High-Temperature Tensile Behavior of Structural Steel Grades with Varying Manganese Contents

Three low-carbon (similar to 0.1 wt.% carbon) grades of structural steel with varying manganese content (0.75-1.5 wt.%) with ferrite-pearlite microstructure were used for the study. The 1.5 % manganese steel is a microalloyed steel with vanadium, niobium, and titanium content, which is strengthened by interphase precipitates. The steels were tensile tested at room temperature and in the temperature range between 200 degrees C-700 degrees C, at 100 degrees C intervals. The elevated temperature flow strengths of the steels studied show higher strength values for the higher manganese steel. It was found that the manganese enhanced the strength at all ranges of test temperatures. The retention factor of the conventional structural steels was less than or equal to 0.50 against 0.66 for a fire-resistant steel grade. The study shows that the addition of elements such as chromium, molybdenum is required to achieve a higher retention factor to fulfill the requirement of fire resistance characteristics.