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Size Range 3-1/8”——11”
Brief Introduction
Hengshan drill collars are made of AISI 4145 H or 4145 H modified alloy steel. The chemical composition is controlled strictly during the refining and forging process. It can be divided into the following three types according to the appearance and material:
Type A(Cylindrical) Be Made of alloy steel and the cross sections of the inside and outside pipe are both round.
Type B(Spiral) Be Made of alloy steel and the outside pipe has spiral grooves.
Mechanical Properties
A type and B type drill collar
OD | Yield Strength MPa | Tensile Strength MPa | Elongation % | Brinell Hardness HB | Impact APV J | |
mm | in | |||||
79.4~171.4 | 31/8~63/4 | ≥758 | ≥965 | ≥13 | 285~341 | ≥54 |
177.8~279.4 | 7~11 | ≥689 | ≥930 | ≥13 | 285~341 | ≥54 |
C type drill collar
OD | Yield Strength MPa | Tensile Strength MPa | Elongation % | Brinell Hardness HB | Impact APV J | |
mm | in | |||||
79.4~171.4 | 31/8~63/4 | ≥758 | ≥827 | ≥18 | ||
177.8~279.4 | 7~11 | ≥689 | ≥758 | ≥20 | ||
Usage As an important part of drill stem, drill collar can supply the drilling pressure for the drill bit and increase the rigidity of drill stem.