THERMOFORMING STEEL ROLLED DIRECTLY FROM MEDIUM THIN SLAB AND HAVING TENSILE STRENGTH GREATER THAN OR EQUAL TO 1500 MPA AND PRODUCTION METHOD

摘要

Thermoforming steel rolled directly from a medium thin slab and having tensile strength greater than or equal to 1500 MPa, comprising the following components (weight%): C: 0.21%-0.25%, Si: 0.26%-0.30%, Mn: 1.0%-1.3%, P≤0.01%, S≤0.005%, Als: 0.015%-0.060%, Cr: 0.25%-0.30%, Ti: 0.026%-0.030% or Nb: 0.026%-0.030% or V: 0.026%-0.030% or a mixture of any two or more of the above in any proportion, B: 0.003%-0.004%, Mo: 0.17-0.19% and N≤0.005%. Production steps comprise: molten iron desulphurization; smelting and refining by an electric furnace or converter; continuous casting; descaling treatment before entering a soaking pit; soaking; heating; high pressure water descaling before entering a rolling mill; rolling; cooling; coiling; austenitizing; mold stamping forming; and quenching. The production process of the present invention is short, surface quality thereof is good, and thickness precision is high; quality requirements for cold-rolled products may be met, and complex deformation may be smoothly completed; moreover, no resilience is present after deformation, and dimensional accuracy of parts is high.