Hardfacing question

Bob...I think you are laboring under a misconception about casehardening.

It must be a decent, alloy to caseharden. And case hardening is only in actuallity a few thousands thick

Now hardfacing..thats putting a very thick layer of very hard material over whatever it is that you are hard facing. It could be crappy mild steel, jello or what have you.

There is good reasons to caseharden. Size must not change, etc etc

But there are very many more reasons to face when making up tools that will be abused and need sharpening regularly.

Gunner

"IMHO, some people here give Jeff far more attention than he deserves, but obviously craves. The most appropriate response, and perhaps the cruelest, IMO, is to simply killfile and ignore him. An alternative, if you must, would be to post the same standard reply to his every post, listing the manifold reasons why he ought to be ignored. Just my $0.02 worth."

Thanks! I was thinking that the Kasenite supplied enough carbon and whatever magic stuff makes for hard steel to work with mild steel. I was aware that it was only a few thousandths thick though.

Bob

Casehardening will work with mild steel. If you start with a decent alloy, you will end up with a tougher item. But casehardening mild steel works.

Maybe you are thinking of nitriding.

Dan

Check out

The hardfacing stuff I have is high manganese rods for use with tig or perhaps oxy acetylene if you have the right flux. It is more for ground contact surfaces than for holding an edge. It goes on kind of in globs much more than steel welding rod. Perhaps you have some other hardfacing substance in mind.

I had a quart sized can of the Kaseite which you heat the piece red hot and roll it around in the powder and then quench and repeat if desired. It worked well for hardening pins that things pivot on instead of buying something specifically designed to be machined and then hardened. Well I did it and installed the pins, they were too hard to file I can attest to that. Unfortunately I have used the can up. I would think that would be a better choice however it might not really end up having the type of edge holding qualities and strength you are looking for. When in high school in Industrial arts I think they called it we used files heated them red hot then quenched then baked for an hour at 350. I forgot where in the process you worked it into the new shape but you might try that instead.

Fran

There are dozens of different hard facing or alloy rods. Some are high strength, some abrasion resistant, some shock resistant, etc. I use some for the bottom of my snow plow blades: make a new wear strip, run it for one snowfall to get the right edge shape, then put on 2 or 3 beads. The result lasts for several seasons. A file just bounces off, this material would need to be ground to shape if needed. Does it stick to the base metal? I've never had a section chip off even when I hit concrete edges and similar.

Case hardening works on mild steel, just that the base metal is not as strong. But the case hardening is only a few thousandths thick (longer soak time yields more depth). You cannot sharpen the surface, you will grind away all of the casehardening.

I've been making my woodworking cutter knives from A-2 steel with good success. In the annealed state it cuts very well with hacksaw, standard mills, drills, etc. Heat to ~1750F in a stainless steel foil bag, cool, temper in the kitchen oven at 400F to 600F depending on what properties you want. A-2 is available from Crucible Steel, McMaster, or Enco. Not cheap but very nice stuff.

BobH wrote:

It does. The Kasenite simply adds carbon to the material you are case hardening - however, as Gunner says, it is a very thin layer. But having said that we used to make one off tools from low or medium carbon steel and Kasenite them. It worked but you needed to re Kasenite them if you re-sharpened them.

Cheers,

Bruce (bruceinbangkokatgmaildotcom)

What's that Lassie? You say that Gunner Asch fell down the old sci.engr.joining.welding mine and will die if we don't mount a rescue by Sat, 07 Nov 2009 09:24:43 -0800:

Are you sure about that? I've seen stuff that had about .050" case to it. (thompson shafts) A real bitch to machine through. Worse to drill and tap a hole that is part into the hard area.

I thought that you could make case hardening quite thick, but usually it's very thin.

What's that Lassie? You say that RoyJ fell down the old sci.engr.joining.welding mine and will die if we don't mount a rescue by Sat, 07 Nov 2009 15:57:14 -0600:

What rod do you use? My boss at work has a snowplow that the edge is worn out.

I use hardfacing to repair anvils. Proper prep and material selection and you get much more wear. Kasenite compound is great stuff and it does have it's uses. However it only gives you a thin layer and once you grind through it you have to retreat the surface.

From what I know (book learning only) you can case harden up to 50 mil or even more, but it takes a long time and it only works if you're using a process that keeps the piece immersed in a high-carbon atmosphere -- the carbon has to diffuse into the steel, so thick cases take hours or even days.

You're not going to improve the steel's grain structure, and a low-alloy steel with carbon is still a low-alloy steel with all it's quenching difficulties and non-high-speed properties, but in theory you can make a 'thick' case.

Why not buy decent tool steel? If you're putting all the effort into the tool you may as well use the right material.

(says the guy who just built two gouges, one out of music wire and the other out of unhardened drill rod -- but that's cause they're my first ones and I'll do it 'right' next time).

As I mentioned, this question came out of a discussion with a friend that was mostly about hardfacing. I know almost nothing about hardfacing and about the same for case hardening. The little bit of reading I did on hardfacing made it sound like adhesion of the hardening material might be an issue.

Thanks everybody for your comments on this, I have learned a few things here.

BobH

Yah...you can get it that thick.if you work at it. But .050 is still only 50 thousands and in most applications...thats simply not thick enough. Snow plow edge...perfect example...that puppy needs to be .500 or more thick just for one season.

I should add Im not a metalurgist..just a machine repair guy with some welding experience here and there....,

Gunner

"IMHO, some people here give Jeff far more attention than he deserves, but obviously craves. The most appropriate response, and perhaps the cruelest, IMO, is to simply killfile and ignore him. An alternative, if you must, would be to post the same standard reply to his every post, listing the manifold reasons why he ought to be ignored. Just my $0.02 worth."

OTOH, on a hand chisel, knife or gouge a 50 mil case would last for years of resharpening.

Though I still think that for a woodworker's tool the right way to go is to just buy some good steel to start with...

Not in a professional cabinetmakers shop . Especially if you have coworkers that like to borrow your chisels to cut nails .

CRINGE!!!!!

Sharpen it..and cut their throats with it after they do that......

"IMHO, some people here give Jeff far more attention than he deserves, but obviously craves. The most appropriate response, and perhaps the cruelest, IMO, is to simply killfile and ignore him. An alternative, if you must, would be to post the same standard reply to his every post, listing the manifold reasons why he ought to be ignored. Just my $0.02 worth."

Don't ask for a blade, what you need to get will be a "Cutting edge", this will bolt on the bottom of the moldboard.