Stainless steel

This page was last edited on 17 March 2018, at 03:16.

In metallurgy, stainless steel, also known as inox steel or inox from French inoxydable (inoxidizable), is a steel alloy with a minimum of 10.5% chromium content by mass.[1]

Stainless steels are notable for their corrosion resistance, which increases with increasing chromium content. Molybdenum additions increase corrosion resistance in reducing acids and against pitting attack in chloride solutions. Thus, there are numerous grades of stainless steel with varying chromium and molybdenum contents to suit the environment the alloy must endure. Thus stainless steels are used where both the strength of steel and corrosion resistance are required.

Stainless steel’s resistance to corrosion and staining, low maintenance, and familiar lustre make it an ideal material for many applications. Stainless steels are rolled into sheets, plates, bars, wire, and tubing to be used in cookware, cutlery, surgical instruments, major appliances and as construction material in large buildings, such as the Chrysler Building. As well as, industrial equipment (for example, in paper mills, chemical plants, water treatment), and storage tanks and tankers for chemicals and food products (for example, chemical tankers and road tankers). Stainless steel's corrosion resistance, the ease with which it can be steam cleaned and sterilized and no need for other surface coatings has also influenced its use in commercial kitchens and food processing plants.

Walt Disney Concert Hall, LA, CA, jjron 22.03.2012
Stainless steel cladding is used on the Walt Disney Concert Hall

Corrosion resistance

Corrosion of alloys in NaCl
Stainless steel (bottom row) resists salt-water corrosion better than aluminium-bronze (top row) or copper-nickel alloys (middle row)

Stainless steels do not suffer uniform corrosion, like carbon steel, when exposed to wet environments. Unprotected carbon steel rusts readily when exposed to the combination of air and moisture. The resulting iron oxide surface layer (the rust) is porous and fragile. Since iron oxide occupies a larger volume than the original steel this layer expands and tends to flake and fall away exposing the underlying steel to further attack. In comparison, stainless steels contain sufficient chromium to undergo passivation, spontaneously forming a microscopically thin inert surface film of chromium oxide by reaction with the oxygen in air and even the small amount of dissolved oxygen in water. This passive film prevents further corrosion by blocking oxygen diffusion to the steel surface and thus prevents corrosion from spreading into the bulk of the metal.[3] This film is self-repairing if it is scratched or temporarily disturbed by an upset condition in the environment that exceeds the inherent corrosion resistance of that grade.[2]

However, stainless steels may suffer uniform corrosion when exposed to acidic or basic solutions. Whether a stainless steel corrodes depends on the kind and concentration of acid or base, and the solution temperature. Uniform corrosion is typically easy to avoid because of extensive published corrosion data or easy to perform laboratory testing.

Unfortunately, stainless steels are susceptible to localized corrosion under certain conditions, which need to be recognized and avoided. Such localized corrosion is problematic for stainless steels because it is unexpected and more difficult to predict.

Crevice corrosion of 316 SS tube and tube sheet in a desalination plant
Stainless steel is not completely immune to corrosion in this desalination equipment


Acidic solutions can be categorized into two general categories, reducing acids such as hydrochloric acid and dilute sulfuric acid, and oxidizing acids such as nitric acid and concentrated sulfuric acid. Increasing chromium and molybdenum contents provide increasing resistance to reducing acids, while increasing chromium and silicon contents provide increasing resistance to oxidizing acids.

Sulfuric acid is the largest tonnage industrial chemical manufactured. At room temperature Type 304 is only resistant up to 3% acid while Type 316 is resistant up to 50oC and up to 20% acid at room temperature. Thus Type 304 is rarely used in contact with sulfuric acid. Type 904 and Alloy 20 are resistant to sulfuric acid at even higher concentrations above room temperature.[3][4]

Hydrochloric acid will damage any kind of stainless steel, and should be avoided.[5][6]

All types of stainless steel resist attack from phosphoric acid and nitric acid at room temperature. At high concentration and elevated temperature attack will occur and higher alloy stainless steels are required.[7] [8] Concentrated sulfuric acid possesses oxidizing characteristics like nitric acid and thus silicon bearing stainless steels also find application.

In general, organic acids are less corrosive than mineral acids such as hydrochloric and sulfuric acid. As the molecular weight of organic acids increase their corrosivity decreases. Formic acid has the lowest molecular weight and is a strong acid. Type 304 can be used with formic acid though it will tend to discolor the solution. Acetic acid is probably the most commercially important of the organic acids and Type 316 is commonly used for storing and handling acetic acid.[9]


Stainless steels Type 304 and 316 are unaffected by any of the weak bases such as ammonium hydroxide, even in high concentrations and at high temperatures. The same grades of stainless exposed to stronger bases such as sodium hydroxide at high concentrations and high temperatures will likely experience some etching and cracking.[10]

Increasing chromium and nickel contents provide increasing resistance.


