Designed to place weight on the drill bit and pump drilling fluids, our drill collars are integral heavy-wall joints manufactured from a solid bar of modified alloy steel. The solid bars are quenched and tempered to obtain the required mechanical properties and then trepanned, drifted, and threaded. Our drill collars are furnished as slick or spiraled; spiraled drill collars have grooves machined in the outside surface that promote the even flow of drilling fluid around the drill collar diameter, equalizing pressure and reducing the occurrence of differential sticking.
Grant Prideco™ drill collars are manufactured from AISI 4145H modified steel and supplied in the as-rolled surface finish condition (alternative surface finishes can be provided). Drill collars are trepanned and drifted to API Spec. 7-1. Full-length heat-treatment processes ensure mechanical properties meet or exceed API Spec. 7-1 requirements. A hardness range of 285-341 Brinell hardness and Charpy “V” notch minimum impact strength of 40 ft-lb at 70 °F are guaranteed 1 in. below the surface.
Drill collar material and process traceability are maintained from receipt of mill-certified raw material to completion of all manufacturing. Serial numbers are die-stamped on drill collar bodies.
We inspect all our drill collars to comply with API standards and Grant Prideco specifications. These inspections include visual dimensional checks as well as ultrasonic inspections over the entire length of the drill collar.
We offer optional slip and elevator recesses to improve handling efficiency and safety. The upper radius of the elevator recess is cold-rolled to increase product fatigue life. Slip and elevator recesses can be used together or separately. Unless otherwise specified, slip and elevator recesses are machined in compliance with API Spec. 7-1.