Mining Drill Bits Classified According To IADC545 12 1/4" High Performance Crushing Rock
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What is Hard Rock Drill Bits
Hard Rock Drill Bit is cut rock by Tungsten Carbide teeth projecting from rolling cutters, which rotate on the drill-bit bearings. Inturn, the drill bit rotates at a high rate, and presses against the bottom hole with a high axial force.
The teeth of the rolling cutters roll over the bottom hole and, owing to the large stresses that develop in the area of contact between the teeth and the rock, cut the rock by crushing and chipping.
All bits the above are manufactured according to strict standards, set forth by the American Petroleum Institute (API).
And classified according to characteristics set forth by the International Association of Drilling Contractors (IADC).
As the hardness of therock increases, the rotation rate decreases and the axial force increases. Destroyed at the mine the rock is removed to the surface by air compressor, mud pump, or a combination of these methods.
How to read an IADC Code properly
First Digit | TOOTH |
1 | Steel tooth bits for Soft Formation |
2 | Steel tooth bits for Medium Formation |
3 | Steel tooth bits for Hard Formation |
4 | TUNGSTEN CARBIDE INSERT BITS
|
5 | |
6 | |
| |
Second Digit | FORMATION |
1 | 1,2,3 and 4 are further breakdown of formation with 1 being the softest and 4 the hardest. |
2 | |
3 | |
4 | |
Third Digit | BEARING/SEAL TYPE |
1 | Standard open bearing roller bit |
2 | Standard open bearing roller bit, air-cooled |
3 | Standard open bearing roller bit with gauge protection |
4 | Sealed roller bearing bit |
Fourth Digit | ADDITIONAL FEATURES |
A | Air application |
R | Reinforced welds |
C | Center jet |
S | Standard steel tooth |
D | Deviation control |
X | Chisel insert |
E | Extended jet |
Working theory of TCI tricone bit
The medium formation TCI tricone bits features aggressive chisel tungsten carbide inserts on the heel rows and inner rows. This design provides a fast drilling rate and added cutting structure durability in medium to medium hard for mations. The HSN rubber O-ring provides adequate sealing for bearing durability.
Tricone bit is connected with the drill stem and rotates along with it, and drive cones to pressed on the rock. Each cone rotates round the axis of its leg and three cones simultaneously revolve around the bit center. The tungsten carbide inserts on the cone shell cause the formation to spall under the weight on bit and the impact load of cone rotating, the debris will be discharged out to hole by compression air.
The medium formation TCI tricone bits features aggressive chisel tungsten carbide inserts on the heel rows and inner rows. This design provides a fast drilling rate and added cutting structure durability in medium to medium hard for mations. The HSN rubber O-ring provides adequate sealing for bearing durability.