Temperature can significantly affect the performance of flat steel. At high temperatures, the strength and hardness of flat steel decrease. This is because the heat causes the microstructure of the steel to change, reducing its ability to bear loads. For example, in applications where flat steel is exposed to high temperatures, such as in furnaces or engine components, it may undergo thermal expansion, which can lead to dimensional changes and potential warping if not accounted for in the design. At very high temperatures, flat steel can also oxidize, forming scale on the surface, which weakens the material over time. On the other hand, at low temperatures, some types of flat steel may become more brittle, reducing their impact resistance. This is a concern in cold climates, where flat steel used in structural applications, such as bridges or pipelines, needs to withstand freezing temperatures. However, certain alloy flat steels are designed to maintain their toughness at low temperatures, making them suitable for such environments. The effect of temperature on flat steel's performance must be considered during the design phase, and appropriate steel grades must be selected based on the expected temperature range of the application.