Herui provides a full range of slick and spiral drill collars in AISI 4145H or AISI 4145H modified steel. All the materials are heat treated in full length with best material quality.

Slick Drill Collar: we can produce from 2 7/8'' OD to 14'' OD drill collar with API, Non API, or special connections.

Spiral Drill Collar: we can produce three right-hand spiral grooves on drill collar. Spiral grooves decrease the volume of contact between well side and pipe, and it leads to reduce the occurrence of differential pressure sticking. The weight of spiral drill collar is 4% less than slick drill collar at small size. Spiral drill collar can be divided in to Type I and Type II according to spiral grooves.

Mechanical properties guaranteed to 1.5" below surface at ambient temperature; Enhanced fatigue resistance (threads cold-rolled, pin-relief groove and box bore back); Phos-coated to prevent galling; and Hardbanding is available upon request.

The upper radius of the elevator recess is cold-rolled to increase product life. Slip and elevator recesses can be used together or separately. Special drill pipe elevator designs can be supplied for automated handling operations to decrease non-productive time.