Garnet sand blasting and shot blasting are common methods for metal surface pretreatment. What are the characteristics of both? Today we will compare the garnet sand blasting and shot blasting pretreatment.
1. Materials and equipment used
The garnet sand blasting is to use the sandblasting machine to hit the high-speed and multi rhombic garnet abrasive to the surface of the workpiece, and form a certain roughness, so as to improve the tension of the substrate surface and increase its surface area. It is also conducive to the better combination of the subsequent coating and the workpiece, and prolongs the service life of the coating.
The principle of shot blasting is to use the motor to drive the impeller body to rotate (directly or with V-belt drive). Under the action of centrifugal force, shot with a diameter of about 0.2~3.0 (including cast steel shot, steel wire cut shot, stainless steel shot and other different types) will be thrown to the surface of the workpiece, so that the surface of the workpiece can reach a certain roughness, making the workpiece beautiful, or changing the welding tensile stress of the workpiece to compressive stress, so as to improve the service life of the workpiece. By improving the roughness of the workpiece surface, the adhesion of the paint film for subsequent painting of the workpiece is also improved.
The purpose of both is to build a certain roughness, improve the physical properties of the workpiece, and provide a better basis for subsequent coating.
2. Effect comparison after treatment
After the garnet sand blasting treatment, the dirt on the workpiece surface is removed, the workpiece surface is slightly damaged, and the surface area is greatly increased, thus increasing the bonding strength between the workpiece and the coating/plating layer. And the surface of the workpiece can restore the metal color. The most important thing is that the garnet sand can go deep into all corners to completely remove dirt. It is applicable to a wider range of metals.
After shot peening, the dirt on the surface of the workpiece is removed, and the surface of the workpiece is slightly but not damaged, and the surface area is increased. Since the workpiece surface is not damaged during processing, the excess energy generated during processing will lead to the surface strengthening of the workpiece substrate. However, shot peening will have dead corners, so it is suitable for batch processing of workpieces with single shape and surface.
