Parveen Drill Collars are made from ultrasonically tested bars of Chrome Molybdenum Alloy Steel (AISI4145 modified material) and available in all sizes and connections as per API std 7 & API RP 7G in Range 2. Drill collar bars are fully heat treated to 285 to 341BHN and Charpy impact value of 40 ft. lb.

PARVEEN basically provides three kinds of Drill Collars. These are :

1) Slick Drill Collars - 30 to 31 ft length
2) Spiral Drill Collars - 30 to 31 ft length
3) Short Drill Collars upto 20 ft length

Following special Drill Collars features are also available on request:

- API stress relief grooves in pin & box.
- API bore back box.
- API slip & elevator recess.
- Cold rolled thread roots.
- Drill collar hard banding.
- Phosphating end connections
- Thread protectors for box & pin.

Ordering Instructions:

- Outside Diameter.
- Inside Diameter.
- Length.
- Connection Size & Type;
Stress Relief Groove (SRG) Or
without SRG feature. Bore Back Box or without.
- Slip and/or elevator recess.
- Spiral details.
- Hard banding.
- Standard or Heavy duty
  Thread protectors.
- Any Special Features, such
  as Phosphating etc.

Stress Relief Grooves
Stress relief Grooves at pin and box end reduce fatigue failure.

Bore Back Box
Bore back box is nothing but gradual reduction of internal dia 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.

Cold Rolled Thread Roots
The cold working on thread roots of the Drill Collars thru inducing compressive stresses with the help of externally loaded roller will increase life of Drill Collar by protecting against bending stress in fatigue.

Drill Collar Hard Banding
Hard banding a Drill collar increases the life of Drill Collar while drilling in an abrasive medium. In hard banding, granular tungsten carbide is deposited upto 1/32" (0.8mm) above Drill Collar O.D. by metal arc, inert gas shielded welding with controlled preheating & post heating.

Note: Hard Banding at other locations are also catered upon request.

Short Drill Collars
Short Drill Collars are made to suit material, sizes, properties & features as specified above except the length is smaller. Short Drill Collars in various lengths are available in slick or spiral. Standard Short Drill collar lengths are 10, 12, 15 1/2 & 20 ft long. For Dimensions, please refer to main Drill Collar section.

Drill Collar Groove
For Elevator and Slip (as per API-7G). It is possible to add elevator and slip recess to Parveen Drill Collar. These recesses allow one to dispense with lift subs and safety clamps and to attain savings in operating time. Recommended Slip & Elevator recess dimensions are given below:

All Dimension are in inches U.O.S

Spiral Drill Collars
Minimize the potential for differential sticking with Parveen's Spiral Drill Collars. They reduce the amount of contact between the drill collar and the wall of hole.

All Dimension are in inches U.O.S

Non Magnetic Drill Collars
Parveen's Non magnetic drill collars meet the standards for chemical composition used in directional drilling and in addition have.
1. Extremely clean steel.
2. Low permeability, high mechanical properties and superior resistances to corrosion cracking.
3. Display high strength and low permeability throughout the product.

Chemical Composition
These non magnetic drill collars are of Cr-Mn type. The Chemical Composition will be such so as to satisfy the following mechanical properties and permeability.

Mechanical Properties

Size	Yield Strength (0.2%)	Tensile Strength (Minimum)	Minimum Elongation Percent	Charpy Impact Value.
3.1/2" Thru 6.7/8"	110,000 psi (758N/mm2)	120,000 psi (827N/mm2)	18	min. 40 Ft lb.
7" Thru 11"	100,000 psi (689N/mm2)	110,000 psi (758N/mm2)	20	min. 40 Ft lb.

Permeability
Relative Magnetic permeability shall be less than 1.010 through the entire length and the level of such permeability to be uniform. This level of permeability to be uniform. This level of permeability remains stable despite fluctuation of local plastic deformation and temperature fluctuation during operation.

Sizes
Size conform to API Spec.7.

Corrosion Resistance
Austenic stainless steel drill collars are subject to cracking due to conjoint action of tensile stress and certain specific corrodents. This is called stress corrosion cracking.

Resistance to corrosion can be demonstrated by subjecting materials from each Drill Collar to the corrosion test as specified in ASTM A262 practice.

Ultrasonic Testing
Drill collar bodies are inspected ultrasonically full length over the circumference of the body before boring. Examination Techniques are specified in ASTM E114(direct contact method) and ASTM E214 and / or ASTM E1001 (immersion method).