Talk:Stainless steel

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[edit] More than just corrosion resistance

The article neglects two outstandingly useful properties of 300 series stainless steel: toughness and heat resistance. Writing from a dim memory, US piping and pressure vessel codes allow relatively higher allowable stresses because of the toughness, and anyone that has to work or cut the stuff quickly gains respect. These alloys are economically useful in the 1000-1300 F temperature range. The article might also mention that 300 stainless is easily welded (TIG welds acquire a beautiful mostly-blue rainbow coloration), the coefficient of thermal expansion is about 1/3 greater than carbon steel, and it is nonmagnetic. Finally, 300 series stainless has a stable austenitic atomic structure at room temperature and above, unlike carbon steel which transforms to a ferritic structure under ~850 F.


I think it would be a good idea to include the other properties of Stainless Steel, plus it would be handy to have a "Common Uses" section, rather than just a bit about how it's been used in sculptures. Editor Supreme (talk) 15:47, 3 May 2008 (UTC)

[edit] Elwood Haynes

In the article Elwood Haynes, it credits Haynes with discovering and patenting stainless steel in 1919. In the stainless steel article, there is no mention of him at all. Either the article on Elwood Haynes is misleading or the stainless steel article erroneously omitted him. Either way, something doesn't quite match. Mazin07 (C)/(T) 23:04, 13 September 2006 (UTC)

Additionally, see [1] (it's a government source too! Mazin07 (C)/(T) 23:04, 13 September 2006 (UTC)

[edit] Correction?

There's a story that stainless steel was discovered by accident when it was noticed that a dumped batch wasn't rusting. But I can't find any reference of this on the web. Anyone know if it's true or not? -Nommo

It's alright, I found something. I added 420 to the list, though someone who actually knows what they're talking about might want to make sure its 100% sound. -Nommo

[edit] Corrosion

This section is important to the consideration of stainless steel, but could be removed and edited into the corrosion citation.-Dogears 18 Jan 2006

[edit] Keep the Corrosion section

There are many forms, instances, and phenomenon of corrosion that are unique to stainless steels; for instance the initiation of the surface corrosion process in requires that the Chromium passivation "film" be broken first. If all special instances were integrated into corrosion, that article would become rather bloated. --Knife Knut 23:22, 21 January 2006 (UTC)

[edit] Improve the Corrosion Section

I would suggest combining the "inter-granular corrosion" and "weld decay" sections into one section titled "sensitization". Both of these sections are dealing with sensitization of stainless steels. What you have called "weld decay" is sensitization of stainless steel at a locilized area. "weld decay" should be a secondary catogory under sensitization. Sensitization is most commonly associated with intergranular corrosion and stress corrosion cracking, however it is also associated with other froms of corrosion such as pitting and crevice corrosion. Also, under "stress corrosion cracking" SCC is said to be a rapid and severe form of corrosion. This may be misleading. SCC is not necassarily "rapid" the orginating crack could have exsisted for months, days, years before a part fails. "Severe" is misleading as well, I think most people will picture part that is covered in red rust. SCC starts as a small crack. Smaller than can be seen with the naked eye. It is severe in that a part can appear to fail unexpectedly and for no reason. Sorry to be such a nag, but I am a metallurgical engineer that has seen and studied many corrosion issues including these.--Slsavage22 15:09, 8 September 2006 (UTC)

You're completely right; I'm also a metallurgist and simply changed it along your suggestions; as you are a qualified metallurgist, next time simply change it, that's what Wikipedia is about! rudy 23:21, 19 October 2006 (UTC)

[edit] Uses of Stainless Steel

What is stainless steel used for? Cutlery and DeLorean cars are the only things coming to mind here. I'd like to have some more info before adding a section. Zoney 21:11, 14 May 2004 (UTC)

I added the "Commercial Value of Stainless Steel" section to provide some of this info. Please elaborate to it if you can. Subversive 4 July 2005 04:51 (UTC)

[edit] about the uses of stainless steel

I want to know that if stainless steel could be used for making aircraft's body, and when comparing with aluminium(without alloying), which type is better. The strength of stainless steel is far better, but for their densities, I'm not sure.

