Quantifying Drill Bit Wear in Rocks of Different Hardness

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  1. Each 1-point increase in rock hardness (f-value) causes exponential growth in bit wear rate. In f=2 sandy soil, cross bits work 80-100 hours continuously.DTH drill
  2. f=6 sandstone shortens bit life to 30-40 hours. In f=10 granite, the same bit lasts only 8-12 hours. Wear patterns vary with hardness.
  3. Soft rock causes uniform abrasive wear: alloy teeth reduce ~0.2mm per hour. Medium-hard rock brings local chipping, 0.5-0.8mm loss hourly.

 

Hard rock leads to tooth tip splintering. Extreme cases see alloy teeth fall off in single impacts.

 

Stats show: when f-value rises from 3 to 9, bit replacement frequency jumps from 1/day to 1 every 2 hours. Downtime cuts effective operation rate by over 40%.DTH drill