HT recipes needed for 52100, 5160, others...

[Kevin R. Cashen]

Originally Posted by fitzo

Kevin (Cashen), have you had any opportunity to pursue that polishing technique I mentioned with the maple wheel?

Not yet, I have not had the time to build the horizontal disk setup itself

[rhrocker]

I'm sorry for not exactly staying on the topic here, but Kevin, I've been wondering how you would look at the samples if it was jagged and broken. If the sample was sawn on a bandsaw, then sanded on some sort of sander, it seems the metal would "flow" across the field. I have a Nikon SMZ-1 that I use for engraving, and have been hoping to use it for looking and studying grain also.

BTT!

[Kevin R. Cashen]

Originally Posted by rhrocker

I'm sorry for not exactly staying on the topic here, but Kevin, I've been wondering how you would look at the samples if it was jagged and broken. If the sample was sawn on a bandsaw, then sanded on some sort of sander, it seems the metal would "flow" across the field. I have a Nikon SMZ-1 that I use for engraving, and have been hoping to use it for looking and studying grain also.

BTT!

A good magnifier would be the best. The problem with microcopic examination is the field of focus is so small that the peaks of the grains cannot be in focus at the same time as the low spots. I have taken then next leap closer to lab work and started mounting samples in a resin because the polishing, no matter how level will always round the edges a bit and then you cannot get images of the edges of the piece in focus. The key concern is heat, you cannot allow the metal to be heated by any method of cutting or grinding. Buffing is not good because it can smear things around.

Your engraving magnifier should work good for examining fractured grain, and one can get a rough idea of things this way, but to really measure grain size and get a precise look at things under a microscope you need to properly polish and etch the specimen. I start with the normal grits with lots of water and work up from 600X through 1200X, 2000X etc... and then finish around 6000X to 8000X by hand before etching in a 5% nital solution. All that dipping a blade in etchant shows is macroscopic transitions from one microstructure to another.

[Larrin]

Originally Posted by Kevin R. Cashen

Wow, I didn't know there was a scope on the market that inexpensive. If you are hoping to do camera work it is very worth it to go with more than a monocular scope, just a binocular with one eyepiece used would do. With the monocular you would be at the mercy of the digital camera interface software for focusing the image, I have yet to find a camera display with resolution to really do it.

I may consider a binocular or trinocular, but for $400 it's almost too cheap to pass up.

[twistedneck]

Originally Posted by Larrin

Oops, I didn't notice that there were two Kevins. I may be getting a metallurgical microscope soon, and I look forward to observing grain size after different treatments. I'm especially interested in the refinement of grain in stainless steels.

I want one too, and i'm also concerned with grain size in stainless. In addition, carbide size is very important - primary and grown after quenching type.

I didn't realize 52100 was so prone to decarb.