# History of stainless steel **URL:** \ **Category:** Factual Questions\ **Created:** [October 27, 2021, 2:05pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314 "2021-10-27T14:05:18Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 27, 2021, 2:05pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/1 "2021-10-27T14:05:18Z")
How does stainless steel resist rust? And who was the first one to figure it out? ---
**Author:** ![ExTank](https://avatars.discourse-cdn.com/v4/letter/e/35a633/32.png) [@ExTank](https://boards.straightdope.com/u/ExTank)\ **Post date:** [October 27, 2021, 2:09pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/2 "2021-10-27T14:09:58Z")
From Wiki: The invention of stainless steel followed a series of scientific developments, starting in 1798 when chromium was first shown to the [French Academy](https://en.wikipedia.org/wiki/Acad%C3%A9mie_fran%C3%A7aise) by [Louis Vauquelin](https://en.wikipedia.org/wiki/Louis_Vauquelin). In the early 1800s, James Stoddart, [Michael Faraday](https://en.wikipedia.org/wiki/Michael_Faraday), and [Robert Mallet](https://en.wikipedia.org/wiki/Robert_Mallet) observed the resistance of chromium-iron alloys (“chromium steels”) to [oxidizing agents](https://en.wikipedia.org/wiki/Oxidizing_agents). [Robert Bunsen](https://en.wikipedia.org/wiki/Robert_Bunsen) discovered chromium’s resistance to strong acids. The corrosion resistance of iron-chromium alloys may have been first recognized in 1821 by [Pierre Berthier](https://en.wikipedia.org/wiki/Pierre_Berthier), who noted their resistance against attack by some acids and suggested their use in cutlery.[[13]](https://en.wikipedia.org/wiki/Stainless_steel#cite_note-13) ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [October 27, 2021, 2:16pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/3 "2021-10-27T14:16:51Z")
In chemical terms, what happens is that the stainless steel contains chromium, which oxidises with oxygen in the air into a thin film of chromium oxide that insulates the iron of the steel from the surrounding air. This protective film of chromium oxide prevents the iron from oxidising, in other words, from rusting. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [October 27, 2021, 2:32pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/4 "2021-10-27T14:32:03Z")
Worth pointing out. Stainless Steel is a bit of a misnomer. SS depends upon the passivated layer of chromium oxide forming on its surface. Contact with the air is a very effective way of ensuring exposed chromium oxidises. But if you disturb that layer in circumstances where there isn’t oxygen present, you leave unprotected metal. Something as simple as scratching SS underwater can lead to rust. SS is also subject to a range of other nasties. Chloride attack is a problem for some. Stress corrosion can lead to the failure of parts in unexpected ways. The protective layer of tough but very thin. Anything that breeches it can lead to failure. The metal within is _not_ corrosion resistant. Aluminium is similar, but doesn’t need an additional metal to get the protective layer, aluminium oxide is itself tough and protective. A large number of systems where corrosive compounds need handling are effected in metal containers that develop similar protective layers. Fluorine for instance. ---
**Author:** ![mcgato](https://avatars.discourse-cdn.com/v4/letter/m/ac8455/32.png) [@mcgato](https://boards.straightdope.com/u/mcgato)\ **Post date:** [October 27, 2021, 5:40pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/5 "2021-10-27T17:40:14Z")
A staff engineer at a former job had a saying: Stainless steel isn’t. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 27, 2021, 7:56pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/6 "2021-10-27T19:56:52Z")
Though not the same as modern stainless steels, there are very much older examples of rust-resisting iron/steel objects - such as this one (the principles of which material are broadly the same - the composition produces a protective passive surface layer): > **[Iron pillar of Delhi](https://en.wikipedia.org/wiki/Iron_pillar_of_Delhi)** > > Pages for logged out editors learn more > > > > The iron pillar of Delhi is a structure 7.21 metres (23 feet 8 inches) high with a 41-centimetre (16 in) diameter that was constructed by Chandragupta II (reigned c. 375–415 AD), and now stands in the Qutb complex at Mehrauli in Delhi, India. It is famous for the rust-resistant composition of the metals used in its construction. The pillar weighs more than 6 tonnes and is thought to have been erected elsewhere, perhaps outside the Udayagiri Cav... ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 27, 2021, 8:29pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/7 "2021-10-27T20:29:06Z")
> [@ExTank](#): > > From Wiki: I long for the old days when the Internet didn’t have all the answers and you had to go to the Dope to find out. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [October 28, 2021, 4:24am UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/8 "2021-10-28T04:24:12Z")
> [@Francis\_Vaughan](#): > > A large number of systems where corrosive compounds need handling are effected in metal containers that develop similar protective layers. **Fluorine for instance.** Derek Lowe mentions this in his classic essay about chlorine triflouride, [_Sand Won’t Save You This Time_](https://corante.com/things-i-wont-work-with/sand-wont-save-you-this-time/), in which he quotes from the book _Ignition!_ by John Clark: > [@](#): > > _It can be kept in some of the ordinary structural metals-steel, copper, aluminium, etc.-because of the formation of a thin film of insoluble metal fluoride which protects the bulk of the metal, just as the invisible coat of oxide on aluminium keeps it from burning up in the atmosphere. If, however, this coat is melted or scrubbed off, and has no chance to reform, the operator is confronted with the problem of coping with a metal-fluorine fire. For dealing with this situation, I have always recommended a good pair of running shoes._ ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [October 28, 2021, 4:30am UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/9 "2021-10-28T04:30:48Z")
