Method of producing steel strip
AssigneeNucor Corporation
InventorsLazar Strezov, Kannappar Mukunthan, Walter Blejde, Rama Mahapatra
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Abstract
Steel strips and methods for producing steel strips are provided. In an illustrated embodiment, a method includes continuously casting molten low carbon steel into a strip of no more than 5 mm thickness having austenite grains that are coarse grains of 100-300 micron width; and providing desired yield strength in the cast strip by cooling the strip to transform the austenite grains to ferrite in a temperature range between 850° C. and 400° C. at a selected cooling rate of at least 0.01° C./sec to produce a microstructure that provides a strip having a yield strength of at least 200 MPa. The low carbon steel produced desired microstructure.
Claims12
A low carbon steel produced by a process comprising the steps of:
- (a) continuously casting molten low carbon steel into a strip of no more than 5 mm thickness with austenite grains that are coarse grains of 100-300 micron width;
- and
- (b) providing desired mechanical properties in the cast strip without changing the chemistry requirements of the steel supplied by cooling the strip to transform the austenite grains to ferrite in a temperature range from 850° C. to 400° C. at a selected cooling rate of at least 0.01° C./sec to produce a microstructure that provides a strip having a yield strength between 200 and in excess of 700 MPa, the microstructure being selected from the group consisting of:
- (i) predominantly polygonal ferrite;
- (ii) a mixture of polygonal ferrite and low temperature transformation products;
- and
- (iii) predominantly low temperature transformation products.
Dependencies are inferred from the claim text.