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Round bar identification

Ben jammin

Plastic
Joined
Oct 28, 2019
Hi guys, I recently was given some round bar stock stamped fcn150. It came from a gun Smith shop that closed. I'm wanting to learn more about the grade of steel and what its suitable for.
 
Be careful with that....

The XRF gun will tell you composition of the material. It won't tell you if it's been heat treated, annealed, etc. and they can give incorrect readings if you don't have a good clean surface to shoot it against.

Now, someone who was properly trained to use an XRF gun should know all this and advise you of it. But woulda, coulda, shoulda...
 
I'm going to make an almost totally unsupported speculation, and encourage you to get the sample XRF-gunned as was already suggested.

I speculate that this is a modified 4140 with an approximate tensile strength of 150,000 psi, quite possibly developed by drawing at an elevated temperature but well below the critical transition temperature.

If it turns out to be something totally different, it will not be surprising.
 
Pet peeve of mine, proprietary end paint symbology. Will the society of engineers ever standardize bar end colors?

Our tool steel supplier is required to spray paint the whole piece.

A11 White
A2 Orange
D2 Yellow
S7 Blue
4140 Red
4140 PH Purple

But yes, they should standardize the colors.
 
Back in the late 90's a grad student did a PhD thesis "WATERMELON MATURITY DETERMINED FROM IMPULSE FREQUENCY RESPONSE", LELDON MARK FARABEE It didn't work to well on watermelons, but it sure could tell what kind of metal was in a sheet or bar as long a there was known to compare it to. It was pretty obvious after trying what we had in the shop that just tapping the metal with a small hammer was enough to compare two pieces to see if they were the same kind of metal.

Try finding a piece of 150,000 psi 4140 the same size as one the small pieces you have ring each one and see if the sound the same. Then hit them with a file, grinder an center punch and see if they work the same.
 








 
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