Why Does the Breaker Tool Mushroom? A Metallurgical View

The deformation and expansion of the tool tip or piston striking surface is called "Mushrooming". This indicates that the steel has lost its properties.

1. Why Does It Happen?

• Overheating: If you strike the same spot for more than 15 seconds, friction heat exceeds 500°C. The steel loses its temper (softens).
• Insufficient Lubrication: Dry friction between the tool and bushing also increases heat.

2. How to Prevent It?

• Strike Duration: Follow the 15-second rule. If the rock doesn't break, don't persist; change the spot.
• Check: If mushrooming starts, grind off the deformed part. Otherwise, broken pieces will get stuck between bushings.