High-strength bolts

Bolts made of high-strength steel, or bolts that require a larger pre-tightening force, can be called high-strength bolts. High-strength bolts are mostly used for the connection of bridges, steel rails, high-pressure and ultra-high-pressure equipment. The fracture of this kind of bolt is mostly brittle fracture. High-strength bolts applied to ultra-high pressure equipment need to be pre-stressed in order to ensure the sealing of the container.

Process flow
The process flow of high-strength bolt nickel-phosphorus plating consists of three parts:
The first part is the pre-treatment process, including the precision and appearance inspection before high-strength bolt plating, manual degreasing, immersion degreasing, pickling, electro-activation and flash nickel plating;
The second part of the electroless nickel plating process;
The third part is the post-treatment process, including processes such as hydrogen flooding heat treatment, polishing and finished product inspection. as follows:
Bolt chemical composition inspection → bolt pre-plating precision and appearance inspection → manual degreasing → appearance inspection → soaking and degreasing → hot water washing → cold water washing → pickling → cold water washing → electric activation → cold water washing → flash nickel plating → cold water washing → remove Ion water washing → chemical nickel plating → deionized water washing → cold water washing → hydrogen flooding → polishing → finished product inspection.