How to perform phosphating treatment on the gearbox frame

The following is the conventional process flow and key steps for phosphating treatment of gearbox frame:

1. Surface pretreatment

Degreasing: Remove animal and vegetable oils, mineral oils, etc. from the surface of the rack. Usually, degreasing agents are used and treated at a temperature of around 60 ℃ for about 10 minutes.

Water washing: Clean with industrial tap water to remove residual degreasing agents on the surface.

Acid washing (rust removal): Treat with hydrochloric acid or other acid solution at room temperature for about 10 minutes to remove heavy rust and burrs, making the metal surface appear silver white.

Washing: Rinse again with clean water to maintain overflow and remove residual acid.

2. Surface adjustment activation (surface adjustment)

Use a gauge to adjust and process at room temperature for 1-3 minutes. This step can refine the grain size and prevent the coarsening of the phosphating film caused by strong alkali and acid treatment.

3. Phosphating film formation

Immerse the rack in phosphating solution. For the gearbox frame, the medium temperature black phosphating process (temperature controlled at 65-75 ℃) is usually used, with a processing time of 7-15 minutes.

For workpieces with large dynamic clearance (such as gearbox gears and machine frames), the unit area mass of the phosphating film is generally required to reach 5-20 g/m ² to provide good anti friction lubrication.

4. Phosphating post-treatment

Water washing and dehydration: After phosphating, water washing and hot water washing are required, followed by dehydration treatment.

Oil immersion/sealing protection: The phosphating film itself has a microporous structure, and the final step usually requires coating with anti rust oil, anti rust grease, or sealing protection treatment. This can improve the rust prevention performance of the workpiece several times or even dozens of times.