Automated Welding Stations for steel tank construction

Vertical and circumferential tank welding in one assembly process

High – quality tank welding depends on more than the welding method itself. Plate alignment torch stability tank movement weather protection and process supervision all influence the welding process.

Nordweld uses two dedicated workstations for two different types of tank shell joints:

• Welding station for Plate Track – for vertical assembly and welding of sheet metal plates

• Automated welding station for circumferential tank welds – for circumferential welding while the tank rotates past a stationary welding torch.

Each station performs a separate task. Together they can be integrated into the tank installation process to support mechanized vertical and circumferential welding.

Both solutions were used during the construction of two industrial stainless steel tanks made of LDX 2101 in Sweden.

Welding Station for Plate Track – vertical tank shell plate welding

A vertical joint connects adjacent plates within one tank shell course. Before welding begins the plates need to be positioned vertically aligned and securely held in place.

The Welding Station for Plate Track combines these operations within an automated containerized workstation.

Two flat steel plates are positioned vertically and locked using hydraulic actuators. The clamping system applies stable and uniform pressure along the weld joint helping maintain accurate plate alignment during welding.

The main advantages of the station include:

• fast and reliable hydraulic clamping

• reduced risk of plate movement or misalignment

• stable plate positioning

• reduced deformation

• reduced preparation time

• adjustment for different plate dimensions and thicknesses.

The workstation is integrated into a customized 10 ft HC container with two entrance doors and is suitable for plates up to 2000 mm high.

Its configuration includes a hydraulic plate clamping device two Gullco 300KAT welding carriages with oscillation units internal lighting a 32 A electrical central and Deep Section Tracks positioned on the inside and outside.

The entire welding operation takes place inside the enclosed container. This protects the working area from wind rain and temperature fluctuations and provides more stable working conditions on site.

During the Swedish project this station was used for the vertical assembly and welding of thicker shell sections produced from flat sheets.

Automated Welding Station for circumferential tank welds

Circumferential welding requires a different working principle.

A circumferential joint connects successive shell courses around the full diameter of the tank. Instead of moving the complete welding setup around the circumference Nordweld keeps the welding station stationary.

The Automated Welding Station for circumferential tank welds remains fixed relative to the tank while Tank Rotators rotate the complete tank past the stationary welding torch.

This makes it possible to perform a continuous circumferential weld while maintaining a fixed position of the welding equipment.

The complete workstation is integrated within a 10 ft HC container. The configuration can use Fronius Arc TIG or Lincoln Plasma technology and includes the main components required for the welding process such as:

• welding power sources

• torch guiding system with manual X-Y slides

• mechanical height sensor

• wire feeder

• cooling system

• purge gas system

• gas distribution system

• welding camera

• CNC camera for the purge gas side

• two monitors.

The system also allows welding to be performed from both the outside and inside of the tank.

Real-time monitoring of the welding process

The circumferential welding station includes an industrial camera and monitor system.

Operators can supervise the welding process in real time using screens inside the workstation. A welding camera monitors the welding area while a second CNC camera is used on the purge gas side.

This provides continuous visual supervision and reduces the need for direct observation through a welding mask throughout the complete welding operation.

The enclosed container also protects the welding process from wind rain and temperature fluctuations.

Because the equipment is integrated into one self-contained unit the station can also be transported and relocated between job sites.

Automated welding stations used during tank construction in Sweden

Both welding stations were used as part of the Nordweld Advanced System with Wheel Trolley during the construction of two large industrial tanks made of LDX 2101 stainless steel in Sweden.

The project combined:

• top-down tank construction

• tank rotation

• processing of material from coil

• preparation of thicker shell sections from flat sheets

• mechanized vertical and circumferential welding

• roof assembly using the rotation system for the shoring tower.

Technical parameters of the LDX 2101 tanks

The project included:

• 2 tanks

• 10300 m³ capacity per tank

• 25.6 m diameter

• 20 m height

• 220 tonnes per tank

• 440 tonnes total steel weight

• LDX 2101 stainless steel

• 6–10 mm shell thickness from coil

• 11–15.5 mm shell thickness from flat sheets

• 9600 total production hours

• approximately 22 man-hours per tonne

The material preparation method was selected according to shell thickness.

For sections between 6 and 10 mm material was processed directly from coil using the Vertical Bending Machine and Decoiler.

For thicker shell sections between 11 and 15.5 mm flat sheets were used together with the Plate Track and the containerized station for vertical assembly and welding.

Circumferential joints were welded using two automated Arc TIG stations installed in 10 ft containers. During welding the stations remained stationary while the tanks rotated.

The project therefore combined two material preparation methods and two dedicated welding operations within one Advanced System with Wheel Trolley configuration.

Two Welding Stations for different stages of tank construction

The two Nordweld welding stations perform different functions.

The Welding Station for Plate Track is used to position hydraulically clamp and weld flat plates vertically.

The Automated Welding Station for Circumferential Tank Welds is used to perform circumferential welds while the tank rotates past a stationary welding torch.

Together they can be integrated into the Nordweld tank building process where mechanized vertical and circumferential welding is required.

Select a Welding Station configuration for your tank project

Planning a stainless steel or carbon steel tank project and looking for a system for mechanized vertical or circumferential welding

Contact Nordweld to select the system configuration based on the tank dimensions material shell thickness and required installation and welding process.