Seam Welders

Longitudinal seam welder machines for sheets, plates, pipes, tanks and other cylindrical vessels.
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Seam Welder Machines

Key Plant manufacture seam welders for SAW, MIG, TIG and Plasma applications.

a flat bed automated seam welder machine

Flatbed series

Flatbed automated seam welder machines for plate joining.

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a Key Plant internal seam welder machines

Internal series

Internal seam welder for smaller weld back bead on outside of the workpiece.

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An easy to load external seam welder

External Series

Easy to load external seam welder machines for increased productivity.

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A Key Plant elevating seam welder

Elevating Series

Elevating seam welder system for increased diameter range.

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Elevating seam welder with platform for real-time view of welding process

Elevating series with Platform

Elevating seam welder with operator platform for real-time view of the weld process.

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Digital and analog controllers


Digital and analog controllers for seam welding machines.

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Increase production and improve consistency and quality of welds with our automated seam welding solutions.

A machine integrated with K-Tig keyhole welding system

Premium engineered automated seam welders.

We design and manufacture a number of models including external, internal, elevating and flat plate machines.

Machines can be supplied full loaded with welding equipment as a “turnkey” package or as the “steel work only”

Systems can be supplied with operator platforms and infeed and support rolls.

As a global leader and over 65 years in welding automation, we can produce specialised designs to suit large diameter and long length components.

Key Plant supplies seam welders to customers all over the world. Perfect for boiler and gas cylinder manufacturing, our seam welding machines are used in a wide and diverse range of industries.

About Key Plant seam welders

Flatbed Series

Seam welders

Plate joining can be incorporated with:

  • Traversing lines
  • Infeed/Outfeed steerable rollers

Internal Series

Seam welders

Internal welding gives smaller weld back bead on the outside of the workpiece, reducing clean-up operations on the external surface.

External series

Seam welders

Easy to load and operate for increased productivity. Remove the gate assembly to feed and offload the workpiece easily.

Elevating Series

Seam welders

  • Increased diameter range
  • Constant working height regardless of diameter
  • Cylinders or flat plate used on same machine
  • Clamping bed raised and lowered with option of operator platform
  • Platform anti-fall safety device.

The advantages of the operator being able to elevate with the clampling bed, by use of an operator platform assist’s the operator’s ability to view in real time the welding and make any small adjustments in set-up or parameters for total flexibility.

Seam welder options & features

Manual and pneumatic edge setting devices

Edge setting devices

Manual and pneumatic loading aids to align plate on machined centre line. Interlocked, to prevent weld carriage travel when loading.

Copper clamping fingers

Clamping fingers

Camping fingers can be manufactured to suit different material types.

  • Copper clamping fingers
  • Chrome plated copper clamping fingers
Gates assembly with integrated limit switches

Gate assembly

Gate assembly with integrated limit switches.

Pneumatic torch lift for changing consumables and giving clearance when loading

Pneumatic torch lift

6″ elevation to torch consumables and give clearance whilst loading and unloading the workpiece.

Elevating mandrel with gas purging

Innovative mandrels

Elevating mandrel with gas purging to accommodate a wider range of material thicknesses.

4" clamping fingers for consistent force

Precision and Consistency

Consistent clamping force across 4″ clamping fingers.

Seam welder foot controls for independent front and rear clamping control

Foot controls

All seam welders are supplied with foot pedals for independent front and rear clamping control.

A Key Plant seam welder clamping bed with edge setters

Clamping bed

Clamping bed with edge setters.

Copper backing bar with options

Copper backing bar options

  • Chrome plated
  • Water cooled
  • Gas purged
  • Profiled backing bar can be machined to suit customer specific requirements.

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