Types of Shot Blasting Abrasive – How to Choose Shot (Bead) Blasting Media


A blasting machine can utilize various materials to clean and polish metal surfaces, which divides into different processes. In this article, we are going to present types of shot (bead) blasting media and how to select them.

What is Shot Blasting?

Shot blasting is a surface finishing process that involves the utilization of a centrifugal blast wheel that fires high-velocity material onto a surface. This clears the surface of any debris or other stuff that may have been there. A hopper is fed by the blast wheel, and it is loaded with the shot media, which can be anything from steel shot to chopped wire to nut shells. Bead blasting is generally removing surface deposits by applying fine glass or other types of beads at high pressure.

Classification of Shot Blasting (Bead Blasting) Abrasive

Metal and non-metal media are usually used for shot blasting (bead blasting).

1. Cast steel shot

– Advantages: relatively low price.

– Disadvantages: easily broken, hollow, overlapping double-sided ball, with irregular shape. Most of the defective steel shots will be removed by early shot peening.

2. Steel wire cutting shot

– Advantages: after use, its roundness will be further improved, and finally become spherical. Compared with the cast steel shot, it has a relatively long life and relatively uniform size. At present, this kind of product is the most widely used medium in the strengthening process.

– Disadvantages: The cut shot must be rounded before use. The unit price is higher than that of cast steel shot, and the size is usually only larger than 0.3mm.

3. Ceramic shot (bead)

– Advantages: less dust.

– Disadvantages: The price is expensive, and it is suitable for low strength. It needs to remove the adsorbed substances. Generally, it is suitable for surface strengthening that requires high metal residues on the surface.

4. Glass ball (bead)

– Advantages: very round, no rust contamination left.

– Disadvantages: It is only used for low strength, and the glass sheet may shallow into the workpiece surface.

How to Select the Shot (Bead) Blasting Media?

1) Know the media you need to use.

The strengthening medium is generally divided into two categories: metal and non-metal, and the above four types are usually selected in the strengthening process.

2) Meet the specification requirements.

Generally, many companies have specific media selection standards and shot blasting (shot blasting) strength (usually based on SAE, AMS2431, MIL13165, VDFI8001, and other standards). For those without reference standards, appropriate media can be selected according to the following points:

– The size and depth of the required residual stress, as well as the requirements for the residual stress in the surface layer (multiple shot blasting (shot blasting) can be carried out to meet the requirements).

– Surface roughness requirements of the strengthened workpiece.

– The hardness of the surface of the strengthened workpiece.

3) Maintenance strength.

The crushing rate and service life of the medium are important factors to maintain strength.

4) Protection against surface damage.

The hardness of the medium and whether the shot is excessively polished (sprayed) are important factors to keep the surface of the workpiece from being damaged. At the same time, the broken shot should be removed in time during the strengthening process, which can not only prevent the surface from being damaged but also maintain the strength to a greater extent. Generally, spiral separation screens are added to the equipment for separation.