PARVEEN drill collars, are made from ultrasonically tested bars of Chrome Molybdenum Alloy Steel (AISI 4145H modified material) and available in all sizes and connections as per API std 7 & API-RP 7G in Range 2. Drill collar bars are fully heat treated to 285 to 341 BHN and Charpy impact value of 40 ft. Lb.