Grain Growth

Ben Sellers

Well-Known Member
I have a question about grain in a blade. I broke a blade today to get a look at the grain. I am not able to see grains with my naked eye, but when I take an extreme close-up picture I can see grain pretty well. This blade was 1095 that was heat treated at 1475 degrees F with a 10 minute wait after the oven (evenheat) got back to temp. Did I wait too long or is this grain acceptable? My intention here wasn't to have a soak period, it was to give the blade enough time to get to temperature. The quench was in unheated P50 and temper was at 450 degrees F. What do you think?



 

Gene Kimmi

KNIFE MAKER
It's hard to tell from the picture, but to me it looks a little large. If you enlarge the first picture, look at the bottom of the break. There is a u shape on the outside of the blade and it's a little darker. This part to me looks like fine grain.

Did you normalize and do grain reduction heats before quenching?
 

KenH

Well-Known Member
Easy way to tell about grain size is to break a file and look at that grain. A drill bit will also show a fine grain. If the grain is so small you can't see with naked eye with a clean break looking more gray than anything - it should be good. It's really hard to photo grain to show size.
 

Gene Kimmi

KNIFE MAKER
Ben,
I know some say you don't need to, but it depends on what state the steel is in when you get it. I always have, just to be safe.

Ed Caffrey has an excellent video from his Knife Maker Training series on refining grain. Also, Kevin Cashen's new dvd on 1084 has great information on getting the most out of your steel. Both well worth the investment.
 

Ben Sellers

Well-Known Member
I've watched the kmt video and its hard to compare. The demonstration of how fast the grain grew was something, but I know it was a couple of hundred degrees too hot too. I am thinking about getting the 1084 video too. Thanks for the heads up.
 
Top