non destructive testing

[cookie munsta]

Hello all,
soon i'll be required to mig weld m/steel cleats on to 75 by 75 3-4 mm thick duragal rhs probably using 1.2 mm solid electrode, am pretty confident that this shouldn't be great issue, but just wondering if there were any time efficient, non destructive ways to make sure the welds are not just sitting on top.
i usually stick weld and find that when it looks good it usually is
Any ideas?

 

[runnach]

Not really any cheap NDT methods that will offer you an idea you have good fusion that I can think of?

Why don't you knock out a few samples, taking note of machine settings, then either do nick breaks or root and face bend tests? When you have satisfactory sound welds, then nail the job together.

Cheers..............

 

[cookie munsta]

yeah that's a good idea, thanks

 

[Hitch]

Cheapes NDT is probably dye penetrant testing. Thouroughly clean the weld, spray the weld in penetrant dye, then leave for a bit, clean again, capilary action draws the dye into any defects. Then spray in white developer, the dye shows up bright red through the developer.

Quite effective for surface defects, but you have to be very thourough with cleaning.
There is a few variations on this, but basic sets come in a set of 3 aerosol cans

 

[cookie munsta]

dye penetrant's are available at most welding stores? if so that would be ideal. using both suggested methods would ensure i couldn't &^$* it up. thanks

 

[Hitch]

I think its a but unnecessary really, as long as your weld looks like it has burned in properly, it will be fine, You could post up some pics of some samples, and we could cast our eye over them for you. Can see most surface defects from a decent phot, and advise where your going wrong, if you are.

 

[runnach]

I wouldn't bother with dye pen, will only show up surface and, to a degree, sub surface flaws, if any. Your concerns are with lack of fusion, sample nicks and bends are the way to go!

 

[Ropeman]

The only way to check for face fusion in this case is ultrasonic or radiography. Ultrasonic shear wave inspection would be a nightmare on 3-4mm material. Best bet is radiography, but it'll cost a fortune.

You are much better off doing sample destructive testing like runnach suggests, if you have to pay for it yourself.