Drill Collars 3.125 Inch 3.375 Inch
Drill Collars 3.125 Inch 3.375 Inch
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Basic Infomation
Place of Origin: China
Brand Name: ROSCHEN
Certification: API
Model Number: 3.125inch 3.375inch
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Drill Collars


Spiral Drill Collars


Non Magnetic Drill Collars

Payment & Shipping Terms
Packaging Details: wooden Box, Bundle
Product Description


Drill Collars 3.125inch 3.375inch



Drill Collars


Command Tubular’s drill collars are made of modified AISI 4145H chromium molybdenum alloy steel. These drill collar bars are full-length heat treated and water quenched to obtain mechanical properties as specified by API Spec 7-1.


Full mechanical and chemical mill test certifications are supplied with all drill collars. These mill test certifications guarantee a hardness range of 285 to 341 BHN and an impact value of 40 ft-lbs at room temperature, one inch below surface.


All drill collar bars are trepanned then drifted to API specifications to ensure close tolerance bores. Drill collars are also supplied with the outer surface either machined or rough peeled.



Drill Collars 3.125 Inch 3.375 Inch 0

Drill Collars 3.125 Inch 3.375 Inch 1


Spiral Drill Collars


The spiral cut is added to a drill collar to prevent the likelihood of differential wall-sticking by reducing wall contact between the drill collar and the wall of the hole. The spiralling starts 22” from the bottom of the slip recess or 79” from the box end and ends 30” from the pin end. Adding spiralling to drill collars reduces the weight by approximately 4%.


Short nonmagnetic drill collars (SNMDCs):

SNMDCs are used between a mud motor and a mud collar to neutralize magnetic interference from the following.


Non-Magnetic Drill Collars


Command Tubular’s non-magnetic drill collars are an integral heavy duty joint that are constructed from a solid bar of austenitic stainless steel. Our non-magnetic drill collars are supplied with a machined surface finish condition.


All non-magnetic collars are hot/cold worked in order to provide them with the necessary mechanical properties. The bars are then trepanned, hot spot inspected and machined. An internal bore treatment is performed on the full length in order to achieve the proper compressive status of the internal diameter.


This provides the collar with optimal resistance to stress corrosion cracking. All of our drill collars are manufactured in accordance with API spec 7, Q1 and recommended practice 7G as applicable.



For more information please contact:



WeChat: +86-137 6419 5009 ; +86-135 8585 5390

WhatsApp: +86-137 6419 5009 ; +86-135 8585 5390

Email: roschen@roschen.com ; roschen@roschen.net


Website: http://www.roschen.com ; http://www.roschen.net

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Get in touch with us
Contact Person : Mr. Bill, George, Michael
Tel : 13764195009
Fax : 86-021-54380177
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