Purpose Of CNC Machining Black Oxidation Treatment
The black oxidation treatment (also known as blackening or blueing treatment) in CNC machining aims to improve the surface properties of CNC machined parts through chemical methods. The specific objectives are as follows:
Improving corrosion resistance:
Black oxidation treatment will form a dense oxide film on the surface of CNC machining parts, which is mainly composed of ferric oxide (Fe-O ₄) and can effectively isolate air and water, thereby significantly improving the corrosion resistance of the parts.
The formation of ferric oxide at high temperatures (about 550 ℃) is known as blueing treatment, as it turns sky blue; The formation of ferric oxide at low temperatures (about 350 ℃) is a dark black color, known as blackening treatment.
Enhanced wear resistance:
The surface of CNC machining parts treated with black oxidation will become harder, and this oxide film can reduce the wear of the metal surface and improve the wear resistance of the parts.
At high temperatures (141 ° C), this process leaves a layer of magnetite coating (Fe ₂ O æ) on CNC machining, which has high hardness and wear resistance.
Improving appearance:
Black oxidation treatment can make the surface of CNC machining parts appear uniform, matte black or dark gray, improving the appearance quality of the parts.
This black or dark gray surface can effectively reduce light reflection, reduce light pollution, and enhance the aesthetics of the parts.
Process temperature and coating type:
When subjected to oxidation treatment at high temperatures (130-145 ℃), a thick black oxide film will form on the surface of CNC machining parts, which is suitable for parts with high requirements for corrosion resistance and wear resistance.
When undergoing oxidation treatment at medium temperature (90-120 ℃), although the formed oxide film is relatively thin, it can effectively reduce the generation of corrosive gases and is suitable for scenarios with high environmental requirements.
Post processing and protection:
After black oxidation treatment, post-treatment steps such as oil coating, wax or paint are usually carried out to further enhance the corrosion resistance and glossiness of the surface of CNC machining parts.
Oil can make the surface shiny and enhance lubrication and corrosion resistance; Wax can make the surface darker but has higher lubrication and corrosion resistance; Paint can provide more long-lasting protection.
Widespread application:
The black oxidation treatment in CNC machining is widely used in mechanical manufacturing, aerospace, automotive manufacturing, electronics and other fields, especially suitable for parts with high requirements for rust prevention, corrosion resistance, and wear resistance.