MANUFACTURING TECHNOLOGY OF DRILL BITS UNDER HIGH PRESSURE AND TEMPERATURE WITH THE APPLICATION OF NEW DIAMOND MATERIALS

Abstract

An original manufacturing technology of diamind drill bits with up to 212 mm at pressures up to 1.5 GPa and temperatures up to 1250 °C was developed. The bits were produced by sintering in a heat insulating jacket, an electrical insulating casing with electri cal heaters in a steel high pressure cell for 120 min. In the manufacture of drill bits by sintering under high pressure in steel HPC it was found that the sintering process is productive and apparatus for it can be used repeatedly. It can be used steel casing for pressing the diamond matrix material on it. The whole body can be made of diamond powder or holes for fi xing of diamonds by the subsequent soldering or by mechanical method. The authors have developed and manufactured a piston-cylinder type of HPC with a working diameter up to 280 mm by a high-pressure chamber. Also they have made a bit of model cutting elements such as polycrystalline carbonado diamonds and have tested their performance properties. When drilling of marble unit at load of 50 kN and the revolutions number of 355 rev/min the mechanical speed was reached up to 20 m/h. It was found that the developed technology allows to keep cutting properties such as carbonado diamonds have, which are analogues of PCD for thermal stability. Strength bit performance allows its operation under the most intense power drilling modes; metal-ceramic matrix provides a reliable fastening of the cutting elements. Carbonado is wear resistant and has high strength. This technology is energy effi cient, environmentally friendly and productive, as the technology can be used for the manufacture of metalceramic wear-resistant, corrosion-resistant casing bit and then fi xing it in the diamond cutting elements by soldering, or mechanical fastening, using a diamond composite materials of PCD types with diff erent thermal stability.