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Product - Drill Collar
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Brief Introduction
The Drilling tools are made from premium chromium molybdenum alloy steel in accordance with API Spec. 7 and API RP7G, residual elements such as sulphur and phosphorus are reduced during the steel steel making process that make the material with high physical properties.

Heat Treatment is a decisive process in the production of drill tools. Heat treatment must be uniform and deep enough to ensure required physical properties in critical threaded sections. Heat treatment programs are established based on the actual chemical analysis of each heat of steel to ensure the materials meet or surpass the requirements of API Specification.

Threads is the most important factor for drilling string. All threads would be machined with CNC Lathes and inspected with related thread gauges in conformance with API Specification. All threads would be phosphated or copperized and the roots cold rolled. All Connections would be equipped with pressed steel thread protectors.

Quality Control is performed strictly with requirement of API Q1 and ISO 9002. We established a standard inspection laboratory center for physical and chemical testing. All testing information obtained is recorded on the inspection certificate furnished with each product. And all inspectors must have relevant qualification.

¡¡ Drill Collars
The drill collars are made of AISI 4145 H or 4145 H modified alloy steel. Its bores are trepanned from one direction with no mismatch. All drill collars are Q&T overall length by our own unique power frequency induction heating treatment machine to ensure the hardness within 285 to 341 BHN which are guaranteed one inch below the surface of pipe.
We also manufactures special Drill Collars with Spiral, Slip and Elevator recesses, Hardbarding and Square Drill Collar.
The drill collars are available in lengths from 10 to 32 feet and outside diameter from 3/1/2" to 10". Nominal sizes and other relevant and important sizes are lilsted below.

Connection interchange list
Connection name
Size
Numbered connection NC
26
31
38
40
46
50
Modifing numbered connection NNC
26
31
38
40
46
50
Internal flush IF
2 3/8
2 7/8
3 1/2
4
4 1/2
Full hole FH
4
Slim hole SH
2 7/8
3 1/2
4 1/2
Extra hole XH
4 1/2
5
Note: NNC threads are the factory own technology which could be interchangable with API NC threads. NNC threads are better for reducing the roots stress than NC thread.

Mechanical Properties
The mechanical properties of the drill collar along the whole length under the room temperature.
Outside diameter of drill collar
inch
Tensile strength MPa
Yield strength MPa
Elongation (L=4D)
%
Impact AKV
J
Brinell Hardness
HB
3 1/8 ~ 6 3/4
¡Ý 965
¡Ý 758
¡Ý 13
¡Ý 54
¡Ý 285
7 ~ 10
¡Ý 930
¡Ý 689
¡Ý 13
¡Ý 54
¡Ý 285


One Inquiry and orders, please specify:

  • Type (slick or spiral grooved).
  • Outside and inside diameters and overall length.
  • Connection size and type.
  • API Stress Relief Groove on pin and box ends.
  • Cast or pressed steel thread protectors.
  • Other special request, for exmaple: slip or elevator recess and hardbanding style.

    For any futher information, please contact us. We can offer you the electrical catalogue of drill tools for your reference.
Add: Shanfu Road E., Shanyang Town, Jinshan Area, Shanghai, China. Zip code: 201508
E-mail£º sales@happiescn.com , happiescn@gmail.com, happiescn@hotmail.com, Website: www.happiescn.com