How does temperature affect the tensile strength of I-beams?

I-beams' tensile strength remains stable at -50°C to 200°C but decreases above 300°C as grain boundaries weaken. At 600°C, strength drops by 50% due to recrystallization, risking failure in fire. For high-temperature applications (e.g., industrial furnaces), heat-resistant alloys with 12-18% chromium retain 70% strength at 600°C. Conversely, cold temperatures (-40°C) increase tensile strength by 10-15% but reduce ductility-why arctic-grade I-beams (e.g., ASTM A572-50) require Charpy impact tests to ensure 27 J minimum energy absorption, preventing brittle fracture under sudden loads.