冲击钻进用金刚石复合材料

The Diamond Composite Material for Percussive Drilling

对单晶金刚石进行了抗动载试验研究，分析了影响其抗冲击能力的因素，介绍了适用于液动冲击器和风动潜孔锤钻进的两种含金刚石复合材料。

iamond is the hardest mineral in the nature, its scratch hardness is 8. 5 times of quartz,but it is fragile and has a poor ability of anti-impact load. It had been thought that the diamond could not be applied in the percussive & rotary drilling, in fact, it is proved that the diamond composite material for liquid hammer bits could resist some impact load and get a good effect of rock breaking. The main reasons are that: first, the diamond not only has a crushig strength,also has some impact strength, and the impact strength is in inverse proportion with grain size of diamond. For example, when the grain size of natural diamond becomes smaller from 20～30stones per carat to 60～ 90 stones per carat, the impact strength grows from 0. 176MPa up to 0. 823MPa; second, the test indicats that when the working condition of diamond in the composite material is tensely inserted in all sides, the impact strength could be improved 5 times than the free condition; third, when the diamond breaks rock with the liquid hammer of small diameter, the rotary action is main, and the impact is supplementary, for its low impract energy(<50J) and high frequences(>40Hz ). The bit material of Down-the - hole hammer droven by gas with big impact energy and low frequences is almost the carbide tungsten. When it breaks rock, the impact action is main and the rotary action is supplementary. We developed a diamond composite material by compounding small diamond powder and metal adhension agent and sintering them to the surface of carbide tungsten by using the technique of transiting layer and HTHP. The performance parameters could fit full percussive drilling, as the follows: first, hardness is HRA87～ 90; second,wearability is 100～1, 000 times of carbide tungsten; third, impact strength is bigger than 33. 33J/cm2.