The drill collar are made of 4145H modified chromium-molybdenum alloy steel according to API Spec 7 and aSY/T 5144 . All threads can be phosphated,copperised or cold worked. All threads are machined with CNC Lathes-Double-Shouldered and a special thread, the max diameter of drill collar is 14 inch.
|
Connection #
|
OD
|
ID
|
L mm
|
DF
mm
|
Bending strength ratio
|
||
|
mm
|
in
|
Mm
|
In
|
||||
|
NC23-31
|
79.4
|
3 1/8
|
31.8
|
1 1/4
|
9150
|
76.2
|
2.57:1
|
|
NC26-35
|
88.9
|
3 1/2
|
38.1
|
1 1/2
|
9150
|
82.9
|
2.42:1
|
|
NC31-41
|
104.8
|
4 1/8
|
50.8
|
2
|
9150 or 9450
|
100.4
|
2.43:1
|
|
NC35-47
|
120.7
|
4 3/4
|
50.8
|
2
|
9150 or 9450
|
114.7
|
2.58:1
|
|
NC38-50
|
127.0
|
5
|
57.2
|
2 1/4
|
9150 or 9450
|
121.0
|
2.38:1
|
|
NC44-60
|
152.4
|
6
|
57.2
|
2 1/4
|
9150 or 9450
|
144.5
|
2.49:1
|
|
NC44-60
|
152.4
|
6
|
71.4
|
2 13/16
|
9150 or 9450
|
144.5
|
2.84:1
|
|
NC44-62
|
158.8
|
6 1/4
|
57.2
|
2 1/4
|
9150 or 9450
|
149.2
|
2.91:1
|
|
NC46-62
|
158.8
|
6 1/4
|
71.4
|
2 13/16
|
9150 or 9450
|
150.0
|
2.63:1
|
|
NC46-65
|
165.1
|
6 1/2
|
57.2
|
2 1/4
|
9150 or 9450
|
154.8
|
2.76:1
|
|
NC46-65
|
165.1
|
6 1/2
|
71.4
|
2 13/16
|
9150 or 9450
|
154.8
|
3.05:1
|
|
NC46-47
|
171.4
|
6 3/4
|
57.2
|
2 1/4
|
9150 or 9450
|
159.5
|
3.18:1
|
|
NC50-67
|
171.4
|
6 3/4
|
71.4
|
2 13/16
|
9150 or 9450
|
159.5
|
2.37:1
|
|
NC50-70
|
177.8
|
7
|
57.2
|
2 1/4
|
9150 or 9450
|
164.7
|
2.54:1
|
|
NC50-70
|
177.8
|
7
|
71.4
|
2 13/16
|
9150 or 9450
|
164.7
|
2.73:1
|
|
NC50-72
|
184.2
|
7 1/4
|
71.4
|
2 13/16
|
9150 or 9450
|
169.5
|
3.12:1
|
|
NC56-77
|
196.8
|
7 3/4
|
71.4
|
2 13/16
|
9150 or 9450
|
185.3
|
2.70:1
|
|
NC56-80
|
203.2
|
8
|
71.4
|
2 13/16
|
9150 or 9450
|
190.1
|
3.02:1
|
|
6 5/8 REG
|
209.6
|
8 1/4
|
71.4
|
2 13/16
|
9150 or 9450
|
195.7
|
2.93:1
|
|
NC61-90
|
228.6
|
9
|
71.4
|
2 13/16
|
9150 or 9450
|
212.7
|
3.17:1
|