I suppose it depends on the crowd you go with :-) Some folks are surprisingly interested and even have a lot of fun smacking hot metal. My brother-in-law calls it hammer therapy. Keep a cold beer handy.
Why can't you hit it bright yellow: They say that tool steels can't take the heat that mild steels can. I am not sure if any damage you do with high heats is irreversible, but I have heard that grain growth is an issue, at a minimum.
Treadle Hammers: In my view, the more parts you have rubbing together, the more of your effort is lost to friction and the less there is available to do the work. Don''t discount the simmple "swing hammer". The "dies not matching" is not a big problem, especially if you use the adapter design at
Pete Stanaitis
You need to know the specs of the metal you are working. Some steels are hot short and some cold short. I can never remember which is which but some steels don't react well when you beat on them at too high of a heat and vice versa. Some of the Railroad material that I played with tends to crack if you don't keep it pretty hot while you work it. I've seen it with leaf spring too (5160?... maybe). Working most basic high carbon steels at welding heat will burn out the carbon over time. The higher the carbon content the lower the forging temp I think is the rule though. Higher alloy material will usually need to be worked hotter (1800+F or so). If at all possible, read the manufacturing specs. They are generally provided in the sales info. The only "irreversable" damage you are likely to do is burn out carbon. Grain can be worked down through proper treatment. Even carbon content can be raised, though you don't want to go there...
GA
I'm still a little unclear on this. Is it that hitting the steel too hot causes the grains to grow when it goes into the final quench, and it does not get as hard as a result?
It's still quite possible that I'm not hitting at high yellow. It's certainly nowhere near that white heat I saw in your coal forge, and my garage is much darker in any case, especially given that I work at night with a single 15 watt bulb. But that is no reason to disregard the correct way to do it, of course!
Perhaps I should have looked more closely the first time around- for some reason, I had it in my head that the adjustment to get the dies to match involved lengthening or shortening the arm on the hammer head- which seemed like it was likely to be more work over the long haul than designing it differently in the first place. The adapter on your page makes a lot of sense, of course. After looking at it again, it does seem like the way to go. It uses far less steel than I had in mind for the other design, which means I can do it that much sooner.
Unfortunately, there were no specs with the metal- I just got it off a rack and the guy cut it in half for me quick. It was a very informal sort of thing.
So, if the problem is a loss of carbon, does it make sense for me to use sparks flying off the piece when it is struck as an indicator that I am forging too hot? That didn't happen much, but it did occur a couple of times when I had it at what I would judge was it's highest temperature. That would really be an easy to spot and useful indicator if it means anything at all...
I'm still learning about the higher carbon steels. I've had the opportunity over the years to work with mild steel, stainless steel and 4140 in a machining capacity along with the odd bits of bronze,
12L14, and a few tool steels- but I've never worked in a shop that did anything that I can recall with 1095, and no hot work at all prior to a couple of months ago, so I'm just guessing at it for now.
If you do use mild steel, you protect it by putting a hard plate on top. Put a tang on a piece of grader blade as a hard plate that drops in the hardy hole in the bottom anvil. On the other hand, if you find some shafting or other 'better than mild', more power to ya.
Steve
If you bought known material from a dealer then there are specs. Look it up on the internet. Try places like Pacific Tool Steel, Admiral or Crucible steels for reference data.
I'm no expert but I think you need to get it hot enough that it starts to sparkle while in the forge before you are burning off carbon. Most steels are safe to work between 1200F and 1800F if you don't want to get technical about it then try to stay in that range. Ultimately the steel will let you know if you mistreat it too badly. of course by that time it may be too late... :-) If you are going to make knives then you should take time to test the results of your work. I recommend using some rods and play around with the heat treating then see what it takes to destroy them. I learned the hard not to make assumptions about the temper of your steel - about the chemistry of it too...
GA
Grain growth begins at "the" critical temperture and continues as long as it stays at that temperture (or hotter). Growth rate may accelerate at higher tempertuers. With a plain carbon steel, this temperture is is around 1450F and grain growth after this point is fairly fast, so I wouldn't recommend leaving it above this temp. more than say 15-20 minutes at a time. Alloys tend to retard the rate of growth considerably and usually REQUIRE much longer amounts of time for carbide formation when hardening. Growth DOES NOT occur as a result of hitting it while too hot. Hitting the steel breaks up the grain - as does Normalizing and Quenching (fast cooling from critical).
