Note: Both belong to shot peening treatment. The main difference lies in the projectile acceleration method.

1. Working Principle (Key Difference)

Shot Blasting Power source: Motor-driven centrifugal impeller. The rotating impeller throws steel shots out by centrifugal force. No compressed air is required.

Air Shot Peening (Pneumatic Shot Peening) Power source: Compressed air. High-pressure air accelerates media through a spray nozzle. An air compressor is necessary.

2. Abrasive Media

Shot Blasting: Mainly adopts steel shot, cut wire shot and steel grit, generally with relatively larger particle size. Typical machines: tumble belt shot blaster, hook-type shot blaster, road shot-blasting machine.

Air Shot Peening: Wide selection of media: steel shot, glass bead, ceramic bead, stainless steel shot and fine abrasives are all available.

3. Impact Force & Surface Roughness

Shot Blasting: High impact force with high working efficiency; produces relatively higher surface roughness. Projection direction is fixed by the impeller. Ideal for large-area rust removal & descaling. Blind spots exist on complex-shaped workpieces.

Air Shot Peening: Nozzle can be adjusted manually or by robot arm for variable impact strength, covering a wide roughness range. Suitable for local areas, cavities and complex curved surfaces. Precision peening for gears & springs mostly uses pneumatic shot peening.

4. Efficiency, Cost & Application

Shot Blasting

✅ Advantages: High throughput for mass production; lower power consumption than compressor-driven systems. Fits large-size workpieces, steel plates, steel structures and castings, road surface texturing.

❌ Disadvantages: Fixed projection angle; hard-to-reach dead corners on complicated parts.

Air Shot Peening

✅ Advantages: High flexibility; nozzle targets any position; adjustable pressure for precision fatigue life improvement. Works for small components, grooves and gear tooth roots.

❌ Disadvantages: Higher energy cost from air compressor; slow for large-area processing, low output.

5. Main Applications

Shot Blasting Applications

Rust & scale removal for castings and steel structures

Surface pre-treatment for steel plates

Texturing for concrete & steel road decks

General stress-relief peening (non-high-precision requirement)

Air Shot Peening Applications

Precision shot peening (aerospace parts, gears, springs for enhanced fatigue life)

Cleaning for complex cavities & local zones

Matte finishing and burr removal

Gentle matte surface finishing by glass bead blasting without heavy substrate erosion

Comparison Table

Extra remark for terminology: People often confuse sandblasting with shot peening. Sandblasting uses angular hard abrasives such as brown fused alumina for cutting-type surface material removal. Shot peening uses spherical media; surface treatment is achieved by plastic deformation from particle impact instead of cutting.