Drill Collars
Drill collars are thick wall tubulars machined from solid steel bars. As an integral part of the drillstring, they provide weight-on-bit to improve drilling performance. The heavy weight of the drill collars increases the downward force on the bit to provide maximum efficiency in breaking down the formation. Roschen provides a range of drill collars in AISI 4145H-modified steel. Material suitable for use in sour service applications can also be supplied on request.
• ODs from 3 1/8" to 8 1/4"
• API and double shoulder connections
• Mechanical properties guaranteed to 1" below surface at ambient temperature
• Cold-rolled thread roots, pin relief groove and box bore back to enhance fatigue resistance
• Phosphate coating on threads to prevent galling
Slip and elevator recesses are availble to improve handling efficiency and safety. These recesses, machined in accordance with API standard RP7G, are available separately or together.
Spiralling, to reduce contact the contact area with the bore wall and prevent differential pressure sticking is possible on most size of collars. The grooves consist of three right-hand spirals, machined using special milling machines.
Tungsten Carbide Hardbanding for improved wear resistance is available in a variety of configurations:
• No slip or elevator groove
– 10" long wear pad 30" from pin shoulder
• Zip groove (slip and elevator)
– 4" long wear pad above elevator recess
– 1" long wear pad above slip recess
– 10" long wear pad below slip recess
• Slip recess only
– 4" long wear pad above slip recess
– 10" long wear pad below slip recess
ROSCHEN@ INC.
ROSCHEN@ GROUP LIMITED
ROBERT ROSCHEN@ LIMITED
ROSCHEN@ HOLDINGS LIMITED
HEFEI ROSCHEN@ TOOL CO., LTD.
ROSCHEN@ GEOLOGICAL TOOL CO.,LTD.
SHANGHAI ROSCHEN@ INTERNATIONAL CO., LTD.
ROSCHEN@ GEOLOGICAL INSTRUMENTS CO., LTD.
EMAIL: roschen@roschen.com ; roschen@roschen.net
Website: http://www.roschendrill.com
http://www.roschenmining.com
http://www.roschendrilling.com
http://www.explorationcoredrilling.com
http://www.roschen.net
http://www.roschen.cn
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