Shanxi North Fenglei Industry Group Co.,Ltd.-Drill collar-Detailed Data
Manufacturing Specification of drill collar
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API threading connection
All API connections comply with dimensional requirements specified in API Spec. 7 latest edition and guidelines presented in API RP7G Latest Edition
Threading Interchangeable Sheet
| Connection Name |
Size
|
|
NC
|
26
|
31
|
38
|
40
|
46
|
50
|
|
NNC
|
26
|
31
|
38
|
40
|
46
|
50
|
|
IF
|
2 3/8
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2 7/8
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3 1/2
|
|
4
|
4 1/2
|
|
FH
|
|
|
|
4
|
|
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Note: NNC threads (or High Torque threads) are the SFMC's own technology which could be interchangeable with API NC threads. NNC threads are better for reducing the roots stress than NC threads.
Cold rolling thread roots
SFMC drill collar thread roots and stress relief features are cold rolled, which is helpful to reduce the fatigue failure of threads by minimizing crack initiation.
Anti-Galling treatment
All SFMC drill collar threads would be phosphatized or copperized in order to lower the possibility of connection galling.
Stress Relieve Recess
API pin stress relief groove and box bore back feature, which can reduce stress in the thread roots and significantly improve the connection fatigue life, are optional on SFMC drill collars if orders and inquiries specified.
As indicated in API Spec. 7-1 latest edition, connections NC23, NC26 (2 3/8 IF) and NC31 (2 7/8 IF) have no enough metal to accommodate stress relief features. |
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