The mechanical properties of 62 SiMnCr 4 steel transformed isothermally at 280ºC for 5-hours were investigated. The hardness of nanobainite steel was equivalent to tempered martensite steel. The hardness decreases significantly at high tempering temperatures in excess of 500ºC. Yield strength of about 2GPa and ultimate tensile strength of 2.3GPa have been achieved for nanobainite steel. Furthermore, the high strength is frequently accompanied by relatively good percentage elongation of 8.25%. The strength decreases and the ductility increases with increasing tempering temperature. Nanobainite steel has a high charpy impact energy of 170 J which decreases linearly with increasing tempering temperature. Fatigue strength of nanobainite steel is higher than tempered martensite, its decreases with increasing tempering temperature.