... sphere compacts in outer rowApplicable FormationsThe hard formation with high abradibility such as hard limestone, dolomite, hard sandstone, chert,etcPayment termsL/C, ... of compacts and decreasing the breakage rate by using the tungsten carbide compact of high strength and toughness.b. Improving the ... , 537G, 617G, 627G, 637G 7 7/8" Kingdream HA737G tungsten carbide tricone drill bit /three cone bit