Autogenous TIG Welding for Tube and Tubesheet Applications

Of the five basic weld joint types that include corner, edge, lap, and tee joints, the butt joint may be the most commonly implemented across industries. This is especially true for pipeline applications and tubing systems used in process operations. And while both pipes and tubes can be used in aerospace, power generation, semiconductor, biopharmaceutical, and food processing industries, pipes are utilized to transfer contents under pressure due to their thicker walls. However, when pressure vessels incorporate a tubesheet—or if bending is required—tubes are preferred.

When welding pressure vessels such as heat exchangers and boilers, large numbers of thin-walled tubes are common. Since tube-to-tubesheet joints are required, welders can use the autogenous TIG welding process to create high-quality butt joints. Arc Machines (AMI) equipment and services enable welders to meet the challenges of tube and tubesheet welding.

Challenges for Welding Tubes and Tubesheets

Tubes assume varied geometric shapes, and the following requirements must be met when welding.

Tube Welding Requirements

Strong welds

Consistent beads

Minimum penetration

Since tubes may transport toxins or sanitary fluids, welds must be structurally sound and consistently reliable. Achieving quality welds can be challenging when the penetration depth from the surface or the wall thickness is usually limited. When attached to tubesheets, there are additional challenges for the welder.

Tubesheet Welding Difficulties

Large numbers of tubes

Tight workspaces

Welding fume safety

Welding multiple tubes close to a tubesheet poses challenges for any welding process. Gaining 360° access, maintaining reasonable welding cycle times, and removing fumes quickly are all difficult tasks to accomplish. Fortunately, TIG welding can mitigate the weld requirements and welding difficulties for tubes and tubesheets.

Addressing Tube and Tubesheet Welding Challenges

GTAW or TIG welding is widely accepted as the fusion process that yields the highest quality welds. There are three techniques available for fusion TIG welding.

Fusion TIG Welding Options

Heterogeneous – filler material is different from the base metals; although, an insert or consumable ring can be used with different base materials.
Homogeneous – filler material is the same as the base metals; although, an insert or consumable ring can be used with the same base material.
Autogenous – no filler material is used

Autogenous welding is the most cost-effective of the techniques listed above, as material costs are significantly reduced, and typically no post-grinding or smoothing is necessary.

Each of the above methods can yield high-quality precision welds that satisfy the tube weld requirements. However, tubesheet challenges are more difficult to overcome. Due to the current welder shortage, not enough welders possess the level of experience and expertise required to generate consistent, high-quality weld joints. Additional challenges include tight work areas and the generation of toxic welding fumes for most materials. However, welders can leverage autogenous TIG welding for a cost-effective and efficient solution.

The Autogenous TIG Welding Solution for Tubes and Tubesheets

The best way to apply autogenous TIG welding that satisfies tube weld requirements and overcomes tubesheet connection is through an automated orbital welding process. Orbital welding adds the attributes listed below to complete the optimal autogenous welding solution for tubes and tubesheets.

THE ORBITAL AUTOGENOUS TIG WELDING SOLUTION
Attribute	Description
Consistency	Automation allows for reliable, high-quality welds to be performed consistently. It also reduces the level of expertise required by the welder or welding equipment operator.
Reduces workspace	Since orbital welding equipment can be operated remotely, the only space required is for the weld head.
Welder safety	By the use of remote control pendants and other devices, the welder or operator can monitor and control the process without exposure to weld fumes.

The attributes listed above can be achieved by implementing AMI’s industry-leading tube and tubesheet equipment materials such as high-purity tungsten electrodes and orbital welding service.

READY TO CONNECT?

Arc Machines, Inc. specializes in high-quality, precision GTAW welding. This includes cutting edge equipment and materials for autogenous TIG welding that will allow you to optimize weld quality, process efficiency, and cost-effectiveness for your tube and tubesheet projects. Additionally, we provide support from experts to help you get the most out of your equipment throughout its lifetime. For inquiries regarding 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.