Thermal Effect on PDC Cutter

It has been known that PDC bits are much more efficient than roller cone bits, but this is traditionally only seen while drilling soft rocks. This could be due to the fact that 50% of the energy for drilling can be dissipated by a worn cutter. In addition to the wear that is caused by the interaction between the rock and cutter, thermal effects can accelerate the rate at which a cutter will wear. 

If thermal effects were neglected, it could result in bit wear being simply a function of the load applied to a bit and the distance traveled while in contact with the rock. As we know, this is not the case. Thermal effects have an impact on the rate at which bits wear.

It is stated that the abrasive wear of metal is related to the hardness ratio of abrasive material and the metal. For soft abrasives with a ratio less than 1.2, the wear ratio is low. As the ratio of relative hardness exceeds 1.2, the wear rate increases considerably. 

When looking at quartz, which is anywhere from 20- 40% of many rock formations, the hardness ranges between 9.8-11.3GPa and that of tungsten carbide is 10-15GPa. These ranges result in a ratio that ranges from 0.65 to 1.13, classifying this relationship as a soft abrasive. When tungsten carbide is used for cutting rocks at or below 350 oC, they experience a wear rate that is similar to that of a soft abrasive as expected.

When the temperature exceeds 350 oC, wear is accelerated and associates better with that of a hard abrasive. From this, it’s concluded that wear increases by thermal effect. To reduce PDC wear, it would be advantageous to control the temperature of the cutters. 

When the study of thermal effects on PDC wear began, 750oC was the maximum safe operating temperature. This temperature was established, because below this temperature microchipping was the wear seen on the cutter. 

Above 750℃ full diamond grains were being removed from the diamond layer and when reaching temperatures above 950℃ the tungsten carbide stud experienced plastic deformation. The understanding of the cutters and PDC bit geometry must be precise to provide adequate information when making a bit selection.

Zzbetter provides a high-quality PDC cutter with good thermal stability. Our team works extremely hard to manufacture quality products. We look forward to serving your business.

If you are interested in PDC cutters and want more information and details, you can CONTACT US by phone or mail at the left, or SEND US MAIL at the bottom of the page.