Effect of EAF Impurities on Microstructure and Mechanical Properties of Low-Carbon Steels

The effects of common electric arc furnace (EAF) impurities, including copper (Cu), nickel (Ni), molybdenum (Mo), and chromium (Cr), were investigated in low-carbon steels. These steel scrap originating tramp elements can influence the microstructures and mechanical properties of steel products. Tramp elements containing test materials were thermo-mechanically rolled to achieve yield strengths between 400–450 MPa with different cooling routes. Various methods of microstructure characterization and mechanical testing were utilized to study the resulting steels. Additionally, thermo-mechanical simulations were conducted using Gleeble 3800 equipment to gather information about flow stress properties. The results indicate that with a lower cooling rate, the microstructure is not significantly affected by tramp elements, however strength levels can be increased and elongation properties decreased, mostly due to the solid solution strengthening effect of impurities. In water-quenched steels, the addition of tramp elements can alter the final microstructure morphology, increasing the ultimate tensile strength but simultaneously improving the ductility. Flow stress is not significantly affected by tramp elements in the temperature range of 950–1050 °C.