Stainless steel for aircraft is possible, but not in current practice.
Normally, aluminum sheets are used. When an aircraft goes in for maintenance, the sheets are removed. Most of them will have tiny pinholes (caused by rocks, ice, lightning...). My father's job for many years was to look for pinholes and seal them. Then, the aluminum was passed to a buffer who made it nice and smooth. Finally, it went back on the plane.
If steel was used, sealing, buffing, and reshaping the panels would take more effort. Since aluminum is cheaper to purchase and cheaper to work with, using steel is not a very good option. Kainaw 18:53, 20 Jan 2005 (UTC
Stainless is used extensively in aircraft - just not for the body panels. Various grades of stainless, and even carbon steels, have mechanical properties greatly exceeding those obtainable by aluminum. Large numbers of heavy load bearing structural members and turbine components are fabricated from steels. User:RyanDiS
You're on to something with the density question. Aircraft aluminum has lower density, and can have better specific strength and/or specific toughness than many steels. Low density is especially important in the body panels, since, for a given mass and specific strength of thin sheet, the one with greater volume will be stiffer. Materials denser than aluminum, such as titanium (still lighter than steel), have been used for body panels (i.e., on the SR-71 Blackbird), but if I'm not mistaken that's mostly done in cases of high operating temperature.
The Mig-25 fighter jet in USSR was made of entirely in stainless steel because it flew too fast at M2.8-M3.0, over melting point of aluminium. It was not made of titanium because Ti is very hard to weld or repair in the field and the MiG-25 was a regular daily service air force jet, albeit a big one. The titanium ore used to make the american SR-71 spyplane was exported from the USSR with trickery. Later the russkies made submarines out of Ti. 195.70.32.136 17:03, 4 January 2006 (UTC)

I seem to remember that the Lightning, a British jet fighter of the 1960's, was made of stainless steel.

Actually it wasn't the Lightning - you may be thinking of the Bristol 188 Ian Dunster 22:50, 20 February 2006 (UTC)

Regarding the uses of stainless steel, it is extensively used in food processing machinery. Glass and stainless are about the only things permitted on the production line. 212.100.250.213 22:21, 10 June 2006 (UTC)

Regarding the uses of stainless steel, it is used extensively in almost every application involving metal that is exposed to corroding environments. The list is longer than is useful to go into, but the list includes everything from aerospace parts, to cutlery, surgical instruments, automotive parts, screws and fasteners, shafts, building materials, etc. On the point of when and where to use stainless steel, knowing also that every grade has particular uses and weaknesses, a guideline is in places where long lasting corrosion protection to everyday environments is needed. Standard non-stainless steels can be plated with nickel, zinc, coated with black oxide, or even painted to be protected from the elements, but this protection is limited to the life of the coating. Scratches and other damage will compromise this protection. The advantage of stainless steel is the passive layer will reform (provided there is oxygen available-which in most cases it is quite abundant) quite quickly after being damaged. Contrary to common belief, aluminum is more expensive than commercial carbon steels, which can be coated/painted to have mild corrosion resistance, so the choice becomes complicated when deciding on metal selection, but stainless steel is common, not overly expensive (except SS 316 and other high-molybdenum and titanium content stainless steels), strong, and fairly maintenance free. 14:17 June 21, 2006.

[edit] Stains Less?

I once heard that stainless steel is so called not because it is without staining(one definition of -less), but instead because it stains less. Can someone confirm or deny? If true, it would be a good addition. Superm401 20:39, Apr 6, 2005 (UTC)

I've got it: Suburban Surgical Superm401 20:47, Apr 6, 2005 (UTC)
Do you believe this? I'm not convinced. My own understanding has always been stainless in the sense of "non-staining" rather than staining less. The website you point to is more likely a modern attempt to avoid the possibility of legal action. If, indeed "stain less steel" had been intended, isn't it rather likely that this catchy phrase would have been trademarked? According to the history site linked to at the end of the article, the original name was "rustless" steel, which can almost certainly be presumed to refer to an absence of rust rather than a reduction. (Something either rusts or it doesn't.) I suggest that this claim be better verified before being included in the opening of the article as fact. 144.213.253.14 08:03, 26 August 2005 (UTC)
I heard the "stains less" definition from my metallurgy professor a few years ago, and he tends to know his stuff. I can try to look it up in my corrosion book, if you want. The truth is, all but a few such alloys do rust, and pitting corrosion is a problem for those that don't, but I wouldn't be surprised if the common name turned out to be a misnomer.--Joel 11:41, 26 August 2005 (UTC)
Stainless steel also rusts, forming a chromium rich oxide layer which is very effective in protecting the rest of the material, so rust-free is strictly spoken not a correct term. In combination with special environments, it can still stain; so that is what I suppose your teacher was talking about. rudy 23:28, 19 October 2006 (UTC)
I worked briefly for a Stainless Steel Association and stainless does indeed refer to stain less, rather than stain free. The manufacturer Ernest Stuart tested the steel in a vinegar solution and noted that it stained less that other matierials put through the test, i.e aluminium. —The preceding unsigned comment was added by 212.100.103.69 (talk) 09:13, 20 December 2006 (UTC).

