1095 cracking?

[ckluftinger]

Yes, that's how i understand it. I have also been told to heat to non-magnetic and cool to no-red three times, too, but Ed Caffrey told us at a hammer-in last year to go just to dull-red. I don't know if there is a preference, but the constant seems to be to heat and cool three times before the annealing cycle. I tend to favor the dull-red procedure as there is less chance of over heating the steel.

[Doug Lester]

Ok, at the risk of putting my foot into it, let me caution about the dull red. Color is the most inaccurate way of estimating temperature. One, it is highly dependent on ambient light. Two, what is dull red to one person may not be to another. For whatever reason, I don't even see red in the steel in my forge. It's all just a shade of orange, even when magnetic, until it turns yellow.

To normalize you must change the phase of the steel or the crystals do not reform. To completely change the phase of the iron crystals in the steel you must exceed upper critical temperature. That's a little above where the steel becomes non-magnetic. Heating to a lower temperature may well show some change in the steel but you have to change phase to normalize. If you heat to between the lower and upper critical ranges then only some of the iron crystals will change phase. I suppose that if you do that three times you may end up with most or all of the crystals changing phases at the end of the three heats.

Doug

[AUBE]

Originally Posted by ckluftinger

I hope not to over-step my bounds, but as I understand it, you should not lay your piece down. This would cause uneven cooling (the area touching the ground would cool faster than the rest) and may cause warping

If you put down a layer of dry wood ash it really cuts down on uneven cooling. I get no warpage when normalizing using this method. Holding it in tongs works too but I normalize 20+ knives per batch so sitting there holding hot steel in tongs gets tedious quick. If you're only doing a blade or two at a time then that works fine.

[AUBE]

Originally Posted by Doug Lester

Ok, at the risk of putting my foot into it, let me caution about the dull red. Color is the most inaccurate way of estimating temperature. One, it is highly dependent on ambient light. Two, what is dull red to one person may not be to another. For whatever reason, I don't even see red in the steel in my forge. It's all just a shade of orange, even when magnetic, until it turns yellow.

Doug

What he says is very true. Light plays a HUGE role in what color the steel appears and everyone has their own opinion on what "black red", "orange" etc are.

Doug brings up a good point with steel color in the forge....I also can't see red while the steel is in my forge but in a dark room I will pull the steel out and drop it an inch below the forge, suddenly you can see those dim reds. The color inside the forge itself masks the colors in the steel.

Using a heat treat oven obviously makes things easier and more precise but with practice you can get decent results with the forge....it just takes a lot of practice.