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Extreme weather and our materials

It used to be said: "If you don't have anything to say, you talk about the weather." But as is well known, rubber boots used to be made of wood and when you talk about the weather today, you usually think of climate change and the extreme weather events that are increasing with it.

Torrential rainfall, arctic temperatures and tropical heat records have not only been measured in recent years. According to the German Weather Service, the highest wind speed ever recorded in Germany was 335 kilometers per hour (Zugspitze, 1985), the maximum temperature was 41.2 °Celsius (Duisburg, 2019) and the greatest amount of precipitation was 312 millimeters within 24 hours ( Zinnwald, 2002).

As is well known, there is a mountain station including a cable car on the Zugspitze, Zinnwald has 417 inhabitants and Duisburg a few more - which in turn means that not only the people themselves but also the buildings they erect are exposed to extreme weather events again and again.

The fact that these do not collapse like a house of cards in the event of a hurricane or strong temperature fluctuations, but remain safe and stable for decades, is of course also due to the steel material. In this article, we would therefore like to take a look at wind, temperature and weather, show you the stresses many structures are exposed to and explain how steel can withstand these extremes.


Heat: Melting steel and dripping sweat

Let's start at the upper end of the temperature scale: The highest air temperature ever recorded is 56.7 °C and was measured in the famous Death Valley in the USA. Stahl can only laugh about that, of course; depending on the alloy, its melting point is in the high three to four-digit range. Or?

In fact, it is not liquefaction that demands the attention of architects and engineers - unless they are designing a turbine - but rather the spatial expansion of a material as temperatures rise.

As you probably know, physical substances expand when heat is added and contract again when the temperature drops. The corresponding formula for linear expansion is:

𝑙0 . 𝛼 . Δ𝑇 = Δ𝑙




the initial length in meters


the material-dependent coefficient of linear expansion in 1/Kelvin (for steel, depending on the alloy, around 12×10-6 to 16×10-6)


the temperature change in Kelvin


the change in length in meters

This means that the steel structure (α=12×10-6) of a 100 meter long bridge will expand by 8.5 centimeters with a temperature change of 70 degrees. The Eiffel Tower, which is made of iron (α=11.8×10-6) and is 330 meters long, is up to 30 centimeters higher on hot summer days than on cold winter days.

In practice, however, this physical phenomenon is easy to master: Steelworkers, structural and civil engineers, even tile and parquet layers always install so-called expansion joints in their constructions. These consist of an elastic material and, in addition to the expansion and contraction of the individual components, also compensate for other influences such as seismic activities.

Cold: Brittle materials and shaking knees

Coming to the opposite end of the temperature scale: the lowest temperature ever measured in a natural environment was reached in Antarctica. On July 21, 1983, the Vostock research station reported -89.2 °Celsius.

Such extreme sub-zero temperatures can even put steel to the ultimate test – in the truest sense of the word. Because with falling temperatures, the toughness of a material continues to decrease; the material becomes more brittle. Its toughness is measured in the so-called notched bar impact test.

A pendulum hammer hits the back of a notched sample with a certain kinetic energy. The type of fracture and, above all, the rebound angle of the hammer allow conclusions to be drawn about the energy absorbed on impact and thus the toughness of a material.

The formula for this is:





the mass of the pendulum hammer in kilograms


the gravitational acceleration (on earth 9.81 m/s2)


the drop height minus the rise height of the pendulum hammer


the impact work in joules

In this experiment, the limit of the steep drop is particularly important for materials – i.e. the temperature at which their toughness decreases rapidly.

Austenitic steels do not actually have a steep drop. They remain reliably tough even at temperatures down to -196 °Celsius and shrug their shoulders at South Pole temperatures.

Incidentally, -196 °Celsius is also the temperature at which liquid nitrogen is stored. Austenitic materials, especially those based on nickel or aluminum alloys, are therefore also suitable for use in the chemical industry. However, it gets even colder:
Absolute zero is known to be -273.15 °Celsius. At -253 °C, liquid hydrogen comes very close to this value. Helium even only liquefies at a temperature of -270 °Celsius.

Since hydrogen is considered to be the energy carrier of the future, the question naturally arises as to whether steel can withstand such sub-zero temperatures. And indeed it can: high-alloy austenitic stainless steels with a chromium content of up to 21 percent and a nickel content of up to 14 percent can withstand temperatures of almost 20 Kelvin.

