Hardening mild steel??

[MIKE MC]

Hi everybody. I am making some butcher dies for my home made guillotine fuller. I know that a tool steel would be better, but all I have at the moment is some mild steel to do the job. It is 3/4 inch thick so I thought maybe if I heated to a dull red or until de-magnetized then dunked it that maybe it would harded somewhat. What are your thoughts about this? Thank you for your responses. Mike.

[John B]

I dont think that will do much to harden them, here is an old method that works for me, is non toxic, and should be easily available to anyone.


To surface harden mild steel.

Take a spoonful of wholemeal flour, add two spoonfuls of salt, add a little water and make into a smooth paste.

Heat the end of the item to be hardened until the paste will stick to it, when you have the item coated where you want it, heat the area to a bright red heat and plunge the item into cold clean soft water. The coated area will be appreciably harder.

Good luck with it,

[Quenchcrack]

But if the metal under the thin skin that you surface hardened cannot support the impact, the surface will collapse into the core just like it wasn't hardened at all. If it is low carbon steel as you say, you need to heat it much hotter than non-magnetic. Quenching from non-magnetic is only good for high carbon steels. Water quench it from a high red but don't temper it. It won't harden much but it might do better than you think.

[Flaming S Forge]

Here is a method I use with good results. I use hard coal in my forge which is high in carbon. Carbon will migrate from the higher source to a lower source at the proper temperature. I first heat the metal to a bright red and sprinkle on borax. Immediately place it back into the fire and bring it up to a yellow heat just under welding sparking heat. Quench it in water and keep moving it around until it is cool. The borax adds a bit of boron to the metal in addition to the carbon being pulled from the coal. I don't know if this works with soft coal since I only ever used hard coal. I made my on touch mark and hardened it this way and it has held up for over 2 years. Using a guillotine will probably require you to re-treat it from time to time if you see it starting to show some deformity. I have also had good results making chisels and center punches using this process. Good luck.

[HWooldridge]

Do a search on this website for "Super Quench". Brine will harden most A36 pretty well, (it is is close to Robb Gunter' original lye/water/surfactant mix, which is no longer recommended due to the dangers of handling and use). In fact, I replace broken post vise springs with A36 versions by hardening in brine but no temper - makes great springs that don't break.

A36 is about 30 points of carbon so it's at the lower level of common spring steels.

[MIKE MC]

Thanks for the replies, I am still learning my way around this great web site. I could have just used the search for a lot of answers. Mike

[Woody]

I have made many dies for my gillotine tool out of mild steel. I just quenched them in iced salt water they are fine for working hot iron. The only problem I had was the ends mushrooming from being hammered. The working ends of the dies are still as good as the day I made them

[Awalker]

Might consider using a case hardening compound.

[ThomasPowers]

case hardening compound is not usually suggested for impact surfaces; just wear surfaces.

Go with super quench!

[KYBOY]

I hardened a railroad spike knife yesterday with Super quench..WOW, what a difference...It screamed at me