Process for controlling and improving die steel continuous casting thick slab internal quality

Abstract

The invention relates to a process for controlling and improving die steel continuous casting thick slab internal quality. By means of control of water amount of a vertical section, a bent section and a straightening section of a continuous casting machine, the water flow of the vertical section is controlled between 12m3 / h and 19m3 / h, the inner arc water flow of the bent section is between 18m3 / h and 26m3 / h, the outer arc water flow of the bent section is between 20m3 / h and 28m3 / h, the inner arc water flow of the straightening section ranges from 4m3 / h to 7m3 / h, and the outer arc water flow of the straightening section ranges from 6m3 / h to 10m3 / h. Through the control of the inner arc water flow and the outer arc water flow of the vertical section and the inner arc water flow and the outer arc water flow of the bent section, the return temperature in the casting blank cooling process is lowered, and cracks generated due to thermal stress are reduced or eliminated; the blank temperature at a straightening interval is controlled to range from 900 DEG C to 1100 DEG C, and cracks generated due to straightening force are reduced or eliminated; sector-shaped section pressing is carried out close to a condensation ending point so that pressing force can be transmitted to the casting blank center, and the problems of thick slab center segregation, center loosening and shrinkage are controlled and solved.

Description

technical field [0001] The invention relates to a process for controlling and improving the internal quality of a mold steel continuous casting thick slab, especially a process for controlling and improving the internal quality of a thick slab with a thickness greater than 260mm. Background technique [0002] Die steel can be roughly divided into cold work die steel, hot work die steel and plastic die steel, which are used for forging, stamping, cutting, die-casting, etc. For high-quality die steel, there are high requirements for the thickness and performance of the steel plate, which requires the continuous casting slab to have a large thickness and good internal quality. Compared with ordinary thickness slabs, due to the larger thickness of the billet, the heat transfer of thick slabs is limited, and internal defects are more likely to occur. The internal defects of thick slab mainly include internal cracks, segregation, porosity and shrinkage cavity. [0003] During th...

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Problems solved by technology

[0008] In order to control and improve the internal quality of the slab, electromagnetic stirring and light reduction technology have been widely used, but as the thickness of the continuous casting slab does not increase, it becomes more difficult to control and improve the internal quality of the slab. It is difficult to meet the production requirements of high-quality thick slabs