en
The bit is designed for drilling of soft abrasive rock formations, e.g. rhyolite, dacite, andesite, soft limestone, conglomerate of sedimentary rocks, coarse-grained mineralized marble, quartzeous shale, phosphorite with phosphate and carbonate cement, overburden of coal seams, also found in shale mines.
Recommended drilling parameters for maximum efficiency of the bit: low and medium rotation speed (60-115 RPM) and axial load from 60 to 160 kN.
Rock strength range - from 3 000 to 6 500 PSI.
| Bit diameter, mm | 215.9 |
| Bit diameter, inch | 8 ½ |
| Bit designation, IADC | 522X |
| Connection thread, API | 4 ½" REG |
| Bearing type | Air-cooled, on rolling bearings |
| Formation type | For soft abrasive formations |
| Rotation speed. RPM | 115-60 |
| Max. applicable load, kN | 60-160 |
| Weight, kg | 33.9 |
| Bearing/cooling type | Roller – Ball – Roller / Air cooling |
| Blow-through type | Side / center |
| Cutting structure | Tungsten carbide inserts |