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DRILL COLLARS
DRILL COLLARS

DRILL COLLARS

Drill collar as one component of a drill string is extremely industrial tubulars used to drill into ground to provides weight on bit for drilling.
Standard :API SPEC 7-1
Steel grade:AISI 4145H
Product introduction
Technical data
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Product introduction
Standard :API SPEC 7-1
Steel grade:AISI 4145H
Sizes:3 1/8" -- 11"
Connected Type:NC, IF, REG
Length:30 – 31 ft ± 6 ft.
Type of design:(1)plain;(2) with a recess of the elevator; (3) with a recess of the elevator and power slips; (4) spiral and a wide range of type mixtures.
Description
Drill collar as one component of a drill string is extremely industrial tubulars used to drill into ground to provides weight on bit for drilling. It is used to conjunction with drill pipe. There are slick and spiral grooved types mainly. Our manufacturing process is certified to API spec 7-1. The drill collar is made of AISI 4145 H or 4145 H Modified alloy steel. Bores are trepanned from one direction with no mismatch. All drill collars are heat-treated with hardness within 285 to 341 BHN, which are guaranteed one inch below the surface of the pipe.

Non-magnetic drill collars offer strength and hardness while preventing magnetic interference that may impair accuracy of magnetic surveys. It is manufactured from special steel material with low permeability, high mechanical properties and superior resistance to corrosion cracking.
Specifications
We supply slick drill collars, spiral drill collars and non-magnetic drill collars; their sizes are from 3-1/8 to 11 inches. Besides the drill collars in the table below, we can supply other drill collars at customers’ request.
 
Technical data
Non-Magetic Drill Collar
Grade Minimum Tensile Strength
psi Mpa
1 90000 621
2 9000 621
3 115000 793
**Non-magetic drill collar can be customized as per customer’s design. The size please refer to the sizes of drill collar.
 
Spiral Drill Collar
OD (in) 4 3/4 6 1/4 6 3/4 7 1/4 7 1/2 8 9 1/2 10 11
Depth of Cut (in) 7/32
±1/32
9/32
±1/16
5/16
±1/16
11/32
±1/16
11/32
±1/16
3/8
±1/16
13/32
±3/32
7/16
±3/32
15/32
±3/32
Spiral Pitch (in) 38
±1
42
±1
46
±1
64
±1
64
±1
68
±1
72
±1
76
±1
80
±1
** Drill collar can be customized as per customer’s design.
Standards
Standard Sizes, Bores, and Connections
Drill Collar
Conn. Size & Type
Min.
OD
Bore Length Bending Strength
Ratio***
Drill Collar
Wt.
(in.) (in.) (ft.) (lb.)
NC 26 (2-3/8 IF) 3-1/2 1-1/2 30 2.42:1 801
NC 31 (2-7/8 IF) 4-1/8 2 30 2.43:1 1041
NC 38 (3-1/2 IF) 4-3/4 2-1/4 31 1.85:1 1451
NC 38 (3-1/2 IF) 5 2-1/4 31 2.38:1 1652
NC 44 6 2-1/4 31 2.49:1 2561
NC 44 6 2-13/16 31 2.84:1 2353
NC 44 6-1/4 2-1/4 31 2.91:1 2806
NC 46 (4 IF) 6-1/4 2-13/16 31 2.63:1 2598
NC 46 (4 IF) 6-1/2 2-1/4 31 2.76:1 3085
NC 46 (4 IF) 6-1/2 2-13/16 31 3.05:1 2877
NC 46 (4 IF) 6-3/4 2-1/4 31 3.18:1 3364
NC 50 (4-1/2 IF) 7 2-1/4 31 2.54:1 3643
NC 50 (4-1/2 IF) 7 2-13/16 31 2.73:1 3434
NC 50 (4-1/2 IF) 7-1/4 2-13/16 31 3.12:1 3714
NC 56 8 2-13/16 31 3.02:1 4675
6-5/8 REG. 8 2-13/16 31 2.60:1 4675
6-5/8 REG. 8-1/4 2-13/16 31 2.93:1 5016
7-5/8 REG. 9-1/2 3 31 2.81:1 6727
7-5/8 REG.** 9-3/4 3 31 3.09:1 7130
8-5/8 REG.** 11 3 30 2.78:1 8970
** Low torque face
*** Ratio of box to pin section modulus – See API RP7G for details
Note: Other sizes and connections are available as well as any other optional features listed
 
Mechanical Property
TTT Yield strength 0.2Mpa Tensile strength b Mpa Elongation 4% Hardness(Brinell) IMPACT VALUE(CHAPPY-V)
mm in inch
79.4-171.4 3 1/8-6 3/4 ≥ 758 ≥ 965 ≥ 13 285-341 ≥ 54
177.8-279.4 7-11 ≥ 689  












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