Search for a welded solutions ends...
...the EB way

Few ideas were forthcoming when TWI was first approached by a world leading engine maker with a unique joining difficulty.

'We want tiny welds performed in extremely thin titanium tubes, with very high weld integrity' they declared. A handful of process options demanded investigation, but one stood out in the crowd...electron beam welding.

End caps machined in a common titanium alloy needed to be joined to a small diameter tube, of half a millimetre wall thickness and similar metallurgical specification. The job also demanded micro-focus X-ray analysis of the results to verify the weld integrity in the fusion zone. In the highly competitive world of motorsports engine manufacture there could be no room for error.

'We used one of our low power EB welding machines to perform the weld autogenously. This machine is fitted with our own electron gun design' TWI's Tim Mitchell told Connect. 'We used carefully developed EB parameters to give the optimum integrity and appearance to these delicate welds'.

TWI has been supporting this client's project for some four years. After developing the welding procedures batches of components have been routinely supplied to the client as requested. Batches of components are turned around quickly, typically in just a few days.

'The sustained integrity of the joint is imperative in this work' according to Mitchell. 'The electron beam solution produces high intensity low heat input welding with a very narrow heat affected zone. And as the microfocus x-rays show we have a high integrity weld. The welding process takes place in a vacuum so there can be no entrainment of gas in the joint, and consequent embrittlement.'

'Typically TWI can develop special welding procedures for clients with difficult problems. The developed welding solution can then either be used by a sub contractor or reproduced at TWI in limited numbers.'

To learn more about TWI's precision electron beam welding capabilities contact Tim Mitchell at TWI, tim.mitchell@twi.co.uk