Metallurgy question, sort of...

chrisstaniar

Well-Known Member
ok, so just something I've noticed and always been curious about. The best I can describe it is they are patterns in the steel that look like a snail trail. They are generally short maybe 1/8" L by 1/16 or 1/32 W.

The only place I've seen this is in 440c and I've only seen it once I've sanded above 600 grit on the flats. They aren't scratches, you can't feel them, and you can generally only see them if you tilt the blade just right in the light (fairly bright light). They also don't always show up on other parts of the blade. The steel is from NJ Steel Baron so it's reputable. I see it pretty regularly on different batches of knives.

I tried to get a picture of it but no dice.

Any ideas?
 
I think I know what your describing. I used 440-C for a long time, then about 8-10 years ago I started seeing something in it like what you describe. I mirror finished all my knives so it was really prominent. The best way I could describe it was it looked like
David Boye’s dendritic stainless steel. I ordered from three different suppliers and it all finished out the same, with funny looking striations running thru the steel. I just switched to CPM-154 and stopped using 440-C.
 
Yeah, i could definitely see that being a bigger issue on a mirror finish. I recently did some AEBL and it isn't visible on those. I went through Jay Fisher's page on 440c but didn't find anything that matched what I was seeing. The closest I found on other sites was that it was just the "grain texture" of the steel showing up. There were some other posts about how it was cut but that didn't match.
 
They generally run at maybe 45 degrees vertically when the blade is held horizontally. They can be on one side of the blade but not the other as with this knife. It has to be the right light and angle to see.

Here's a pic, my phone doesn't do it justice.

IMG_4628.jpg
 
Have you tried grinding them out, say another .010" or so? It's odd on one side shows and not the other.
 
I went thru the same thing, it something with how it's made, in my opinion. like I said, I ordered from three differant suppliers and it was all the same. which leads me to believe there's one mill making all of it. I used it for years and never had a problem then all of the sudden the finish got wierd. it worked out ok for me because I was ready to move on to another type of steel.
 
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