Specifications:

API Drill collar as per API SPEC 7-1
1.OD:3 1/8"-11"
2.Material:AISI4145H
3.Length:10`-31`

Description:
1. Material: 4145H.
2.ID:2"-3".
3. Standard: API 7-1.

A. Slick Drill Collar
Note: Drill collar is mainly used to provide bit weight to drill bit so that drill pipe is in tension. Especially drill collar can keep drill bit centralized and hole track by large rigidity. The Drill collar are manufactured strictly from API Spec7-1 standard.
B. Spiral Drill Collar
Note: Spiral drill collar is used to reduce contact area with hole so as to avoid efficiently bit sticking from diffirential pressure. The drill collars are manufactired strictly according to API Spec7-1Standard.
C. Spiral Drill Collar With Elevator Groove And Slip Groove
Note: Elevator groove and slip groove made on box thread face of slick drill collar or spiral drill collar can be 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. Hardbanding is optional at customers' requests.
D. Non-magnetic Drill Collar
The as cold rooled 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 and the mechanical performance is greatly enganced.
E.Other type Dill Collar