Talk:Heat treating

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General name?[edit]

Heat treatment is a very general topic name. Could we find a more specific name for this page, if we wanted a topic on just the heat treatment of metals? Hardening (metallurgy) is kind of that, but is only a part of it. — Sverdrup 8 July 2005 07:44 (UTC)

Personally, I have no objection to changing it to Heat treatment (metallurgy), (or even back to Heat treatment for that matter), especially is you plan on creating other articles. However, in most common usage, when people hear "heat treatment" metals usually is the first thing that comes to mind. Fewer people are going to think about chocolate#tempering. If the article is renamed, I think the general terms should still redirect here, with a note at the top of the page leading the the DAB page. Another thing to consider is that, other than heat treatment of wood, there aren't any other articles which we could add to a DAB page, so, perhaps we should wait until there is a need for such a page. Zaereth (talk) 20:52, 25 June 2012 (UTC) (Oops, I didn't realize this was an old question, which someone else just added a title to.) Zaereth (talk) 20:56, 25 June 2012 (UTC)

Much is missing[edit]

This article, as it currently stands, is clearly written from the viewpoint of an edged weapons fan. There is little technical information (even in a form suitable for a layman) about, for instance, ferrous metallurgy (a murky reference to crystals is about it), and none relevant to non-ferrous metallurgy.

This is a tremendously important topic bearing on (to pick only a few): welding (not a good idea for items which depend on proper heat treatment for their properties -- unless it's followed by appropriate heat treatment), construction (eg, mild steel beams and columns), machinery (eg, automobiles, engines generally, ...). WP should have a better article. Perhaps someone could walk through a text and paraphrase? ww 19:46, 14 December 2005 (UTC)

What about measuring hardness? (talk) 12:41, 27 September 2012 (UTC)

That info is found in the hardness article. However, you are correct in pointing out that we previously had no links to that or similar articles. I added some links near the beginning of the article. Zaereth (talk) 23:33, 27 September 2012 (UTC)

carbon-steel phase chart[edit]

Well, i'm an engineering student myself. Regarding this Heat Treatment for metal, i think we should include the Metal-Carbon Phase Chart which determine the heating temperature of metal base on its carbon percentage to achieve particular micro structure, this is really important.--Dehanz 18:28, 9 October 2006 (UTC)

I would love to see an Iron-Cementite (or Iron-Graphite, though alot of charts show both) phase chart. Finding one in the public domain could be difficult, though - copyrights last for 95 years, and some of the information in that chart is only forty years old. Someone would have to find an author willing to release the diagram into the public domain. Lyrl Talk Contribs 21:37, 9 October 2006 (UTC)

Phase diagrams describe alloy systems in a state of equilibria, which is not the case during heat treatment. A T-T-T diagram is much more useful than a phase diagram during heat treating. Phase diagrams are reletively unimportant in heat treatment as kinetics effect the process (i.e. the times involved in the steps are not infinite). Also, a Fe-C diagram would be too narrow for this article. Save the phase diagram for steel, phase diagram, or heat treatment of steel. Iepeulas 17:33, 18 October 2006 (UTC)

TTT diagrams don't make any sense for people not familiar with phase diagrams, however. And phase diagrams are useful for understanding why steels of different carbon contents are heat treated differently. If a source were found for such diagrams, I would support including both phase and TTT diagrams in this article. Lyrl Talk Contribs 18:46, 21 October 2006 (UTC)
Check out the heat treatment section in carbon steel. I created a iron-carbon phase diagram over there with a couple of heat treatment ranges. I agree that the TTT charts are really what's important when it comes to heat treating. --Wizard191 (talk) 13:53, 14 March 2008 (UTC)


Hi. I can't edit the page over this because i'm not sure, but i think i see an error in the article that requires better knowledge than mine to ascertain as such: it says that "during annealing, small grains recrystallize to form larger grains." I've been a blacksmith for some years now and have always been under the impression that it was the other way around. if this is not the case, i feel like a moron and stand corrected. however, i thought i'd better point it out, just in case. Hephaestus III (talk) 03:07, 26 May 2010 (UTC)

Well it's partially correct. See Annealing_(metallurgy)#Stages_of_annealing for the real story. I'm going to try and fix the text here to match the annealing article. Wizard191 (talk) 18:04, 26 May 2010 (UTC)

Article needs some improvement[edit]

There seems to be quite a bit of information that is missing from this article. I know it's suppose to be a summary, but there is a lot of info that seems relevant to understanding this complex subject. For instance, hardenability of metals, as well as the effects of carbon on the maximum and minimum hardness of steels, is not mentioned. Pearlite grain size, which is formed during annealing, is mentioned, but not austenite grain size, which forms due to temperature and ultimately determines the martinsite grain size, also is not covered. The three differing phases of steel, namely austenite, ferrite, and cementite, are not well described, nor are the differing microstructure which the heat treating produces, like pearlite, martinsite and bainite. Many other forms of heat treatment should also be summarized here, like spheroidizing, austempering, martempering and stress relieving.

