical solution, you must first clean the appearance of the bolts. During the treatment, analyze whether the chemical composition meets the requirements at intervals of one week. "After the blueing treatment, rinse with water.
When using acidic oxidation method to "bluish" the liquid, pay attention to the working temperature of "bluish" should be 100%, and the treatment time should be 45 minutes to 45 minutes.
Through the above introduction, Hex Head Bolts Manufacturers hopes that you can simply refer to the content of this article in future use.