All grades resist damage from aldehydes and amines, though in the latter case grade 316 is preferable to 304; cellulose acetate will damage 304 unless the temperature is kept low. Fats and fatty acids only affect grade 304 at temperatures above 150 °C (302 °F), and grade 316 above 260 °C (500 °F), while 317 is unaffected at all temperatures. Type 316L is required for processing of urea.[5]

Localized corrosion

Localized corrosion can occur in a number of ways, e.g. pitting corrosion, crevice corrosion and stress corrosion cracking. Such localized attack is most common in the presence of chloride ions. Increasing chromium, molybdenum and nitrogen contents provide increasing resistance to localized corrosion and thus increasing chloride levels require more highly alloyed stainless steels. In general, higher chromium, molybdenum and nitrogen contents provide greater resistance to localized corrosion. Design and good fabrication techniques combined with correct alloy selection can prevent such corrosion.[11]

Localized corrosion can be difficult to predict because it is dependent on many factors including:

  • Chloride ion concentration (Unfortunately, even when the chloride solution concentration is known, it is still possible for chloride ions to concentrate, such as in crevices (e.g. under gaskets) or on surfaces in vapor spaces due to evaporation and condensation.)
  • Increasing temperature increases susceptibility
  • Increasing acidity increases susceptibility
  • Stagnant conditions increase susceptibility
  • The presence of oxidizing species, such as ferric and cupric ions

High temperature corrosion (scaling)

At elevated temperatures all metals react with hot gases. The most common high temperature gaseous mixture is air, and oxygen is the most reactive component of air. Carbon steel is limited to ~900oF in air. Chromium in stainless steel reacts with oxygen to form a chromium oxide scale which reduces oxygen diffusion into the material. The minimum 10.5% chromium in stainless steels provides resistance to ~1300oF, while 26% chromium provides resistance up to ~2200oF. Type 304, the most common grade of stainless steel with 18% chromium is resistant to ~1600oF. Other gases such as sulfur dioxide, hydrogen sulfide, carbon monoxide, chlorine, etc. also attack stainless steel. Resistance to other gases is dependent on the type of gas, the temperature and the alloying content of the stainless steel.[12][13]


Electricity and magnetism

P4150144 cable tyrolienne inox
left nut is not in inox and is rusty

Like steel, stainless steel is a relatively poor conductor of electricity, with significantly lower electrical conductivity than copper. Other metals in contact with stainless steel, particularly in a damp or acidic environment, may suffer galvanic corrosion even though the stainless metal may be unaffected.

Ferritic and martensitic stainless steels are magnetic. Annealed austenitic stainless steels are non-magnetic. Work hardening can make austenitic stainless steels slightly magnetic.


When stainless steel parts such as nuts and bolts are forced together, the oxide layer can be scraped off, allowing the parts to weld together. When forcibly disassembled, the welded material may be torn and pitted, a destructive effect known as galling.[14] Galling can be avoided by the use of dissimilar materials for the parts forced together, for example bronze and stainless steel, or even different types of stainless steels (martensitic against austenitic). However, two different alloys electrically connected in a humid, even mildly acidic environment may act as a voltaic pile and corrode faster. Nitronic alloys, made by selective alloying with manganese and nitrogen, may have a reduced tendency to gall. Additionally, threaded joints may be lubricated to provide a film between the two parts and prevent galling. Low-temperature carburizing is another option that virtually eliminates galling and allows the use of similar materials without the risk of corrosion and the need for lubrication.


Stainless steel nyt 1-31-1915
An announcement, as it appeared in the 1915 New York Times, of the development of stainless steel in Sheffield, England.[15]

The corrosion resistance of iron-chromium alloys was first recognized in 1821 by French metallurgist Pierre Berthier, who noted their resistance against attack by some acids and suggested their use in cutlery. Metallurgists of the 19th century were unable to produce the combination of low carbon and high chromium found in most modern stainless steels, and the high-chromium alloys they could produce were too brittle to be practical.

In 1872, the Englishmen Clark and Woods patented an alloy that would today be considered a stainless steel.[16]

In the late 1890s Hans Goldschmidt of Germany developed an aluminothermic (thermite) process for producing carbon-free chromium. Between 1904 and 1911 several researchers, particularly Leon Guillet of France, prepared alloys that would today be considered stainless steel.[17]

Friedrich Krupp Germaniawerft built the 366-ton sailing yacht Germania featuring a chrome-nickel steel hull in Germany in 1908.[18] In 1911, Philip Monnartz reported on the relationship between chromium content and corrosion resistance. On 17 October 1912, Krupp engineers Benno Strauss and Eduard Maurer patented austenitic stainless steel as Nirosta.[19][20][21]

