The drill collar is made from AISI 4145H or finish rolling structural alloy steel. The deep hole’s process and heat treatment: The drill collar is processed as per API SPEC 7 standard.The technology for heating processing has been used in the product’s full length range to ensure the mechanical property reaching the requirements of APISPEC 7, and one inch below the pipe surface can ensure its charpy V-notch impact energy at 40ft-lb.
In the entire producing process of drill collar, the test data of each item’s performance test, from workblank,heat treatment to connecting thread and other manufacturing process, have been preserved. And, for easy reference, each product has an item number on that single product.
Necessary detection procedure：
Drill collars’ detection is completely as per API standard, which includes size detection and ultrasonic wave and magnetic particle test within the product’s full length range. Cold pressing process of thread bottom: The drill collar’s thread root and its elevator recess both undergo the cold rolling process, thus decreasing crack diffusion and having increased the upper radius pressure resistance. In this way, the drill collar’s anti-fatigue performance is fortified and its service life is increased.
Phosphatization or copper plating treatment:
All the threads undergo phosphatization or copper plating treatment so as to increase their corrosion resistance and avoid tool threads’thread gluing phenomenon.
Drill collar slip, elevator groove, and elevator clear size of opening (API RP 7G):
Our company can process slips and elevator grooves on the drill collar as per user’s requirements. This kind of grooves can guarantee security in operation needing not lifting sub and safety mounting board. The size and shape of slips and elevator grooves confirm to API RP 7G specifications.
We can provide steel or internal plastic steel ring deformed bar protector (screw protector cap) for the product as per user’s requirements.