Drill Collar is the basic component in the BHA which provides weight on the bit for drilling and keeps the drillsting in tension.
 
GM Drill Collar has been approved by the NS-1 certification, it is 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.
 
Features and Benefits   A hardness range of 285 to 341 BHN and a Charpy impact value of 40 ft-lbs are guaranteed at evenly distributed 16 points in any sections at room temperature;   Connections are completed(phosphate coated)to protect them from the elements after machining and to help prevent galling upon initial make-up;   Thread roots are cold rolled on API and H-90 connections;   Pressed steel thread protectors are supplied for all drill collar that are equipped with standard connections ad protectors are supplied for all drill collar that are equipped with standard connections