The Thermal Dynamic Simulation Of Diamond Bit Brazing Process

The brazed diamond tools have many advantages such as high strength ofcombination between diamond and matrix, large clearance for debris, fast cuttingspeed. In the use of traditional single-layer brazed diamond bit, the detachment ofdiamond particle can results in diamond tool failure. Therefore our deep geologicalexploration is in urgent need of a long life of diamond bits.In this paper, a new emerged multi-layer brazed diamond drill bit for the field ofgeological exploration is been researched. Because of the potential hot crack in thedrill bit, the cooling process in the production is been studied.After the heat preservation process, the drill bit and graphite mold are taken outfrom the furnace for cooling, the temperature fields of rapid cooling using the waterjacket and slow cooling in the natural environment have been researched usingnumerical simulation, The temperature fields of two cooling condition are obtained.The speed of cooling process using water jacket is much faster than the speed ofnatural cooling, the cooling effect of water jacket is significant.The thermal stress fields for rapid cooling using the water jacket and slow coolingin the natural environment have been studied using finite element simulation, Thethermal stress fields of the two cooling conditions have been obtained. Thetemperature gradient between diamond bit and graphite mold in the cooling processresults in the inconsistency between the various parts deformation and thermal stress.In addition, the thermal expansion coefficient among steel body, nickel-chromiumfiller metal and graphite mold are very different. In the cooling process, the shrinkageof diamond bit is greater than the shrinkage of heart mold, so the drill bit graduallyhoops the heart mold tight, and makes it difficult to separate, and could easily lead topotential hot crack.Observation from the multi-layer brazed diamond bit manufacture proved that thenumerical simulation of temperature field and thermal stress are basically the same asthe actual production process.