Table 2: The effect of heat-treatment on the average mechanical properties of AISI 4140 steel alloy.

Austenitizing temperature and time Austempering temperature and time UTS (MPa) YS (MPa) % Elongation Strain hardening exponent ("n")
950 C/2 hours 322 C/2 hours 1286 ± 129 1011 ± 130 6.1 ± 3.0 0.15 ± 0.02
Annealed [14] 655 415 25 ---
885 C/1 hour [15] 349 C/1 hour 1527 1369 5.9 ---
885 C/1 hour [15] 322 C/1 hour 1646 1481 5.5 ---
850 C/40 min [16] Oil Quenched + 300 C/60 min 1720 1528 11.9 ---