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  • spiral drill collar
  • china drill collars
  • spiral drill collars
  • drill collars specifications

Drill Collars

The drill collars are made of 4145H modified chromium-molybdenum alloy steel acc.to API Spec.7 and SY/T 5144.All threads can be phosphated, copperized or cold worked.

■ Precauciones

The drill collars are made of 4145H modified chromium-molybdenum alloy steel acc.to API Spec.7 and SY/T 5144.All threads can be phosphated, copperized or cold worked. All threads are machined with CNC Lathes-Double-shouldered and special threads. And a special the max diameter of drill collar is 14 inch.

◆ Standard sizes, bores and connections of spiral drill collar

Connection OD ID L(mm) Bending strength ratio DF mm Bending strength ratio
  mm in mm in      
NC23-31 79.4 31/8 31.8 11/4 9150 76.2 2.57:1
NC26-35 88.9 31/2 38.1 11/2 9150 82.9 2.42:1
NC31-41 104.8 41/8 50.8 2 9150or9450 100.4 2.43:1
NC35-47 120.7 43/4 50.8 2 9150or9450 114.7 2.58:1
NC38-50 127.0 5 57.2 21/4 9150or9450 121.0 2.38:1
NC44-60 152.4 6 57.2 21/4 9150or9450 144.5 2.49:1
NC44-60 152.4 6 71.4 213/16 9150or9450 144.5 2.84:1
NC44-62 158.8 61/4 57.2 21/4 9150or9450 149.2 2.91:1
NC46-62 158.8 61/4 71.4 213/16 9150or9450 150.0 2.63:1
NC46-65 165.1 61/2 57.2 21/4 9150or9450 154.8 2.76:1
NC46-65 165.1 61/2 71.4 213/16 9150or9450 154.8 3.05:1
NC46-47 171.4 63/4 57.2 21/4 9150or9450 159.5 3.18:1
NC50-67 171.4 63/4 71.4 213/16 9150or9450 159.5 2.37:1
NC50-70 177.8 7 57.2 21/4 9150or9450 164.7 2.54:1
NC50-70 177.8 7 71.4 213/16 9150or9450 164.7 2.73:1
NC50-72 184.2 71/4 71.4 213/16 9150or9450 169.5 3.12:1
NC56-77 196.8 73/4 71.4 213/16 9150or9450 185.3 2.70:1
NC56-80 203.2 8 71.4 213/16 9150or9450 190.1 3.02:1
65/8REG 209.6 81/4 71.4 213/16 9150or9450 195.7 2.93:1
NC61-90 228.6 9 71.4 213/16 9150or9450 212.7 3.17:1
75/8REG 241.3 91/2 76.2 3 9150or9450 223.8 2.81:1
NC70-97 247.6 93/4 76.2 3 9150or9450 232.6 2.57:1
NC70-100 254.0 10 76.2 3 9150or9450 237.3 2.81:1
85/8REG 279.4 11 76.2 3 9150or9450 266.7 2.84:1

Main Technical Parameters

China Spiral Drill Collars Specifications:

◆ Our China Spiral Drill Collars Mechanical Properties

OD Min.Yield Strength
σt Mpa
Min.Tensile Strength
σb Mpa
Min.Elongation % Brinell hardness
HB
Impact value
(V-notch CHARPY)
AK J
mm in
88.9-174.6 3 1/8-6 3/4 ≥758 ≥965 ≥13 ≥285 ≥54
177.8-279.4 7-11 ≥689 ≥930

◆ Dimensional Tolerances Of Spiral Drill Collar

OD OD ID L mm Bevel Diameter DF
mm in
≤88.9 ≤3 1/2 +1.2 0 +1.6 0 +152.4 ±0.4
>88.9-114.3 >3 1/2-4 1/2 +1.6 0
>114.3-139.7 >4 1/2-5 1/2 +2.0 0
>139.7-165.1 >5 1/2-6 1/2 +3.2 0
>165.1-215.9 >6 1/2-8 1/2 +4.0 0
>215.9-241.3 >8 1/2-9 1/2 +4.8 0
>241.3 >9 1/2 +6.4 0