Similar developments were taking place contemporaneously in the United States, where Christian Dantsizen and Frederick Becket were industrializing ferritic stainless steel. In 1912, Elwood Haynes applied for a US patent on a martensitic stainless steel alloy, which was not granted until 1919.[22]

Harry Brearley
Monument to Harry Brearley at the former Brown Firth Research Laboratory in Sheffield, England

In 1912, Harry Brearley of the Brown-Firth research laboratory in Sheffield, England, while seeking a corrosion-resistant alloy for gun barrels, discovered and subsequently industrialized a martensitic stainless steel alloy. The discovery was announced two years later in a January 1915 newspaper article in The New York Times.[15] The metal was later marketed under the "Staybrite" brand by Firth Vickers in England and was used for the new entrance canopy for the Savoy Hotel in London in 1929.[23] Brearley applied for a US patent during 1915 only to find that Haynes had already registered a patent. Brearley and Haynes pooled their funding and with a group of investors formed the American Stainless Steel Corporation, with headquarters in Pittsburgh, Pennsylvania.[24]

In the beginning stainless steel was sold in the US under different brand names like "Allegheny metal" and "Nirosta steel". Even within the metallurgy industry the eventual name remained unsettled; in 1921 one trade journal was calling it "unstainable steel".[25] In 1929, before the Great Depression hit, over 25,000 tons of stainless steel were manufactured and sold in the US.[26]

Stainless steel families

Within stainless steels, there are four families

When nickel is added, the austenite structure of iron is stabilized. This crystal structure makes such steels virtually non-magnetic and less brittle at low temperatures.
Significant quantities of manganese have been used in many stainless steel compositions. Manganese preserves an austenitic structure in the steel, similar to nickel, but at a lower cost.
For greater hardness and strength, more carbon is added. With proper heat treatment, these steels are used for such products as razor blades, cutlery, and tools.
Several heavy pieces of bent pipe with flange connections, strapped down to a wooden pallet
Pipes and fittings made of stainless steel

Stainless steels are also classified by their crystalline structure:

Austenitic stainless steel

  • Austenitic stainless steels Also called 200 and 300 series, stainless steels have an austenitic crystalline structure, which is a face-centered cubic crystal structure. Austenite steels make up over 70% of total stainless steel production. They contain a maximum of 0.15% carbon, a minimum of 16% chromium, and sufficient nickel and/or manganese to retain an austenitic structure at all temperatures from the cryogenic region to the melting point of the alloy.
  • 200 Series—austenitic chromium-nickel-manganese alloys. Type 201 is hardenable through cold working; Type 202 is a general purpose stainless steel. Decreasing nickel content and increasing manganese results in weak corrosion resistance.[27]
  • 300 Series. The most widely used austenite steel is the 304, also known as 18/8 for its composition of 18% chromium and 8% nickel.[28] 304 may be referred to as A2 stainless (not to be confused with AISI grade A2 air hardening alloy tool steel containing about 5% chromium). The second most common austenite steel is the 316 grade, also referred to as A4 stainless and called marine grade stainless, used primarily for its increased resistance to corrosion. A typical composition of 18% chromium and 10% nickel, commonly known as 18/10 stainless, is often used in cutlery and high-quality cookware. 18/0 is also available.
Superaustenitic stainless steels, such as Allegheny Ludlum alloy AL-6XN and 254SMO, exhibit great resistance to chloride pitting and crevice corrosion because of high molybdenum content (>6%) and nitrogen additions, and the higher nickel content ensures better resistance to stress-corrosion cracking versus the 300 series. The higher alloy content of superaustenitic steels makes them more expensive. Other steels can offer similar performance at lower cost and are preferred in certain applications. For example ASTM A387 is used in pressure vessels but is a low-alloy carbon steel with a chromium content of 0.5% to 9%.[29] Low-carbon versions, for example 316L or 304L, are used to avoid corrosion problems caused by welding. Grade 316LVM is preferred where biocompatibility is required (such as body implants and piercings).[30] The "L" means that the carbon content of the alloy is below 0.03%, which reduces the sensitization effect (precipitation of chromium carbides at grain boundaries) caused by the high temperatures involved in welding.

Ferritic stainless steels

  • Ferritic stainless steels generally have better engineering properties than austenitic grades, but have reduced corrosion resistance, because of the lower chromium and nickel content. They are also usually less expensive. Ferritic stainless steels have a body-centered cubic crystal system and contain between 10.5% and 27% chromium with very little nickel, if any, but some types can contain lead. Most compositions include molybdenum; some, aluminium or titanium. Common ferritic grades include 18Cr-2Mo, 26Cr-1Mo, 29Cr-4Mo, and 29Cr-4Mo-2Ni. These alloys can be degraded by the presence of sigma chromium, an intermetallic phase which can precipitate upon welding.

