Impact Energy Asset
Official BLAST APEX Particle Velocity Chart for engineering audits.
Download PDF ReferencePressure vs Velocity Matrix
| Nozzle PSI | Velocity (m/s) | Impact Energy | Typical Micron |
|---|---|---|---|
| 60 PSI | ~140 m/s | Moderate | 25 - 40µm |
| 80 PSI | ~180 m/s | High | 50 - 75µm |
| 100 PSI | ~220 m/s | Ultra-High | 75 - 100µm |
| 120 PSI | ~250+ m/s | Supersonic | 100µm+ |
Velocity Logic
Abrasive velocity is the square of kinetic energy. Small increases in PSI result in massive gains in cleaning speed. However, excessive velocity beyond 110 PSI with soft media like Garnet causes particle shattering, increasing dust levels and reducing recyclability without improving cleaning rates.
Recommended Pressures
- Shipyards (Garnet): 90 - 105 PSI
- Refineries (TC): 80 - 100 PSI
- Restoration (Glass): 40 - 60 PSI
Frequently Asked Questions
What is the optimal blast velocity for Sa2.5 surface preparation?
Optimal blast velocity for Sa2.5: 300-450 m/s (Mach 0.87-1.31). This velocity range provides maximum particle impact energy for removing mill scale and rust without excessive plastic deformation of the substrate. Below 250 m/s, cleaning rate drops significantly. Above 600 m/s with soft abrasives like garnet, particle fragmentation becomes excessive.
How does pressure affect abrasive velocity?
Abrasive velocity is proportional to the square root of pressure: doubling pressure increases velocity by 1.41x (NOT 2x). Going from 5 bar to 10 bar: velocity increases from ~310 m/s to ~440 m/s — only a 42% increase for doubling pressure. This is why nozzle bore size is more important than pressure for cleaning speed.
What happens if blast pressure is too low?
Low blast pressure (<4 bar) causes: (1) Insufficient impact energy — mill scale and rust stay attached. (2) Shallow profile depth — below 30µm Rz. (3) High abrasive consumption — particles bounce off rather than cut. (4) Increased rebound — operator safety hazard increases. Minimum 4 bar at the nozzle is required for Sa2.5.