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  #11  
Old 10-12-2017, 08:09 AM
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Very nicely written and explained, Matt!
I learned some things and I enjoyed reading it.
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  #12  
Old 10-12-2017, 09:37 AM
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Quote:
Originally Posted by cutter View Post
Very nicely written and explained, Matt!
I learned some things and I enjoyed reading it.
Glad I can contribute sometimes


I should add, that there are quite a few steels over 1% carbon that are good tool steels. The reason I said the average blacksmith is most interested in the .6-1% range is that the steels with exceptionally high carbon come with lots of other alloys. D2 for example makes a hell of a knife and comes in at 1.5% carbon, it also has so many other alloys (12% chrome for example) that it is an air hardening steel, doesn't forge well, and requires special equipment to reliably heat treat.
For someone that wants to use a forge and hammer, the medium carbon range, and more simple alloys are best.
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  #13  
Old 10-12-2017, 10:27 AM
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If you can find a piece of an old bed frame or T-post, it may well be rerolled rail steel. Jersey Shore up in PA makes a lot of stuff from old high carbon rails.
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  #14  
Old 10-12-2017, 03:35 PM
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Originally Posted by digger doug View Post
No, your the google searching cut & paste some words you found under a rock
troll.

Your posting WRONG INFROMATION.

If you don't what the carbon content of Mild steel is, don't "wing it".
Real "Got ya" moment for you wasnt it? Do you think if i cut & paste something it would have such an obvious typo in it? I made a typing error, thankyou for bringing it to my attention!

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  #15  
Old 10-12-2017, 05:33 PM
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In the trade we have points of carbon and tenths of hundreds of inches. What's a decimal point shifted by one place here or there? Politicians shift a couple places all the time. Million, billion, trillion, whatever. Just a bunch of zeroes hanging around, which they can identify with.
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Old 10-12-2017, 09:19 PM
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Originally Posted by USMCPOP View Post
In the trade we have points of carbon and tenths of hundreds of inches. What's a decimal point shifted by one place here or there? Politicians shift a couple places all the time. Million, billion, trillion, whatever. Just a bunch of zeroes hanging around, which they can identify with.
Enough for the local internet hero to come out and correct the error it would appear. I dont mind being corrected, its the asshat attitude that is kind of out of place. I suppose feeding the trolls is cheap entertainment though.

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  #17  
Old 10-13-2017, 12:25 AM
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At least you know you are being read when the trolls pick up on a error .
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  #18  
Old 10-13-2017, 03:24 AM
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At least you know you are being read when the trolls pick up on a error .


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  #19  
Old 10-13-2017, 07:29 PM
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Originally Posted by biker55 View Post
Hello all, is there an easy test to find out if the metal contains carbon. also, how high of a carbon content do you need to make a fire striker? thanks
Use an old file or old rasp.. .90 -1.2 carbon is what you want.. These throw the best sparks..

Problem is they will be brittle as all get up..

A case hardened striker is the best but most don't ever bother..
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  #20  
Old 10-13-2017, 07:36 PM
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Quote:
Originally Posted by Matt Shade View Post
The easiest test to see if a steel has much carbon is to do a spark test. If you touch it to a grinding wheel and sparks stay in one piece and travel a long way there isn't much carbon. If sparks split off and the spark trail has a lot of forks in it, then you have carbon. The spark trail from grinding high carbon steel has a kind of fuzzy look to it.

Beyond the spark test the next thing to do is to heat a sample piece until it is non magnetic and quench it. Then you can test it with a file to see if it hardened or you can break it and look at the grain structure. High carbon steel should snap cleanly and have a grain that looks very fine like talcum powder, after being quenched.

A good striker should be as hard as a knife blade. You want it hard enough that it doesn't just dent or tear, otherwise you won't get sparks from it.
Just to add into Matt's excellent post.. When you quench something to make it hard,, Ideally you want to quench it as the temperature rises to teh transition temp, for the most part and you don't want the steel to sit at the transition temperature to long as it will create a large grain growth which is bad, also you will get some decarb..

Some steels have alloys added to control grain growth but believe me when I say that an W1 steel or a vintage rasp or file make the best strikers as they have less alloys.. I have found low alloy or no alloy steels shed the best sparks..

might be different now but i'm not up on the newer alloys and how they function as strikers..

Quote:
Originally Posted by Matt Shade View Post
Here is an Iron-Carbon Phase Diagram for steel. I am borrowing it out of course materials from a class I took at OSU, hopefully they don't have a problem with that

As you can see across the bottom, steel can have a carbon content anywhere between zero, and 2 percent.

The line designated at .8 percent carbon is the eutectoid line. At room temperature this is the difference between the crystal structure being ferrite + pearlite, vs. cementite +pearlite. That isn't important to the average person, but if you have ever heard the term eutectoid or hypo eutectoid that is where it comes from.

What is important to the average blacksmith is the austenite range, which is the diamond shaped zone in the upper left. Austenite is formed when all of the carbon has dissolved into solution, and coincidentally the steel turns non magnetic while it is in this state, which gives us a surefire way to know we have reached the right temperature.

Austenite is not actually useful for tool making. It is soft. If you find a stainless steel that is labeled as an "austenitic stainless steel" for example, it has enough alloy in it that it is austenitic at room temperature. It will be too soft to use for things like knife blades etc and cannot be hardened beyond work hardening which is only useful if you like to ruin drill bits.

The useful thing about austenite is that when we cool it down really fast, the carbon is trapped in a matrix called Martensite. Martensite is the hardened form of steel, and is what we need for knives, chisels, axes etc.

As a general rule, the carbon content will dictate how hard the steel can get. All steel with carbon is hardenable, but not to the same extent. Steel up to the .40% range can actually still be machined fairly easily after being hardened and are used a lot in things like gun parts. For a hatchet head that needs to be tough you might get away with steel in the .50% range, but for knives or chisels and other cutting tools you really want to stay in the .60%-1% range.

You also have the benefit of being able to temper steel and draw its hardness back to wherever you want it. So it's generally better to work with high carbon steel that can be hardened beyond what you want, than it is to use lower carbon and hope that you can achieve its maximum hardness. O1 straight out of the quench for example may have a hardness of RC64 or more, and you can dial that back as far as you want by tempering. 1040 may only come out of the quench at RC40 and there is nothing you can do to make it RC55.
Brilliant post Matt, Keep up the great work and I'll come to your class..
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