API Certificate Core Barrel 133mm Roller Cone Bit

133mm Roller Cone Bit Tungsten Carbide Inserts Full Covered Roller Cone Bit for Hard Rocks Drilling Core Barrel 133mm roller cone bit is made by tungsten carbide inserts are full fitting on surface ,it is different from traditional Single cone roller bit that inserts are groove-inserts-groove design. Steel material of arm and cone is important for the quality, we use 15MnNi4Mo steel for cone, and we use 15CrNiMo steel for arm, it is standard steel material for oil well