Martensitic stainless steels

  • Martensitic stainless steels are usually not as corrosion-resistant as the other two classes but are extremely strong and tough, as well as highly machinable, and can be hardened by heat treatment. Martensitic stainless steel contains chromium (12–14%), molybdenum (0.2–1%), nickel (less than 2%), and carbon (about 0.1–1%) (giving it more hardness but making the material a bit more brittle). It is quenched and magnetic.

Duplex stainless steel

  • Duplex stainless steels have a mixed microstructure of austenite and ferrite, the aim usually being to produce a 50/50 mix, although in commercial alloys the ratio may be 40/60. Duplex stainless steels have roughly twice the strength compared to austenitic stainless steels and also improved resistance to localized corrosion, particularly pitting, crevice corrosion and stress corrosion cracking. They are characterized by high chromium (19–32%) and molybdenum (up to 5%) and lower nickel contents than austenitic stainless steels.
The properties of duplex stainless steels are achieved with an overall lower alloy content than similar-performing super-austenitic grades, making their use cost-effective for many applications. Duplex grades are characterized into groups based on their alloy content and corrosion resistance.
  • Lean duplex refers to grades such as UNS S32101 (LDX 2101), S32202 (UR2202), S32304, and S32003.
  • Standard duplex refers to grades with 22% chromium, such as UNS S31803/S32205, with 2205 being the most widely used.
  • Super duplex is by definition a duplex stainless steel with a Pitting Resistance Equivalent Number (PREN) > 40, where PREN = %Cr + 3.3x(%Mo + 0.5x%W) + 16x%N. Usually super duplex grades have 25% or more chromium. Some common examples are S32760 (Zeron 100 via Rolled Alloys), S32750 (2507), and S32550 (Ferralium 255 via Langley Alloys).
  • Hyper duplex refers to duplex grades with a PRE > 48. UNS S32707 and S33207 are the only grades currently available on the market.
  • Precipitation-hardening martensitic stainless steels have corrosion resistance comparable to austenitic varieties, but can be precipitation hardened to even higher strengths than the other martensitic grades. The most common, 17-4PH, uses about 17% chromium and 4% nickel.

The designation "CRES" is used in various industries to refer to corrosion-resistant steel. Most mentions of CRES refer to stainless steel, although the correspondence is not absolute, because there are other materials that are corrosion-resistant but not stainless steel.[31]


There are over 150 grades of stainless steel, of which 15 are most commonly used. There are a number of systems for grading stainless and other steels, including US SAE steel grades.

Comparison of standardized steels


Steel no. k.h.s DIN


Steel name

SAE grade UNS
1.4512 X6CrTi12 409 S40900
410 S41000
1.4016 X6Cr17 430 S43000
1.4109 X65CrMo14 440A S44002
1.4112 440B S44003
1.4125 X105CrMo17 440C S44004
440F S44020
1.4310 X10CrNi18-8 301 S30100
1.4318 X2CrNiN18-7 301LN
1.4301 X5CrNi18-10 304 S30400
1.4307 X2CrNi18-9 304L S30403
1.4306 X2CrNi19-11 304L S30403
1.4311 X2CrNiN18-10 304LN S30453
1.4948 X6CrNi18-11 304H S30409
1.4303 X5CrNi18-12 305 S30500
X5CrNi30-9 312
1.4841 X22CrNi2520 310 S31000
1.4845 X 5 CrNi 2520 310S S31008
1.4401 X5CrNiMo17-12-2 316 S31600
1.4408 G-X 6 CrNiMo 18-10 316 S31600
1.4436 X3CrNiMo17-13-3 316 S31600
1.4406 X2CrNiMoN17-12-2 316LN S31653
1.4404 X2CrNiMo17-12-2 316L S31603
1.4432 X2CrNiMo17-12-3 316L S31603
1.4435 X2CrNiMo18-14-3 316L S31603
1.4571 X6CrNiMoTi17-12-2 316Ti S31635
1.4429 X2CrNiMoN17-13-3 316LN S31653
1.4438 X2CrNiMo18-15-4 317L S31703
1.4541 X6CrNiTi18-10 321 S32100
1.4878 X12CrNiTi18-9 321H S32109
1.4362 X2CrNi23-4 2304 S32304
1.4462 X2CrNiMoN22-5-3 2205 S31803/S32205
1.4501 X2CrNiMoCuWN25-7-4 J405 S32760
1.4539 X1NiCrMoCu25-20-5 904L N08904
1.4529 X1NiCrMoCuN25-20-7 N08926
1.4547 X1CrNiMoCuN20-18-7 254SMO S31254

Standard finishes

Matte surface of pipe, with a few horizontal scratches
316L stainless steel, with an unpolished, mill finish

Standard mill finishes can be applied to flat rolled stainless steel directly by the rollers and by mechanical abrasives. Steel is first rolled to size and thickness and then annealed to change the properties of the final material. Any oxidation that forms on the surface (mill scale) is removed by pickling, and a passivation layer is created on the surface. A final finish can then be applied to achieve the desired aesthetic appearance.

