Comparison of sand blasting and shot blasting in Dalian

The research shows that in terms of damage, when there is tensile stress on the surface of metal materials, it is much easier than compressive stress. When there is compressive stress on the surface, the fatigue life of materials is greatly improved. Therefore, for parts prone to fatigue fracture such as shafts, shot peening is usually used to form surface compressive stress to improve the service life of products. In addition, metal materials are very sensitive to tension, which is why the tensile strength of materials is much lower than the compressive strength, This is also the reason why metal materials generally use tensile strength (yield, tensile) to represent material properties.

The principle of shot blasting is to use the motor to drive the impeller body to rotate (directly or driven by V-belt), and by the action of centrifugal force, throw the projectile with diameter of about 0.2 ~ 3.0 (including cast steel shot, steel wire cutting shot, stainless steel shot and other types) to the surface of the workpiece, so as to make the surface of the workpiece reach a certain roughness, make the workpiece beautiful, or change the welding tensile stress of the workpiece to compressive stress, so as to improve the service life of the workpiece. By improving the surface roughness of the workpiece, the paint film adhesion of the subsequent painting of the workpiece is also improved. The implication is that shot blasting can be the previous process of painting process.

Comparison of sand blasting and shot blasting in Dalian

Although the two processes have different spraying power and methods, they both aim to impact the workpiece at high speed, and their effects are basically the same. In comparison, shot blasting is more fine and easy to control the accuracy, but the efficiency is not as high as shot blasting. It is suitable for small workpieces with complex shapes. Shot blasting is more economical and practical, easy to control the efficiency and cost, and can control the particle size of shot to control the spraying effect, but there will be dead corners, It is suitable for batch processing of workpieces with single shape and surface.

The shot blasting time depends on the shot blasting effect of the workpiece in the shot blasting process. The principle is to achieve the required shot blasting strength. (usually about 30 minutes) in addition, it should be noted that the shot blasting intensity is mostly measured by Almen's arc altimeter described in SAE standard j442. Almen altimeter uses 70 carbon steel with standard size of 0.8, 1.3 or 2.4mm thick and its hardness is hrc44 ~ 50. Fix the sample on a special fixture, conduct shot blasting on one side, and then measure the arc height of the bent steel bar sample with altimeter to obtain the shot blasting strength.

Shot blasting is a processing technology that acts on the metal surface, similar to sand blasting and shot blasting. By throwing spherical projectile particles onto the surface of metal workpiece, the surface roughness of workpiece is changed by strong impact force, which also improves the paint film adhesion of subsequent painting of workpiece, so as to improve the mechanical properties of workpiece.