... soft & medium hard rock formations, also for making cemented carbide inserts for other drill bits.HK20.1YK20YK25HK25.114.5714.5014.5014 ... medium hard and hard rock fomations, also for making inserts for other drill bits.HK40HK5014.2014.0086.585.524502400 Mainly ... drilling medium hard and hard rock fomations, also for making inserts for other drill bits.Grades for applications in oil fieldsGradesDensity ...