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FAQ: What are the one-shot pipe welding processes and why are they being developed?

   

Frequently Asked Questions

One-shot pipe welding usually involves a solid state (or forge welding) process to join two lengths of pipe in one attempt. As the title implies, the weld cycle times are short when compared to multi-pass fusion welding techniques.

A variety of processes have been developed for one-shot pipe joining. Those which have been investigated include:-

  • Flash welding (forge process)
  • Radial friction welding (RFW) (forge process)
  • Shielded active gas (SAG) (forge process)
  • Homopolar welding (forge process)
  • Electron beam welding (reduced pressure or high vacuum variants) (fusion process)
  • Explosive welding (high energy rate process)
  • Continuous drive rotary welding (forge process)
  • Induction butt welding (forge process)
  • Friction stir welding (forge process)

The main advantage of using these techniques instead of multi-pass fusion welding, are the fast weld cycle times which are economically attractive, especially when joining corrosion resistant (CRA) pipeline. Also, as the equipment is usually semi-automatic in operation, non-welder trained labour can be used to produce reproducible, good integrity welds.

Interest in these processes has accelerated over the last five years and is linked with the increased need to use CRA pipeline such as martensitic stainless steel, duplex stainless steel or titanium alloys. CRA pipeline is often needed in marginal fields where there is a corrosive environment.

For more information see Joining Technologies or please contact us.

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contactus@twi.co.uk