1) Our Drill Collars accord with API SPEC 7-1 standard, and we get the right to use the API 7 LOGO.
2) Material: AISI 4145H
3) Size OD: 3 1/8 ,3 1/2 ,4 1/8 ,4 1/2 ,5 ,6 ,6 1/4 ,6 1/2 ,6 3/4 ,7 ,7 1/4 ,7 3/4 ,8 ,8 1/4 ,9 ,9 1/4 ,9 3/4 ,10 ,11
4) Length: 9150mm,9450mm

The drill collars are made of AISI 4145H forging or finish rolling alloy structural steel. The drill collar are trepanned and drifted to API Spec 7. Grinding crafts adopted finish boring technology eliminates regions of the weld stress concentration, making welding appearance more perfect, and increases their life. The full length thermal treatment ensure the mechanical performances fullfil even exceed API Spec 7 requirements. Its hardness ranges from 285 to 341HB, moreover, charpy V notch minimum impact strength of 40 ft lb at 70 are guaranteed one inch below the surface.

From receipt of mills certified raw material to the completion of all the processing, in each process of which complete traceablity mechanism workcraft. Serial numbers are die stamped on bar bodies.

All our drill collars are inspected to comply with the API standards. These inspections include fluorescent magnetic particle detection and inner ultrasonic flaw detection and hardness detection over the entire body of the drill collar as well as other mechanical performance detection.

The thread roots, as well as the elevator recess, shall be cold rolled. Cold rolling creates such a compressive upper radius stress that increases fatigue resistance by minimizing crack initiation. All connections shall undergo phosphate coated or copper plating process to ensure corrosion resistance, so as to avoid galled thread. Steel, cast steel, and plastic steel thread protectors for the drill stem products are subject to your requirements.

We can also supply various types of short drill collar, it is used to adjust the location of downhole drilling tool and improve the function of drilling tool, it has the same mechanical property as drill collars, also it can be made according to special requirements.

1) Our Drill Collars accord with API SPEC 7-1 standard, and we get the right to use the API 7 LOGO.
2) Material: AISI 4145H
3) Size OD: 3 1/8 ,3 1/2 ,4 1/8 ,4 1/2 ,5 ,6 ,6 1/4 ,6 1/2 ,6 3/4 ,7 ,7 1/4 ,7 3/4 ,8 ,8 1/4 ,9 ,9 1/4 ,9 3/4 ,10 ,11
4) Length: 9150mm,9450mm

The drill collars are made of AISI 4145H forging or finish rolling alloy structural steel. The drill collar are trepanned and drifted to API Spec 7. Grinding crafts adopted finish boring technology eliminates regions of the weld stress concentration, making welding appearance more perfect, and increases their life. The full length thermal treatment ensure the mechanical performances fullfil even exceed API Spec 7 requirements. Its hardness ranges from 285 to 341HB, moreover, charpy V notch minimum impact strength of 40 ft lb at 70 are guaranteed one inch below the surface.

From receipt of mills certified raw material to the completion of all the processing, in each process of which complete traceablity mechanism workcraft. Serial numbers are die stamped on bar bodies.

All our drill collars are inspected to comply with the API standards. These inspections include fluorescent magnetic particle detection and inner ultrasonic flaw detection and hardness detection over the entire body of the drill collar as well as other mechanical performance detection.

The thread roots, as well as the elevator recess, shall be cold rolled. Cold rolling creates such a compressive upper radius stress that increases fatigue resistance by minimizing crack initiation. All connections shall undergo phosphate coated or copper plating process to ensure corrosion resistance, so as to avoid galled thread. Steel, cast steel, and plastic steel thread protectors for the drill stem products are subject to your requirements.

We can also supply various types of short drill collar, it is used to adjust the location of downhole drilling tool and improve the function of drilling tool, it has the same mechanical property as drill collars, also it can be made according to special requirements.