Steel Properties

Steel is an alloy, consisting mainly of iron, with a carbon content of 0.2% to 2.1% by weight. Though the use of carbon is most common for the production of steel, other alloying materials like tungsten, chromium and manganese are also used. The proportions and forms in which these elements are used, affect the properties of the steel that is produced - increasing the carbon content for instance, yields a steel with increased strength. This is particularly important in the making of steel for different purposes - the strength of steel needed to make a beverage can, is obviously different from what is needed to make railway tracks. There are various types of steel, and the use of this alloy is widespread across industry and infrastructure owing to its characteristics.

Properties of Steel

Tensile Strength
Tensile strength is the amount of stress that a substance can take before becoming structurally deformed. The tensile strength of steel is comparatively high, making it highly resistant to fracture or breakage, a key point in its use in infrastructure building.

Ductility
One of the useful mechanical properties of steel is its ability to be changed in shape by the application of force, without fracture. The ductility of steel enables its use in the making of different shapes and structures, such as thin wires, or large automotive parts and panels.

Malleability
This is the steel property that allows it to be deformed under compression, a property closely linked with ductility. The malleability of steel is used to compress it into sheets of variable thickness, often created by hammering or rolling.

Durability
The hardness of steel is high, reflecting its ability to resist strain once formed. It is long-lasting and greatly resistant to external wear and tear.

Conductivity
Steel is a good conductor of heat and electricity. These steel properties make it useful in the making of cookware for domestic use, as well as electrical wiring.

Luster
One of the physical properties of steel is its attractive outer appearance. It is silvery in color with a shiny outer surface.

Rust Resistance
The addition of certain elements makes some types of steel resistant to rust. Stainless steel for instance contains nickel, molybdenum and chromium which improve its ability to resist rust.

In addition to the above, the following is an indicative steel properties chart, which illustrates the differences in the properties of different types of steel. Steel is identified by grades, which are defined by specific organizations that set standards for grading - mild steel and two grades of stainless steel, 304 and 430 are discussed below.

Material	Thermal Conductivity Btu/(hr-ft-ºF)	Density (lbs/in3)	Specific Heat (Btu/lb/ºF)	Melting Point ºF	Thermal expansion (in/in/ºFx10-6
Steel, Mild	26.0 - 37.5	0.284	0.122	2570	6.7
Steel, Stainless 304	8.09	0.286	0.120	2550	9.6
Steel, Stainless 430	8.11	0.275	0.110	2650	6

Interesting Steel Facts

• Steel is the most recycled material in North America - close to 69% of steel is recycled annually, more than plastic, paper, aluminum and glass combined.
• Steel was first used for skyscrapers in the year 1883.
• It takes more than the wood of 40 trees to make a wood framed home - a steel framed home uses 8 recycled cars.
• The first steel automobile was made in the year 1918
• 600 steel or tin cans are recycled every second.
• 83,000 tons of steel were used to make the Golden Gate Bridge.

The uses of steel are exhaustive and extensive. With recycling of steel, a practice that is commonly followed, its environmental impact is greatly reduced. It has been used for everything from making implements for agriculture, to building bridges, railway tracks, cars, engines and airplanes. In fact, you'd be hard pressed to go through a single day without coming across this extremely versatile metal. Steel properties enable its usage in a wide variety of ways that makes this metal all but indispensable to the human race. Over the years the production of steel has increased to its current levels of close to 1300 million tons a year. Whether it's a knife to cut a fruit, an electric razor, a hair pin, or an entire building, there's a little bit of steel in everyone's life!