Printable View
Do any of you perform or have performed any form of NDT on welds in critical areas? Starting a frame chop on my ironhead project before too long, I've got quite a bit of practice time ahead and quite a bit of destructive testing that will occur before undertaking that task. I'm just wondering if you do any form of testing on your projects, dye penetrant, have an ultrasound/xray/magnaflux/etc.
I've magnafluxed a lot of welded crankshafts, and while it finds other flaws in them, I've never felt that it tells much about the quality of the weld. They all look somewhat bad. Maybe I've just never seen a really bad crank welding as we sent that work out to a top notch place. But on aluminum we did lots of dye check, and that stuff shows all kinds of flaws in welds. The thing is I've almost always known right when I was welding when something isn't right and is going to fail the dye. Impurities will either show up in the puddle or sometimes you can tell by the color of the arc when something is outgassing and messing things up. Aluminum shows everything and is very unforgiving about contamination.
For mild steel and chrome-moly as long as you don't overheat the part and get full penetration and proper fillets, the weld is almost always stronger than the base metal. The biggest problem is what the heat does to the metal right next to the welds. Ideally you would anneal and re-heat treat the welded assembly to relieve stress and repair the grain structure throughout. But that would only be required in things that were designed to absolute minimum weight/strength ratios. Most of the time you just factor the welding into the design and run a slightly larger tube or thicker wall or use a butted tube design to compensate for the welding.
We've used Ultrasonics, Eddy Current, Standard Red-dye, UV dyes, X-ray, etc on various welds over the years.
What are you looking to find with NDT on a harley frame? It should be pretty straight forward. just watch out for concave fillets. They may "look" like a great weld to some, but they will have less strength as compared to a properly filleted joint.
Use an ER70 filler on it and clean it fairly well. If you are tigging it, make the joint fit-up nice and tight.
Come to think of it, doesn't a Harley qualify as destructive testing of a frame? Never had a bike try to shake me to pieces like one of them. ;)
Well, as I'm welding a number of critical areas on the frame, chopping the rear end off and building a hardtail, raking and stretching the neck, both areas of high stress and both lead to little pieces of pavement in your body if they fail.
Anything remotely critical in the Navy was NDT'd by an evil, anal bastard who liked to make you work double-shifts LOL.
Everything that can be will be slugged and gussetted, and like I said, it'll be done after I get back up to speed, I'm just wanting that little bit more reassurance.
What Dye kits do you use? I have accounts with a number of industrial supply companies to pick them up from.
In the real world of backyard fixer uppers, having access to the fancy things you mention is almost impossible,,,best to practice on scrap until you are confident that you can do it,,,when there is doubt there is no doubt,,,keep practicing until you are confident in your work..and there is no doubt.Quote:
Originally Posted by Trip59
Futher to this discussion of joining tubing,,,I have seen others do this and done this myself,,,it's called spudding,,,take a short solid piece or a small section of tube that will just slip into the tube you are joining,, and then do your welding,,the tube make break but not at the weld when you use this trick,,using a spud also helps with alignment.
There is always doubt... when there is no doubt, bad things happen.
Your LWS probably has visible dye check kits in stock. There are a bunch of brands, but they all work about the same. One thing is don't mix and match between brands. The cleaner, dye and developer are made to work together. Dynaflux is one brand. The UV stuff where I used to work was something like Dye-Check or Dy-Chek. I thought it was made by the people that make Dykem, but a quick search tells me that's not the case.Quote:
Originally Posted by Trip59
Here is the type we have at work. We don't buy kits, rather cases of each. Even have had liquid dye rater than spray for some applications.
http://www.zorotools.com/g/00035751/k-Spotcheck%20Kit/
Welds can be a bit tricky to inspect with dye as the surface condition of the weld itself can be difficult to remove the dye, leading to indications wen developed.
One other point. Being a good weld inspector takes as much or more experience than being a good welder. Just like buying the best welder will not instantly make you a good welder, having the best inspection equipment will not make you a good inspector. Both things take practice and experience. I would practice on the material types and thicknesses you intend to work with until you can always pass a bend test without issues. Then if you want the piece of mind of having your welds checked, send your frame out for professional inspection. At the same time you can have your frame laser checked for alignment. No job would have the welder inspect his own work anyway, that kinda defeats the point. Find that anal evil bastard from the Navy, or someone like him, when he says your work is good, you know it is.
Gotcha!
Well, like I said, I plan to do numerous destructive tests on identical material and joints till I'm comfortable. I wish I knew one of the NDT guys around here, though the way things have gone with my rate in the Navy, they've probably contracted most of it out now anyhow.