One kind ct90 stage hot strip continuous tube and its production method

CT90 seed stage continuous pipe hot rolled strip, its chemical composition and wt%: C: 0.05 ~ 0.10%, Si: 0.10 ~ 0.30%, Mn: 0.40 ~ 0.90%, P≤0.015%, S≤0.0020%, Cu: 0.25 ~ 0.40%, Ni: 0.15 ~ 0.35%, Cr: 0.50 ~ 1.00%, Mo: 0.10 ~ 0.20%, Nb: 0.020 ~ 0.050%, V: ≤0.010, Ti: 0.010 ~ 0.030%, N≤0.0050%, al: 0.015 ~ 0.060%, Ca: 0.0008 ~ 0.0025, B: 0.0008 ~ 0.0015. Production methods: heating the slab and the slab after the smelting; rough rolling; finishing; cooled in three stages; after coiling coil insulation wall into slow cooling. The present invention, by adding B, reducing the C content, and improved tissue segregation steel HIC resistance and to ensure the passing resistance to SSCC; by recombination of Cu, Ni is added to improve the hot brittleness of Cu; controlled cooling stages, to achieve duplex microstructure regulation, reducing the yield ratio of the steel strip.