Cutting 15n20

[gregfisk]

Hello All,

I'm still learning so here is another new thread asking for information that will hopefully help others out at well. I have only made a few knives so far and all of them have been with 1/16" thick 1095. Recently after reading around the web I decided to try 15n20. I excitedly purchased several pieces of 1/16" thick sheet stock to make my usual Santoku kitchen knives. I normally cut my 1095 on a modified 14" band saw that I installed a treadmill motor in so that I could slow it down. It worked great for the 1095 but when I tried my new 15n20 everything came to grinding halt. This stuff is hard! And I can tell it is going to trash my blade within minutes.

So, what is the best way to cut this steel? Should I anneal it? if so how? I haven't spent a lot on bandsaw blades, should I get a better blade? If so which one? Or should I use some other method?

I'm kind of bummed since I wasn't expecting such a drastic difference between the 1095 and the 15n20. I just hope it will be worth it in the end, I liked the idea of the added nickel and I wanted to try something different.

Thanks for your help - Greg

 

[milkbaby]

If it's reclaimed bandsaw steel, it can be around low 40s HRc hardness so it'll eat sawblades and drill bits. Even the stuff I bought from a steel supplier that's supposedly in annealed state seems to be a lot harder to cut and drill than annealed 1084; maybe it work hardens while sawing and drilling, I dunno. I don't have a bandsaw but cut everything by hand with bimetal hacksaw blade. I still use drilling lube when sawing or drilling the stuff because it will heat up from the friction.

Scroll down to the bottom just before the footnotes in this article: https://knifesteelnerds.com/2019/06/17/annealing-part-2/

Basically if you're like me and just use a forge without temperature control, then thermal cycle by heating to about 1600F (about one and a half shade or so above non-magnetic) then air cool to black; then at austenitizing temp about 1500F (one half to one shade above non-magnetic) then air cool to black, then subcritical temp about 1400F (just about non-magnetic) and then stuff in dry pearlite/vermiculite/kitty litter in a big container to insulate and let cool down very slowly/overnight. Basically these steps you'd do after forging before you started any cutting, grinding, or drilling.

If you have a temperature controlled kiln, then it's something like hold at 1250F for an hour then turn off heat and let cool inside the kiln. There's a certain temperature drop per hour recommended, but I can't remember off the top of my head. Don't take my word for the temperature either, look it up to be sure LOL

 

[gregfisk]

Thank you WLK ; ),

I have a gas forge like you so I’ll try what you suggest. This steel was purchased from AKS, I have a call into them but haven’t heard back yet. I read somewhere 15n20 comes from them at a hardness of 42 or 43? All I know is it’s a lot harder than the 1095 I’ve been using and now I wish I hadn’t purchased so much of it. Since my pieces are only 2”x12” maybe I’ll just grind it into shape.

Do you or is there anyone who knows what steels come hard and which ones don’t? Or does it depend on where you buy it?

Thanks again for your help.

 

[milkbaby]

I think from what I've read is that AKS tends to send steels in good condition to work, but see what they have to say about it.

My 15n20 is from Aldo/New Jersey Steel Baron and I believe it's cold rolled annealed, but it's still a pain to saw and drill as received from them. Different sellers may sell steel in different conditions. One nice thing about the reclaimed bandsaw 15N20 is that you can advertise your knife as such (reclaimed steel) but it's harder to work due to the hardness.

 

[kbright]

An angle grinder with a metal cutting disc cuts fast, but rough.

 

[gregfisk]

An angle grinder with a metal cutting disc cuts fast, but rough.

Thank you for the response. I’ve seen a lot of people doing this on YouTube. It seems pretty crude for cutting out a knife but I may end up trying it. I went ahead and ordered a Lenox bandsaw blade that someone recommended in another thread. Hopefully it’ll work well and not wear out too fast.

 

[John N]

If your steel is in an unknown condition, just lop it with a 1mm cutting disc in a 4.5" angle grinder. Very ecconomical, very very quick.

 

[gregfisk]

Thanks John, I’ve never cut steel that way but I will give it a try

 

[milkbaby]

A lot of people use an angle grinder with cut off disc. But make sure to wear PPE and remember it's only meant to cut straight. If the disc shatters, it can maim or kill you, so be careful.