Talk:Austenite

Disputed

Austenite isn't exclusive to iron. Other alloys with no iron, like nickel-titanium (nitinol), can also form austenite. Therefore, defining austenite solely as a phase of iron is wrong and misleading.

Either the definition should be corrected, or the page should be renamed as just austenitic iron. 2803:9800:9A04:75C4:5D65:8564:7CB3:5F36 (talk) 20:52, 1 April 2024 (UTC)

Seems to me to be more a matter of semantics than anything else. The material named after Roberts-Austen was originally the solution of gamma-iron and carbon (that is, it wasn't applied to pure iron, but only to the solution). Same way that martensite was named after Martens. The term "martensite" usually only applies to iron-carbon alloys, but a similar transformation called the "martensite transformation" can occur in many alloys and even non-metals, including aluminum and titanium alloys, although it tends to have the opposite effect on material properties that the same type of transformation has on steel. But the phase is rarely called martensite in any other material but steel. Similarly, these alloys can experience what some may call an "austenite transformation" when heated, that is, when the separate phases of the alloy combine into a high-temp solution. Some people may even call it austenite, but in my experience calling any phase other than steel that simply causes confusion so it's pretty rare. Zaereth (talk) 04:01, 3 April 2024 (UTC)

Stabilization

The stabilization text says (eliding) that more than a monolayer can be grown because practice agrees with theory. That is not a correct statement: it is not the practice equals theory situation that allows the thicker layers. A better statement would be that more than a monolayer can be grown up to a critical thickness, the experimental value of which is in good agreement with theory. —Preceding unsigned comment added by 68.183.97.153 (talk) 16:55, 17 December 2009 (UTC)

Edit of 'behavior in plain-carbon steel' section

I copy-edited the section discussing tempering in plain-carbon steel. I think I didn't introduce any mistakes into the description of the process, but it should be checked for accuracy, as I'm not knowledgable at all as the metallurgic process - my edit was simply for readability. Specifically, the line at the end, "If a low-hardenability steel is quenched, a significant amount of austenite will be retained in the microstructure." seems awkward:

1) what dose 'low-harden-ability' refer to - is this describing a steel with low hardness, or a steel that has a low capacity to *be* hardened by other metallurgic processes?

2) what is the significance of a large amount of austenite remaining in the microstructure of the steel? Is this of some importance to the resulting product? I have no idea what the answers to these are, so I just left that sentence as it.

--Jim Witte 216.9.142.238 (talk) 04:38, 26 August 2010 (UTC)

See hardenability for an explanation on it. The significance of retained austenite is that it's not martensite, which is what is wanted when steel is quenched. Therefore you only get case hardening not through hardening. That's just a really rough outline. Wizard191 (talk) 16:40, 26 August 2010 (UTC)

UK English or US English?

Per WP:ENGVAR and WP:RETAIN, it is generally considered inappropriate to change American spelling to British (or vice versa), unless there is an overriding reason to do so.

In the last few days there have been multiple reverts (all in good faith, I believe) from multiple editors switching the spelling of certain words: behavior/behaviour, centered/centred, and color/colour.

Rather than continue a revert war, I have invited all the editors here to discuss this issue and seek consensus.

Here is the relevant history of the page:

On 22:19, 24 May 2003 the page was created as a stub. The original page had one aspect that was UK ("Face-Centred") and one that was US ("1333°F (about 723°C)".) "Centred" is clearly UK, and using °F as the primary unit of measurement is clearly US (note that the inverse is not true; many US scientists prefer °C)

On 21:20, 18 April 2005, the word "Color" was added, where it co-existed with "Centred" until two days ago when the revert war started.

On 09:35, 26 February 2007 "1333°F" was changed to ""996 K."

On 17:50, 9 September 2009 the word "Centered" was added, where it also co-existed with "Centred" until two days ago.

On 29 December 2010, IP user 89.168.109.232, (who has a history of changing pages to UK English whether they need it or not) attempted to make the entire page UK English. Materialscientist reverted 89.168.109.232, 85.210.61.130 reverted Materialscientist, Guymacon reverted 85.210.61.130, and 89.168.110.64 reverted Guymacon and added a UK English tag to the talk page.

At that point I rolled back everything to the version that has been up for years, removed the UK English tag from the talk page, and invited everyone involved here to talk it out. Guy Macon 03:09, 1 January 2011 (UTC)

(As mentioned above) I did revert spelling change once, but then, after examining the article history, realized that it is was uncertain. Let us decide the spelling to avoid warring. WP:ENGVAR says if there is no consistency in the initial version, the spelling of major contributor(s) is to be adopted. Both Marshallsumter and Polyparadigm apparently used US spelling with an admixture of "face centred" (which they might think is a technical convention). I admit the situation is dubious, but my vote is for US spelling. Materialscientist (talk) 03:24, 1 January 2011 (UTC)

Good analysis of the problem! I agree that it is a curios case as the initial version contained both aspects. Indeed, I agree that the preferential use of Fahrenheit may be counted as such an aspect. Nevertheless, I want to add that due to WP:UNIT, preference should be given to SI units even if AE is used. I see that currently, this is the case. So, from my side, I would be fine to label the article as an AE-spelled one. I hope that the messages placed on the IPs talk page will succeed, and the IP will stop making useless changes. Tomeasy _{T C} 21:53, 1 January 2011 (UTC)

I don't want to throw a screw ball in this, but from the analysis above I would say that UK English is the correct deduction per WP:ENGVAR. Nothing at WP:ENGVAR states anything about using units as part of the deciding factor. At another article (vitreous enamel) there was concenssus that the unit type shouldn't be used as a deciding factor (see Talk:Vitreous_enamel#English_variations). Wizard191 (talk) 15:06, 3 January 2011 (UTC)

Please don't think that you are throwing a screw ball into anything. You have added some very useful information. It's pretty clear that everyone involved wants to do whatever is best for the article and whatever best follows Wikipedia guidelines. I know I personally have no preference for UK or US English; I just want it to be consistent and stable.

