Forging case hardened steel

[austunts]

I was wondering if it is Ok to forge case hardened rollers as I have just come across a couple and am not sure

[bigfootnampa]

They will probably forge just fine but mostly behave as mild steel would.  The case hardening is quite thin and will not retain any influence post forging.

[ThomasPowers]

What do you want to make out of them?  As noted the base metal is fairly low carbon and and the hardened layer is quite thin.

[austunts]

Thanks
I was going to weld some together and was unsure how the casing would react in the gas forge.
Looks like I have a new supply of steel for a little while.

[ThomasPowers]

Weld them together to get what?  Stock to forge into a tripod?  Large amounts of mild steel trivially small amounts of high carbon---not good for blades or tooling that would profit from being at least medium carbon.  Are you sure they are case hardened, the smaller ones may be 52100 which is high C indeed!  Can you forge the end of one down to say 1/8 thickness and then heat to non magnetic and quench the thin part in water and then WEARING PPE! put it in the vise and tap it and see if it breaks/shatters/bends?

 

If that alloy has a lot of Ni or Cr in it they may be hard to weld to each other without a bit of plain steel in between 

[austunts]

Being a sculpture, I found the shapes interesting and should be able to create something out of them. They are 1"x 3" rollers out of a 6' bearing used in the mining industry which has been refurbished, so I'm pretty sure they are case hardened.
We all have our own approach to blacksmithing. Thanks for the advise I'll your suggestion.

[ThomasPowers]

Everybody can go their own way; but if you are asking *us* to spend our time helping you; it behooves you to provide as much detail as possible so us old geezers aren't worrying about *another* person trying to make blades from not appropriate material.

 

"I'm going to use them in a sculpture"  defines a much different solution space!

[Quarry Dog]

Wait, they're roller bearings?  Aren't bearings usually pretty hard stuff?  I've seen plenty of bearings sheared through on heavy equipment.

[Frosty]

No Jerome they're NOT necessarily HC at all. Sheared steel isn't a sign of high carbon all things being equal. Shattered or snapped is a "maybe for HC. Or do you mean shattered, crushed, broken?

 

Roller bearings can support huge loads because the force is distributed over the length of the roller, the case hardening is to resist wear.

 

Not to pick on you but you offer a lot of advice here, is your knowledge and skills sets up to helping folk break into the craft? I know I ask myself that question frequently. One major part of the craft is failure analysis, you have to be able to figure out what went wrong and why, maybe one of the most important parts in fact.

 

Frosty The Lucky.

[Quarry Dog]

Thanks for clearing up that question of mine Frosty.

  I've seen my dad bring home some 1" or 2" ball bearings from his job where he sets up quarry equipment (crushers, screens, conveyers, batch plants, etc.) that were broken up into sometimes 2, 8, 10, or even more pieces, with some really small pieces missing, so i figured they were pretty hard stuff.  Of course this was long before I ever started smithing, which is why I started with a question instead of just jumping straight in kicking down the walls, since I've never actually worked bearings.

  Since starting blacksmithing a year and a half ago, I had figured that they were heated, quenched, and then baked to the desired temper, or even 1 step heat treated (quick dips and let the heat from the inside temper the skin...same idea as quench the tip and let the colors run) so that the inside was soft and the outside was hard.  I had never actually had a chance to test that idea out by heating and beating one myself though, which is why I started in with a question instead of a statement.

[ThomasPowers]

Ball bearings are often 52100 and excellent knife steel but profits from experience *before* working it!

 

Bearing races may be 52100 when small and something like case hardened 9620 when large---the dividing line is mentioned on the side by a friend who was a metallurgist for a bearing manufacturer.

[Frosty]

When I reread my post I was afraid I'd offended you or worse. I'm not nearly so good at saying things as I used to be.

 

Throughout this thread I'm pretty sure we're looking at the incorrect use of a trade/craft jargon at one level or another. The original question is about forging case hardened steel. A few follow up questions and we're left wondering if the original question is really about forging. Then using a gas forge comes up and I'm even more confused. But that's not really important.

 

We made an assumption the person asking knows what they're asking and try to answer it as best as we can. Once we get some more info the thread diverges into us talking about case hardened vs. high carbon and sure could go farther.

 

I'm thinking one of our biggest challenges sharing the craft is the language. Jargon has a bad rap but in most cases it has an important purpose. It lets folk talk about a subject and everybody who hears or reads knows exactly what's been said or asked. For instance if I said,"I REALLY had to draw that one out." Most everybody here would know exactly what I meant but what if the listener was a psychologist or counselor? They would be more likely to think I had to ask a lot of leading questions to get to someone to reveal some darned thing.