[edit] 420

Why is there a broken link to 420? Why aren't any other types linked to anything, broken or not? I work in a centrifugal steel foundry, if you need or want specific alloy %, or anything else, lemme know. Joe I 00:52, August 20, 2005 (UTC)

My guess is it's a cannabis joke that no one cares about enough to delete. If you'd like to write articles about a few of the more important alloys, that would be great, but I believe more good might come from improving the metallurgy articles we already have. I'm curious what a centrifugal foundry is, though.--Joel 03:03, 20 August 2005 (UTC)
I suppose that it is a foundry specializing in centrifugal casting - Leonard G. 03:12, 20 August 2005 (UTC)
That's pretty obvious to me now, but I needed someone else to put it together. I'll go ahead and make a redirect.--Joel 03:53, 20 August 2005 (UTC)
I swear I posted a response to you on Fri., guess I forgot to save or something. Sorry, looks like you got a good answer in centrifugal foundry tho. Anymore Q's and I'll double check I save it next time. :)

[edit] "Stain" clarification

I am under the impression that the stain in stainless reffers to rusting, not to how much the surface will hold a stain. Is this correct? If so, it would be worth noting in the article. Certainly when I was little I was confused as to why it wouldn't be called "rustless steel". —BenFrantzDale 15:24, 29 November 2005 (UTC)

[edit] How high is "moderately high"?

Like, a temperature range? 30C? 40C?

"When subjected to high concentration of chloride ions (eg. sea water) and moderately high temperatures, localized severe corrosion known as pitting corrosion can occur."

Most common stainless steels such as 316 are fine up to temperatures around 26-28C, depending on application. This critical temperature can be reduced be other factors in the designated environment. —Preceding unsigned comment added by 202.53.199.75 (talk) 23:54, 11 September 2007 (UTC)

[edit] How is Stainless Steel Made?

This article contains lots of information about corrosion, but NOTHING about how stainless steel is cast, poured, machined, whatever.

How is the chromium added to the iron? Can it be cooled in the open air? Remelted?

—The preceding unsigned comment was added by 68.5.64.178 (talk • contribs) .

Unfortunately, I learned that and forgot almost all of it. I still own the textbook, but probably won't get around to adding it. Most steel alloys don't cast well, unless they have a lot of dissolved nitrogen to fill in as it shrinks. Most alloys benefit from forging. It's much more difficult to melt than plain carbon steel, but can certainly be recycled.--Joel 22:41, 14 September 2006 (UTC)

[edit] AISI Equivalency

I just removed the following comment from the section on Types of Stainless Steel:

A random website, http://www.finishing.com/156/89.shtml, claims that 18/8 is equivalent to 301, 302, and 304. Any better sources would be appreciated

The short answer is that there's overlap, but not a direct equivalence. I don't have a good reference for this, but I have a couple of specifications handy and some general knowledge. AISI designations basically correspond to ASTM grades of the same number, and the composition of 302 and 304 are listed below:

AISI ASTM UNS Cr Ni C Mn P S Si
302 MT302 17.0-19.0 8.0-11.0 0.08 to 0.20 max 2.00 max 0.040 max 0.030 max 1.00
304 MT304 18.0-20.0 8.0-11.0 0.08 max max 2.00 max 0.040 max 0.030 max 1.00
304 TP304 S30400 18.0-20.0 8.0-11.0 0.08 max max 2.00 max 0.045 max 0.030 max 1.00

I don't think there's any standard for 18/8, it just refers to chromium/nickel compositions of approximately 18% chromium and 8% nickel by weight. So a given batch of 18/8 might meet 302 or 304 definitions, but it depends on the other elements, especially carbon. Going the other way, many people say that 301, 302, 304 are part of the 18/8 family, even though a designation of 17/8 might make more sense for 302. It gets even more complicated as you look at a broader range of alloys and material standards.--Yannick 13:52, 30 July 2006 (UTC)

"'18/8' is probably the most commonly used stainless steel and contains 18% chromium and 8% nickel. This steel is also known as '304' (in the American AISI grade designation system) or 1.4301 in the European BS EN 10088 standard." - http://www.bssa.org.uk/articles/showarticle.asp?id=145 —The preceding unsigned comment was added by 212.100.103.69 (talk) 09:51, 20 December 2006 (UTC).

[edit] Rouging?

We seem to have two quite-different definitions of "rouging":

  • (Older) Stainless steel can actually rust quite rapidly if it fails to form its protective oxide can actually rust quite rapidly if it fails to form its protective oxide layer. This tends to happen when the stainless has had carbon steel forced into its surface, as by being dragged over carbon steel during installation, brushing with carbon steel, grinding with a contaminated wheel, or temporary welds to carbon steel.
  • (Newer) Rouging is a very peculiar phenomenon, which occurs only on polished stainless steel surfaces with very low surface roughness in a pure water environment. This effect is mostly common in the pharmaceutical industries. The whole effect is caused by the simple fact, pure water is lacking any ions and pulls the metal ions of the passive stainless steel surface into the solution. Iron ions do not dissolve at neutral pH and will precipitate as an iron hydroxide film, which has a reddish colour, hence the name rouging.