  • No. 0: Hot rolled, annealed, thicker plates
  • No. 1: Hot rolled, annealed and passivated
  • No. 2D: Cold rolled, annealed, pickled and passivated
  • No. 2B: Same as above with additional pass through highly polished rollers
  • No. 2BA: Bright annealed (BA or 2R) same as above then bright annealed under oxygen-free atmospheric condition
  • No. 3: Coarse abrasive finish applied mechanically
  • No. 4: Brushed finish
  • No. 5: Satin finish
  • No. 6: Matte finish (brushed but smoother than #4)
  • No. 7: Reflective finish
  • No. 8: Mirror finish
  • No. 9: Bead blast finish
  • No. 10: Heat colored finish—offering a wide range of electropolished and heat colored surfaces


The arch rises from the bottom left of the picture and is shown against a featureless clear sky
The 630-foot-high (190 m), stainless-clad (type 304) Gateway Arch defines St. Louis's skyline
Chrysler Building detail
The pinnacle of New York's Chrysler Building is clad with Nirosta stainless steel, a form of Type 302[32][33]
 A stylized figure of a male human with outstretched arms and head tilted slightly forward, wearing a winged and crested helmet, mounted on the facade of a building
An art deco sculpture on the Niagara-Mohawk Power building in Syracuse, New York
Inside detail of DEMACO DTC-1000 Treatment Center for Fresh Pasta Production (October 1995) 002
Stainless steel is used for industrial equipment when durability and cleanability are important


Stainless steel is used for buildings for both practical and aesthetic reasons. Stainless steel was in vogue during the art deco period. The most famous example of this is the upper portion of the Chrysler Building (pictured). Some diners and fast-food restaurants use large ornamental panels and stainless fixtures and furniture. Because of the durability of the material, many of these buildings still retain their original appearance. Stainless steel is used today in building construction because of its durability and because it is a weldable building metal that can be made into aesthetically pleasing shapes. An example of a building in which these properties are exploited is the Art Gallery of Alberta in Edmonton, which is wrapped in stainless steel.

Type 316 stainless is used on the exterior of both the Petronas Twin Towers and the Jin Mao Building, two of the world's tallest skyscrapers.[33]

The Parliament House of Australia in Canberra has a stainless steel flagpole weighing over 220 metric tons (240 short tons).

The aeration building in the Edmonton Composting Facility, the size of 14 hockey rinks, is the largest stainless steel building in North America.


The Helix Bridge is a pedestrian bridge linking Marina Centre with Marina South in the Marina Bay area in Singapore.

  • Cala Galdana Bridge in Menorca (Spain) was the first stainless steel road bridge.
  • Sant Fruitos Pedestrian Bridge (Catalonia, Spain), arch pedestrian bridge.
  • Padre Arrupe Bridge (Bilbao, Spain) links the Guggenheim museum to the University of Deusto.[34]
Monuments and sculptures
  • Unisphere, constructed as the theme symbol of the 1964 New York World's Fair, is constructed of Type 304L stainless steel as a spherical framework with a diameter of 120 feet (37 m) (New York City)
  • Gateway Arch (pictured) is clad entirely in stainless steel: 886 tons (804 metric tons) of 0.25 in (6.4 mm) plate, #3 finish, type 304 stainless steel.[35] (St. Louis, Missouri)
  • United States Air Force Memorial has an austenitic stainless steel structural skin (Arlington, Virginia)
  • Atomium was renovated with stainless-steel cladding in a renovation completed in 2006; previously the spheres and tubes of the structure were clad in aluminium (Brussels, Belgium)
  • Cloud Gate sculpture by Anish Kapoor (Chicago, Illinois)
  • Sibelius Monument is made entirely of stainless steel tubes (Helsinki, Finland)
  • The Kelpies (Falkirk, Scotland)
  • Man of Steel (sculpture) under construction (Rotherham, England)
  • Juraj Jánošík monument (Terchova, Slovakia)

Stainless steel is a modern trend for roofing material for airports due to its low glare reflectance to keep pilots from being blinded, also for its properties that allow thermal reflectance in order to keep the surface of the roof close to ambient temperature. The Hamad International Airport in Qatar was built with all stainless steel roofing for these reasons, as well as the Sacramento International Airport in California.


Stainless steels have a long history of application in contact with water[36] due to their excellent corrosion resistance. Applications include a range of conditions from plumbing[37], potable[38] and waste water treatment[39] to desalination[40]. Types 304 and 316 stainless steels are standard materials of construction in contact with water. However, with increasing chloride contents higher alloyed stainless steels such as Type 2205 and super austenitic and super duplex stainless steels are utilized.[41]

Important considerations to achieve optimum corrosion performance are[42]:

  • choose the correct grade for the chloride content of the water;
  • avoid crevices when possible by good design;
  • follow good fabrication practices, particularly removing weld heat tint;
  • drain promptly after hydrotesting.

