Drill collars are manufactured from AISI 4145H modified steel, and
are supplied in the "as rolled" surface finish condition.
Alternative surface finishes are available.
Trepanning and Heat Treatment:
Drill collars are trepanned and drifted to API Spec 7-1.
Full-length heat-treatment processes ensure that 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 one inch below
Drill collar material and process traceability are maintained from
receipt of the mill's certified raw material to completion of
manufacturing. Serial numbers are die stamped on bar bodies.
Rigid Inspection Procedures:
We inspect all our drill collars to ensure compliance with API SPEC
7-1 standards. These inspections include visual dimensional checks
as well as ultrasonic inspections over the entire body of the drill
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
Phosphate-coated or Copper Plating:
All connections are phosphate-coated or copper plated to improve
resistance to corrosion.
Slip Groove, Elevator Groove and Size:
Dynoland offers optional slip and elevator recesses to improve
handling efficiency and safety. Unless otherwise specified, slip
and elevator recesses are machined in compliance with API spec 7-1
Our company offers steel, cast steel and plastic steel thread
protectors for its drill stem products.