A Process for Controlling and Improving the Internal Quality of Die Steel Continuous Casting Thick Slabs

Abstract

The invention relates to a process for controlling and improving the internal quality of mold steel continuous casting thick slabs. Through the control of the water volume in the vertical section, bending section and straightening section of the continuous casting machine, the water flow rate in the vertical section is controlled at 12-19m3 / h ;In the bending section, the water flow rate of the inner arc is controlled at 18-26m3 / h, and the water flow rate of the outer arc is controlled at 20-28m3 / h; 10m3 / h. The invention reduces the return temperature of the slab cooling process by controlling the water flow of the inner and outer arcs of the vertical section and the bending section, and reduces or eliminates cracks caused by thermal stress; controls the water flow of the inner and outer arcs of the straightening section, and controls the temperature of the slab in the straightening section to 900 ~1100°C, reduce or eliminate cracks due to straightening force; near the end of solidification, implement a fan segment reduction, which can transmit the reduction force to the center of the slab, control and improve the center segregation, center looseness and shrinkage of the thick slab. hole.

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...

AI Technical Summary

Problems solved by technology

In the production of thick slabs, center porosity, shrinkage cavities and internal cracks are particularly serious. When using thick slabs to produce thicker steel plates, it is difficult to ensure the quality of the plates by using the usual rolling compression ratio. Ultrasonic flaw detectors can be used to detect internal cracks. defect

[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