Pulp, Paper and Biomass conversion

Stainless steels are used extensively in the Pulp and Paper industry for two primary reasons, to avoid iron contamination of the product and their corrosion resistance to the various chemicals used in the paper making process.[43][44]

A wide range stainless steels are used throughout the paper making process. For example, duplex stainless steels are being used in digesters to convert wood chips into wood pulp. 6% Mo superaustenitics are used in the bleach plant and Type 316 is used extensively in the paper machine.

Chemical Processing and Petrochemical

Stainless steels are used extensively in these industries for their corrosion resistance to both aqueous, gaseous and high temperature environments, their mechanical properties at all temperatures from cryogenic to the very high, and occasionally for other special physical properties.[45][46][47][48]

Food and Beverage

Austenitic (300 series) stainless steel, in particular Type 304 and 316, is the material of choice for the Food & Beverage industry. Stainless steels do not affect the taste of the product, they are easily cleaned and sterilized to prevent bacterial contamination of the food, and they are durable.

Stainless steels are used extensively in:[49]

  • Cookware
  • Commercial food processing
  • Commercial kitchens
  • Brewing beer
  • Wine making
  • Meat processing

Acidic foods with high salt additions, such as tomato sauce, and highly salted condiments, such as soya sauce may require higher alloyed stainless steels such as 6% Mo superaustenitics to prevent pitting corrosion by chloride.


Automotive bodies

The Allegheny Ludlum Corporation worked with Ford on various concept cars with stainless steel bodies from the 1930s through the 1970s to demonstrate the material's potential. The 1957 and 1958 Cadillac Eldorado Brougham had a stainless steel roof. In 1981 and 1982, the DeLorean DMC-12 production automobile used Type-304 stainless steel body panels over a glass-reinforced plastic monocoque. Intercity buses made by Motor Coach Industries are partially made of stainless steel. The aft body panel of the Porsche Cayman model (2-door coupe hatchback) is made of stainless steel. It was discovered during early body prototyping that conventional steel could not be formed without cracking (due to the many curves and angles in that automobile). Thus, Porsche was forced to use stainless steel on the Cayman.

Some automotive manufacturers use stainless steel as decorative highlights in their vehicles.

Passenger rail cars

Rail cars have commonly been manufactured using corrugated stainless steel panels (for additional structural strength). This was particularly popular during the 1960s and 1970s, but has since declined. One notable example was the early Pioneer Zephyr. Notable former manufacturers of stainless steel rolling stock included the Budd Company (USA), which has been licensed to Japan's Tokyu Car Corporation, and the Portuguese company Sorefame. Many railcars in the United States are still manufactured with stainless steel, unlike other countries who have shifted away.


Budd also built two airplanes, the Budd BB-1 Pioneer and the Budd RB-1 Conestoga, of stainless steel tube and sheet. The first, which had fabric wing coverings, is on display at the Franklin Institute, being the longest continuous display of an aircraft ever, since 1934. The RB-2 Was almost all stainless steel, save for the control surfaces. One survives at the Pima Air & Space Museum, adjacent to Davis–Monthan Air Force Base.

The American Fleetwings Sea Bird amphibious aircraft of 1936 was also built using a spot-welded stainless steel hull.

Due to its thermal stability, the Bristol Aeroplane Company built the all-stainless steel Bristol 188 high-speed research aircraft, which first flew in 1963. However, the practical problems encountered meant that Concorde employed aluminium alloys.

The use of stainless steel in mainstream aircraft is hindered by its excessive weight compared to other materials, such as aluminium.


Surgical tools and medical equipment are usually made of stainless steel, because of its durability and ability to be sterilized in an autoclave. In addition, surgical implants such as bone reinforcements and replacements (e.g. hip sockets and cranial plates) are made with special alloys formulated to resist corrosion, mechanical wear, and biological reactions in vivo.

Stainless steel is used in a variety of applications in dentistry. It is common to use stainless steel in many instruments that need to be sterilized, such as needles,[50] endodontic files in root canal therapy, metal posts in root canal–treated teeth, temporary crowns and crowns for deciduous teeth, and arch wires and brackets in orthodontics.[51] The surgical stainless steel alloys (e.g., 316 low-carbon steel) have also been used in some of the early dental implants.[52]

Culinary use

Stainless steel is often preferred for kitchen sinks because of its ruggedness, durability, heat resistance, and ease of cleaning. In better models, acoustic noise is controlled by applying resilient undercoating to dampen vibrations. The material is also used for cladding of surfaces such as appliances and backsplashes.

