AUP Drill Collars are manufactured from 4145H modified quenched and tempered steel. Strict metallurgical specifications are followed to insure that full length heat treating produces a consistent maximum depth of hardness.
DRILL COLLARS are made from 4140/4145 seamless chromemoly alloy trepanned solid bar stock or from seamless mechanical tubing. To ensure optimum strength and ductility, each bar is heat treated to a Brinell Hardness Range of 285/341. Additionally, all bars are impact tested to 40 ft. lbs. Izod Z minimum to ensure hardness at least 1" below the surface.
Each bar is machine straightened to within 1/8" in any 5' length and to 3/16" in total axial length. All threads are precision inspected for manufacturing accuracy. These tests and others ensure that all Hacker Drill Collars meet or exceed API specifications.