Thermomechanical treatment of S275JR steel: impact on microstructure, hardness, and impact toughness
Conference Object Open access M33
2025
Stamenković, Uroš 
Marković, Ivana
Manasijević, Dragan
Nedeljković, Milan
University of Belgrade - Technical Faculty in Bor
Proceedings [Elektronski izvor] - 56th International October Conference on Mining and Metallurgy - IOC 2025, 22-25 October, 2025, Bor Lake, Serbia
446
449
English
M33 - Conference paper at an international conference, printed in full
This study investigates how different thermomechanical treatment procedures affect the hardness, microhardness, impact toughness, and microstructure of S275JR structural steel. For the experiment, an as-received rectangular bar of structural steel was normalized at 900 °C for 60 minutes. Following normalization, the samples were pre-strained (cold deformed) by 8% at room temperature using a rolling mill. After deformation, the samples were aged for 30 minutes at temperatures of 100 °C, 150 °C, 200 °C, and 250 °C. The hardness, microhardness, impact toughness, and microstructure were analyzed for both the as-received sample and treated samples. The results indicated that normalization improved both hardness and impact toughness due to grain refinement. The straining conducted after normalization led to an increase in hardness but a decrease in impact toughness as a result of work hardening. The subsequent aging further strengthened the material, likely due to the interaction between dislocations and secondary phase particles, such as Fe3C and other alloying elements.
S275JR steel, normalization, strain aging, impact toughness, hardness
DOI
10.5937/IOC25446S
ISBN
978-86-6305-164-5