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Slab Continuous Casting Simulation Soft Reduction

Author: ZhangHaiFeng
Tutor: ZhangXingZhong
School: Yanshan University
Course: Mechanical Design and Theory
Keywords: Continuous casting Dynamic soft reduction Soft reduced amount Solidification heat-transfer Finite element method
CLC: TF777.1
Type: Master's thesis
Year: 2010
Downloads: 151
Quote: 1
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Abstract

Centerline segregation and center porosity in the process of continuous casting would have a great effect on the inner quality of continuous casting products, And therefore it is necessary to search the technique to control the segregation and porosity in the final continuous casting of carbon steels.At present, dynamic soft reduction is the comparative desirable technique to eliminate the problem of centerline segregation and center porosity.This thesis is a detailed study on dynamic soft reduction applied status of a certain steel mill’s thin-slab casting, which analyses the definite method of dynamic soft reduction’s the first principles, the development course and the process parameters.Evaluate the use effect of this confiscator’s dynamic soft reduction by comparing with confiscators without the equipment of dynamic soft reduction in the aspect of casting blank quality. He results of experiment indicate that it decreases centerline segregation and center porosity, meliorates the inner quality of continuous casting products and improves the capability of products that this steel mill adopted dynamic soft reduction.Previous study has shown that reduced amount should obey the following rules,It can reduce or eliminate the center segregation and porosity. Meanwhile internal crack should not occur during the soft reduction. Finally the reduction should not decrease the proper life of rollers and segments. After analyzing and calculating the stress, strain and displacement of strand during soft reduction, the optimal soft reduced value and its distribution at various casting speed are ascertained. The first step is to obtain soft reduced zone, thickness of liquid core, shape of mushy zone and distribution of temperature of slab by thermal numerical simulation. Then a coupled calculation of thermo ethnical model is carried out for the determination of reasonable soft reduced amount and assignation. In this study, The results are as follows:(1)The more rapid casting speed is, the longer liquid core is. The casting speed and the length of liquid core obey nearly lineal relationship. As the casting speed increases 0.1m/min, the length of liquid core increases about 1.45 m.(2)The more rapid casting speed is, the longer reduced zone is. The casting speed presents linear relationship with the length of soft reduced zone. When the casting speed increases 0.lm/min, the length of soft reduced zone increases about 0.15 m.(3)Casting speed has little effect on the thickness of liquid core at the beginning of soft reduction. It can be believed that the optimal soft reduced value is a constant on the assumption that casting conditions except casting speed are the same.(4)Optimal soft reduced amount decreases with the reduced thickness of liquid core. When the thickness of liquid core is larger, the act of soft reduction is easier, and the efficiency of soft reduction is higher.

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