Welcome to Your Resource

Steel is utilized in a wide range of buildings and constructions since steel is an extremely versatile and reliable building material. Until the middle of the 19th century, steel could not be mass produced and creating entire buildings from steel was therefore more or less impossible. Today, steel is one of the most reasonably priced building materials and appreciated world wide. When it comes to construction work, steel is by far the most frequently used metal building material. In theory it would of course be possible to construct a metal building from other metals with similar properties, e.g. titan, but in real life this is not a practical solution due to economical and practical factors.

Steel can either be used to create an entire building, or be combined with other building materials. Everything from weight carrying parts to roofs, walls and covering can be made from steel. Creating an entire building from steel will make it possible to rapidly erect an affordable building without having to give up factors such as durability, safety and design. Earlier, steel buildings were often quite unattractive and barren, but today you can get stylish steel buildings that look great and create a comfortable atmosphere. It is also common to combine steel with other types of building materials, e.g. concrete. In skyscrapers, steel is usually used to create a durable frame system, while concrete is utilized for walls, floors and roofing.

When you create a steel building, different types of steel should be used for different parts of the construction. Weigh carrying parts should for instance be made from very strong steel that is capable of withstanding all the stress that will be placed on it during the entire life of the building. When you construct an outdoor wall or protecting cover from steel, you should instead choose a steel type that has been developed especially in order to withstand the everyday wear and tear of the elements without requiring maintenance. In a building that contains large pieces of steel, light-weight steel is often the ideal choice since this will reduce the amount of stress on the weight carrying parts.

So, why is some steel types heavy and others light-weight? Why should you choose one type of steel for building parts that will exposed to a lot of tensile stress and another type of steel when you need a building material with high yield strength? To understand why there are so many different types of steel, we must take a closer look at the compounds that make up steel.

Steel consists chiefly of iron atoms, but unlike pure iron, steel will also contain plenty of carbon atoms. Iron atoms form strong sheets within the alloy, but without the presence of any carbon atoms these sheets will slide pass each other, thus making the material weak. If you add carbon atoms to pure iron, the carbon atoms will prevent the iron sheets from sliding over each other, and this is why steel is many times stronger than iron and useful as a building material. Modern steel plants will vary the amount of carbon in steel in order to create a wide range of different building materials that are all perfect for their particular task. By adjusting the carbon content in steel, it is possible to affect the weight, elasticity, brittleness, hardness, ductility and tensile strength of the building material.

The more carbon a piece of steel contains, the stronger it will be. Strong steel is of course important when you create such things as weight carrying parts in a building, but too high a carbon content is undesirable since the carbon also makes the steel more brittle. Creating steel that will be used as building material is therefore always a trade-off between strength and flexibility. An iron-carbon ratio that is ideal for a steel roof might for instance be highly unsuitable for a weight carrying piece and vice versa. Steel with a carbon content that exceeds 1.5 percent is very brittle and is called cast iron.

Before steel is utilized as a building material, it should go trough processes known as hardening and tempering. By hardening the steel, it is possible to achieve the desired iron-carbon ratio and make the steel very strong. At room temperature, the most stable form of iron is called ferrite iron. This material has a low carbon content is therefore soft and malleable. At room temperature, you can not force iron to take up more than 0.021 wt % of carbon and making it strong enough for construction work is therefore impossible without heating it. By heating up the ferrite iron beyond 910° Celsius, you make it possible for the material to dissolve up to 2.04 wt % of carbon and turn into austenite iron. During the hardening process, the iron will be heated repeatedly and rapidly cooled off with water or oil. If you manage to cool of the iron fast enough, the carbon can not escape and the iron will be stronger and stronger even at room temperature. You will end up with an alloy that is much stronger than ferrite iron, but also less flexible. This alloy is usually much too brittle to be utilized as building material, and a second process known as tempering must therefore be carried out. The metal must be re-heated so that small imperfections can escape from the alloy. This will remove internal stress and the alloy will turn into tempered steel.