Effect of boron addition on the hot ductility of SAE 5160 steel

The effect of boron on the hot ductility of SAE 5160 steel was evaluated through computational simulations (Thermo-Calc® and DICTRA) and physical simulations carried out on a Gleeble® 3800 process simulator.Hot ductility tests were performed at heating rates of 10 °C/s, followed by cooling at two controlled rates (0.5 °C/s and 1 °C/s) to test temperatures between 700 °C and 1200 °C, which corresponds to the range in which billet straightening occurs.For each condition, the reduction of area was measured, and fracture surfaces were examined by SEM to identify the underlying fracture mechanisms.The results showed that boron addition significantly increases the hot ductility temperature range.For the higher cooling rate (1 °C/s), the boron-containing steel maintained reduction of area values above 70% across nearly the entire test interval, reaching approximately 90% at peak ductility, and eliminating the high-temperature embrittlement trough observed in the boron-free steel.These findings demonstrate that boron addition is beneficial to the hot ductility of SAE 5160 steel, provided that appropriate processing conditions are applied.