What are the influencing factors of sandblasting on metal surface properties

Sandblasting coarsening is one of the important links in thermal spraying technology. Coarsening affects the bonding strength of coating and substrate to some extent. In the practical application of the factory, the matrix is usually roughened by dynamic sandblasting equipment.

The change of sandblasting gas pressure has a great influence on the internal stress on the surface of the matrix. The use of high pressure gas sandblasting on the surface of thin plate and long piece often causes the distortion of the workpiece, and the surface of soft matrix (such as aluminum, zinc, babbitt alloy, etc.) will be inlaid with abrasive blasting. In addition, with the increase of the gas pressure, the surface activity of the matrix is enhanced, the surface roughness value is increased, and the blasting efficiency is improved. Steel, stainless steel, alloy steel workpiece, gas pressure value should be ≥ 0.5Mpa. For soft matrix workpieces, the gas pressure value should be less than 0.3MPa.

The change of sandblasting distance will affect the sandblasting efficiency, followed by the impact on the metal surface roughness. Generally, the metal surface hardness is greater than 45HRC, the sandblasting distance is 100mm~150mmm, the matrix surface hardness is between 25HRC~45HRC, the sandblasting distance is 150mm~200mm, and the soft matrix surface hardness is less than 150HB. The sand blasting distance is 250mm~300mm.

The change of sandblasting Angle mainly affects the roughness of the metal surface. When the sandblasting Angle changes from 30° to 75°, the roughness increases with the increase of the sandblasting Angle, but the sandblasting Angle is 70° to 80°.

The change of sandblasting time has a great influence on the degree of metal surface activation. Generally, the surface activity increases with the increase of the fixed sandblasting time of the workpiece, but the surface activity basically reaches saturation when the sandblasting time reaches about 20S. Generally, the surface roughness of the substrate reaches Sa3 level, and the blowing time is about 5S~10S.