Cookware and bakeware may be clad in stainless steels, to enhance their cleanability and durability, and to permit their use in induction cooking (this requires a magnetic grade of stainless steel, such as 432). Because stainless steel is a poor conductor of heat, it is often used as a thin surface cladding over a core of copper or aluminium, which conduct heat more readily.

Cutlery is normally stainless steel,[53] for low corrosion, ease of cleaning, negligible toxicity, as well as not flavoring the food by electrolytic activity.


Stainless steel is used for jewelry and watches, with 316L being the type commonly used for such applications. It can be re-finished by any jeweler and will not oxidize or turn black.

Valadium, a stainless steel and 12% nickel alloy is used to make class and military rings. Valadium is usually silver-toned, but can be electro-plated to give it a gold tone. The gold tone variety is known as Sun-lite Valadium.[54] Other "Valadium" types of alloy are trade-named differently, with such names as "Siladium" and "White Lazon".


Some firearms incorporate stainless steel components as an alternative to blued or parkerized steel. Some handgun models, such as the Smith & Wesson Model 60 and the Colt M1911 pistol, can be made entirely from stainless steel. This gives a high-luster finish similar in appearance to nickel plating. Unlike plating, the finish is not subject to flaking, peeling, wear-off from rubbing (as when repeatedly removed from a holster), or rust when scratched.

3D printing

Some 3D printing providers have developed proprietary stainless steel sintering blends for use in rapid prototyping. One of the more popular stainless steel grades used in 3D printing is 316L stainless steel. Due to the high temperature gradient and fast rate of solidification, stainless steel products manufactured via 3D printing tend to have a more refined microstructure; this in turn results in better mechanical properties. However, stainless steel is not used as much as materials like Ti6Al4V in the 3D printing industry; this is because manufacturing stainless steel products via traditional methods is currently much more economically competitive.

Recycling and reusing

Stainless steel is 100% recyclable.[55] An average stainless steel object is composed of about 60% recycled material of which approximately 40% originates from end-of-life products and about 60% comes from manufacturing processes.[56] According to the International Resource Panel's Metal Stocks in Society report, the per capita stock of stainless steel in use in society is 80–180 kg in more developed countries and 15 kg in less-developed countries.

There is a secondary market that recycles usable scrap for many stainless steel markets. The product is mostly coil, sheet, and blanks. This material is purchased at a less-than-prime price and sold to commercial quality stampers and sheet metal houses. The material may have scratches, pits, and dents but is made to the current specifications.

Nanoscale stainless steel

Stainless steel nanoparticles have been produced in the laboratory.[57] This synthesis uses oxidative Kirkendall diffusion to build a thin protective barrier which prevent further oxidation.[58] These may have applications as additives for high performance applications. For examples, sulfurization, phosphorization and nitridation treatments to produce nanoscale stainless steel based catalysts could enhance the electrocatalytic performance of stainless steel for water splitting.[59]

Health effects

Stainless steel is generally considered to be biologically inert, but some sensitive individuals develop a skin irritation due to a nickel allergy caused by certain alloys.

Stainless steel leaches small amounts of nickel and chromium during cooking.[60]

