Talk:Cementation process

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This article had got the cementation and crucible processes in completely the wrong order. I will correct that. Peterkingiron 16:03, 8 April 2006 (UTC)Reply

long since done. Peterkingiron (talk) 16:12, 12 July 2009 (UTC)Reply

I have deleted a mention of the name of the process being derived from its use of "cement powder" because I do not believe it. It is far more likely to be the other way around. In any event, I have grave doubts as to the correctness of the statement. Barraclough (1984, pp.35-6) refers to additives but implies that additives were gradually abandoned in favour of plain charcoal. This is the leading work on the process as used at Sheffield. Peterkingiron (talk) 16:12, 12 July 2009 (UTC)Reply

Unlike modern steelmaking, it increased the amount of carbon in the iron

Umm...I'm not getting this.

Isn't steel basically iron that has been crystallized by adding carbon?

Ergo, is it not true that (a) iron (an element) doesn't contain carbon (another element), except as an impurity, (b) carbon is ADDED to iron to create steel, and (c) steel ALWAYS contains more carbon then the iron from which it is made?

Am I missing something here? Lexington50 (talk) 10:11, 12 June 2012 (UTC)Reply

That bit was inserted here in 2006. You'd have to ask that editor, Petri Krohn, what he had in mind, but I suspect he was thinking about the stage in which steel is produced from carbon-rich pig iron by decreasing the amount of carbon, e.g. by burning it out in a blast furnace. Iron ore may include carbonates along with other minerals, and more carbon is added when smelting with charcoal to produce pig iron. Vaughan Pratt (talk) 17:29, 19 October 2013 (UTC)Reply

Lexington has not understood the processes. "Iron" is (confusingly) used both for wrought iron (commercially pure iron) and pig or cast iron, which contains 4-5% carbon. Steel is an intermediate product between these. It is possible to get to steel by starting with either and at differents both have been used. Cementation is (or rather was) a process starting with bar iron and adding carbon to it in the solid state. This is a process of a kind that people do not get taught about in school. Modern processes tend mostly work by melting scrap of varying carbon contents, perhaps with some pig iron, to produce the desired result. Peterkingiron (talk) 15:28, 24 October 2013 (UTC)Reply

Well, thanks for the gratuitous condescension, but it is simply a fact of chemistry that elemental iron does not contain carbon. Where I think the confusion arises is that the iron used in steelmaking may contain impurities, including carbon, and that the end product (steel) can ultimately contains less carbon than the feed stock (say, pig iron). In any case the sentence as it stands is at best highly misleading. Lexington50 (talk) 09:53, 10 January 2014 (UTC)Reply

Ah, andy d. It just wouldn't be Wikipedia without you.

I probably should have floated the definition here in talk before making the edit, but here goes. As in other metal-related cementation processes (Brass, Arsenical Bronze, Iron, etc) the term cementation indicates a dissolution of a gas or liquid into a solid.

Ipso facto, the MUCH later Huntsman's process (which liquifies the iron/steel) does not belong here. Therefore I suggest my edit be reinstated.

Riventree (talk) 17:27, 20 February 2016 (UTC)Reply

Cementation happens before the crucible process. As you describe, carbon is diffused into the iron by heating iron bars in a suitable atmosphere (formed from some variety of carbon donor blistering). For shear steel, the blister iron is then cut and forge-welded repeatedly, distributing the carbon from the surface to the body of the bars and allowing further diffusion to make steel. For crucible steel, the blistered iron is broken up and then re-melted.

But both of these begin with a cementation process. Andy Dingley (talk) 00:49, 21 February 2016 (UTC)Reply