Difference between shot blasting and shot peening for metal surface treatment

Difference between shot blasting and shot peening for metal surface treatment:

Dalian metal surface treatment

The difference between shot blasting and shot blasting: shot blasting is driven by high-pressure wind or compressed air, while shot blasting is generally a high-speed rotating flywheel to throw steel sand at high speed. Shot blasting has high efficiency, but there will be dead corners, while shot blasting is flexible, but the power consumption is large. Although the spraying power and mode of the two processes are different, they are aimed at high-speed impact workpiece, and the effect is basically the same. Comparatively speaking, shot blasting is fine and easy to control precision, but the efficiency is not as high as shot blasting, which is suitable for small workpieces with complex shapes. Shot blasting is economical and practical, easy to control efficiency and cost. It can control the spraying effect by controlling the particle size of shot peening material, but there will be dead corners, so it is suitable for batch processing of single shape workpieces. The choice of the two processes mainly depends on the shape of the workpiece and the machining efficiency.

Difference between shot blasting and sand blasting: shot blasting and sand blasting are driven by high-pressure air or compressed air, which blow out at high speed to impact the workpiece surface to achieve cleaning effect, but the effect varies with different media. After sandblasting, 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 / coating. The surface of the workpiece after sandblasting is metal, but due to the rough surface, the light is refracted, there is no metallic luster and it is dark. After shot peening, the dirt on the workpiece surface is removed, the workpiece surface is slightly damaged and the surface area increases. Because the workpiece surface is not damaged during processing, the excess energy generated during processing will lead to the surface strengthening of the workpiece substrate. After shot peening, the surface of the workpiece is also metallic, but because the surface is spherical and the light is partially refracted, the workpiece is processed into matte effect.

Phosphating. Phosphating is the process of forming phosphate chemical conversion film by chemical and electrochemical reaction. The formed phosphate conversion film is called phosphating film. The main purpose of phosphating is to protect the base metal and prevent the metal from being corroded to a certain extent; Used for priming before coating to improve the adhesion and anti-corrosion ability of paint film; It is used for antifriction and lubrication in the process of metal cold working.

Passivation. The mechanism of passivation can be explained by thin film theory, that is, passivation is due to the interaction between metal and oxidation properties, resulting in a very thin, dense, good coverage and firmly adsorbed on the metal surface. The film exists as an independent phase, usually a compound of metal oxide. It can completely separate the metal from the corrosive medium, prevent the metal from contacting the corrosive medium and make the metal alkaline.