What is a shot blasting machine

Shot blasting machine is a surface treatment equipment that removes rust and oxide layer on the surface of the workpiece. Making use of high-speed rotating impellers (blast turbines) under the role of centrifugal force to throw steel shot/ steel grits to hit the surface of the parts at high speed, eliminate the stress and increase the hardness of the workpiece, to achieve the purpose of rust removal. Generally speaking, shot blasting equipment is suitable for the workpiece with regular shape, blast wheels are arranged in all directions of the shot blasting chamber according to the size and character of the material object which achieves steel shot completely cover the parts.

Application field of Shot Blasting Machine

Shot / abrasive blasting machine is used in the automobile industry, casting/forging industry, steel/steel structure industry, rail transportation industry, etc.

Usually, almost all iron-containing workpieces need shot blasting, such as casting parts, sheet metal welding parts, steel plates, steel structural parts, hardware, electroplated parts, etc. That is not only to remove the rust and oxide scale on the surface of the object items but also to improve the indispensable preparation process before the quality inspection. The surface treatment of the workpiece will clean up the oxide scale and rust on the surface, and form a rough surface on the steel surface, eliminate internal stress and increase the adhesion of the paint, which greatly increases the service life. The surface treatment of non-ferrous metal castings, such as aluminum alloys, copper alloys, zinc alloys, etc., in addition to removing oxide scales and eliminating surface defects of the castings, the main purpose is to increase the quality of the coating surface after the shot blasting the metal workpiece. According to modern metal strength theory, increasing the dislocation density inside the metal is the main direction to improve the strength of the metal. The practice has proved that blasting is an effective method to increase the metal dislocation microstructure. This is of great significance for some metals that cannot be hardened by phase transformation (such as martensite quenching, etc.) or need to be further strengthened on the basis of transformation hardening. The components and parts of aviation, aerospace industry, automobiles, agricultural machinery, and others required lighter weight, but the requirements for reliability increasing. An important technological measure is to use a shot blasting machine to improve the strength and fatigue strength of components. Also, it's important to choose a reliable shot blasting equipment manufacturer to buy the equipment.

Constituent Part of Shot Blasting Machine

Shot blasting equipment is mainly composed of 5 parts:

① Blast turbine ( blast wheel)

Including motor, blast turbine shell, wear-resistant parts, feed pipe, and safety device, is the core component of shot blasting equipment.

② Abrasive collection, separation, and transport system

Including screw conveyor, bucket elevator, separator (air wash cleaning system), abrasive cleaning up system, and abrasive control system.

③ Workpiece transport system

Different types of shot blasting machines have different types of workpiece conveying devices. Such as roller conveyor, mesh belt, rubber belt, hook system, overhead rail system, etc....

④ Dust collection system

Including cartridge filter dust collector and baghouse filter dust collector.

⑤ Electric control system

Shot Blasting Machine Working Principle

Take roller conveyor shot blasting machine as an example to explain the shot blasting machine working principle: through type shot blasting machine is mainly used for stress relief and surface rust removal of steel plates, I-beams, H-beams, steel pipe, and steel structural parts with higher dimensions. During the working process of the shot blasting machine, the electrically controlled speed-adjustable roller conveyor conveys the object items into the shot blasting chamber, and its surfaces are hit and rubbed by powerful and dense steel shots from different coordinate directions. The oxide scale, rust layer, and dirt on the surface quickly fall off, and the steel surface obtains a certain smooth surface and hardness, which improves the adhesion of the film and the steel, the internal quality of the steel, and prolongs its service life.

Used blasting media and contaminants (pill dust mixture) falling on the steel surface are blown by the brush to the screw conveyor, and then into the vertical and horizontal screw conveyors, then reclaim into the bucket elevator and then into the air wash cleaner system, the cleaned abrasive get into the storage hopper to recycle, the residual will get out of the recycling system from the air wash cleaner system. The dust is collected to the dust collector system by the exhaust pipe, the purified air is discharged into the atmosphere, and the particulate dust is captured and collected in the dust collector, and then discharged into the atmosphere is clean and pollution-free air.

Operating Conditions of Shot Blasting

1. Unevenness of working face <20 mm; No water and relatively dry; Slope<25 °.

2. Ambient temperature: -20℃ ~ 60℃;

The surface temperature of steel plate is more than 3℃ higher than the dew point.

3. Humidity:

① steel surface shot blasting relative humidity is not more than 90%.

② the relative humidity of concrete shot blasting is not more than 95%.

4. Altitude: 0 ~ 3000m; Do not operate in rain or snow weather.

Derusting Grade of Shot Blasting

The derusting grade of shot blasting machine is divided into four grades, which are expressed by "SA".

Sa1: Mild shot blasting descaling.

No grease, dirt on the steel surface, without loose oxide scale, rust, and paint coating.

Sa2: Thorough shot blasting descaling.

No grease, dirt on the steel surface, oxide scale, rust, and others have been basically removed, the surface of the steel has blasting dents formed after shot blasting, and the anti-slip coefficient reaches 0.35～0.45.

Sa2.5: Very thorough shot blasting descaling.

No visible grease, dirt, oxide scale, rust, and paint coating on the surface of the steel, and any remaining traces should only be light spots or strips. The surface of the steel has blasting dents formed after shot blasting, and the anti-slip coefficient reaches 0.45～0.5.

Sa3: Clean shot blasting descaling.

No visible grease, dirt, oxide scale, rust and paint on the surface of the steel, and the surface show a uniform metallic luster.

Work Efficiency of Shot Blasting Machinery

Take steel plate shot blasting machine for example:

Blasted steel plate: steel plate quality grade SA2.5 to SA3

speed: SA2,5 about 3-4 m/min.

Speed: SA3 about 2-3 m/min.

Processing area per hour: SA2.5, about 75-100 m2 / h