Tubesheet Welding

Inside view of tubular stainless steel heat exchanger Polysoude

Nowadays tubesheet welding is becoming an essential process as much industrial equipment like heat exchangers, steam turbines, condensers, air coolers or boilers are composed by thousands of metal tubes. These tubular constructions are usually assembled on thick metal plates and TIG welded (GTAW) for best performance and long lasting. Automated tube to tubesheet welding has replaced manual welding for advanced productivity and reproducibility of the tube-to-tube sheet joints and of course to shorten production times of industrial tube heat exchangers.

Orbital tube-to-tubesheet welding: Applications and Equipment

Tubesheet welding applications

Tube-to-tubesheet orbital welding applications are used to manufacture boilers and tube heat exchangers for all kinds of industries, however the heaviest equipment is found in the plants of chemical or petrochemical industries and electric power stations.

Nearly all weldable metals and alloys are used in the field of tube to tubesheet welding applications, but the range of the tube dimensions is relatively restricted. Their diameter range covers 12.7 mm to 101.6 mm, the wall thicknesses are between 0.5 mm and 5 mm. Most of the tube diameters measure between 19.05 mm (3/4") and 38.1 mm, with wall thicknesses between 1.65 mm and 3.4 mm.

Everything you need to know is here : free download our New Free Handbook about tubesheet welding and industrial tube heat exchangers 

tubesheet welding head autogenous welding TS-34 production of stainless steel heat exchanger
automatic tube-to-tube sheet orbital tubsheet welding head with wire feeder on stainless steel heat exchanger
tube to tubesheet welding head SPX compact to weld tubes on production of heat exchanger

Orbital Welding Equipment

In most cases, equipment used for automated tube-to-tubesheet welding is strictly adapted to the application and desired level of automation: 

  1. Tubesheet welding machine is featuring three controlled axes (gas, current, rotation) is composed of a stationary installed power source so called a Smart Welding Station and a tube to tubesheet welding head, which executes fusion welding without the addition of filler wire.
  2. Welding equipment, with four controlled axes (gas, current, rotation, wire), comprises a stationary installed welding power source and a tube to tubesheet open welding head. This equipment is suitable for single pass welding; two passes must be welded in two separate steps. 
  3. Welding equipment fitted with five controlled axes (gas, current, rotation, wire, AVC) is composed of a TIG / GTAW power source designed to control 6 axes and a welding head of the type TS 8/75 tube to tube sheet welding head with AVC configuration, allowing the chaining of multiple passes with filler wire. The raising of the torch between the passes can also be programmed and is carried out without interruption of the weld cycle.
  4. Welding equipment furnished with six controlled axes, (gas, current, rotation, wire, AVC, oscillation), comprises a PC Smart Welding Station power source and a tube to tubesheet welding head of the type SPX compact so called TIG 20/160. The equipment allows multi-pass welding; the torch can be displaced in radial direction.

Orbital tube to tubesheet welding weld preparations

Specific requirements of tubes and weld preparations

In orbital tube-to-tubesheet TIG welding, planning brings success: 

  1. The tubes must be seamless or with flattened weld seam
  2. Joints must have J-preparations, ensuring reliable melting of the base of the tube edge, especially in the vertically down position. 
  3. If a good thermal conduction is requested, the play between the tube and the bore can be eliminated by a slight expansion of the tube.
  4. The contact zone between the tube and the tubesheet must be clean, to avoid the formation of unacceptable blowholes.
  5. A full expansion of the tubes inside the tubesheet must never be carried out before automatic welding, as this causes explosive degassing effects. 

Flush tubes

Depending on the application, orbital TIG welding of flush tubes with or without filler metal is possible, using different joint designs: 

  • Standard preparation 
  • J-preparation
  • V-preparation 
  • Relief groove

Tubesheet welding scheme of preparations of the tubesheet for seal or strength welds with flush tubes

Welding of flush tubes without filler wire

Most often standard preparation is carried out for welding flush tubes. For applications without filler wire on tube diameters between 10 mm and 32 mm, specially developed welding heads are used and the complete sequence is carried out automatically.

Welding of flush tubes with filler wire

Welding equipment fitted with four or five controlled axes can be used. The open tube to tubesheet welding head should be configured accordingly: 

  • Integrated or external wire feeder 
  • With or without AVC 
  • With or without shielding gas chamber
  • Torch angle of 0° or 15°.

Welding of protruding tubes

Protruding tubes are always welded using filler wire, but with welds beginning with a fusion pass, different joints can be used: Standard preparation without groove, J-preparation or V-preparation.

Tubesheet welding scheme of preparations of the tubesheet for seal or strength welds with protuding tubes

Welding of recessed tubes

Joint designs are: Standard preparation without groove, J-preparation, V-preparation, Welding behind the tube plate (frequently used in the petrochemical industry).

Tubesheet welding scheme of preparations of the tubesheet for seal or strength welds with recessed tubes

Learn more about tubesheet welding and weld preparation here :

Who we are

Polysoude specialises in the design, development and manufacture of innovative arc welding solutions. The brand is synonymous with world-leading expertise in 3 core sectors: automatic orbital TIG welding systems, automated TIG and plasma welding solutions and TIGer™ weld overlay.
Situated in Nantes since 1961, the company manufactures a variety of power sources and orbital welding equipment, like a wide range of open and closed welding heads.
Nowadays, as a smart factory-oriented company, Polysoude products are all designed to be ready for Industry 4.0.

Contact us

Join our community on LinkedIn: @Polsyoude

Follow us on our social media: 

Facebook @polysoude 

Instagram @polysoudeglobal