How to Choose the Material of the DTH Drill Bit?

Table of Contents

DTH drill bits apply to large-scale open-pit mines, underground ore mining, anchoring engineering, quarrying rock drilling, construction engineering rock drilling, and large-scale engineering construction. Because of its wide application, it is very critical to choose a suitable material for the DTH drill bit to ensure its stable quality.

Many factors should be considered when choosing the material for the DTH drill bit. Since the DTH drill bit is mainly composed of the drill body and carbide button, the choice of the drill body and the carbide button should be given priority in materials selection.

Choice of drill body material

DTH drill bit

The determination of the material of the drill bit body should be according to the performance requirements of the drill bit and the characteristics of the brazing process.

Drill bit performance requirements

The strength of the drill bit head should be high to meet the abrasion of rock powder during rock drilling, and the transition between the head and the shank adapter should have good strength and toughness, to avoid early fracture under the complex stress state of multiple impacts, tension, compression, and torsion. The key must have good wear resistance or strength, while the end of the shank adapter must have higher hardness to avoid being piled up by the DTH hammer.

Characteristics of the brazing process

After finishing welding, the drill bit should not be heat-treated again, and the head welded with cemented carbide needs to be cooled slowly to prevent cracking of the weld. The strengthening of the drill bit body is done at once with the brazing process.

Selection of carbide button

Tungsten carbide buttons are very complex when working, so choose the corresponding carbide button for different rock hardness, geological structure, and the actual working condition of the drill bit.

Spherical button

Spherical button

The button shape is hemispherical, with high strength and good wear resistance, mainly used as a gauge button of the drill bit, suitable for corrosive and very hard rocks, but the rock drilling speed is slow.

Parabolic button

Parabolic button

The button shape is parabolic, with high strength and good wear resistance, mainly used for the gauge button or middle button of the drill bit, suitable for corrosive medium and relatively hard rocks, and the rock drilling speed is faster than that of spherical buttons.

Conical button

Conical button

The button shape is conical, the strength of the carbide button is general, the wear resistance is poor, mainly used for the middle buttons of the drill bit, suitable for medium corrosiveness, medium hardness of the rock, the rock is soft in the case can also do the gauge button; rock drilling speed is faster.

Sharp button

Sharp button

The button shape is sharp and acute, and the carbide button has poor strength and wear resistance. It is mainly used as the middle button of the drill bit, which is suitable for soft rocks with high speed and low tooth breakage rate, and has the fastest drilling speed under the same conditions, but the carbide wears fast and is easy to break teeth.

Column button

Column button

The button shape is a cylinder, which generally does not participate in direct drilling to break rocks, but is inserted on the outer circle of the large drill bit as a gauge button to reduce the wear of the drill bit surface.

Other types: compound angle button

Compound angle button

The button shape is the compound angle, and the carbide button has higher strength and drilling speed. It is suitable for soft and medium hard rock.

Other factors to be considered

Material of drill bit

Most DTH drill bits are made of high-hardness steel to cut and drill holes in rock or soil. Harder steels provide better wear resistance and longevity. However, in unique cases, the use of alloy steel can cope with geological conditions that are harder or contain unique chemical compositions.

Geological conditions

If the geological conditions are hard rocks, such as granite or gneiss, more wear-resistant and abrasion-resistant material is required.  However, if the geological conditions are soft soils or sandy strata, ordinary high-hardness steel drill bits may be sufficient.

Drilling depth

The diameter and length of the drill bit are directly related to the drilling depth. Generally speaking, larger diameter and longer length bits may require more durable materials to cope with larger cutting forces and wear.

Budget and cost

The cost of drill bits varies with different materials and manufacturing processes. According to the budget and engineering requirements, the balance between the performance of the material and the cost needs to be combined.

Additional functions and special requirements

Some DTH drill bits may require special features, such as cooling or water injection during drilling. These functions may require unique materials or coatings.

In summary, the choice of material for the DTH drill bit depends on several factors, and it is advisable to consult a professional DTH drilling tool supplier or geological engineer to make the most suitable choice according to the specific project requirements. It is also advisable to conduct tests and comparisons to evaluate the performance of different material drill bits in practical applications to make a more informed decision.

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