Can a subject matter expert please sort this out?

Atlant 13:22, 19 September 2006 (UTC)

There was no mention of Cobalt or Nickel alloys of stainless steel but both these metals are used quite oftenin conjunction with chromium

[edit] Stainless Steel Grades

I added detail here about different grades. Source: McMaster Carr Catalog #111. Maybe someone with more knowledge can covert this into a comparison table for the different grades.

12.65.12.129 22:35, 13 November 2006 (UTC)

[edit] External link removal

I've removed the following link recently added by User:217.198.129.244:

http://www.nstm.com.ua/products/?lang=en (titled on page as 'Stainless Steel Tubing')

My feeling is that this is an inappropriate addition to the page and I'm moving it here for review.

--User:Ceyockey (talk to me) 11:09, 12 December 2006 (UTC)

[edit] Chromium Content

The minimum chromium content for an iron alloy to be classed as stainless is 10.5% in the EN European standard. An alloy containing less that that wouldn't be regarded as stainless in Europe. AISI clearly has different standards to Europe, but these are not universal.

[edit] New Section - "Surface Treatment"

Is it worth having a new section under "Corrosion" or under "Finish" called "Surface Treatment"? There are many ways to limit staining and corrosion of stainless steel, particularly in specific environments. Ozzibloke 02:09, 31 January 2007 (UTC)

I'd certainly say "yes".
Atlant 14:14, 31 January 2007 (UTC)

[edit] Miscellaneous edits 7/4/2007

I haven't visited this article for several months, so I've made several edits that I thought would be better described here, since I can write a little more than what you get in the edit summary:

  • AISI site was referenced for definition of stainless steel, at least as of 3/4/07. Some time since then, the URL was changed to a corporate site, but the title was left the same. This looks like linkspam to me, and the site in question had no definitions I could find. Now, someone will want to look at this closer, however, because the AISI site defined a minimum of 10% Chromium where the article indicates 10.5%. Additionally, neither "ferrous alloy" nor "iron-carbon alloy" are included in the AISI definition, even though that change was also made. I added a {fact} tag for this.
  • Provided source for Edmonton Composting Facility size and cleaned up wording.

--Quintote 03:28, 5 July 2007 (UTC)

[edit] Silver pieces smaller because of specific gravity?

The paragraph "Commercial value of stainless steel" states: "The specific gravity of stainless steel is also slightly lighter than silver allowing designers to create larger pieces."

This seems a strange statement to me: why would a low (rather than "light") specific gravity (isn't "(relative) density" more to the point?) allow designers (or actually: producers) larger pieces. For very large things strength per mass maybe would be interesting but actually the main reason silver pieces are smallish is the price.

If someone can make sense of this statement or of a slight modification please explain. As stated now I would like to remove the sentence. Pukkie 13:40, 13 August 2007 (UTC)


Germs? There was also some discussion that Stainless Steel is sort of 'germ and virus resistant' and thats why it is used on doors to restrooms. Heard stories that germs and viruses do not survive long on stainless steel for those few non-hygienic people that do not wash their hands and leave little things on the doors. Any truth?? —Preceding unsigned comment added by 130.76.32.19 (talk) 15:25, 26 October 2007 (UTC)

[edit] History

The content of the article at [2] might prove useful in the history section here. Given that the amount of chromium required to produce true stainless steel is crucial and that the name 'stainless steel' is credited to Harry Brearly it seems somewhat unfair to use the term stainless steel in reference to other experimenters who had not hit on the magic proportion, as on the Elwood Haynes article. Might it be more prudent to use something akin to the term 'corrosion resistant steel alloy' or some such in these instances. Jooler 23:27, 1 September 2007 (UTC)

[edit] Stainless Steel XM19

What is exactly Stainless Steel XM19? What is the chemical composition? I've never heard of it before and I noticed it is not in the article. 68.143.88.2 15:55, 4 October 2007 (UTC)

[edit] Intersitital/Substitutional

Is it an Interstitial or Substitutional alloy? If this is listed in the page it isn't where it should be, right near the start. --203.30.68.49 00:35, 29 October 2007 (UTC)

[edit] Common Types of Stainless Steel Sold to Consumers in the U.S. and Abroad

In the types of stainless steel section of the article, it would be useful to address various trade names of stainless steel sold in the U.S. For example, VG-1, VG-10, 4116 Krupp, AUS 8A, etc. pierrerosen 19:00, 03 January 2009 (UTC)