Spiral drill collar

Spiral drill collar
Size Range: 3-1/8--11
Cylindrical, spiral, non-magnetc Type
Mechanical properties can mee
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.
Type C(Non-magnetic) Be Made of stainless alloy steel with rather low Magnetic permeability and the cross sections of the inside and outside pipe are both round.
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.