Xi'an Tydrillbits Co.,Ltd is one of the most famous China tricone rock bits manufacturers, welcome to wholesale cheap tricone rock bit from our factory. 1.the strength and wear resistance of inserts are improve by using carbide inserts with high strengthand high wear resistance.2.Surface of the high precision bearing heat treated by using advanced heat treatment process to improve the load capacity and service life of the bearing.3.The service life of the bearing is further extended by adopting harder and mort wear resistant material for thrust bearing.4. Preventing reflux structure has dual function, it can avoid air counterflow and dust entering into bearing when the air-compressor stop working accidentally, and separate air and water in order to avoid water entering into bearing when it works normally to prolong the life of bearing.5.This series oil well rock bit  use Sealed roller bearing structure. With rollers arranged in grooves recessed in the cone body, the size of the bearing journal is increased.6.Thrust bearing surfaces are hardfaced and treated with friction reducing technology.7.This series oil well rock bit use Journal bearing. Hardfaced head bearing surface. Cone bearing inlaid with friction reducing alloy and then silver-plated. The load capacity and seizure resistance of the bearing is greatly improved. Size Type In mm 8 1/2 215.9 SVT437G SVT4 Drill bit size , type recommended parameter 47G SVT517G SVT527G SVT537G SVT547G SVT617G 9 1/2 241.3 SVT437G SVT447G SVT517G SVT527G SVT537G SVT547G SVT617G 12 1/2 311.1 SVT437G SVT447G SVT517G SVT527G SVT537G SVT547G SVT617G   IADC  Parameters Apply to formation Bit pressure(KN/mm) Rotate speed (r/mm) 437 447   0.35~0.9 240~70 Low compressive strength and high drill ability of extremely soft stratum, such as clay, shale, gypsum and halite, soft shale, soft limestone 517 527 0.35~1.0 220~60 Low compressive strength and high drill ability of soft stratum, such as clay, shale, gypsum and halite, soft shale, soft limestone 537 547 0.45~1.0 220~50 Low compressive strength and high drill ability of extremely soft stratum, such as clay, shale, gypsum and halite, soft shale, soft limestone 617 0.45~1.0 200~50 Hard strata with high compressive strength, such as abrasive shale, limestone, sandstone, dolomite and anhydrite marble