What are the Tube to Tubesheet Joint Types?

Heat exchangers or gas condensers form a critical part of the applications that use process fluid for heating or cooling applications. Especially, the shell and tube type is used commonly across petrochemical refineries, the food and beverage industry, power plants, and other major industries for extensive heating, cooling, or refrigeration. Fabricating these exchangers, however, is a unique challenge in itself.

Tube to tubesheet welding is the primary fabrication process for shell and tube-type exchangers. The multiple tubes require connection to the tubesheet, which can be achieved using a suitable tube to tubesheet joint type. Each joint type has a unique welding demand, which is the key to enhancing overall operational productivity.

Tube to Tubesheet Joint Types

Tube to tubesheet welding can be done manually, or it can be automated with orbital welding. Regardless, weld preparation is an important step. Once the right material is selected, the tube and tubesheet surface must be cleaned, and their edges prepared. This can be done so using various tube to tubesheet joint types.

1. Protruding tubes

One way to prepare the connection of tube to tubesheet is by protruding the tubes slightly through the sheets. The weld requirement of these joint types are —

Use of filler wires in most cases
Protruded length of the tube must be at least 5mm
The preferred weld angle for thin-walled tube (1.6 to 2.11 mm) is 15° and for thick-walled tube (>2.5mm) is 30°
Weld preparation include V-groove, J-groove, or no groove

2. Recessed tubes

These joint types have the tube slightly recessed into the sheet to weld around it. This type of welding requires —

J or V preparation of the tube plate
It may require more than one weld pass depending on the tube thickness
Filler wire may be used
Typically desired when strength welding
include V-groove, J-groove, or no groove

3. Flush tubes

When flush welding tubes to tubesheet, the joint design may be carried out using the following criteria —

With or without filler metal
J, V, or standard grooving of the tube ends. Some applications may also require relief grooves
For mechanically strong welding, it is desired to have more than one pass
include V-groove, J-groove, or no groove

Typically, tubes are recessed or protruded from the tube sheet during strength welding. The flush welding seals the tube and tube sheet meeting at the same level. Specialized open or closed weld heads can help manufacturers achieve quality while welding different tube to tubesheet joint types.

Orbital Welding Is Suitable For All Joint Types

Orbital welding is known for its precision and quality when fabricating critical tube to tubesheet joint types. With its automated parameter control, orbital welding allows the optimization of heat input, voltage, gas flow, feed rate, and weld head movement, which are the key to tube to tubesheet welding. As a result, the different tube to tubesheet weld head configurations can easily access the recessed or protruded joints.

AMI weld heads such as the Model 6 are suitable for welding in any position, the different tube to tubesheet joint types. With a compatible power supply and weld heads paired together, orbital welding is sure to enhance the productivity and quality of your tube to tubesheet welding project.

READY TO CONNECT?

Arc Machines, Inc., a leading supplier of advanced orbital welding equipment, provides a range of weld heads and power supplies compatible with fabricating different tube to tubesheet joint types. For inquiries regarding these and other products, contact sales@arcmachines.com. For service inquiries, contact service@arcmachines.com. Arc Machines welcomes the opportunity to discuss your specific needs. Contact us to arrange a meeting.