Non-Magnetic Heavy Weight Drill Pipe API Spec 7-1 Oilfield Drilling Tool The non-magnetic drill collar is made of low-carbon stainless steel independently developed by our company and follows API and SY/T5144 standards. The threads can be processed with cold rolling. Our company can machine double-shoulder threads and other specifications of special threads. The Company possesses a complete set of petroleum drilling tool production lines and mainly produces large deep-hole