1022 rod...

[Joe Gwinn]

then why can't they duplicate it? :-) Why can no one duplicate an original Bowie knife blade? hocus pocus :-)

Who says they can't duplicate it? Far better steels are available these days, although some people swear by the old carbon steels. And a lot of the magic is in the forging, hardening and tempering recipe, which is hard to deduce from chemical analysis and micrographs of the crystal structure. So, somebody has to be very interested in reproducing the old recipe, trying this after that, or be lucky.

I saw a television show many years ago about a Japanese bladesmith from a family of bladesmiths going back centuries. The bladesmith in the story was also a degreed metalurgist, and was figuring out how the old blade steels were made, what part of the process was necessary and what part was ritual, and why the old blade steels were so good, the intent being to find ways to make such steels using modern mechanized methods.

[R.G.]

From a book I was reading recently, I think wrought iron was made by a process called puddling where cast iron was remelted with iron oxides, and apparently the oxides disassociated into iron and oxygen, which grabbed the carbons in the castiron and escaped as CO2. An operator stirred the mix with an iron rod, taking advantage of the difference in melting temps of iron and iron plus carbon mixtures to accumulate a ball of pure(r) iron.

The balls were heated and beaten (wrought?) into bars.

Stuff was put through this up to three times.

I think oxygen blast furnaces turn out low carbon wrought iron, but the necessary admixtures for the proper steel are shoved right into the melt at this stage.

I'll see if I can find the book in the pile.

If you're puzzling over the effect of carbon fraction on magnetic properties, don't forget mechanical issues. "Cold rolled" is actually cold drawn, and the surface is very mechanically stressed as supplied. Mechanical stress makes the BH curves squarer. Annealing makes the metal magnetically softer as well as mechanically softer.

[Possum]

annealing....

What is the proper way to anneal steel? Using a torch, and or a small kiln? I've heard you can heat small pieces of steel on a bed of sand so they cool slower, I'm interested in a cheap easy way to do this. the how do you TELL if you've successfully annealed it correctly? Does amount of carbon determine annealing method?
Very interested in this subject....

[black_labb]

annealing involves heating it up and then letting it cool slowly. cant remember if it involves keeping it at the elevated temperature or not. cooling the steel as slow as possible will keep it ductile. basically you want the grain sizes to be as big as possible i believe. the amount of carbon wont effect the annealing (assuming it is below 0.8%, which is pretty much all steels.

[SteikBacon]

I did some annealing couple months ago at school. How long and temperature depends on the steel and size. We had two different types of steel. You need to stay at the temperature (holdingtime??) some time, but there should not be any danger annealing too long. I think we used 175 celsius, not so hot, in 15-20 min. Steel need some time to stabilize at such temperature. Then let it cool in air slowly to avoid stress on the outside. So we should be able to do it easy, and let it cool down with the stove for even slower cooling.

[jonson]

Joe answered the cheap way of annealing in the dowel pin thread a few weeks ago Possom. Iron pipe + end caps + some paper to burn the oxygen in there.(that was the key to stop it blowing up) and chuck it all on the barbque or something and leave it there till it cools down. It does work thanks Joe.

[black_labb]

well if the temp needed is only 175 degrees celcius as steik bacon stated, why not make a small roast and use the slugs in the stuffing. maybe you could get some extra mojo out of them by digesting it.

or just put them on a separate tray.

id leave it in the oven after you take the roast out to let them cool as the oven cools as well. should do quite a reasonable job.

[Joe Gwinn]

What is the proper way to anneal steel? Using a torch, and or a small kiln? I've heard you can heat small pieces of steel on a bed of sand so they cool slower, I'm interested in a cheap easy way to do this. the how do you TELL if you've successfully annealed it correctly? Does amount of carbon determine annealing method?

All of these methods work well. Basically, any method that gets the metal up to a red heat and allows the steel to cool slowly will work. If this is done in open air, the outside metal will convert to oxide (the scale). If this is done in an oxygen-free atmosphere, no scale will form. With carbon steels, the process is not very fussy at all.

If annealing is successful, the metal will be very soft. The classic test is to try to file a corner.

Straight carbon steels all anneal about the same, regardless of the amount of carbon they contain. Alloy steels are a different matter. To take the extreme example, "air hardening steel" (alloy A2 is a common air hardening steel) is just that, and ordinary annealing processes will instead harden such a steel. Annealing such a steel requires a special furnace and much higher temperatures.

