Steel is often used in the construction of all types of buildings, from barns, carports, and sheds to houses, garages, and skyscrapers. In particular, it is often used to construct the frames and foundations of buildings, as it is resilient and binds well to concrete. Becoming commonplace during World War II, steel remains a standard building material to this day.
Properties of Steel
“Properties” refers to the integral attributes of a material. In the case of a physical material like steel, this largely refers to physical and chemical attributes. However, it should be noted that there are different types of steel, and alterations of the material will also alter its properties to varying degrees.
Yield Strength
Yield strength refers to how much force needs to be applied to a material before it experiences deformation. Below the yield point, the material will resume its previous form when the force is no longer being applied. One of the reasons that steel is commonly used in construction is because steel (particularly alloys such as carbon and stainless steel) has a high yield strength, and therefore can withstand a lot of stress before experiencing permanent changes to its physical dimensions.
Tensile Strength
Tensile strength refers to how much force needs to be applied to a material before it breaks. Steel alloys demonstrate high tensile strength in addition to high yield strength, which further lends to their resiliency and value to construction. For example, a steel frame can help prevent a building from collapsing during an earthquake, as so much force is needed to cause the material to fracture.
Hardness
Hardness refers to a material’s resistance to localized deformation, or in other words, the amount of pressure that needs to be applied to the material’s surface before indentation occurs. Steel is one of the hardest known metals, although the specific alloy and how it is treated can alter the hardness. Steel is often tempered to improve its hardness, and, by extension, its resistance to damage such as dents and abrasion.
Elongation
Elongation refers to how far a material can be stretched before it experiences breakage. When a material has a higher percentage elongation, it is said to be ductile, while materials with a lower percentage elongation are said to be brittle. The percent elongation of steel depends highly on the alloy, and therefore, different alloys are often used for different purposes in construction, depending on how elastic or unyielding they need to be.
Mild steel is the type most commonly used in construction, as it has a relatively high percentage elongation, and therefore is less prone to breakage during an event like an earthquake. Meanwhile, alloys like carbon steel with lower percentage elongation but are harder, will sometimes be used in structures like beams to reinforce the framework of a building.
Characteristics of Steel
A characteristic of a material refers to its behavior and its predictably changeable features. When speaking of the characteristics of steel, we are largely referring to how it can be predictably altered by the introduction of an element such as force or heat.
Weldability
Weldability describes the ability of a material to be joined with other materials through a melting process. The weldability of steel depends on the particular alloy, with lower-carbon alloys like mild steel being more easily weldable. In construction, it is often important that the framework material can easily be welded to other materials, and therefore low-carbon steel is very valuable in this respect as well.
Hardenability
The hardenability of a metal refers to its ability to be hardened through heat treatment. Often, following the hardening process, the metal is tempered, which is done by exposing it to a lower heat, and is meant to ensure that the metal is not too brittle following the hardening process. Only steel with a high carbon content can be hardened and tempered properly.
Machinability
The machinability of a metal refers to its ability to be shaped through processes like cutting, grinding, and drilling. Materials with good machinability are highly valuable to construction processes due to their ability to be adjusted without losing their structural resistance, which is very important for customization projects in particular. Steel alloys with a medium amount of carbon are the most machinable, as high-carbon steel alloys are very difficult to cut, while low-carbon steel alloys tend to deform too much and stick to tools.
Workability
Workability refers to a metal’s ability to be re-formed without experiencing defects such as cracks. Common industrial processes that involve re-forming metals include bending, forging, extruding, and rolling. Low-carbon steel is the most workable due to being highly ductile.
Wear Resistance
Wear resistance refers to a combination of factors such as hardness that impact how likely a metal is to sustain damage like abrasion and erosion over time. High-carbon steel is the most resistant to wear.
Corrosion Resistance
Corrosion resistance refers to how resistant a metal is to the deterioration of its intrinsic qualities through chemical processes, such as the formation of rust. Stainless steel is an example of a steel alloy with high corrosion resistance, while carbon steel is an example of a steel alloy with very low corrosion resistance.
Uses of Steel
Steel isn’t only widely used in the construction of buildings. Some other common uses for it include:
- Vehicle parts;
- Appliance parts;
- Infrastructure;
- Medical tools;
- Kitchen tools;
- Construction tools;
- Mines.
However, while steel is a very useful material in many contexts, it is prudent to always compare and contrast its appropriateness for a project against other options for resilient materials, such as burnt clay bricks or yellow pine wood.