Did you know that aluminium is one of the elements most frequently occurring in the earth’s crust? It is included in the group of light metals and is nearly three times lighter than iron. With adequate heat, working aluminium alloys reflect mechanical parameters improvement several fold compared to pure aluminium. Thanks to their low density aluminium alloys have perfect relevant strength, which means the strength vs relevant weight ratio.
Aluminium is characterised with high resistance to weather conditions and, thus, to corrosion. It is a good heat and electricity conductor. It is also a highly plastic material.
Stainless steel obtains its special properties by the addition of alloy elements, particularly chromium. Corrosion resistance properties of steel originate from the passivation process, which is the creation of a thin coat of oxides limiting air access. The more alloy elements the inside steel, the better corrosion resistance properties are achieved. The fact that stainless steel is weakly attracted by magnet, and the more noble it is the less magnet attraction is observed, is quite interesting.
Carbon steel is the alloy of iron and carbon, with the carbon content of approx. 2%. The fact that the 2% carbon content is a generally accepted value differing steel from cast iron is interesting. The level of carbon content also affects the hardness of the steel – the more carbon, the harder the steel.
Depending on the type of treatment, the steel may be either hot or cold rolled.
Hot rolled (HR) steel is one of the least expensive and corrosion susceptible materials. Corrosion protection is added, for example, by zinc plating or powder coating.
Cold rolled steel is available in any thickness, but the most frequent interval is 0.3–3 mm. Compared to hot rolled steel its surface is smoother and better finished. Such type of steel is protected against corrosion by zinc plating, electro-galvanising or coating.
Corten steel reflects improved resistance to weather conditions thanks to the protective coating which is formed on its surface with time. Copper, chrome, nickel and phosphorus present in the steel develop a layer of oxides (patina) on the surface of the metal as a result of sunlight, rain and wind. Patina protects the steel against further rusting. Its protective coat may become damaged, for example by scratching, but it will be recreated with time, providing further protection.
The patina coat built up as a natural process is becoming more and more stable with time while the colour becomes deeper. Compared to regular steels, such characteristics of Corten steel makes it a very interesting, durable and frequently used material.