Talk:Vitreous_enamel is an interesting read. For example, I was not aware that "aluminium" is correct even in US-English Chemistry pages. That's good to know. (Note that there are two sections on US/UK English; I missed one on my first reading.)

It is true that nothing at WP:ENGVAR states anything about using units as part of the deciding factor, but it is also true that nothing at WP:ENGVAR states anything about using color/colour as part of the deciding factor. WP:ENGVAR is a general guideline, not an exhaustive list of all allowable deciding factors.

The third opinion at Talk:Vitreous_enamel was that "Celsius is a worldwide standard, and even US-context articles use that standard. All US scientists use the metric system. This is an article about a scientific subject, so it would naturally use the metric system. This is not an argument for using either US or UK spelling." which mirrors what I wrote above: "Using °F as the primary unit of measurement is clearly US (note that the inverse is not true; many US scientists prefer °C)". From this I conclude that "°C" is not evidence of UK English, but "°F" is evidence of US English (and is something that should be corrected to "°C" or "°K" in scientific articles such as this one no matter what style of language they are written in.)

Based upon the above, and on the fact that the original was a stub with one example of UK English that may have been a simple typo, and on the fact that all the major contributors after the original stub was created used US English, and on the fact that the word "Color" remained untouched from April 2005 to December 2010, in my opinion the stability of articles clause of WP:ENGVAR applies, and the version that stood for five years prior to the 29 December 2010 edits should be retained. I am very much open to arguments that the December 2010 edits should be put back in.

I am also quite disappointed that our three IP editors were willing to engage in multiple reverts but are not willing to join a discussion here on the talk page. If any of them are reading this, you are more than welcome to state your case and seek consensus. This is about making Wikipedia better, not about winning a battle over language. Guy Macon 19:01, 3 January 2011 (UTC)

"...but it is also true that nothing at WP:ENGVAR states anything about using color/colour as part of the deciding factor." I don't know if I agree with that; "colour" is definitely an arrow towards the UK side of things. Also, I still wouldn't rely upon the choice of which temperature scale is used, because oftentimes if a source gives a temperature in one scale that is what is going to be copied into the article. But again, I don't want this to become a long drawn out thing (like Vitreous enamel), so if others feel that the US variety should stand, I'm OK with that. Wizard191 (talk) 20:05, 3 January 2011 (UTC)

(Slightly) Different Carbon Solubilities noted

This article mentions two slightly different maximum carbon solubility figure - 2.03% and 2.04%, at two slightly different temperatures - 1150C and 1146C, respectively. Neither of these is cited. Do we have a reliable source for either figure? —Preceding unsigned comment added by 98.213.37.202 (talk) 06:14, 14 March 2011 (UTC)

Check out the note at steel: [1]. Wizard191 (talk) 17:57, 18 March 2011 (UTC)

st 35.8 carbon steel tube

pleas explain about some other type of tube for boiler and the hardening proccess on this material. like other sites — Preceding unsigned comment added by 2.146.10.236 (talk) 08:29, 24 October 2011 (UTC)

Austenite versus gamma iron

This article needs some work, which I will probably get to sometime in the near future. The first thing I think that's important to note is that, in most metallurgy books, austenite and gamma iron are considered two separate phases. These used to mean the same thing in archaic terminology. For example, in the late 1800s to early 1900s, gamma ferrite meant the pure form of iron, whereas gamma iron referred to austenite, which is a solution of iron and carbon. In this archaic terminology, beta ferrite was the pure form, and beta iron referred to the "solid solution" called martensite. Similarly, alpha iron referred to the archaic term "troostite," which is now called martensite.

Today, however, ferrite referrs to iron in a pure (or mostly pure) form, regardless of what allotrope it is in. The two are usually used interchangeably, (ie:gamma iron = gamma ferrite). Austenite referrs to the stable solid solution of iron and carbon, (ie: austenite = gamma iron + carbon, which may be unstable, in the case of retained austenite), and martensite is the metastable solution, (alpha iron + cartbon).

The difference can be illustrated like this: When steel is heated to the A₃ temperature, the alpha iron changes to gamma iron. When this happens, the flood gates open, and the carbon atoms gathered at the grain boundaries move freely into the crystal's interior, turning the gamma iron into austenite. The alpha iron must first change into gamma iron before the austenite can form. Likewise, the carbon must have time to precipitate, moving out of the crystal and back into the grain boundaries, thus changing the austenite into gamma iron before alpha iron can be formed. If the change is too quick, the carbon atoms become trapped in the lattice, preventing the change back into alpha iron, and martensite forms. Zaereth (talk) 22:53, 20 June 2012 (UTC)