 

Consider how many of the young folk entering the trade have as their entire experience base WOW, other RPGs or movies. The poor guys THINK they know something but they're not in a position to even ask good questions and certainly can't understand the answers let alone be able to sift through answers from guys who have their knowledge based on RPGs or maybe, who knows what.

 

It isn't really their faults they don't know what they're saying or think they're hearing but it sure can get frustrating for all of us. We get frustrated at the repeat questions of another kid who wants to learn blacksmithing by forging a Damascus sword and hasn't bothered to read any of the bladesmithing threads here. So, as any folk who've been following the forum know, our frustration turns to short tempers and sometimes anger. Of course our reactions frustrate them and that shortly turns to anger and we all lose.

 

Ain't life a pip?

 

Frosty The Lucky.

[Quarry Dog]

  Eh, no sweat Frosty.  There are two very important things that are hard to transmit by written language, especially nowadays with all of the throw-away words and loss of the mind-to-hand barrier.  Intent, and Emotion.  That's why I try not to get too wrapped around the axle, and try to watch what I type, and genuinely take a look at myself when someone calls me out.

  I will admit, I've only been at this hot metal thwacker stuff for about a year and a half.  I have been welding since I was about 8 though, although there were about 7 years where I didn't have access to welding equipment due to not being stationed near home, and it has taken a lot of work to get back into the swing of it.  Now that I'm out I'm going for a few certs before I get a job doing it, and I've already gotten my 3/8" 3G (vertical up) MIG cert, and I'm working on stick now.

  I'll admit I do over-engineer stuff, and I may be overly cautious in my treatment of unidentified metals, but I got both of those tendencies from mistakes I made early on in life, namely broken tools resulting from either under welding something, or quenching things after a weld, namely a 4" earth auger welded to a 1/2" bit in one of those big two handled drills.  I broke 3 bits, and the 4th time I hit a rock and my 13 year old frame was thrown around it twice by the time I let go of the trigger.  Every now and then I forget lessons like that and get a refresher course when I least want it, although not as bad as all that.  That auger is still working pretty good though, more than 15 years later, as well as other tools I made back then.

  I also probably ramble more than Frosty claims he does, and I don't have a tree to blame.

 

  Back to business.  I looked up 52100 on the ASM app (whoever posted that app, thank you again, I've already used it twice while making tools), and boy, after the weird stuff for the heat treat ("Refrigerate to -95°F after quench?!?!?"), I can see why they destructed so bad when they decided they were done.  Their forging heat range is very narrow too, barely more than a 400° swing, with 1695 as the minimum.  I'm not sure I have that kind of patience/heat control just yet.

  Now, the question I would pose, since it applies to what AU Stunts posted.  What are large roller bearings usually made from?  Same 52100 as ball bearings, or just case hardened softer stuff?  I realize the application is slightly different, but I imagine deformation would still be a bad thing, as ellipses don't roll right, and neither do shards.

[Frosty]

You sure got me on that one, I don't think there is a "Usual alloy." I'm thinking asking Timken or the competition is the best bet for good info. What I do "know" is the larger they are generally the lower the carbon content necessary but I doubt they ever drop below medium carbon unless they turn to high alloy. I'm thinking something like 4140 as the bottom end alloy. But that's a guesstimate.

 

Also, the faster they turn, generally the lower the pressure deformation they suffer but the higher the heat and abrasion resistance then need.

 

Breaking augers brings back memories. It probably won't come up again but if it does, use tubing instead of solid bar for extensions and subs. there may be more steel in solid bar but it bends FAR easier than tube.Auger puts tremendous torque stresses on the steel and any flex will end up failing sooner than later.

 

And yeah, I've been thrown on the ground by a hand power auger. Heck, both of us but I rigged a kill line to the plug wire before I'd run one. Just hearing the stories about the other guys getting the snott beaten out of them made that little mod a no brainer.

 

Frosty The Lucky.

[Quarry Dog]

Yeah, I was 13, hadn't had enough time to hear all the old "Take it from me..." stories.  Still haven't, but I've heard a lot more since then.  I'm not sure if the rig I was using would take a tube.  As I recall is was actually made for like 1/2" or 3/4" or some large drill bit.  It basically resembled an electric motor, about 10" to 12" across the housing, with 2 handles sticking out either side, and a chuck out the bottom.