15n20 thoughts

[JTknives]

I was thinking about 15n20 the other day after receiving and email about how to drill it. We all know that most 15n20 is pre hardened. It’s not just the steel from bandsaw blades that are hard it’s new steel as well. This go me thinking a little. Maybe we are thinking about it all wrong. I looked up temper charts and the ones I could find don’t list any tempers that get the steel down to the hardness I see in the 15n20 I get. This sparked an idea. Us that make 15n20 Damascus know its crazy hard right after forging, and it has to be annealed befor working. What if saw manufactures don’t use 15n20 because it’s super tough but because it comes hard. And what if the steel manufactures push 15n20 as saw steel because it comes off the rollers already hard. What I’m getting at is I don’t think the steel manufactures are heat treating the 15n20. I think the hardness we see is the resulting hardnes from them heating it up and rolling it out. We all know 15n20 will air harden to an extent. So then it begs to ask was 15n20 ever designed to actualy be heat treated or just used as rolled.

 

[javand]

You can get it actually annealed and from non-coil stock, and it cuts ok, although it will work-harden quick.

From my experience, it eats even premium bi-metal bandsaw blades raw, but I never bother annealing my damascus billets before cutting them. The blades I use eat it up no prob in this form, and I've yet to wear one out cutting damascus that hasn't been annealed, mostly I screw them up doing other things, and toss them when they start cutting crooked.

On the other hand, for processing even new 15n20, because of the nickel (not the hardness), I've started using carbide tooth blades, which handle it no problem. I usually cut it in stacks 3-4 inches tall.

The bandsaw blades are heat treated(hardened and tempered to a desirable spec, they'll tell you the specifics if you ask), as is all of the material if you get it from the "strip steel" division typically. You have to talk outside that division if you want flat, annealed, never coiled stock, and be very specific. You can get it clean ground, sheared to specific lengths and pick from certain slit widths this way.