A cast carbon steel strip is prepared by continuously casting in a twin roll caster and cooling to transform the strip from austenite to ferrite at a temperature range between 400.degree. C. and 850.degree. C. at cooling the strip to transform the austenite to ferrite within a temperature range between 400.degree. C. and 850.degree. C. at a cooling rate of greater than 100.degree. C./sec without inhibiting the cooling rate to form cast strip that is less than about 1% austenite and has a packet size of at least 10% greater than 300 .mu.m, is either (i) a mixture of polygonal ferrite and low temperature transformation products or (ii) predominantly low temperature transformation products, and has a yield strength of at least 450 MPa. The cast strip before cooling is passed through a hot rolling mill to reduce the thickness of strip by at least 15% and up to 50%.