... compacts and decreasing the breakage rate by using the tungsten carbide compact of high strength and toughness.b. Improving the resistance ... and capacity of the bearing by applying carbide layer on head bearing surfacec. Increasing the reliability of bearing ... , 537G, 617G, 627G, 637G 7 7/8" Kingdream HA737G tungsten carbide tricone drill bit /three cone bit