RichR
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Registered: 17th Oct 01
Location: Waterhouses, Staffordshire
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How would you crack detect/NDT the weld made joining two channel sections together to form a box section if the weld had been subsequently plated in and not accessible for a Dye Penetrant test. i.e. the weld to be checked is now behind a plate which can't be removed
I've been reading about X Ray and Ultrasonic but I can't fathom if this would work if the weld itself was behind a 4mm thick aluminium plate.
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Eddx14xe
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Registered: 12th Jan 10
Location: Hertfordshire
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When I've seen engineering / oil rig programmes they all use x ray. I would expect the pipes laying on the sea bed and going down to oil wells are more than 4mm thick.
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Eddx14xe
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Location: Hertfordshire
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According to Google the radiographic line camera can penetrate up to 25mm in steel.
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RichR
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Registered: 17th Oct 01
Location: Waterhouses, Staffordshire
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but are they looking at the welds on the surface of the pipes rather than internal? The videos/document I've found on the internet, I can only see X Ray being used on surface welds.
We've been steered away from X Ray because of Health and Safety issues apparently so looks like Ultrasonic is the only alternative but not sure if this would work through 4mm plate where the palting is the same grade of material as the actual channel/box section
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RichR
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Registered: 17th Oct 01
Location: Waterhouses, Staffordshire
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quote:
Originally posted by Eddx14xe
According to Google the radiographic line camera can penetrate up to 25mm in steel.
would it show a difference if the plating was the same material spec as the channel?
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Eddx14xe
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Location: Hertfordshire
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Can't answer that question I'm afraid. It's just what I found on Google and nothing I can find answers your question.
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RichR
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Location: Waterhouses, Staffordshire
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yeah, I'm having the same difficulty. Spoken to a test engineer at Airbus who is going to phone us back - just wondered if Ste or anyone else in the aircraft industry would have an idea
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Seany
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Registered: 13th Dec 06
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Radiography is what we used in the yard, I'm sure it can tell the difference between layers by the hollows they leave.
We used it on war ships with very little tolerance for air bubbles and cracks.
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fred7
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Registered: 17th May 04
Location: Rugeley, Staffordshire
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ultrasound will do it no probs. On the stations the ndts usei it on alot thicker plate than that.
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RichR
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Registered: 17th Oct 01
Location: Waterhouses, Staffordshire
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Radiography it is
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Ellis
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Registered: 11th Sep 07
Location: Aberdeenshire
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UT might work also if it doesn't bounce back at the change of material into the adjacent plate.
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RichR
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Location: Waterhouses, Staffordshire
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Classification have called out Radiography so that's the way we have to go
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Ste
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Registered: 5th Mar 03
Location: Taif, Saudi Arabia
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All the eurofighters at my work are x rayed before they start engine ground runs. It is dangerous and the area has to be cleared of people when they do it, but the results are really good. They use it mainly in my place of work to look for any foreign objects around the air intakes. The pictures look like what you see at airport baggage scanners and it looks through several layers of skins and tells you depth etc.
Most of the stuff with suspected cracks is dyed and x rayed but not sure if they can do crack checks without the dye.
I would rather lose by a mile because i built my own car, than win by an inch because someone else built it for me.
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richc
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Registered: 24th Mar 07
Location: Ilkeston
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Radiograph
Would have been alot easier to dye pen it before the plate went on top.
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RichR
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Registered: 17th Oct 01
Location: Waterhouses, Staffordshire
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It was dye penned before but it's turned out the external NDT company who did the Dye Pen aren't qualified to do it, nor did they follow the BS EN standard testing procedure. it wasn't picked up by classification until after the lift structure was plated in, painted and fitted to the boat, overload tested and the boat 75% finished. Also turns out said company isn't insured either.......
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alan-g-w
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Registered: 9th Nov 07
Location: Glasgow
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Holesaw/ drill a hole in the plate, try to apply the penetrant and developer as per usual, use an endoscope to check it then TIG the hole back up
[Edited on 04-07-2012 by alan-g-w]
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