The steel QStE380TM-0.04~0.08C

0.20~0.35Si

1.20~1.35Mn

≤0.015P

≤0.010S

0.015~0.025Nb

0.005～0.015Ti 6~12 mm hot rolled plate for auto beam has been researched and produced by hot metal pretreatment - 210 t top and bottom combined blown converter - LF refining - two strand vertical-bending concaster(65 mm slab)- 6-stand SMS mill control rolling and cooling process. The examination results showed that the structure of plate was ferrite + minor pearlite with grain size 4~7 pm

of which the mechanical properties met to requirement of standard

the maximum difference of yield strength of plate at different direction was 30 MPa

the maximum difference of tensile strength was 20 MPa and the ambient impact energy of majority plate was 140～180 J.