Both _Ignition_! and Derek’s column are some of my favourite reading. I found a copy of Ignition! in my university library about 30 years ago, and loved it. It is now on-line (although the copyright status of that seems unclear.) The story of the early chemistry of fluorine makes grim reading. Despite working out how to handle it without major catastrophe in the lab, most experimenters succumbed to the toxic effects of low level dosages. It is a foul element in the raw. ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [October 28, 2021, 4:44am UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/10 "2021-10-28T04:44:00Z")
> [@Francis\_Vaughan](#): > > The story of the early chemistry of fluorine makes grim reading. Despite working out how to handle it without major catastrophe in the lab, most experimenters succumbed to the toxic effects of low level dosages. It is a foul element in the raw. Then you’re no doubt familiar with [Lowe’s column on FOOF](https://corante.com/things-i-wont-work-with/things-i-wont-work-with-dioxygen-difluoride/) (O2F2 dioxygen difluoride), of which he writes: > [@](#): > > And a hard core it is! This stuff was first prepared in Germany in 1932 by Ruff and Menzel, who must have been likely lads indeed, because it’s not like people didn’t respect fluorine back then. No, elemental fluorine has commanded respect since well before anyone managed to isolate it, a process that took a good fifty years to work out in the 1800s. (The list of people who were blown up or poisoned while trying to do so is impressive). And that’s at room temperature. At _seven hundred freaking degrees_ , fluorine starts to dissociate into monoatomic radicals, thereby losing its gentle and forgiving nature. But that’s how you get it to react with oxygen to make a product that’s worse in pretty much every way. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [October 28, 2021, 12:16pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/11 "2021-10-28T12:16:57Z")
The second additional metal in stainless steel is nickel. Typically you are getting poor stainless steel if there isn’t almost as much nickel as chromium. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [October 28, 2021, 12:54pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/12 "2021-10-28T12:54:49Z")
Stainless Steel covers a wide variety of alloys. It would be correct to say that the characterising property of SS is the use chromium for corrosion protection. But once you have that, there are lots of uses that are better served with further additives. Nickel is most certainly the next element off the rank in terms of usefulness in SS. After that, probably molybdenum. The usual way of dividing SS types is based upon crystal structure and that gets you divisions into: austenitic, ferritic, martensitic, duplex, and precipitation hardened. The ones you tend to encounter in daily life are down to three of these. Duplex and precipitation hardened are rarer beasts, and can come at significant increases in cost. The others are: Austenitic, 200 and 300 series SS, usually adds quite a bit of nickel, and includes the well known 304 and 316 grades. 304 is often called 8/18 and is what most flatware and cookware is made from: 8% nickel, 18% chromium. 316 adds molybdenum, which improves resistance to chloride pitting (which is why it is used for marine applications.) Martensitic includes the 400 series SS, and includes heat treatable and hardenable varieties that can be used for engineering purposes, tooling, chefs knives, and the like. Mostly without nickel, but some add a up to 4% to improve ductility or corrosion resistance. You will see chefs knives emblazoned as CrMo. Ferritic, also 400 series SS, often has no nickel, although a couple of grades have a little. This gets you a cheap SS. Your kitchen sink is probably made of it, as will be any other sheet SS in your kitchen. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [October 28, 2021, 1:50pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/13 "2021-10-28T13:50:20Z")
I used to work with some older engineers/technicians who used a magnet to test for stainless steel; if the magnet stuck, it’s not really stainless steel. But I would think a magnet would stick to chromium-iron alloys, so not a perfect test? ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [October 28, 2021, 2:21pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/14 "2021-10-28T14:21:58Z")
It isn’t a perfect test. It isn’t just a matter of the chromium. Nickel reduces the magnetism, so there is a weak correlation between better resistance to corrosion. Usually one tries to sort simple steel from SS with a magnet. SS can still be weakly magnetic. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [October 28, 2021, 2:37pm UTC](https://boards.straightdope.com/t/history-of-stainless-steel/953314/15 "2021-10-28T14:37:19Z")
Fluorine has its challenges and Titanium, which is very resistant to corrosion otherwise, cannot be used with it. The bad guy though is pure Oxygen, pure oxygen with sufficient pressure / acceleration or velocity, eats stainless steel or other steels like candy and has caused many accidents. Many rocket or shuttle failures result from pure Oxygen eating metal parts.