Wuxi IDEAL Machinery Manufacturing Co., Ltd. will talk with you in detail about the rust removal requirements of Wuxi shot blasting machine and the reasons for peeling.

The common method of sand blasting or shot blasting derusting for surface knowledge of Wuxi shot blasting machine is to use compressed air to spray sand with a certain grain size on the rusted surface of the part through the spray gun. It can not only remove rust quickly, but also prepare the surface for painting, spraying, electroplating and other processes. The surface treated by sand blasting can reach a clean surface with a certain roughness, and then improve the binding force of the covering layer and the part.

Commonly used sand blasting methods include dry sand blasting, wet sand blasting, dust-free sand blasting and high-pressure water sand blasting.

The dry sand blasting has large dust, which hinders environmental protection and damages health; Although there is no dust in the wet process, water will rust the surface again. The way to prevent it is to add 1% - 15% antirust agent (trisodium phosphate, sodium carbonate, sodium nitrite, etc.) and emulsifier or soapy water in the water to make its surface not rust in a short period of time, and then apply curing primer.

Dust-free sand blasting is the continuous circulation of sand adding, sand blasting and sand collection recovery in a closed system to avoid dust flying.

High-pressure water sandblasting is mainly used for large-scale derusting, such as hull, oil tank, oil tank, boiler, etc. The water is also often involved in passivating agent and soapy water.

Shot blasting or sand blasting:

1. Rust removal quality grade request:

① All steel surfaces to be coated with water-based inorganic zinc-rich coating need to be shot blasted or sandblasted to reach the Sa2.5 level of ISO8501-1 (GB8923-88).

② When repairing the coating locally, it is necessary to polish the steel surface to ISO8501-1 (GB8923-88) St3.

2. Surface roughness request: the surface roughness request shall be controlled within 35~65 μ M range.

3. Abrasive:

① In order to ensure that the steel surface reaches the regular cleanliness and surface roughness after shot blasting or noise blasting, it is recommended to use the stainless steel sand with the particle size of 0.3-0.8mm in the shape of corner or bead.

② The abrasive used shall be dry to clean and shall not be contaminated by organic matter.

4. Compressed air: compressed air for sand blasting, the pressure shall not be less than 0.5MPa.

Features: After shot peening, the surface of the casting will show a thin layer of skin that will rise or even fall off. It can be easily removed by hand, and the size, area and orientation are not fixed. This phenomenon is called peeling after shot blasting.

Cause:

1. The casting is not compacted, and the surface has casting defects such as cold shut, delamination, bubbles and poor alloy flow fusion.

2. The steel shot blasting speed is too high.

3. Shot peening time is too long.

4. The method of hanging parts is unreasonable, unstable, and collides with each other.

5. The shape and quality of steel shot are poor and not smooth.

6. The steel shot contains sharp magazines.

Cleaning method:

1. The casting surface is dark. Adjust the die casting process parameters or equipment parameters of Wuxi shot blasting machine.

2. Properly reduce the shot peening speed of the shot peening machine.

3. Properly reduce the shot peening time.

4. Use a reasonable hanger to ensure that the casting is fixed during the shot peening process. If necessary, use a special fixture.

5. Purchase steel shot with regular shape.

6. Select or replace steel shot.

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