[SteikBacon]

well if the temp needed is only 175 degrees celcius as steik bacon stated, why not make a small roast and use the slugs in the stuffing. maybe you could get some extra mojo out of them by digesting it.

or just put them on a separate tray.

id leave it in the oven after you take the roast out to let them cool as the oven cools as well. should do quite a reasonable job.

Why not make special potted muffins instead...

[David Schwab]

then why can't they duplicate it? :-) Why can no one duplicate an original Bowie knife blade? hocus pocus :-)

One thing they can't duplicate is Damascus steel. They've tried too, and they can't figure out exactly how they made it.

[black_labb]

Why not make special potted muffins instead...

youve got alot to learn about pickups if that's what your thinking. you need to use meat to get that meaty sound everyone loves from humbuckers.

[R.G.]

What is the proper way to anneal steel? Using a torch, and or a small kiln? I've heard you can heat small pieces of steel on a bed of sand so they cool slower, I'm interested in a cheap easy way to do this. the how do you TELL if you've successfully annealed it correctly? Does amount of carbon determine annealing method?
Very interested in this subject....

I found the book I was talking about - "Hardening, Tempering, and Heat Treatment", part of a Brit workshop series. I highly recommend it; it's the best single book on steel heat treatment in all forms I've ever found. At 124 pages and under $20, it's an incredible value if you're interested in what heat treatment for steel involves in a simple, straightforward manner. I suggest you go buy a copy. The author's name is "Tubal Cain" obviously a pseudonym.
The ISBN is 0-85242-837-5. Almost all of the info I state below came from it, as backed up by "Machinery's Handbook" where I checked the details.

I was right. They used to make wrought iron by puddling and hammering. Then there were two methods developed for removing the carbon from cast iron in melt furnaces, last by a guy named Bessemer. Today nobody makes it because it's hard and expensive to make in little batches by puddling, it's cheap and easy to make if you make 1000 tons or more at at time and can put up the capital investment to do that, but no one will buy 1000 tons of wrought iron. They want a few pounds up to a few tons. If they want more than that, they want steel.

Annealing is more involved than any of the posts here have captured yet. You have to heat the steel above its austentitic transition temperature, which varies with the steel's carbon content. This is 900-920C for low carbon steels down to as low as 760C for high carbon steels, the temp coming down for increasing carbon content. "Red" can mean anywhere from dull red at about 700C to bright red at 900C, so getting the steel red is not sufficient for all steels. It has to be the right red If you're an experienced blacksmith you can judge temperature for annealing by eye within 20-30 degrees. I'm not, and there aren't many of those around.

The steel must be held at this temperature for one hour per inch of thickness in the smallest dimension. The steel must not be held too long, as this causes coarse grain growth which can ruin the steel's mechanical properties at least. Once to temperature, the steel should be cooled as slowly as you can manage to do it. This allows the steel to pass through the pearlite forming regions and avoid any hardening by forming martensite.

While this can be done on a onesy-twosy basis by packing your steel into an iron pipe loosely capped and tossed into a bed of coals in a wood fire in the back yard while praying to the iron gods and tossing salt over your left shoulder, if you want to do it with any hope of control you need a furnace capable of 950C and some controls. Fortunately, this is easy and cheap to do as many people take up home ceramics, buy a 2300C ceramics kiln, then find out that it's hard and practically give the kiln away. I can get one for under $300 any day in my area. You can also construct one from firebricks and electrical heating coils. The same book gives a design for a treatment furnace like this.

well if the temp needed is only 175 degrees celcius as steik bacon stated

It's not. That's a lowish tempering temperature for steel that has been hardened by being heated above its transition temperature and quenched to make it hard and (unavoidably) brittle. Tempering restores some toughness so it doesn't crack like glass. I'm pretty sure steik bacon did run into that, but in another context.

One thing they can't duplicate is Damascus steel. They've tried too, and they can't figure out exactly how they made it.

Damascus has been duplicated. It turns out that it depends on getting the right steel with the right (wrong?) impurities. It depends heavily on vanadium as I remember, and historically this was obtained in Damascus by importing "wootz" steel from India. The guys who found this out have duplicated the characteristics and patterns of the classical Damascus steel blades. Putting "Damascus wootz vanadium" into google turns up
The key role of impurities in Ancient Damascus Steel blades
and Reproduction of Damascus steel wootz patterns and blade forging

[SteikBacon]

youve got alot to learn about pickups if that's what your thinking. you need to use meat to get that meaty sound everyone loves from humbuckers.

My humbuckers are full of bacon.

[jonson]

My humbuckers are full of bacon.

I'd Steik my life on you really trying to lead us up the garden path with your filling. I think your telling Porky pies.

[cwood3]

Hambuckers.......????