China Fasteners steel parts are blackened, and some are also called blue.
　　The principle is to quickly oxidize the surface of steel products to form a dense oxide film protective layer.
　　Blackening treatments are now commonly used by traditional alkaline heating blackening and later normal temperature blackening.
　　Normal temperature blackening process is mainly completed by the following process steps:
1) Cleaning; 2) Degreasing: the workpiece must be completely immersed in the degreasing solution; the concentration of the degreasing solution is 12-14, the processing time is 10-30min, and it shakes up and down several times every 3-5 minutes. Degreased powder; 3) Water washing; 4) Pickling: pickling solution concentration ph value 2-4, processing time 5-10min; 5) water washing; 6) blackening: pool liquid concentration ph value 2.5-3.5, processing time 10- 12min; 7) Wash with water; 8) Blow dry; 9) Grease.
　　Full Threaded Stud's blackening process has the following advantages: 1. Blackening is safe without electricity, and alkaline high temperature blackening requires 100% electricity. 2. Improve work efficiency: it takes 1-2 minutes in total. 3. The blackening cost is low, the equipment is simple, and the operation is convenient; the blackening time is strictly controlled. 4. Strong process adaptability: solved the problem that nodular cast iron can not blacken. Blackened for wear resistance and rust prevention.