GA
Holy cow, Kyle! :) That is cool. :)
Alvin in AZ
What I *do* have right at home for immediate use is a 5 gallon pail full of M2 punches and dies. Most likely, some of these will become hammer heads and bottom plates, especially where both the punch and the die appear to be undamaged. All of them were scrapped for one reason or another, but some of those were for relatively unimportant reasons for this application, like the sleeve that the punch rode in cracked or the spring broke- as noted above, it's sort of amazing what gets thrown out for lack of a simple replacement part.
Since it appears that mild steel with a hard plate is the standard way to go, I'll no doubt go this route. I'll see if the fella at work is up to filling in some of the die holes with whatever he thinks will work- but if not, I know there are some that were used with square punches that will work as plates with precut hardie holes.
Looking at this application, I'm glad I took the time to ask if I could have the used bucket of discarded tooling- it was destined to be tossed in the regular mild steel dumpster otherwise.
It would seem that there is no way to avoid being technical about it. I'm a little amazed at the level of sophisitication in blacksmithing, as I had always considered it kind of a primitive "heat up the metal then beat it with a hammer" sort of situation. But considering how long it's been around as a trade, I shouldn't be all that shocked.
That's all right, though. I'm up for it, and it would seem that the idea of doing it has got the gears of some people I work with rolling. It's kind of funny that over a decade of woodworking as led to a small handful of paying jobs, but a couple weeks of goofing around with blacksmithing perked up so many ears that I have to remind people that I'm not very good at it yet so they don't try to give me jobs I can't handle.
Perhaps I'm missing something here, and I'd certainly appreciate the guidance.
I read through a book on metallurgy, and what I gathered from it was that after the steel reached the critical temperature, it transformed into another state where the atoms in the metal crystals rearrange themselves into a different geometrical configuration. From what I more or less know (or at least can guess at) from basic chemistry, my assumption was that this structure persists as it continues to heat up, with the essential difference being that the crystal structures begin to move further and further apart until they are arranged in a strand formation rather than a grid, and can easily slide against one another to form a liquid state.
From my understanding (which may be wrong,) the annealing process is a matter of bringing the material to the critical heat and allowing it to cool very slowly. The slow cooling allows the grains to grow without fracturing, resulting in a more malleable structure. Quenching causes the grains to fracture quickly, resulting in a very fine grain structure that is harder and more brittle.
It didn't really mention grain growth when the material is past the critical temperature, but it was not a very detailed textbook. It was pretty frustrating considering the way they dealt with topics- basically every process was a very simple broad explanation followed with a picture of a giant industrial machine and a a caption that said "here's a big machine in Pennsylvania (which you could never afford) doing this to 10000 tons of steel per hour."
Just remember: There are two things that will send a blacksmith to Hell; hitting cold iron and not charging enough. :)
Keeping in mind that I'm no metallurgist I don't see anything too off in what you just said. My understanding of it is that the carbon material tends to flow along the grain lines and the more stratification you get, the less strength you will have in a hardend work piece. You get a better molecular bonding from a fine grain when tempered since all that cabon is well mixed with the iron. In addition I'm told that a finer grain structure reduces the depth of hardening at quench. This is what helps to create the really cool swirls and color variation so charished by those in pursuit of hamon lines. Another benefit of shallower hardening is that the blade will be less hardend in the middle, making it less prone to catastrophic failure from impact or torsion.
Again, I'm just another dummy on the newsgroup and I probably have a fair number of my own misconceptions. Do your own studying and challange what you think you know, then back it up with practical experiments. There is no substitute for destroying a piece of metal to find out what works.
GA
It was hard for me to accept this at first, but now I don't mind so much. I'm playing with some 1095 samples right now, it's almost like I don't care if I heat-treat my project knife or not.....of course I have others planned. :)
matthew ohio
About a hundred years ago it was iron with different levels of carbon in it that you could detect with a spark test if nothing else... now there's all these alloys to deal with...
Alvin in AZ (not a blacksmith)
Which one? :)
"Metallurgy Theory and Practice" by Dell K Allen is the one to buy.
Last I looked the shipping and the book were about half and half the cost from Amazon.
Yes and iron's the only metal to do that too. Funny but both crystal forms are 83% full of iron atoms.
One is magnetic and the other is non-magnetic.
