Patent ID: 7117925
Filing Date: 2006-10-10
Classification: B21B,B22D,C22C

Abstract:
1. A cast steel strip prepared by a process comprising the steps of: supporting a casting pool of molten low carbon steel on a pair of chilled casting rolls forming a nip between them and continuously casting solidified strip of no more than 5 mm in thickness and including austenite grains by rotating the rolls in mutually opposite directions such that the solidified strip moves downwardly from the nip; passing the strip through a rolling mill in which it is hot rolled to produce a reduction in the strip thickness of at least 15%, and cooling the strip to transform the austenite to ferrite within a temperature range between 850° C. and 400° C. and at a cooling rate of more than 100° C./sec to form cast strip that is less than about 1% austenite and has a packet size of at least 10% greater than 300 μm, 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.