The Welding Institute

NDT, The Welding Institute and TWI

16 Feb 2023 12:00 PM | Anonymous

Although TWI Ltd and The Welding Institute are separate entities, there remains a level of cross-over between the two organisations, as demonstrated by Fellow CEng Alan Gifford, who related the story of how he, as a Professional Member, was influential in bringing non-destructive testing needs to the attention of TWI Ltd.

As part of our centenary celebrations, The Institute reached out to Alan, who was working for Internal Combustion Ltd at the time of this tale, to take up the story for us here:

"In the mid-1960s we (International Combustion Ltd) had accepted a contract to supply a 140 ton boiler drum in 4.5 inch (110mm) thick low alloy steel for an overseas client who, in turn, had appointed a British inspection body to oversee the manufacture and testing.

We had, as an error of judgement, also unfortunately accepted a 100% ultrasonic testing procedure of the seams to an exacting ultra-high sensitivity scan.

The circumferential welds were made by submerged arc welding, with pre-heat of 100°C minimum.

When the ultrasonic testing was performed under the surveillance of a very diligent inspector, numerous very small inclusions were found.

The repair of these ‘flaws’ was by excavating a groove up to 4” (100mm) deep, preheating and then hand welding to execute the repair.

This was a very costly, technically unnecessary and time consuming operation.

In addition, the drum was occupying an already planned, big area of shop floor space.

We appealed to the client for a relaxation of the standard but, as we later found out, he did not require the drum due a change of programme.

Whilst this was in hand we came across a similar reflector in a welded test plate associated with one of the seams.

By careful cutting and machining we managed to expose the fault - it was a very small slag inclusion (maybe 1.5mm across the section) and about 80mm from the outer surface and it would have required a big excavation.

I showed the section to my directors to try and explain the numerus repairs, ‘What does the BWRA Institute think?’ I was asked.

So a meeting was set up with Doctor Richard Weck, who was the boss there at that time.

A colleague and I soon headed to Cambridge and duly explained our problem.

Dr Weck said that TWI did not deal with non-destructive testing as it was the role of the NDT specialists.

I said NDE was an integral part of manufacture and then produced the polished and etched section and asked him to comment on it.

His bushy eyebrows twitched and he studied it for maybe couple of minutes and said, ‘That looks a very good weld.’

I then said but that is a reject and pointed out the inclusion.

I cannot recall his exact words, but they were not very complementary, and then he sent for a young Tim Jessop who, as I recall, was the most NDE-minded person there and said to him, ‘Can you really find defects as small as that?’

Tim said something like, ‘Yes, at high sensitivity, I suppose’

‘Then we must know more about NDE here’ doctor Weck replied.

Thereafter, NDE testing of welds was on the agenda at TWI.

But, as far as our client was concerned, no relaxation was offered, since he did not want the drum to be delivered.

So we had to do all this work, which did nothing to improve the product.

I, for one, was more than happy when we were finally able to ship the drum and I kept that section for many years but eventually lost it.”

- Alan F Gifford CEng, FWeldI

So, while the work may not have helped International Combustion Ltd with their client at the time, it was influential in progressing NDT at TWI Ltd, creating an important part of the business ever since!

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