Both 83% full but the empty spaces are arranged different and certain spaces turn out to be bigger empty spots when the iron is non-magnetic. Just big enough for carbon, boron, phosphorous or nitrogen to slip-in. :)
You quench the iron and those "impurities" get trapped inside the magnetic crystal structure and distort the crystal putting both stress and strain on each crystal that happened to.
That results in a "hard" crystal. ;)
Not really but I suppose that's close enough. (Figs. 6-1 and 6-2 P-160 and P-161)
Oooo... P-165 Fig. 6-4... Those aren't welding rods! ;) The process is working the other way... sorta like they are forming "welding rods" but are really plates and we are seeing them edge on. (always wanted to post that;)
Yeah sort of, plenty close enough like Kyle said. :)
That's one type of annealing.
Sorry but "sort of" and "close enough" are not going to cover it this time. ;)
Grain size is dynamic while heating and forging and cooling freezes the grain growth, especially after the iron becomes magnetic again.
Yeah, not written for practical use. :/
MT&P is a classroom textbook but was written more like a book from the 30's and is geared towards a more "hands-on" time in history.
From MT&P...
Cool diagram huh? :)
Rant mode on ;)
Alloying has made a big difference with what a guy can get away with. I figure there are many little things that used to have to be done to get simple straight carbon steel with "too much" sulfer and phosphorous in it to turn out as good as the old timers got it to turn out.
Some of that might be lost. :/
But in my experience most is not "lost", it's more sinister than that...
Made fun of and/or claimed to be un-necessary hocus-pokus "because I don't do that and it turns out fine" but they are using the new cleaner steels, see? ;)
And so certain methods are no longer "supported" by the "in crowd".
Betcha that's-done-more to "lose" the old ways, more than anything.
Been There Seen That many times! :/
Alvin in AZ
Okay, that makes sense. It's a much clearer mechanism than what I had as a working idea. From what I had seen, the iron in an annealed state had a Fe atom on each corner of a "cube", as well as one in the center of each "face" of that cube. When it was heated, it appeared that five of those atoms on the faces migrated elsewhere (presumably to go make another cube) and one of them slid to the center.
That would account for the space where the other elements slip in, if I'm understanding this correctly.
Not at all- it belonged to one of the welders at work, and I suspect that that particular class was just filler when he got his degree.
That has to be the best picture I've seen of the process by far. I think you just sold me on the book with that one. Thanks for the link.
Yep. I think you're right on. That happens with every trade, from what I've observed. I always try to arrange working next to the oldest guy I can find- they usually know a trick or two, and I like to learn 'em.
Thanks for the detailed response- that did fill in a few gaps, and certainly helps out!
Each of those "faces" is shared with an identical "cube". Insead of "making another cube", those atoms are likely to migrate into the center of a neighboring cube.
John
Prometheus wrote:
Metallurgy math...
1 + 1 = 42% of an alloy does "X".
2% of a different alloy also does "X". 1/2% of each alloy together does "X" too. That's a total of 1% alloy doing "X".Half as much total "expensive" alloy and get the same results. :)
No wonder steels have a list of alloys as long as your arm, huh? ...and that's just the beginning, just the "money angle". :)
O1's a good example of cheap. :)
Mn based to get oil hardening properties, instead of having to use more expensive Cr. O1's got a little of W -and- Cr in it to control the grain size and it just takes a little of each "together" to get the job done. Mn isn't one of the better grain size reducers, but Mn is cheap(!) and makes for a relatively strong and easy to work steel. :)
Face centered cubic (FCC) and body centered cubic (BCC) are the two crystal patterns described there.
I never bothered to keep track of which one was which, because why would it really mattrer? :/ But realized during class one day, FCC is hot-ass austenite and you can "feel that on your face". ;)
Ok so, austenitic stainless steel ain't always hot. :/ What of it? ;)
Mn Si Ni and Co (and who knows what else) substitute for the "about same sized" iron atoms.
You'll see them described as "ferrite strengtheners" as a result.
Cold, hot, quenched, annealed or whatever, they strengthen the iron (ferrite) by "solid solution". Nothing like C P B and N.
Cool, it's my "first metallurgy book" and still the best, IMO :)
On the metallurgy NG, "books for beginners" is asked for ever so often and I always check out the "competition"... so far Allen's got 'em hammered. :) And MT&P's price, clinche's it tight. ;)
Cool. :)
Alvin in AZ and usenet's #1 steel-metallurgy-parrot :)
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