I'll freshen up on my books, and try to add some stuff to this article within the next few weeks. Zaereth (talk) 03:19, 20 November 2010 (UTC)

I've taken a bit of time to give this some great consideration. As opposed to most other alloys, there are so many different ways to heat treat steel. Perhaps it would be best to create an article titled "Heat treatment of steel," and then provide a main article link with a brief summary here. Then we can summarize the processes with links to the various articles, like martensite, austempering, carbonitriding, etc... over there. Does that idea sound good to anyone, or would it be best to keep everything here? Zaereth (talk) 01:58, 6 January 2011 (UTC)
Maybe? The thing is that all of the steel heat treating processes are already articles of their own right, so there are summaries here. Perhaps it would be better to create sections for each metal and then put the correct processes under that? Wizard191 (talk) 15:18, 6 January 2011 (UTC)
Hmmm, yes I'd also thought of that. If we create a section for each different alloy that might make the info easier to find for those who are looking for something specific. Of course the downside is that the article could get very long. Still, it seems like it may be better to keep it all in one place. I've also just discovered that, besides the steel article, there is also a carbon steel article, in which most of the processes are already described and linked, much in the same manner that I was thinking. Perhaps it would be best to just link to that from here? I like to avoid redundancy, but still make the info easy to find.
So many different way to procede. Which do you think would be best? Zaereth (talk) 17:48, 6 January 2011 (UTC)
Well the one thing I'm not worried about right now is article size, because its only 10k right now. As such, I wouldn't create a new article, but try and organize it better here. As far as the heat treating info at carbon steel, I would probably move that section over to this article once this article is more organized, because the info is also applicable to alloy steels, so its not quite proper to keep it there. (That was one of the first main contributions I made to Wikipedia many years ago, and I didn't really know where to best put it, so it ended up there). Wizard191 (talk) 18:30, 6 January 2011 (UTC)
Ok, that sounds splendid. I'll have to do some reading on non-ferrous alloys, and the amount of time I can devote to Wikipedia is very limited, but I'll try to see what I can do to help soon. (Nice contribution, by the way. It's exactly what I was looking for.) Zaereth (talk) 01:27, 7 January 2011 (UTC)


I've been giving this quite a bit of thought while reviewing my sources. I find it hard to give an adequate description of heat treating without giving a brief description of the physical processes that make it possible, in particular, dissolution/solubility, diffusion, precipitation and allotropy. I think a couple of paragraphs could probably give a decent description of the roles these phenomena play in heat treating. I'd probably follow that up with a brief description of the roles played by composition, temp, and time, such as the difference between eutectoid versus hyper-eutectoid, microstructure and phase changes. Then I would probably have a section about the various generalized techniques, much like is already there, but to include such things as stress-relieving and surface hardening. The main addition I would provide there is to describe how, while these techniques are often applied similarly to different alloys, the objectives (desired results) are often very different. (For instance, quenching steel will give very different results than quenching aluminum.)

Once all of the basic information is in place, it should be much easier to explain the processes as applied to different metals. I'd probably start a section beginning with allotropic metals, such as carbon steel, alloy steel, cast iron and titanium and iron-nickel alloys. Then move on to alloys that harden by precititation, like copper, magnesium, lead and precious metal alloys. I'd probably finish up with special cases, like mangalloy, in which the ductility can be altered, but the hardness can't. Or uranium, which is heat treated to prevent corrosion.

Lastly, a quick description of how heat treatment is applied to non-metallics, like glass should be included.

How does that sound? Zaereth (talk) 19:12, 18 March 2011 (UTC)

It sounds quite good overall. The only note I would make is to not get too deep into the details of dissolution/solubility, diffusion, precipitation, and allotropy, because they all have their own article, which can be linked for the in depth detail. Wizard191 (talk) 13:42, 23 March 2011 (UTC)
Agreed. I only want to describe how these phenomena apply to heat treating, so that further explanations will make more sense to those who know nothing about the subject, without boring those who do. I tend to work rather slow, since Wikipedia is just something to do when I'm on break or on hold, so I'll probably just add a few paragraphs at a time over the next few months. Thanks for you assistance, for it's nice to be able to toss ideas around to see what sticks. Zaereth (talk) 18:41, 23 March 2011 (UTC)

Phase diagram[edit]

I'm not sure if this is the right place to bring this up. The iron-carbon phase diagram, as nice as it may be, is slightly inaccurate. The melting point for a hypereutectic cast iron should have a much steeper line. On the pure iron side, the melting point looks correct at 1535 degrees C, but a cast iron with 6.67% carbon will liquify at 1837 degrees C. It may not be worth mentioning, as these cast irons do not seem to find much use, but, if someone who is good with graphics comes along, perhaps it would be simple enough to correct. Zaereth (talk) 20:37, 25 April 2011 (UTC)

I'll see if I can correct it soon. Wizard191 (talk) 22:13, 25 April 2011 (UTC)
Wow, that was fast! Thanks for your help. That looks good. Zaereth (talk) 18:04, 26 April 2011 (UTC)
Well it's easy for me to modify SVG files, but the PNG formats not so much. So that's why I changed the file. Wizard191 (talk) 18:13, 26 April 2011 (UTC)