High Quality API 7-1 Non-magnetic Drill Collar

Materials:
The non-magnetic products of Dongying Lake is made from high-class low carbon stainless steel, and completely meets the requirement of API Spec 7-1 and SY/T5144 Standard. It has good low magnetic permeability, high mechanical property and perfect enduring intergranular corrosion cracking performance. It is mainly used for the inspection in the process of petroleum drilling, and the structure is the same with the ordinary drill collar.

Trepanning and Heat Treatment:
Drill collars are trepanned and drifted to API Spec 7-1. Full-length heat-treatment processes ensure that mechanical properties meet or exceed API Spec 7-1 requirements. A hardness range of 285-341, Brinell hardness and Charpy "V" notch minimum impact strength of 40 ft-lb at 70 F are guaranteed one inch below the surface.

Traceability:
Drill collar material and process traceability are maintained from receipt of the mill's certified raw material to completion of manufacturing. Serial numbers are die stamped on bar bodies.

Rigid Inspection Procedures:
We inspect all our drill collars to ensure compliance with API SPEC 7-1 standards. These inspections include visual dimensional checks as well as ultrasonic inspections over the entire body of the drill collar.

Cold Rolling:
Drill collar thread roots, as well as elevator recess upper radius, are cold-rolled. Cold rolling creates a compressive recess upper radius stress condition that increases fatigue life by minimizing crack initiation.

Phosphate-coated or Copper Plating:
All connections are phosphate-coated or copper plated to improve resistance to corrosion.

Slip Groove, Elevator Groove and Size:
Lake offers optional slip and elevator recesses to improve handling efficiency and safety. Unless otherwise specified, slip and elevator recesses are machined in compliance with API spec 7-1 guidelines.

Thread Protectors:
Our company offers steel, cast steel and plastic steel thread protectors for its drill stem products.


Nominal size
OD
ID
L (mm)
DF(mm)
Bending Strength
ratio
mm
Inch
mm
inch
NC31-41(2-7/8IF)
104.8
4-1/8
50.8
2
9150
100.4
2.43:1
NC35-47
120.7
4-3/4
50.8
2
9150
114.7
2.58:1
NC38-50(3-1/2IF)
127.0
5
57.2
2-1/4
9150
121.0
2.38:1
NC44-60
152.4
6
57.2
2-1/4
9150/9450
144.5
2.49:1
NC44-60
152.4
6
71.4
2-13/16
9150/9450
144.5
2.84:1
NC44-62
158.8
6-1/4
57.2
2-1/4
9150/9450
149.2
2.91:1
NC46-62(4IF)
158.8
6-1/4
71.4
2-13/16
9150/9450
150.0
2.63:1
NC46-65(4IF)
165.1
6-1/2
57.2
2-1/4
9150/9450
154.8
2.76:1
NC46-65(4IF)
165.1
6-1/2
71.4
2-13/16
9150/9450
154.8
3.05:1
NC46-67(4IF)
171.4
6-3/4
57.2
2-1/4
9150/9450
159.5
3.18:1
NC50-67(4-1/2IF)
171.4
6-3/4
71.4
2-13/16
9150/9450
159.5
2.37:1
NC50-70(4-1/2IF)
177.8
7
57.2
2-1/4
9150/9450
164.7
2.54:1
NC50-70(4-1/2IF)
177.8
7
71.4
2-13/16
9150/9450
164.7
2.73:1
NC50-72(4-1/2IF)
184.2
7-1/4
71.4
2-13/16
9150/9450
169.5
3.12:1
NC56-77
196.8
7-3/4
71.4
2-13/16
9150/9450
185.3
2.70:1
NC56-80
203.2
8
71.4
2-13/16
9150/9450
190.1
3.02:1
6-5/8REG
209.6
8-1/4
71.4
2-13/16
9150/9450
195.7
2.93:1
NC61-90
228.6
9
71.4
2-13/16
9150/9450
212.7
3.17:1
7-5/8REG
241.3
9-1/2
76.2
3
9150/9450
223.8
2.81:1
NC70-97
247.6
9-3/4
76.2
3
9150/9450
232.6
2.57:1
NC70-100
254.0
10
76.2
3
9150/9450
237.3
2.81:1