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JL Riffe

Batch annealing S7 & D3

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So.... in the process collecting all my steel to move it over to my new shop..... I figure I have nearly 200lbs of S7 and D3 (punches and dies for tablet presses) I've been collecting this stuff for years and have never used any of it, I need to either learn this steel or scrap it.

My question is; rather than annealing this stuff a few pieces at a time anyone reckon I can just build a large hardwood bonfire and cook the steel for x number of hours and achieve a suitable anneal?

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no.

you need to read up on the steels you have rather than just jump in with a wild guess.  D3 is air hardening, so how did you figure that a wood fire going to anneal it ?

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I have read up on the steels. I have a crapload of this steel to deal with and in lacking a suitable furnace/kiln or oven to achieve my objective, I need a work around. One or two burns being preferable to deal with the lot of it.

I am not talking about a weenie roast campfire. Think of a wood fired kiln burn. enough steel with enough hardwood charcoal in a reduction environment to achieve a suitable annealed state with these steels.

If this is simply not possible without very precise temperature and cool down controls then I will simply scrap it or maybe experiment with a small scale foundry to melt this down... with some low carbon and see what happens.

Suggestions would be nice, snark not so much.

Edited by JL Riffe

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That wasn't snark, it was plain talk.

Your best bet for annealing either of those is to take it to the heat treater.  S7 especially requires specific soak times and ramping reduction with soaks at temp.

This is NOT a backyard wood fired kiln project.

Frosty The Lucky.

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Ok, I can accept that Frosty. Thanks. 

I suspect the better solution is to scrap the material for salvage price and work with more forge friendly mats. I just hate letting go of steel but if it is outside of one's ability to work properly its only taking up space and time trying to save it.

Thanks again.

 

...and I apologize for the "snark" comment Steve. I could have framed my question in better context.... and not gotten my back up as a result.

 

Edited by JL Riffe

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Why do you want to anneal - do you plan to machine all of the stock?

And S7 is great chisel and punch steel - so learn to use it.

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The problem is that is has been shaped, hardened and heat treated, then used in production for years. My experience with other hardened and tempered steels tells me that to rework the metal into new forms you have to relieve all the stress otherwise you have a mess full of fractures. I have also found that S7 crumbles like a dry biscuit when forged outside of 2k deg +. There is a lot of steel bound up in the 1 1/2" x 6'' punches which I would love to make use out of in some form or fashion. 

Ok... there is one other thing to consider. These punches have literally undergone millions of compression cycles on a rotary tablet press at 3 to 5 tons per cycle. Fracturing is undoubtedly an issue with an unknown quantity of this metal.

 

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Annealing won't remove the fractures, so I would say just learn to forge it,and get on with it. 

 

Scrap is in the tank, and you would make more selling it on EBay ,or other listing sites.

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Here is an alternative for you.  For the value of the material it would be worth while to build several Frosty t burners (see recent posting in gas forge forum)  and create a large volume "fire pit"  or  other temporary "kiln" to anneal portions of your stock pile.  Temperature can be monitored for the cheap price of an infrared thermometer ( I paid 10 bucks) available at Harbor freight. Between eye ball and cheap instrument you may be able to salvage all or at least part of you stock.  Keep in mind the Raku kilns that potters use. Those are basically wire cages lined with kao wool.   

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DON'T SCRAP IT!   Trade it to other smiths for what you want---a much better return on your investment!

I would love to get my hands on some S7 for another couple of slitting chisels; my S1 one works great!  (it was used to make pills and the end had fractured.)

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IMG_20150801_204309.thumb.jpg.7f289d53eeI'll bet there are plenty of people on here who would be willing to pay a reasonable price for known S7 steel. Myself included. Scrapyard steel can be great and I use the heck out of it, but I'd pay you a fair price for your S7. I don't mind working hard at the forge and anvil because I also enjoy the learning experience while forging it.

I have some unused 1045 2 1/2" round, around 30" each, if you are interested in a trade.

Edited by Anthony San Miguel

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That's trading stock, scrap prices are too low to pay gas to haul it to the scrap yard. How about listing some dimensions so the buyers can start figuring their orders?

Frosty The Lucky.

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Ok... trades might be a thing I just need to parse this a  bit. I won't sell the stuff for scrap.

Charlotte, thank you for an excellent idea and I believe it might be a workable alternative  to what I had in mind. 

Just to elaborate on the original premise. My thought was to use fire brick as a surround for x number of punches.... literally like packing a kiln but using oak as the fuel source or more importantly the coals which would yield a higher thermal output than the wood itself.

With the punches surrounded by fire brick they are protected from oxidation that would result from supplying air to the coal bed, hence keeping them in a reducing atmosphere as opposed to oxidative and the resultant growth of scale and loss of mass to burned metal. Granted, heating the entire mass of brick and steel will take a longer pre-heat period. With the addition of the IR thermometer that Charlotte mentioned one could monitor the temp of the entire mass and it might (might) be possible to bring the metal up to the critical soak temp and hold it there. The fire brick will add thermal inertia which should prevent or minimize a critical loss of heat to the metal and thus allow a sustainable maintenance of the spec'd soak temperature.

But..... it could equally be a doomed experiment...... but that is the work-around I mostly had in mind. 

 

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It will still scale up with that set up, but who cares really....... To keep them clean would require an inert atmosphere. We use nitrogen to purge the oxygen out of the furnace at work.

I am still not sure why you want to anneal these unless you want to make things out of them on a lathe,or other cold process. 

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I had planned on reworking them as ideas spring to life, whether I put them in the forge or grind out a shape. Just want some softened up before hand and ready to go when inspiration strikes.

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I used D2 for making punch and die sets when I had my shop, and I just got some S7 that they tossed out at work. I think the first thing you will want to do is determine what you want to make from what you have first. The S7 may make an interesting hammer, or power hammer tooling, but 1.5" diameter is pretty hefty for hand punches, etc. You might want to try trading some of it off for material that is closer to what you need. The D series steels can get brittle hard, so more attuned to machine usage in my opinion. Situations where you need something very hard IE; punching-shearing, but can keep the set up rigid.

He said he has D3 not D2

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Honestly, the D3 dies I am at a complete loss as to what to do with. There is not enough metal, per die, to get more than a small throwing hawk out of..... so they are just sitting around waiting for inspiration to strike or for me to build a small smelter to do some back-yard foundry work.  ....but that's on the back, back burner.

Power hammer, or in my case treadle hammer tooling is a definite possibility however.

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Hmm,  I'd be inclined to keep one each round punch and die per size and the same with the oval.  I would think of welding up a fixture to hold then doing railing and gates.

If you don't plan on working that way then try trading the punches for 4140 or other alloy rounds.  That is my take any way.  The dies will still make good nice size alternative to a pritchel hole  mounted on a steel plate above your hardy they would be a treat.

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You can also "nibble" with this type of tooling in a press - i.e., do some trimming when necessary: sheet metal, forging flash, etc.

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