The surface temperature of profiled beam blank of Nb microalloying steel SM490YB-0.09～0. 13C

1.35 ~1.50Mn

0.04～0.06Nb during concasting by CIT-M Infrared Pyrometer. The results showed that the traverse surface temperature of beam blank was uneven

the surface temperature of beam at measured location in secondary cooling and straightening area were generally in the brittle low temperature range between 650 ℃ and 750℃ of steel SM490YB; and due to interval water spraying cooling between supporting rollers

the re-rise rate of temperature of beam surface between some supporting rollers in secondary cooling area was higher than 100 ℃/m the limits of metallurgical rules. It shall be to adopt weakening cooling process during casting profiled beam and adjust distribution of spraying nomles in order to increase the surface quality of profiled beam.