Wind: swaying buildings and tousled hair

In addition to the temperature, a standard weather report always includes the wind. So far we have been spared from hurricanes that devastate entire regions

in this country there can be hurricanes with wind speeds of over 160 kilometers per hour. The highest wind speed ever measured in our latitudes is even 335 kilometers per hour.

However, it does not have to be 10 Beaufort for wind to affect buildings. Even everyday air circulation is enough to cause buildings to sway. In the wind-stricken USA, for example, there is a regulation that a house may move sideways by a maximum of 0.5 percent of its height.

For an average single-family house ten meters high, that would be five centimeters. A real skyscraper like the Burj Khalifa in Dubai (at 828 meters it is still the tallest building in the world), on the other hand, should sway by a clearly visible 4.14 meters at its top.
Of course, engineers and architects try to prevent such extreme fluctuations. For example, by adapting the aerodynamics of their constructions accordingly. Or through measures such as in Taipei 101 (508 meters high, 1.3 meters effective fluctuation): There, between the 87th and 92nd floors, a huge steel ball suspended on ropes floats, which absorbs the fluctuations and is also intended to protect the building from earthquakes.

Which leads us straight back to the material steel. Because no matter how resourceful the designers are, the influence of the wind cannot be completely compensated. Therefore, the selection of the right steel grades is of crucial importance for your work:
Suitable steels for building construction are precisely standardized in relevant regulations, such as the Construction Products Ordinance (BauPV), the building inspection approval of the German Institute for Building Technology (DIBt) or the Euronorm with its CE mark. Two material properties play an important role here: On the one hand, the transition from elasticity (a material returns to its original state after a load) to plasticity (a material remains in the deformed state after a load); on the other hand, its rigidity – i.e. the resistance of a body to external loads.

The values ​​that a material must achieve in order to be suitable for a specific application are precisely regulated in the relevant regulations. So if you have set yourself the task of outstripping the Burj Khalifa, you can look it up there - or simply use our inquiry tool for your project and get advice from our experts.

Rain: Rusting metal and wet clothes

Of course, rain is always part of the weather. The catastrophe in the Ahr Valley in the recent past showed us just how dangerous large amounts of precipitation can be. On the other hand, if there is no rain, shipping on German canals comes to a standstill and farmers fight against crop failures.

When it comes to water and steel, however, people usually think of a completely different problem, namely rust. In the article on our online tools, we have already dealt with the topic in detail. There we explain in detail what the PREN of a material is all about, how the corrosion resistance classes (CRC) are to be understood and why rust is not the only form of corrosion. At this point we would therefore like to limit ourselves to corrosion caused by rainwater.

Rain causes iron, and therefore some types of steel, to rust as a result of an electrochemical reaction in combination with oxygen. Roughly simplified, the following happens:
Oxygen alone does not damage iron, otherwise the metal would already rust in the dry air. When oxygen meets iron, only two electrons per molecule migrate from the metal into the gas. This process forms a thin layer of iron-II-oxide, which protects the iron from further destruction.

However, if water comes into play, the oxygen does not combine with the iron, but reacts with the water molecules on the metal surface and takes the electrons from them. The iron, in turn, wants to compensate for this loss and reacts with the water.
In this redox reaction, hydroxide ions are formed first. These in turn react with the iron ions in the metal and form iron(II) hydroxide - this oxidation is also known colloquially as rust. Incidentally, seawater accelerates the process due to its higher electrical conductivity.
Stainless steels prevent oxidation through their alloy: They are alloyed with nickel and, above all, chromium with a proportion of at least ten percent. The chromium content of the material forms a protective passive layer of chromium oxides on its surface, which does not react further with water and oxygen.

To put it simply: In the right alloy, steel is reliably protected against corrosion. Even seawater cannot harm them. The supports of a wind turbine in the North Sea are made of steel, just like the platform of an oil rig in the Pacific, and nothing has rusted away there so far.

Every weather condition has its steel

Our materials are therefore easily able to withstand extreme heat and freezing cold and easily withstand even the greatest temperature fluctuations. They are also immune to the forces of the wind; not to mention corrosion from water and oxygen.

Above all, the selection of the right type of steel is decisive. It goes without saying that we will not leave you alone. We will be happy to answer any questions you may have about the weather resistance of our products or to take your order directly. Just contact us.

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