[TheForge] Re: Pure Iron vs. Cast Iron

[David E. Smucker]

Ekaterina,  Industrially today carbon is mostly removed with an oxygen lance 
in the Basic Oxygen Furnace.  Or for special steels it is done under vacuum 
by injecting a mixture of gases.   You might want to read up on the Bessemer 
process -- you might be able to reproduce that on a small scale using air, 
as Bessemer did rather than oxygen.  Bessemer's complete autobiography is 
available on the web for free.   It is a very interesting read and includes 
a lot of technical history.

http://www.history.rochester.edu/ehp-book/shb/start.htm

Historically in the wrought iron process it was done in a puddling furnace 
lined with a bed of iron oxide, at temperatures below the melting point --  
but still mushy.  The process also involved the use of a covering slag --  
which was the source of the SiO2 in the final material.  Lots of operator 
judgment was call for.  After it got to the correct state it was removed as 
a mushy ball of material and hammered.  There was also a process that 
predated this where they worked directly from the iron ore to produce a 
"bloom" that was also hammered.  Some of the knife makers have been making 
material this way.  Dan Fogg, worked a knife he had made from such material 
at the Madison conference in 2007.

Dave
----- Original Message ----- 
From: "Ekaterina Harrison" <ekaterina at wildblue.net>
To: <theforge at mailman.qth.net>
Sent: Friday, March 28, 2008 12:22 PM
Subject: [TheForge] Re: Pure Iron vs. Cast Iron


> Hi Dave, Peter and Andy,
>
> Thank you all for your responses. It helped a lot.
>
> Dave, It makes me wonder what it actually takes to remove the carbon  from 
> the pig iron.
> I know that it is not too big a deal to pour it. I do have plans for a 
> cupalette.  Just have not had the time to build it, yet!
> If it is not too complicated a process I can easily see making simple 
> sand molds casting which can then be forged into more complicated  shapes.
>
> Ekaterina
>
>
> On Mar 28, 2008, at 8:39 AM, theforge-request at mailman.qth.net wrote:
>
>>
>> Message: 10
>> Date: Fri, 28 Mar 2008 10:32:39 -0400
>> From: "Peter Hirst" <saltydog335 at aol.com>
>> Subject: Re: [TheForge] Pure Iron vs. Cast Iron
>> To: "Sponsored by ABANA" <theforge at mailman.qth.net>
>> Message-ID: <00df01c890e0$9351e130$6500a8c0 at Codfish>
>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>> reply-type=response
>>
>> It might be well to specifically point up the irony (heh-heh) that  iron,
>> wrought or pure, has  (little or) no carbon, but steel does, and  cast 
>> iron
>> has even more carbon than steel does.
>> ----- Original Message -----
>> From: "David E. Smucker" <davesmucker at hotmail.com>
>> To: "Sponsored by ABANA" <theforge at mailman.qth.net>
>> Sent: Friday, March 28, 2008 7:38 AM
>> Subject: Re: [TheForge] Pure Iron vs. Cast Iron
>>
>>
>>> Ekaterina,
>>>
>>> Pure iron is just that plain iron. No alloy and No carbon.  (Carbon  is
>>> really an alloy element but we don't think that way most times.)   As we
>>> start to add carbon to iron we get steel.  Low carbon is around 0.2  of 
>>> 1
>>> percent carbon -- mild steel.  This is also sometimes called points  of
>>> carbon or 20 points.  Most high carbon steel today is around 1  percent
>>> carbon (100 points.)  We often also call this a tool steel.  W1 for
>>> example is 1 percent carbon.  Medium carbon steels are around a 1/2
>>> percent carbon 0.5 of 1 percent or 50 points.  Steels may also have 
>>> lots
>>> of different alloying elements added greatly changing their  strength 
>>> and
>>> other characteristics.  Steels can have a maximum of 2 percent 
>>>  carbon --
>>> above 2 percent carbon, we have the cast irons.  Up to I believe  the 
>>> max
>>> the iron can "hold" is 6.67 percent carbon.  Your ductile iron is  one 
>>> form
>>> of the "cast irons".  Gray cast iron another.
>>>
>>> Historically there was a very common product called "wrought iron"
>>> sometimes today called "real wrought iron".  It like "pure iron" had
>>> almost zero carbon, maybe a very small amount.  But it did have  Silicon
>>> Oxide stringers in it from the manufacturing / refining process.  To
>>> confuse things even more -- it was made from cast iron or pig iron by
>>> removing the carbon.  Same is true today for the manufacture of raw
>>> steel -- it starts out a liquid cast iron from a blast furnace --  also 
>>> a
>>> lot of recycled steel is added.
>>>
>>> Hope that helps a little.
>>>
>>> Dave Smucker
>>>
>>>
>>> ----- Original Message -----
>>> From: "Ekaterina Harrison" <ekaterina at wildblue.net>
>>> To: <theforge at mailman.qth.net>
>>> Sent: Friday, March 28, 2008 12:50 AM
>>> Subject: [TheForge] Re: File Making, sniffing up wrought iron
>>>
>>>
>>>> Hi All,
>>>>
>>>> I must admit that some of this is going over my head. <sigh> Perhaps
>>>> this was already answered and I missed it.
>>>> I have spent a few years working in various foundries and have  poured
>>>> some ductile iron. However, I really did not get a chance to find  out 
>>>> as
>>>> much as I had wanted to about the various aspects of iron. Perhaps
>>>> somebody here can answer this - What is the difference between  iron 
>>>> that
>>>> is cast and what you are referring to as pure iron?
>>>>
>>>> Ekaterina
>>>
>
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