WEBVTT - Is Stainless Steel Really Stainless? 0:00:01.920 --> 0:00:06.960 Welcome to Brainstuff production of iHeart Radio, Hey brain Stuff 0:00:07.000 --> 0:00:11.760 Lauren Vogel Bomb Here. From bathroom sinks and kitchen appliances 0:00:11.840 --> 0:00:15.080 to New York's Chrysler building and the St. Louis Gateway arch. 0:00:15.560 --> 0:00:18.800 The world sometimes seems like it's covered in stainless steel, 0:00:19.560 --> 0:00:23.440 and why not. The material is not only sturdy and versatile, 0:00:23.640 --> 0:00:27.520 but also stainless, as the name implies. But is it 0:00:27.600 --> 0:00:32.640 really impossible to stain stainless steel? Stainless steel is a 0:00:32.640 --> 0:00:35.560 family of materials that gets its handle from corrosion and 0:00:35.600 --> 0:00:41.159 oxidation resistant properties that protect it from rust and unsightly blotches. Generally, 0:00:41.240 --> 0:00:44.080 these steels are a mixture of iron and at least 0:00:44.120 --> 0:00:47.760 ten point five percent chromium, sometimes rounded to eleven percent 0:00:47.800 --> 0:00:52.720 by engineers. When exposed to oxygen and moisture. For instance, 0:00:52.720 --> 0:00:56.200 when a stainless steel pan is nicked or dinged, chromium 0:00:56.280 --> 0:00:59.720 is an element that produces thin oxide film that coats 0:00:59.760 --> 0:01:04.120 the product. This self repairing feature of stainless steel ensures 0:01:04.160 --> 0:01:08.800 that the object will always look smooth and shiny. Various 0:01:08.800 --> 0:01:12.440 European and American metallurgists claimed to have invented this wondrous material. 0:01:13.440 --> 0:01:16.880 We do know that Croup Iron Works in Germany created 0:01:16.920 --> 0:01:19.720 an acid resistant steel as early as nineteen o eight, 0:01:19.959 --> 0:01:22.479 which was used for the hull of a yacht. Two 0:01:22.480 --> 0:01:26.200 other German researchers discovered the relationship between chromium content and 0:01:26.360 --> 0:01:30.080 corrosion resistance. That metal containing at least ten point five 0:01:30.440 --> 0:01:35.600 chromium had a greater resistance to corrosion. Meanwhile, American Elwood 0:01:35.600 --> 0:01:39.640 Haynes patented one type of stainless steel precursor in nineteen eleven. 0:01:40.080 --> 0:01:43.679 An English researcher Harry Brearley developed a similar material around 0:01:43.680 --> 0:01:47.280 the same time. After a four year dust up in 0:01:47.319 --> 0:01:51.200 which Haynes successfully opposed Brierly's attempt to patent his version 0:01:51.200 --> 0:01:54.400 of the steel, the two pooled resources to market their 0:01:54.400 --> 0:01:58.360 wares as the American Stainless Steel Company. These and other 0:01:58.400 --> 0:02:02.360 stainless metals found their way to cutlery, airplane parts, golf clubs, 0:02:02.400 --> 0:02:07.160 and other items almost immediately, but not all stainless steel 0:02:07.400 --> 0:02:11.519 is created equal. There are four main types of stainless steel, 0:02:11.680 --> 0:02:16.400 classified by structure and composition. The most common variety is astenatic. 0:02:17.720 --> 0:02:21.720 Of the stainless steel produced falls in this category. Astenetic 0:02:21.800 --> 0:02:24.640 steels can be found in products ranging from cutlery and 0:02:24.680 --> 0:02:29.440 cookware to automotive trim and industrial applications. The material contains 0:02:29.480 --> 0:02:32.960 at least sixteen percent chromium, no more than zero point 0:02:33.000 --> 0:02:37.200 one five percent carbon, and usually includes nickel or manganese 0:02:37.240 --> 0:02:42.040 for added durability. Meanwhile, for Riddic stainless steels contain up 0:02:42.040 --> 0:02:45.320 to twenty seven percent chromium, often as well as aluminum 0:02:45.400 --> 0:02:49.079 or titanium, but if little or no nickel, that means 0:02:49.120 --> 0:02:52.639 that while these materials are highly resistant to corrosion, they're 0:02:52.680 --> 0:02:56.639 less durable than their austenetic cousins. For Ridic steels are 0:02:56.720 --> 0:03:00.400 more affordable than austenetic varieties and are commonly used in flers, 0:03:00.480 --> 0:03:05.480 exhaust systems, kitchen counters, and sinks. Then we have martin 0:03:05.600 --> 0:03:08.720 zitic stainless steels, which are less corrosion resistant than the 0:03:08.760 --> 0:03:11.760 first two types, but are noted for their extreme strength 0:03:11.800 --> 0:03:16.480 and durability, and the material contains twelve to fourteen chromium 0:03:16.760 --> 0:03:20.800 along with small amounts of molybdenum and carbon. These steels 0:03:20.840 --> 0:03:23.720 also contain little to know nickel less than two percent 0:03:25.160 --> 0:03:27.919 Martin's that ex stainless steels are magnetic and are often 0:03:28.000 --> 0:03:30.519 used in products where this feature is useful like a 0:03:30.600 --> 0:03:32.920 kitchen back splash, to which a spice rack or other 0:03:32.960 --> 0:03:38.720 metal object can be attached without using fasteners. Finally, duplex 0:03:38.720 --> 0:03:42.000 stainless steels combine the benefits of austenite and ferrite to 0:03:42.120 --> 0:03:46.280 provide enhanced decay resistance and beefed up strength and durability. 