Coiling temperature control method for hot-rolled high-strength dual-phase steel

Abstract

The invention relates to a hot-rolled high-strength dual-phase steel coiling temperature control method, and belongs to the technical field of hot continuous rolling plate production methods. According to the technical scheme, the method comprises the steps of strip steel rolling speed setting, cooling water use mode setting between racks, coiling temperature multi-target-value control in the strip steel length direction, independent coiling temperature cooling codes set in a model table, coiling temperature target values of different length sections are set, and coiling temperature control is conducted. And the coiling temperature control model configures the laminar cooling header and issues the configuration to the first-stage programmable controller to dynamically control the opening and closing of the laminar cooling header. The method has the beneficial effects that the dual-phase steel independent cooling codes are set in the coiling temperature control model, the coiling temperature of the strip steel with the specific length section is set and controlled according to multiple target values, and the dual-phase steel thin-specification product production and cooling process is optimized; the technical problems that the coiling temperature of the high-strength dual-phase steel deviates from a target value and fluctuates and the like can be effectively solved.

Description

technical field [0001] The invention relates to a method for controlling the coiling temperature of hot-rolled high-strength dual-phase steel, and belongs to the technical field of hot-rolled sheet production methods. Background technique [0002] After hot-rolled 700MPa and above high-strength dual-phase steel CR550 / 980DP, HC820 / 1180DP and other steel grades are coiled into coils, the head and tail of the strip are in contact with the inner and outer circles of the coil, and the temperature drop rate is relatively different from that of the strip in the middle of the coil. Large differences, and different cooling rates lead to different phase transformation processes, this inhomogeneity is inherited to the later process, resulting in different properties of the head and tail tissue, and the yield is low. Theoretically, the cooling control method with coiling temperature (CT) compensation at the head and tail of the strip can better solve the problem of inconsistent performa...

AI Technical Summary

Problems solved by technology

[0002] After the hot-rolled 700MPa and above high-strength dual-phase steels such as CR550 / 980DP and HC820 / 1180DP are rolled into coils, the head and tail of the strip are in contact with the outside ring of the coil, and the temperature drop rate is higher than that of the strip in the middle of the coil. There is a big difference, and different cooling rates lead to different phase transformation processes. This inhomogeneity is inherited to the subsequent processes, resulting in inconsistent properties of the head and tail tissues, and a low yield

Theoretically speaking, the cooling control method using strip head and tail coiling temperature (CT) compensation can better solve the problem of inconsistent performance of the strip head and tail, but in actual production, it is found that the coiling temperature U-shaped cooling control stability is poor , In the continuous production process, individual steel coils often have no dry end, and the strip coiling temperature (CT) after the dry end section is lower than the target value; the target value of the final rolling temperature (FDT) of thin-gauge products below 2.5mm is high, and the non-use machine Inter-stand cooling water rolling process, the strip running speed is slow, the cooling process is unreasonable, the measured coiling temperature of the dry head section and hot tail section of the strip steel is lower than the target value, etc.

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