X-Ray scanning

[Atlas Knife Company]

Can an x-ray be used to check the welds in a damascus or san-mai billet? If so, what should I be looking for? My friend has a portable x-ray machine so the pics are free. He has no experience reading metallurgical x-rays, however.

I'm thinking have the camera perpendicular to the welds and look for dark lines showing a bad weld?

 

[Finedges]

When reading radiographs, you're looking for differences in densities, or black/whites and greyscales. Variances in different steels won't show, but air space or gaps in the steel will show up as a different density, or shade of grey. Steel shows as white, air as black. Any poor welds should be apparent. Make sure at least two views are taken. One from the side, one from the top. Best of luck, post pics if you can!

 

[SteelSlaver]

The normal source for X-raying metal is Cobalt 60 and is more intense (and dangerous than what they use for tissue. They set up a pretty pig exclusion zone around the shot (something like 50' in every direction). I don't know what type of machine you have but I would think if it is normally used for tissue it might work with a long exposure time and then again it might not.
Finedges pretty much covered it on reading. Knowing just what you looking at in the discrepancy areas is kind of an art. I am used to pipe weld X-rays and besides slag and porosity, there is the edge tie ins etc. I would think that bad laminations of a poor weld would show up pretty well with the right X-ray set up.

Next time my brother who is a certified welding inspector goes out on a job I will have him take a piece of bad damascus and get it shot. Should be interesting.

 

[me2]

It's tough to see unless you have a good technique. An x-ray tube will offer the best chance of success. Use low energy (KeV) and high intensity with the slowest speed film you're willing to tolerate, or maybe try a good digital setup, which I have no experience with. Also, let me make the Damascus. You'll see some kind of mess for sure then. Cracks and inclusions will potentially be very small, so something placed on the film as a flaw of known size will tell you how small an indication can be and still be visible. Image quality indicators (IQI) are the standard for this, but you may not have them. Try some very fine wire and see if you can see it as it's laid across the piece, maybe some small guitar wire or even the very fine copper from electrical wire.

 

[Atlas Knife Company]

It's a digital setup, and I will definitely post pictures. I'll print this thread and show him before we take the actual x-rays.

Thanks guys. I'll let you know how it turns out.

 

[mete]

The choice of type of NDT [non-destructive testing ] depends on what you're looking for .Improper laminate bonding is not for x-ray ! Ultrasonics is the best ! I recently reshaped a laminate blade and uncovered some slag at the interface .It won't be more than cosmetic but it could have been detected by either X-ray or ultrasonics.