David56

Depends entirely on how you want to heat treat it. Traditional heat treating on japanese blades is a very detailed process that can't be covered in a simple post. Wally Hayes has a good DVD out on making a sevicable "ghetto katana" that covers alot of those aspects. However, I would question why you want to make a katana as a first sword. They aren't exactly the easiest of swords to make properly. While 5160 is generally a good sword making steel, I am not how it will react to the traditional heat treating methods as I have never tried it. Aside from the one masochistic endeavor of meking one from tamahagane steel my old apprentice and I bloomed, all of the katana I have made since have been laminated 1085 over 1018 to more closely approximate the composition of the old blades. I highly recommend doing some in depth research on how they were made, and you will realize that they aren't at all a simple undertaking. But don't let me discourage you from trying. You might just be a natural at it, I am just suggesting you do some serious research on the subject or you might just end up trashing some otherwise valuable steel.

I have purchased a few new leaf springs(5160 tempered, air hardening) to use as straight katana sword blades with lenghts of 24" to 29". This is going to be my first attempt at making swords, but have worked with metal for many years.
So after cutting out my blade with a plasma cutter, and bringing the shape of the blade to is desired appearance, except for its final sharpening, then i must forge the blade to a non-magnet state for 5 mins, and then cool in wood ash or oil. Is this correct? Would appreciate any wisdom that you all may have. Thanks