See also


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  3. ^ International Nickel Company (1983). "The Corrosion Resistance of Nickel-Containing Alloys in Sulphuric Acid and Related Compounds". Nickel Institute.
  4. ^ C.M. Schillmoller (1990). "Selection and Performance of Stainless Steel and other Nickel-Bearing Alloys in Sulphuric Acid". Nickel Institute.
  5. ^ a b Davis (1994), Stainless Steels, Joseph R., ASM International, p. 118, ISBN 978-0-87170-503-7
  6. ^ C.M. Schillmoller (1988). "Alloys to Resist Chlorine, Hydrogen Chloride and Hydrochloric Acid". Nickel Institute.
  7. ^ International Nickel Company. "Corrosion Resistance of Nickel-Containing Alloys in Phosphoric Acid". Nickel Institute.
  8. ^ C.M. Schillmoller. "Selection and Use of Stainless Steel and Ni Bearing Alloys in Nitric Acid". Nickel Institute.
  9. ^ C.M. Schillmoller (1992). "Selection and Use of Stainless Steel and Nickel-Bearing Alloys in Organic Acids". Nickel Institute.
  10. ^ C.M. Schillmoller (1988). "Alloy Selection for Caustic Soda Service". Nickel Institute.
  11. ^ "Material Selection and Use in Water". Nickel Institute.
  12. ^ American Iron and Steel Institute (April 1979). "High Temperature Characteristics of Stainless Steel". Nickel Institute.
  13. ^ Elliott, Peter (August 1990). "Practical Guide to High Temperature Alloys". Nickel Institute.
  14. ^ British Stainless Steel Association (2001). "Galling and Galling Resistance of Stainless Steels". SSAS Information Sheet No.5.60.
  15. ^ a b "A non-rusting steel". New York Times. 31 January 1915.
  16. ^ "It's Complicated: The Discovery of Stainless Steel - Airedale Springs".
  17. ^ "The Discovery of Stainless Steel".
  18. ^ "A Proposal to Establish the Shipwreck Half Moon as a State Underwater Archaeological Preserve" (PDF). Bureau of Archaeological Research, Division of Historical Resources, Florida Department of State. May 2000.
  19. ^ "ThyssenKrupp Nirosta: History". Archived from the original on 2 September 2007. Retrieved 13 August 2007.
  20. ^ "DEPATISnet-Dokument DE000000304126A".
  21. ^ "DEPATISnet-Dokument DE000000304159A".
  22. ^ Carlisle, Rodney P. (2004) Scientific American Inventions and Discoveries, p. 380, John Wiley and Sons, ISBN 0-471-24410-4
  23. ^ Howse, Geoffrey (2011) A Photographic History of Sheffield Steel, History Press, ISBN 0752459856
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  28. ^ Stainless Steel – Grade 304 (UNS S30400).
  29. ^ ASTM A 387/ A387M – 06a Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum
  30. ^ Material Properties Data: Marine Grade Stainless Steel. Retrieved on 29 June 2012.
  31. ^ Specialty Steel Industry of North America (SSINA), Frequently asked questions, retrieved 2017-04-06.
  32. ^ "Start of production: First coil on new mill". Archived from the original on 30 May 2013. Retrieved 14 September 2012. .
  33. ^ a b "What is Stainless Steel?". Archived from the original on 24 September 2006. Retrieved 31 December 2005.
  34. ^ "Stainless Steel Bridge in Bilbao". Outokumpu. "Stainless steel bridge". Archived from the original on 22 January 2013.
  35. ^ Gateway Arch Fact Sheet. Retrieved on 29 June 2012.
  36. ^ Nickel Institute. "Stainless Steel In The Water Industry". Nickel Institute.
  37. ^ NiDI (1997). "Stainless Steel Plumbing". Nickel Institute.
  38. ^ R.E. Avery, S. Lamb, C.A. Powell and A.H. Tuthill. "Stainless steel for potable water treatment plants". Nickel Institute.
  39. ^ A. H. Tuthill ans S. Lamb. "Guidelines for the Use of Stainless Steel in Municipal Waste Water Treatment Plants". Nickel Institute.
  40. ^ Water Research Foundation (2015). "Guidelines for the Use of Stainless Steel in the Water and Desalination Industries". Nickel Institute.
  41. ^ Nickel Institute. "Stainless steel in the Water Industry". Nickel Institute.
  42. ^ Nickel Institute. "Guidelines for Alloy Selection for Waters and Waste Water Service". Nickel Institute.
  43. ^ Nickel Institute. "Pulp and Paper". Nickel Institute.
  44. ^ A. H. Tuthill (2002). "Stainless Steels and Specialty Alloys for Modern Pulp and Paper Mills". Nickel Institute.
  45. ^ G. Kobrin (Nov 1998). "Stainless Steels for Chemical Process Equipment". Nickel Institute.
  46. ^ "The Role of Stainless Steel in Petroleum Refining". Nickel Institute.
  47. ^ G. Kobrin (November 1978). "Stainless Steels in Ammonia Production". Nickel Institute.
  48. ^ Nickel Institute. "Chemical Processing, Pharmceutical and Petrochemical Industries". Nickel Institute.
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  50. ^ Malamed, Stanley (2004). Handbook of Local Anesthesia, 5th Edition. Mosby. ISBN 0323024491. p. 99
  51. ^ Anusavice, Kenneth J. (2003) Phillips' Science of Dental Materials, 11th Edition. W.B. Saunders Company. ISBN 0721693873. p. 639
  52. ^ Misch, Carl E. (2008) Contemporary Implant Dentistry. Mosby. ISBN 0323043739. pp. 277–278
  53. ^ McGuire, Michael F. (2008). Stainless Steels for Design Engineers. ASM International. ISBN 9781615030590.
  54. ^ "What is Valadium?".
  55. ^ Johnson, J., Reck, B.K., Wang, T., Graede, T.E. (2008), "The energy benefit of stainless steel recycling", Energy Policy, 36: 181–192, doi:10.1016/j.enpol.2007.08.028
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  57. ^ Wu, Wenjie; Maye, Mathew M. (2014-01-01). "Void Coalescence in Core/Alloy Nanoparticles with Stainless Interfaces". Small. 10 (2): 271–276. doi:10.1002/smll.201301420.
  59. ^ Liu, Xuan. "Facile Surface Modification of Ubiquitous Stainless Steel Led to Competent Electrocatalysts for Overall Water Splitting". ACS Sustainable Chemistry & Engineering. 5: 4778–4784. doi:10.1021/acssuschemeng.7b00182.
  60. ^ Safe Cookware

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