Steel hardening questions

[D1005]

Ok, I've searched this forum, as well as the internet, and read until I have a headache, but am so unclear on many things. Seeking comments, but especially corrections as the internet has a wealth of information, it's often incorrect information.

First, I have junkyard steel, it's what I can afford and thus have.

2nd, I'm making narrowish shoes to go on shanks for rippers ahead of a blade for the driveway. 3/4" thick, 1 3/4" high, 4" or so long. Cutting a 45° angle to make the toe. The 45° angle will be facing the dirt, thus be getting the wear.

The steel is pretty easy to work, so it will also probably wear fairly quickly, and I'm thinking it might be a good idea to attempt to harden the face of the steel attacking the dirt.

I've watched videos of spark tests, and frankly, all the sparks look the same to these old, tired, eyes.

From what I've read, heat it up red hot with the torch, and dunk it in used motor oil or water. That's what I have, that's what's cheap, those are my choices.

Depending on the unknown carbon content, it might get hard, it might not. So it'll either wear longer, or not, either way I'm not out much, fun experiment.

Used motor oil or water? I'm probably mistaken, but there is carbon in the oil which might aid the hardening process in low carbon steel, but water cools faster so the carbon that is available in the steel hardens it better?

From the videos I watched, oil usually, but not always, flashes flame when the metal first goes in, but if quickly dunked, soon goes out. A big enough, steel container to completely drop the foot and shank into, with a flat top so it can be covered in case of fire could prove to be a challenge, but if not found, could rule out the oil choice. I'm a bit of a pyromaniac, but have no interest in burning down the neighborhood.

Heat the foot starting at the top of the angle, and work down to the point so the red hot doesn't go real deep, and stays fairly uniform, thus harden only the surface, leaving the rest not as hard, thus not as brittle and prone to snapping? Annealing seems like a wasted process in this application as it's such a thick piece and it won't be red hot all the way through, and be all fully hardened.

Dang, that got long, sorry, but tried to give all pertinent information.

Thanks in advance, Dale

 

[Canus]

Since you have no idea as to the alloy of the junkyard steel you are probably looking at an exercise in futility. If you have access to a stick welder you would probably be better off to get some hard face rods and build up the shanks of the rippers.

 

[T Bredehoft]

Hard face rods, look for stellite. I used it with TIG, don't know about stick welding, but it was really something. We had to use a 'green wheel' to grind it, anything else became worn away. Lay a 3/16 layer of stelling on your wear surfaces and forget hardening.

 

[RJSakowski]

The best way to become familiar with spark testing is to get some steels of various carbon content and spark them. An old file would be a good candidate for high carbon (~1.4%). Grade 8 bolts are usually a medium carbon (~ .7%). Grade 2 bolts and common nails are fairly low carbon (~.2%).
Spark test them on a medium grit grinding wheel. Angle grinders don't work as well in my experience. Compare the spark stream of each sample. Low carbon steel has fairly long yellow streamers with modest branching at the ends. As the carbon content increases, the streamers get shorter with more of a starburst effect. High carbon steel will have multiple branching.

When testing an unknown steel compare it to your known samples. You should be able to get a fairly good indication of the carbon content.

Alloy steels are a different matter. Alloying materials affect the spark pattern differently. M2 HHS steel has a darker orange streamer with no branching. O1 tool steel is similar. 18-8 stainless has very little sparking.

 

[Mitch Alsup]

Used motor oil or water? I'm probably mistaken, but there is carbon in the oil which might aid the hardening process in low carbon steel, but water cools faster so the carbon that is available in the steel hardens it better?

Carbon diffuses into steel at high temperatures.
Red hot steel dipped into motor oil is neither hot enough nor hot long enough for any significant diffusion to take place.
At best you will get a few molecular layers carbonized.

If you want to up the carbon content in the steel, you liberally coat the steel in carbon (paste), and then coat the carbon in a ceramic (clay) before heating to yellow (?white?) hot temperatures and letting the diffusion take place for at least an hour.

 

[magicniner]

If you stated your requirement you would be helping people to help you, Silver steel and 01 Tool steel are available at reasonable prices.

If you need hardened parts find or buy the right material for your job.
Unless of course your time and your work is worth nothing?

 

[BtoVin83]

There's a couple of ways to do this. First you don't want to heat and quench the whole ripper shank as this makes it brittle, if you temper it then the wear surface is not as hard as you would like. Second, flame harden the wear portion only by heating and quenching. This makes the wear portion hard but the shank is not brittle. Last get some tungsten rod, this is a steel tube with tungsten powder in it. Apply it by oxy acetylene torch or adding to the puddle using an arc welder. Stellite is like bubble gum compared to tungsten.

 

[magicniner]

If you have worn components use hard facing rods to build them up, I used to do this to repair farm equipment using an MMA setup.

 

[RJSakowski]

You might try some of the farm supply stores. They sell replacement shoes, teeth, etc. for cultivators and the like. These are hardened steel and used for a purpose similar to what you want to do.

 

[GL]

From my experience, and maybe I should do more, but driveway maintenance is a not something that happens that often - like once every couple of years. Based on that, and your situation may be different, about anything would work. As you said, either it will wear away, or it won't. Hard surface rod is what they rebuild bucket teeth with. Even S70 wire in a MIG welder will be harder than mild steel - and maybe you already have that in your arsenal. The farm supply store is a good thought, replacement parts are pretty cheap for these kinds of wear items. My box blade only has 4 or 5 rippers. Depends on how hard you want to play.