Command Energy’s drill collars are made of modified AISI 4145H chromium molybdenum alloy steel. These drill collar bars are full-length heat treated and water quenched to obtain mechanical properties as specified by API Spec 7-1. Full mechanical and chemical mill test certifications are supplied with all drill collars. These mill test certifications guarantee a hardness range of 285 to 341 BHN and an impact value of 40 ft-lbs at room temperature, one inch below surface. All drill collar bars are trepanned then drifted to API specifications to ensure close tolerance bores. Drill collars are also supplied with the outer surface either machined or rough peeled.