1.How does the substrate (metal layer) behave at low temperatures?
The steel plate itself is a metal material, and its low-temperature brittleness is mainly related to the "low-temperature impact toughness" of the steel. The toughness of ordinary low-carbon steel will gradually decrease when the temperature drops, but the base plate of the civilian color steel plate is mostly low-carbon steel, which has good low-temperature toughness. In a conventional low-temperature environment above -30℃, the strength and toughness of the metal itself will not decrease significantly, nor will it become "brittle and easy to break" due to low temperature.
2.How does the coating (paint layer) behave at low temperatures?
The coating is the key factor that determines whether the color steel plate "becomes brittle":
The coating is mostly organic coating, and its low-temperature performance is related to the "glass transition temperature" of the coating - when the ambient temperature is lower than Tg, the coating will change from a flexible state to a hard and brittle state, and it is easy to crack and peel off.
3.What is the difference between high-quality and low-quality coatings?
High-quality coating: Tg is low. In most areas of my country, the coating can still maintain flexibility and will not become brittle due to low temperature.
Low-quality coating: Tg is high. In the cold northern regions, the coating will become brittle due to low-temperature hardening. If it is subjected to external force at this time, it may crack or peel off.
4.What precautions should be taken in actual use?
Pay attention to the coating quality
When purchasing, give priority to high-weather-resistant coatings, which have better low-temperature toughness and are suitable for cold northern regions. Avoid using inferior and low-priced color steel plates.
Avoid external impact at low temperatures
Even for high-quality color steel plates, the toughness of the coating and substrate will decrease slightly at extremely low temperatures. At this time, heavy objects and violent vibrations should be avoided to prevent cracking of the coating or damage to the substrate.
Check the coating status regularly:
After winter in northern regions, check whether there is cracking or peeling of the coating on the surface of the color steel plate. If damage is found, repair it with special repair paint in time
5.In summary, does the environment have the greatest impact on color-coated steel?
In most areas (winter temperature ≥ -30℃), regular color steel plates (high-quality substrate + weather-resistant coating) will not become brittle due to low temperature and can be used normally.
Only in extremely low temperatures (such as below - 40℃) or when using inferior coatings, the coating of the color steel plate may become hard and brittle and crack, but the substrate (low carbon steel) itself is not easy to become brittle due to low temperature.