Invalidation Mode of Tungsten Carbide Rock Drilling Button

The invalidation modes of tungsten carbide rock drilling button include the phenomenon of thermal fatigue and the detachment of the button. 

In order to drill a hole in the rock, tungsten carbide rock drilling button impacts on and break the rock violently. During this process, it will inevitably generate the wear owing to the collision and rubbing between the button and rock. The wear without the crashing is a kind of normal invalidation mode.

During the drilling and rubbing, the hard particles enter into the soft bonded part of the button which will be worn away first. And then through the process of the cutting, the bonded WC grain will be peeled off so that the small part of the button will be worn away. With the machine loading, the button has worn continuously, and the contact area continues to expand. The speed of abrasion will accelerate. 

The phenomenon of thermal fatigue will occur during the use of rock drilling button, such as in the oil field, the mining, well drilling and so on. The surface temperature of the alloy will rise owing to the collision and the rubbing between buttons and the rock. Under the condition that the contact pressure, speed and frequency are high, the temperature can reach 700 degrees. Meanwhile, the cooling water or other cooling mediums have the quenching effect on the alloy, thereby generating the crack of button. That’s how the thermal fatigue occurs.

The button will be detached when we use it. The fragment in various sizes or debris will be peeled off from the button surface. Large pieces of spalling can greatly shorten the life of the button, which is disastrous. As for the alloy with low tenacity, the spalling will occur obviously. The internal crack will also occur during the operation, which will lead to the early failure of rock drilling button. If the crack is generated in a deep hole, the crack may smash upward and cause longitudinal cracking of the upper part of the button.

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