The drill collars are made of 4145H modified chromium-molybdenum alloy steel acc. to API Spec.7 and SY/T5144. All threads can be phosphated, copperised or cold worked. All threads are machined with CNC Lathes-Double-Shouldered and special threads, the max diameter of drill collar is 14 inch.

Main products includes: common drill collars, spiral drill collars, nonmagnetic drill collars.

Besides, elevator and slip recesses can be machined to meet the customers' requirements.