Opinions on this grain structure

R

R.C.Reichert

Joined
Jul 26, 2008
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So I snapped a couple of my 1/8" 1084 blades just because I wanted to see what the crystalline structure looked like. These were tempered for two 2 hour cycles at 400° prior. I know ideally they should not be tempered beforehand, but I just wanted to see anyways. So...does this look acceptable?


 
It looks OK. Maybe a tad larger grain that perfect. It is hard to tell in photos unless it is a clear close-up.

Tell us how you did the HT.
 
I'd listen to Stacy before anyone nevermind me but to me that looks large
Shouldn't see any grain just a matt grey colour
 
I think the grain may just look coarser than it is because the blade has been tempered. I can never tell the difference between roughness and large grains. I have broken some 80CRV2 coupons as quenched and after tempering, and the tempered sample looked a lot coarser, but the grain size should have been identical.
 
Grain looks a little larger the optimal but like was said it hard to tell from the resolution of the picture. You should not be able to see individual grains, it should be a smooth satin gray color.
 
It's hard to tell in the picture. It is best to look at fracture grain of untempered steel. It needs to be as brittle as possible.
 
This was 1084 that I bought from Knifemaker.ca. and I believe he gets all of his stuff from NJSB. I was told by the supplier that this steel did not need normalizing because I was only doing stock removal.

So for heat treat, all I have is my forge. I brought the steel up to non-magnetic and held for about another 30 seconds to one minute, just long enough to get one shade brighter and even out the color. It was an even orange color. I then quenched into 120° canola and tempered in my kitchen oven for two 2 hour cycles at 400° F.

Last night I decided that I would temper for one more hour at 420° because the blades seemed a little hard yet.
 
The best way I've found to compare grain structure is to break an old high carbon (NOT case hardened) file and look at the grain. You won't really see any "grain", just a gray look. As others have said, untempered steel.
 
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