Abstract: A method for strengthening of carbon and low alloy steels and steels produced thereby wherein a carbon or low alloy steel is partially austenitized to produce a ferrite-austenite mixture, the resulting ferrite-austenite mixture is quenched to an intermediate temperature to render the austenite metastable, with the quenching being at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, and working the quenched steel at a temperature up to the maximum temperature at which bainite can exist whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture having high levels of machinability, strength and toughness.