Thermoforming steel with tensile strength of 1,700MPa level and production method thereof

The invention discloses thermoforming steel with tensile strength of 1,700MPa level, which consists of the following components in percentage by weight: 0.27-0.50% of C, 0.28-0.50% of Si, 1.20-1.60% of Mn, 0.32-0.60% of Cr, 0.025-0.055% of Ti, 0.002-0.005% of B, 0.010-0.06% of Als, less than or equal to 0.012% of P, 0.010-0.035% of Nb or 0.30-0.45% of Mo or less than or equal to 0.50% of the mixture of Nb and Mo, less than or equal to 0.008% of S, less than or equal to 0.005% of N and less than or equal to 0.005% of O. A production method comprises the following steps of: molten iron desulphurization, converter smelting and blank casting; heating of the cast blank; rough rolling; finish rolling; laminar cooling; reeling; acid pickling and cold rolling; annealing; flattening; finishing and shearing; heating in protective atmosphere; moulding; quenching; and low-temperature tempering for later use. According to the thermoforming steel disclosed by the invention, the tensile strength is greater than 1,700MPa, and the yield ratio is not over 0.70; when used for manufacturing structural parts and safety parts of an automobile, the thermoforming steel not only can reduce the body weight of the automobile, but also can realize yield deformation in the case of automobile accidents to absorb energy and impact force; and therefore, the thermoforming steel is not broken immediately, and the safety of a driver and passengers is effectively protected.