Pre-Mixed Steel Shot and Steel Grit

Shandong Haishan Industrial Technology produces a pre-blended abrasive that combines spherical steel shot and angular steel grit in a controlled ratio. The company operates with an annual production capacity of 100,000 tons and supplies customers in over 50 countries. This Pre-Mixed Steel Shot and Steel Grit is intended for general surface preparation on steel and iron workpieces with light to moderate rust, mill scale, and surface contaminants. It removes the need for users to store and mix two separate abrasives on site.

The standard blend uses approximately 70% steel shot and 30% steel grit by weight. Steel shot provides impact energy to break brittle scale and create a uniform anchor profile, while steel grit adds cutting action to remove rust and light welding slag. The ratio is designed to balance cleaning speed, surface roughness, and abrasive consumption for common blasting applications. The exact mix can be adjusted according to the workpiece condition and coating specification.

Product Specifications

Chemical composition and hardness are verified on each production batch. Particle size distribution is checked by sieve analysis according to SAE J444. The two components are heat-treated to the same hardness range to prevent uneven wear during use.

How the Blend Works

• Steel shot component: Spherical particles strike the surface and create a compressed, slightly rounded profile. This is useful for removing brittle scale and for forming an anchor pattern that is not excessively rough.
• Steel grit component: Angular particles scrape and cut, removing rust and mill scale that impact alone cannot dislodge. The grit also increases the surface profile depth where needed for high-build coatings.
• Combined effect: The blend aims to produce a surface that is cleaner than shot alone and less rough than grit alone. It can be used directly in wheel blast machines and air blast systems without pre-mixing on site.

Actual cleaning results depend on blasting pressure, standoff distance, and the condition of the steel. Users should perform a test area to confirm the required cleanliness and profile before full production.

Applications and Limitations

This pre-blended abrasive is suitable for:

• Surface preparation of steel plates, profiles, and fabrications with light to moderate rust
• Removal of sand and light scale from small and medium castings
• Cleaning of mechanical parts before repainting or inspection
• Anti-corrosion pretreatment for ordinary structural steel
• General surface cleaning of hardware and fabricated components

It is not recommended for:

• Extra-heavy welding slag or very thick mill scale, which require a higher proportion of angular grit or a coarser abrasive
• Ultra-thin sheet metal (below 3 mm) or precision parts where the grit component may cause excessive roughness
• Applications requiring very low surface roughness (below 25 μm)
• Shot peening or surface strengthening, which require spherical shot only

Recommended Blasting Parameters (Starting Points)

These values are starting points, not universal settings. Actual parameters should be adjusted based on the workpiece, coating requirement, and equipment type.

Quality Control and Documentation

Each batch of pre-blended abrasive is tested for blend ratio, chemical composition, hardness, and particle size distribution. The laboratory uses a direct-reading spectrometer, Rockwell hardness tester, and sieve shaker. Certificates of analysis and test reports are provided with each shipment. Additional documents, including ISO 9001:2015 certification and metallographic reports, are available on request.

 

Packaging and Storage

Standard packaging is 25 kg bags with a moisture-resistant PE inner liner inside a woven polypropylene outer bag. For export orders, 1,000 kg bulk bags on pallets are available, and pallets are prepared to meet ISPM 15 requirements. Store in a dry, covered area. The product does not have a fixed shelf life when kept dry and uncontaminated, but packaging should be checked for damage before use.

Frequently Asked Questions

Why should I choose a pre-blended abrasive instead of mixing steel shot and steel grit myself?

Pre-blending ensures a consistent ratio and uniform distribution of the two components. On-site manual mixing often leads to uneven proportions, which can cause inconsistent cleaning results and surface profile. The factory-controlled blend also saves storage space and reduces handling labor.

Can the 70/30 ratio be adjusted for my specific application?

Yes, the ratio can be adjusted based on the rust condition and the required surface profile. For heavier rust or thicker scale, a higher proportion of steel grit may be recommended. For lighter cleaning and smoother profiles, a higher proportion of steel shot may be better. We can recommend a blend after reviewing your workpiece and coating specification.

What is the difference between this blend and using steel shot alone?

Steel shot alone is less effective at removing rust and mill scale because it relies primarily on impact. It leaves a smoother surface but may require longer blasting time. The addition of angular steel grit provides cutting action, which speeds up cleaning and creates a slightly deeper anchor profile.

Is this blend suitable for shot peening?

No, this blend is not intended for shot peening. Shot peening requires spherical shot only to produce a uniform compressive stress layer. The angular steel grit in this blend would cut the surface and damage the peening effect.

Can this abrasive be used in a wheel blast machine?

Yes, it is compatible with most wheel blast machines and air blast systems. The particle size distribution is selected to flow well through common equipment. You may still need to adjust wheel speed or abrasive flow to achieve the desired profile.

How do I know which particle size to choose?

Particle size should be selected based on the contaminant type and the required surface profile. Coarser grit removes heavy rust faster but leaves a rougher surface, while finer grit produces a smoother finish but may take longer. We can provide a recommendation if you share your workpiece details and coating requirement.