At what temperature does steel begin to lose strength?

Steel begins to lose strength significantly around 600°F (approximately 315°C). At this temperature, the mechanical properties of steel, including its yield strength and tensile strength, start to decrease. This phenomenon is crucial in engineering, especially in construction and firefighting, as it affects the integrity of steel structures and components under high-temperature conditions.

While the other temperatures listed can indeed impact steel's properties, they do not mark the critical point at which noticeable strength loss occurs. At temperatures lower than 600°F, the changes in steel's strength are minimal, making 600°F a significant threshold for engineers to consider when assessing structural integrity in fire scenarios or other high-temperature applications. Understanding these temperature effects is vital for ensuring safety and performance in engineering design.