Steel in different weather conditions –Blog 6

I am very much awaited to write on the topic " How weather conditions affect the construction material  steel ".This has been on all of our minds ever since we started this subject, as somehow the usage and application of steel in construction depends on the climatic conditions due to the reactive properties of steel.

Weather conditions decide the duration for construction, durability and life span of the constructed building. Temperature changes are different in every country, state, and within countries and states and even within regions and cities, it is based on whether they are near the sea, mountains or places of heavy snowfall and precipitation. Weather condition is also a factor in determining cost and expenditure of the construction as the required surface treatment and finishing has to be done for its maintenance and longevity.

Let us see how different temperatures affect the material “steel” in construction:

At Low temperatures:

Extreme cold temperature causes steel to lose its ductility (the ability to bend to a certain extent without breaking) and increase the property of brittleness (tendency to deform before fracturing) of steel. As temperature decreases steel becomes more brittle and it is likely to break immediately without the signs of deformity. It becomes more sensitive to impacts with a sudden breakage. This shift is known as the “ductile-to-brittle-transition” temperature (DBTT).

In order to increase the tensile strength and resistance to shock of steel in low temperatures stainless steel with high content of nickel and nitrogen are preferred.

During snow, thunderstorms and rains:

All these three conditions of weather produces moisture which reacts with steel to produce rust due to the process of oxidation. This is applicable even to coastal areas where the humidity and moisture content present in the air causes rusting of steel.

The oxidation of steel can be prevented by the process of galvanization, metallic coating, painting, powder coating etc. Steel with high content of chromium can increase the corrosion resistance.

At high temperature:

Extreme hot temperature is also a problem to steel since it has a property of conducting heat. Due to the heat gained in the material steel is susceptible to thermal expansion and becomes more ductile which reduces its tensile strength. This thermal expansion and ductility might lead to a gradual damage/collapse to the parts which are exposed to solar radiation beyond their resistance. This is due to the plastic properties of steel. Temperature strength of materials is expressed by "creep strength" - the ability of the material to resist distortion over a prolonged exposure to a high temperature/ solar radiation.

This can be prevented by the application of certain surface treatment in order to resist the heat absorption and increase the surface reflection of steel in the form of polish, painting, metallic coating etc. Steel often having high content of chromium and molybdenum to increase its strength and hardness; and steel with nickel content to increase its tensile strength.

From this we can say that the use of steel in construction is very different in different climatic conditions. Hence, we will have to look into their properties which makes it to withstand the changes occurred over a period of time and see to that their treatment remains form application to the time construction is finished and lasts for a long period of time after that. As the climatic conditions keep changing nowadays it is important to choose the correct and most recent materials that is suitable for the particular region based on its function.

 

-Theerthana✌