Soft! Steel shot media of a hardness on MOH’s scale 2 – 2.5
It should be noted that any abrasive described as 6 and over on the MOH scale is classed as abrasive
Steel Alloy – Soft low carbon steel shot for more delicate , toleranced components
(Sometimes identified as metal bead)
Soft low carbon steel shot that has a hardness of <200 HV, or only 12 – 15 RC. The shape is nearly perfectly spherical and the density is >7 gm/cc. (all but the same as standard steel). Soft steel shot is produced as only virgin, premium quality cast steel shot neither reclaimed materials nor other materials are added in during the manufacturing process. The waste generated from the use of this shot is non-hazardous and can be disposed of in the same manner as shot waste from SAE grades of steel shot or grit. Soft low carbon steel shot does not work harden which means that its performance does not change during its life cycle.
When compared with standard SAE grades of steel shot, soft steel shot is much more durable with as much as twice the life of standard steel shot. And because of the low hardness larger sizes of soft steel shot can often be substituted for finer standard SAE steel shot which means even longer life in the blast system. The larger sizes remain in use for a longer time before being drawn out by the separator.
The density of soft low carbon steel shot is identical to standard SAE steel shot so it is ideal for blasting in a standard, centrifugal wheel type blast machine from any of the machine manufacturers. The blast media flows and circulates easily through the blast machine and the air-wash separator will work as well as with standard SAE steel shot. Or, the media can be used in a pressure type air blast cabinet and the air pressure can be lowered to as low as 40 psi for blasting truly delicate parts.
Soft low carbon steel shot is available in six (6) sizes that range from SS70 to SS330 and most sizes closely follow the SAE size specifications as spelled out in the specification SAE J444. At present, the finer sizes such as SS70 is used for blasting aluminium die castings and for cleaning delicate moulds in the aluminium, rubber and glass making industries. The larger sizes are used for blasting ferrous parts and machined surfaces with no texturing or damage to cast-in logos, part numbers or machining reference points. The added impact of the larger particle sizes without any corresponding surface damage, needs to be considered for removing ceramic shell material in investment casting applications and especially from softer metal components.
The more commonly used medias are:
- aluminium oxide
- white aluminium oxide
- urea and other plastic abrasives
- corn cob grit
- walnut shell grit
- glass beads
- crushed glass grit
- silicon carbide
- steel grit
- steel shot
- chilled iron grit
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Post written by
Shot Blasting Technical Manager