Solution to Failure of Tungsten Carbide Rock Drilling Button

1. Solution to the wear of abrasive particle

When there is no other failure mechanism which plays an important role, the lifetime of bits depends on the wear state of the tungsten carbide button. The service life of the bits can be extended by improving the wear resistance of buttons appropriately. In addition, the wear resistance of the side button should be higher than that of middle button. 

2. Solution to the thermal fatigue

Several or even hundreds of cracks can be observed on the surface of the button when the thermal fatigue occurs. Decreasing the contact time between buttons and rocks can minimize the damage caused by the thermal fatigue.

3. Solution to the detachment

If buttons detach excessively, the situation can be improved by increasing the tenacity and decreasing pores. Besides, the cobalt content should be increased and the WC grain should be grinded at the expense of the decrease of the wear resistance. 

4. Solution to the internal cracks

To a certain extent, the internal cracks exist in all buttons. Normally, these cracks are small and are few in number. But if the operating condition is poor and the impact and the tangential stress on the button are large, these small cracks will be ruptured owing to stress concentration. As a result, the failure of the bit will occur in advance. Therefore, the better the tenacity of the material is, the less sensitive the crack is.

5. Solution to rupture of the covered parts

During the processing of bits, the finish of the button after grinding should be guaranteed. In addition, we should ensure that it will not be out of circularity and not produce cracks caused by the grinding. Meanwhile, the perforations pf bits should be round without tapers and the bottom of perforations should have a supporting shape which is suitable for the button bottom. During the cold pressing or thermal inserting, the fit between the button diameter and perforation diameter is also an extremely important factor.  

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