The term ‘stainless steel’ covers a wide range of iron alloys that are generally resistant to oxidation and corrosion. As well as a minimum chromium content of 10.5%, several other metallic elements can be added to add functionality to the final product. These include nickel, molybdenum, copper and titanium. Non-metallic additions to stainless steel include carbon and nitrogen.
The anti-corrosion properties of stainless steel are what make the material so desirable for manufacturing and other industrial uses. Other elements are added to imbue the metal with added qualities, such as formability. Stainless steel is strong, highly tensile and requires little maintenance. Furthermore, it can be re-used many times over. Architects often choose stainless steel for its aesthetic qualities when designing buildings and developing internal and external architectural features.
The first stainless steel is thought to have been created by Harry Brearley in 1913, when he produced a corrosion resistant metal containing 12.8% chromium and 0.24% carbon. In the production process, the chromium creates a thin layer of oxide on the surface of the metal, known as the ‘passive layer’. It is this layer that protects against corrosion.
Where there is a requirement for materials to be corrosion-resistant, then stainless steel is the most obvious metal of choice. There are over 150 types of stainless steel, divided into four main groups: austenitic (the most common non-magnetic form), martensitic (extra-strength), ferritic (magnetic with reduced anti-corrosion properties) and duplex (50/50 mix of austentic and ferritic), all offering a huge number of applications.
- Architecture and construction
- Cutlery and cookware
- Surgical instruments and razor blades
- Infrastructure, such as bridges
- Transportation, including car, trains and aviation
The name ‘stainless’ steel was first used when the cutlery company, R.F. Mosley, first used the word ‘stainless’ to describe a range of knives that couldn’t be stained by vinegar.
Stainless Steel – Grade 304
|Property||Minimum Value (S.I.)||Maximum Value (S.I.)||Units (S.I.)||Minimum Value (Imp.)||Maximum Value (Imp.)||Units (Imp.)|
|Atomic Volume (average)||0.0069||0.0072||m3/kmol||421.064||439.371||in3/kmol|
|Bulk Modulus||134||151||GPa||19.435||21.9007||106 psi|
|Modulus of Rupture||205||310||MPa||29.7327||44.9617||ksi|
|Shear Modulus||74||81||GPa||10.7328||11.7481||106 psi|
|Young’s Modulus||190||203||GPa||27.5572||29.4426||106 psi|
|Latent Heat of Fusion||260||285||kJ/kg||111.779||122.527||BTU/lb|
|Maximum Service Temperature||1023||1198||K||1381.73||1696.73||°F|
|Minimum Service Temperature||0||0||K||-459.67||-459.67||°F|
|Resistivity||65||77||10-8 ohm.m||65||77||10-8 ohm.m|
|Oxidation at 500C||5|