Spiral grooved Drill Collars have spiral grooving on the surface of the drill collars in order to reduce contact area with hole so as to avoid efficiently bit sticking from differential pressure. Our Drill Collars are manufactured strictly according to API Spec 7-1. They are manufactured from 4145H modified quenched and tempered steel, strict metallurgical specifications are followed to insure that full length heat treating produces a consistent maximum depth of hardness.

 

Features and Benefits

●A hardness range of 285 to 341 BHN and a Charpy impact value of 40 ft-lbs are guaranteed at evenly distributed 16 points in any sections at room temperature;

●Connections are completed（phosphate coated）to protect them from the elements after machining and to help prevent galling upon initial make-up;

●Thread roots are cold rolled on API and H-90 connections;

●Pressed steel thread protectors are supplied for all drill collar that are equipped with standard connections

Stress Relief Groove & Bore Back Box

Stress relief grooves improve bending strength of pin and box connections and, therefore,    durability. Stress relief grooves for box and pin are defined by API. 

Bore back box is nothing but gradual reduction of internal diameter by gradually increasing material cross sectional area at critical section. This will ultimately reduce drastically stress concentration during Static / Dynamic loading and prevents box connections from failure.

Recommended Hardbanding Location

-Drill collars with slip and elevator recesses (ZIP)

4”long wear pad above elevator recess

1”long wear pad above slip recess.

10”long wear pad under slip recess

-Drill collars with slip recess:

10”long wear pad under slip recess,

4”long wear pad above slip recess.

-Drill collars without slip and elevator recesses:

10”long wear pad at 30”from pin shoulder.

Hardbanding

We provide several hardbanding materials for Customer’s choice: Arnco-100XT, Arnco-300XT, TCS-8000;

Slip and Elevator Recess

Slip and elevator recesses improve downhole handling efficiency and safety. Slip and elevator recesses are machined in accordance with API 7-1.