Double Wall Drill Pipes

Double Wall Drill Pipes are used in drilling of wells with diameter 84 and 93 mm and depth up to 300 m in soils of II-V drillability classes with seams of soils up to VII drillability class in the fulfilment of all necessary prospecting and geochemical operations, in geological mapping and exploration of deposits of solid minerals.

Drilling of wells is carried out with hydro-transport of the core delivered on the surface along the internal channel of the double drill string.

Double Wall Drill Pipes

Technical characteristics of pipes

Standard size Pipe Connector Length L, mm Weight, kg Thread
External diameter D, mm Wall thickness t, mm External diameter D1, mm Internal diameter d1, mm OD of tong recess S, mm
TBDL-75 75 7 75 56.5 63 4098 25.3 SPK-73
TBDS-73 73 6 75 56.5 63 4098 48.2 SPK-73

Mechanical properties of pipes (at least)

Parameters DWDP-75 DWDP-73
Pipe Connector Pipe Connector
Tensile strength, MPa 539 882 390 882
Yield strength, MPa 323 686 255 686
Elongation, % 16 15 12 15
Hardness HRC 26 26


  1. Mechanical properties of connectors indicated after the volumetric heat treatment.
  2. Surface hardness after heat treatment – not less 45 HRC.