Drill Collars are integral heavy-wall joints that are manufactured from a solid bar of modified alloy steel. The solid bars are quenched and tempered to obtain the required mechanical properties, then trepanned, drifted and threaded. All drill collars are heat-treated with hardness within 285 to 341 BHN, which are guaranteed one inch below the surface of the pipe. Lake Petroleum could supply slick type drill collar, spiral drill collar and Non-magnetic drill collar (NMDC).
