High blackening efficiency, no acid mist, improved working environment, cost-effective, and does not require specialized equipment. Not only is it suitable for large-scale blackening treatment, but it is also suitable for blackening treatment of small batches and sporadic workpieces. In the process of blackening at room temperature, an important part is the pre cleaning of the workpiece. Before blackening, the workpiece must be cleaned with # degreaser #, otherwise it will affect the final blackening effect.
There are more methods for direct blackening of copper and copper alloys, including alkaline sulfide solution and cuprammonium salt solution. The former can obtain dark gray black on copper and copper alloys, while the latter can obtain pure black on brass. There are specialized blackening agents available on the market now, mainly acidic solutions containing copper and selenium salts.
The blackening time can be adjusted appropriately according to the actual situation. For example, as the amount of blackening increases, the effective ingredients of the blackening agent are constantly consumed, and the blackening speed gradually slows down. It is necessary to extend the blackening time appropriately. Also, the blackening time should be longer in winter and shorter in summer.
Dalian blackening surface treatment formula and process:
1. Formula: Sodium hydroxide, sodium nitrite, sodium phosphate, water.
2. Process: Heat the solution to 130-145 degrees Celsius, and then treat for about 50-80 minutes.
Blackening+oiling is a popular coating for industrial fasteners because it is cheap and looks good before fuel consumption. Due to its blackening, it has almost no rust prevention ability, so it will rust quickly without oil. Even in the presence of oil, the salt spray test can only last for 3-5 hours.
Blackening is a common method of chemical surface treatment, which involves producing an oxide film on the metal surface to isolate air and achieve rust prevention. When the appearance requirements are not high, blackening treatment can be used, and the surface of steel parts is blackened, also known as bluing.