0:03:46.520 --> 0:03:49.640 Metallurgists typically look to create a mix that's half austenitic 0:03:49.720 --> 0:03:52.720 and half fretic. The result is a material that features 0:03:52.760 --> 0:03:55.240 more chromium and less nickel than is found in pure 0:03:55.240 --> 0:03:59.760 austenitic steels, about twenty two to chromium and five percent nickel, 0:04:00.200 --> 0:04:03.720 as well as a high level of molybdenum. These steels 0:04:03.720 --> 0:04:08.320 are primarily used in chemical plants and piping applications. You 0:04:08.480 --> 0:04:11.320 may have noticed our use of the term resistant when 0:04:11.320 --> 0:04:15.600 referring to these stainless steel's capacity for avoiding blemishes. So 0:04:15.840 --> 0:04:19.480 is the material just stain resistant or completely stain proof? 0:04:20.920 --> 0:04:24.200 And despite the hearty protection that it affords users, stainless 0:04:24.200 --> 0:04:29.000 steel is more stain less than stainless. In other words, 0:04:29.200 --> 0:04:33.000 while the material is highly resistant to discoloration, blemishes, and 0:04:33.120 --> 0:04:37.400 other imperfections, it's not completely impenetrable. And just look at 0:04:37.440 --> 0:04:39.760 the Gateway Arch, which is starting to show its age 0:04:39.800 --> 0:04:43.080 with rust and k after five decades of welcoming tourists 0:04:43.120 --> 0:04:47.080 to St. Louis. The protective layer of film covering a 0:04:47.160 --> 0:04:50.599 stainless steel object can break down over time, leading to 0:04:50.680 --> 0:04:55.160 corrosion and pitting. In addition, compounds like chloride, hydrogen and 0:04:55.240 --> 0:04:58.599 hydrogen sulfide often cause the film to stress and crack. 0:05:00.080 --> 0:05:02.720 The level of rest resistance provided by a particular steel 0:05:02.839 --> 0:05:06.000 depends largely on the materials used to create it. The 0:05:06.040 --> 0:05:10.479 more chromium, the more corrosion protection. The sturdier. Stainless steels 0:05:10.520 --> 0:05:13.880 also feature at least eight percent nickel, which provides further 0:05:13.960 --> 0:05:19.480 defense against tarnish. Some products are tagged with numbers indicating 0:05:19.480 --> 0:05:23.560 their proportions of chromium and nickel. For instance, eighteen over 0:05:23.640 --> 0:05:26.320 ten flatwear is sold at a premium because it has 0:05:26.360 --> 0:05:30.119 eighteen percent chromium and ten percent nickel content, providing greater 0:05:30.160 --> 0:05:35.160 protection against corrosion than ordinary flatwear for household users. It's 0:05:35.160 --> 0:05:38.680 important to understand that many metals advertised as stainless steel 0:05:38.880 --> 0:05:43.520 are actually stainless steel plated. The plate is corrosion resistant, 0:05:43.640 --> 0:05:46.680 but is susceptible to damage if cut or scratched deep 0:05:46.760 --> 0:05:50.200 enough to reach the underlying material. Because the plates can 0:05:50.240 --> 0:05:53.400 also wear off over time, buyers should clarify whether a 0:05:53.400 --> 0:05:57.239 particular product is made completely of stainless steel or simply plated. 0:05:58.920 --> 0:06:01.880 Whether plated or not, your stainless steel appliances and other 0:06:01.920 --> 0:06:05.080 products need to be cleaned most of the time. Good 0:06:05.080 --> 0:06:07.680 old fashioned soap and water will do the trick. For 0:06:07.800 --> 0:06:11.599 tougher stains, Professionals recommend a variety of household remedies. A 0:06:11.640 --> 0:06:14.279 couple dabs of olive oil or window cleaner can remove 0:06:14.360 --> 0:06:17.599 most of those pesky fingerprints and smudges, while white or 0:06:17.640 --> 0:06:21.520 cider vinegar will restore shine. And don't use steel wool 0:06:21.560 --> 0:06:24.920 pads or harsh cleaning powders, as they'll scratch the surface. 0:06:25.600 --> 0:06:27.440 If you need to remove burnt on food from a 0:06:27.440 --> 0:06:30.320 stainless steel pan, let it soak in warm water and 0:06:30.320 --> 0:06:32.919 then clean it with baking soda and a gentle nylon 0:06:33.080 --> 0:06:41.000 or plant based scouring pad. Today's episode was written by 0:06:41.040 --> 0:06:43.599 Chris Opfer and produced by Tyler Clang. For more on 0:06:43.640 --> 0:06:45.760 this and lots of other shiny topics, visit how stuff 0:06:45.800 --> 0:06:48.400 works dot com. Brain Stuff is production of i Heeart 0:06:48.480 --> 0:06:50.880 Radio or more podcasts. My heart Radio is at the 0:06:50.920 --> 0:06:53.719 iHeart Radio app, Apple Podcasts, or wherever you listen to 0:06:53.760 --> 0:06:54.600 your favorite shows.