Welding of tanks and vessels is performed using dedicated welding machines when the components are circular and articulated robots when they are not.

Typical applications in this area utilizes seam tracking for welding water heater tanks and is for welding truck fuel tanks.  These two applications use single pass welding which is adequate for low pressure vessels. On the other end, high pressure vessels having wall thickness of up to 200mm require more complex features for multi-pass welding of deep narrow gap joint.

Tank welding

A manufacturer of gas and electric water heaters uses the GMA welding process to weld the longitudinal joint in the shell and the circumferential end caps. 

The existing process involved a special welding machine with one torch that was manipulated over the joint to be welded. To achieve sound welds, the torch must be maintained by the operator at the proper position in the joint.  Laser vision has enabled faster travel speeds (sometimes in conjunction with tandem arc) to be achieved with a dramatically lower leak rate.

Fuel tanks for trucks

The square shape of these tanks makes it difficult to use dedicated or Cartesian systems to weld them; therefore articulated robots are being used.

Laser vision seam tracking systems are applied for two types of welds; first to weld stiffeners inside the tanks and second, to weld the caps of the tanks. The first installation uses a standard GMA welding process. The more recent installations are using GMA welding or tandem twin wire technology allowing welding speeds of up to 4 meters on these complex shapes.

Narrow gap welding

In order to minimize the welding cycle time and deformations on plates of up to 250mm in thickness, manufacturers are adopting the method of narrow gap welding. The difficulty with these types of parts is getting access to the joint due to the tooling and adequately positioning each welding pass inside the narrow space available.

Multi-pass Submerged Arc Welding is used and special torches are applied to fit this application. Servo-Robot has developed a special tracking system which can view the complete joint including a sensor head that has the same narrow width as the welding torch.

TMO – Walker stainless

Large tanks made from stainless or aluminum is used to store liquids for overland hauling.  To maintain the proper liquid temperature water jacked must be used.  Servo-Robot seam finders are used to precisely locate pre-formed holes on the circumference using joint finding to allow the pre-programmed robot path to be corrected and to measure the gap optimize weld parameters.