case hardening materials

[icequencher]

hey yall,i'm new here and have alot of questions.right now,i have a [i think] mild steel sword shaped and filed.i want to heat treat it.since you can't heat treat like high carbon,how do i case harden,i've been reading up on case hardening,and have an understanding of the method.what carbon substances can i use.bones,horse hoove shavings.[none of which are readilly available here].thanx for the advise.-

all that is gold does not glitter,the old that is strong does not wither,
the deep roots are not touched by the frost,from the ashes a fire shall be woken,a light from the shadows shall spring,renewed shall be blade that was broken,
the crownless again shall be king-

Bilbo Baggins-




-John

 

[FullerH]

Doesn't case hardening leave a rather brittle surface? I seem to remember that it does. If so, I shouldn't think that you would want it on a sword blade.

 

[Bartleby]

If you have an object that is case hardened, only the outermost surface is affected. The process is usually done for wear resistence on things like gun parts, which come into contact with other metal surfaces. Sometimes it is used on small parts as decoration. Something as long as a sword blade will be almost impossible to have even results on and will not look good. You will need a pretty big set up, including ventilation to get the job done. If you are seeking to use the process on the edge, you will remove the casehardened surface when you sharpen. You may be better off starting your project over with carbon steel...

 

[wnease]

Case hardening might give you an edge, but only if you sharpen it on one side. Sharpening both sides will expose the mild steel as cutting edge, which only works for one cut. The mild steel blade will flop around and take a set in the air...hit something and it will bend right over it. For that matter, mild steel is not stiff enough to support a cutting edge unless very very thick.

You can, supposedly, get carbon to migrate into the steel at a rate of about 6 thou per hour if the the steel is in a carbon rich low O2 atmosphere @ 1400 F. Sharpening will remove a few thou each time, so count on many hours at critical temperature. Carbonized steel will end up around .6% which will fully harden, however the core probably will have less carbon and be soft. The grain structure will likely be coarse from all that heating, and I would expect warping from uneven carbon content. Remember you still have to heat treat the blade after.

I've wanted to try this for years but I have piles of projects waiting to be made from piles of high carbon around. It takes a fair bit of fuel to do this...far more than it would take to heat treat. If you try it I'd love to hear how it goes.