Surface treatment of aluminum alloy castings

- Nov 08, 2018-

1. Sandblasting (shot spraying)

The process of cleaning and coarsening metal surface by impact of high speed sand flow.


  • Increase fatigue resistance and adhesion;

  • Prolong the durability of the coating;

  • Conducive to the flow of paint and decoration.

sand blasting

2. Anodization

The process of forming a layer of oxide film on an aluminum product (anode) due to the action of external current under corresponding electrolyte and specific process conditions. It is the most widely used and successful process at present.


  • Increase surface hardness;

  • Increase wear resistance;

  • Extend service life;

  • Enhanced aesthetics;


3. Polishing

The surface roughness of aluminum alloy die castings is reduced by mechanical, chemical or electrochemical methods to obtain the machining method of bright and smooth surface.


  • mechanical polishing, 

  • chemical polishing, 

  • electrochemical polishing.


  • mechanical polishing + electrolytic polishing, close to the stainless steel mirror effect (disadvantages - easy to leave fingerprints).


4. Wire drawing

Metal wiredrawing is the manufacturing process of scraping aluminum alloy die castings out of wires repeatedly with sandpaper.


  • straight stretch drawing, 

  • random stretch drawing, 

  • spiral drawing, 

  • thread drawing.


  • make the metal matte in a fine hair gloss, products both fashion and technological sense.

wire drawing(1)

5. High-light cutting

A fine engraving machine is used to cut parts to produce local highlights on the surface of aluminum alloy die castings.


  • Mainly used in mobile phone, TV metal frame, plus anodizing and wire-drawing process, which makes the whole product full of fashion sense and sharp sense of technology.

High-light cutting

6. Two-color anodization

Two-color anodization refers to the anodization of aluminum alloy die castings with different colors assigned to specific areas.


  • Complex process and high cost;

  • However, through the contrast between the two colors, it can better reflect the high-end and unique appearance of the product.

    Two-color anodization