Drill collars are manufactured from AISI4145H structural alloy steel through forging and fine rolling.
Trepanning and Heat treating: Drill collar manufacturing follow API SPEC7, heat treatment processing keep full length to ensure the mechanical property meet API SPEC 7 standard. Under the body surface one inch the hardness charpy V-notch force achieve 40ft/lb.
Traceability: Drill collar material and process traceability are maintained from receipt of certified raw material to completion of all the manufacturing. Serial numbers are die stamped on bar bodies.
Rigid inspection procedures: We inspect all our drill collars to comply with API standards. These inspections include visual dimensional checks as well as ultrasonic inspections over the entire body of the drill collar. Cold rolling: drill collar thread roots as well as elevator recess upper radius are cold rolled. Cold rolling creates a compressive recess upper radius stress condition that increases fatigue life by minimizing crack propagation.
Phosphate-coated or copper plating: All connections are phosphate-coated or copper plating to improve resistance to corrosion.
Slip groove, elevator groove and size: Our company offers optional slip and elevator recess to improve handling efficiency and safety. Unless otherwise specified Slip and elevator recesses are machined in compliance with API RP7G guidelines.
Thread protectors: Our company offers steel and cast steel and plastic steel thread protectors for its drill stem products.