Drill Collar

Product Type:


A. Slick Drill Collar: mainly used to provide bit weight to drill bit so that drill pipe is in tension



B. Spiral Drill Collar: used to reduce contact area with hole so as to avoid efficiently bit sticking from differential pressure



C. Spiral Drill Collar With Elevator Groove And Slip Groove: used as lifting sub and safety slip when trip out. The technical parameters for elevator groove and slip groove is as per API SPEC7_1. Hard banding is optional at customers' request



D.Non magnetic Drill Collar: cold rolled finish on both ID and OD surface with unique technical process strengthen the structure and ensures the tools with optimal resistance to stress, corrosion & cracking







Main Features:



Materials: structure steel alloy forged or rolled from AISI 4145H.



Processing and thermal treatment of deep holes: Thermal treatment is conducted over the whole length of the products. Its Brinell hardness ranges between 285 and 341. And impact energy of its Charpy V shaped notch can be 40 ft lb at a temperature of 1 inch below the surface of the pipe.



Testing procedures: Testing of surface dimensions and ultrasonic wave and magnetic particle testing over the whole length of a product will be included.



Cold forming of thread bases:Cold rolling must be done for the bolt root and elevator recess of a drill collar. Thus, the bearing capacity of the upper radius will be increased via reducing crack diffusion to increase fatigue strength of a drill collar and extend the service life.



Phosphating or brass plating:Phosphating or brass plating will be conducted for all screw threads to increase their corrosion resistance and avoid thread jamming of drilling tools.



Screw thread protector: Steel or plastic-steel ring thread protectors are provided for protecdion.