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30 years of zelkot

Advantage Through


Tube bending

Our company is equipped with the latest boiler tube hydraulic benders. Very specialized tooling allow us to cold bend tubes up to 168,3mm in diameter and with maximum bend radius of  7D while the minimal bend radius to tube diameter is equal to 1 (R/D=1).

Lately we have developed a new method of production of tube bends with bend radius to tube diameter equal to 0,5 (R/D=0,5) for tubes in diameter up to 88,9mm.

Over the years we have specialized in bending of composite tubes (overlaid with superalloys or austenitic fillers) as well as corrosion and erosion resistant thermal or plasma sprayed surfaces.

We also have a modern gang bending machine for panels up to 2000mm in width and with tube diameter up to 101,6mm.


Our company has a large inventory of qualified welding procedures according to EN ISO 15614-1, EN ISO 15614-8, and ASME IX. We are able to weld all steel grades according to CR ISO 15608 and are specialized in welding the following materials:

  • Ferritic steels: P265GH, P355GH, 16Mo3 (T/P1), 13CrMo4-5 (T/P12), 10CrMo9-10 (T/P22)
  • Martensitic steels: X10CrMoVNb9-1 (T/P91), X10CrMoVNb9-2 (T/P92)
  • Austenitic steels: 309, 310, TP321H, TP347H(FG), Super304H, 253MA, 310HCbN (HR3C)
  • Heat resistant ferritic steels: X10CrAlSi24, X8CrTi25, X18CrN28
  • Superalloys: 622, 625, 686, 800HT

Recently we have qualified welding technologies for the newest martensitic and bainitic steel grades:

  • VM12-SHC
  • T23 (7CrWVMoNb9-6)
  • T24 (7CrMoVTiB10-10)

Our welding technology is based on industry standard processes such as SMAW (111), SAW (121), GMAW (131/135), FCAW (136) and GTAW (141). In our company we have also introduced an innovative panel welding line which allows us to produce membrane walls for all types of boilers.


Lately we have expanded our machining capacities with new CNC machine tools to include:

  • 3+3 axis CNC bed type milling machine with X travel up to 6250mm
  • 3+2 axis high speed CNC milling machine with X travel up to 2940mm
  • 3+1 axis CNC milling machine with X travel up to 1250mm
  • 3 axis CNC milling machine with X travel up to 1000mm
  • 2 axis CNC lathe with automatic feeder


Our key products - economizers, superheaters, boiler walls, headers, openings, pipelines, heat exchangers, condensers, tanks, steel constructions, spirals.

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We are constantly developing bending and welding technologies in cooperation with Polish and European R&D units.

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Our products are being used in boiler devices and installations with innovative technical, which help to improve environment.

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