Title: Effect of uneven solidification on the quality of continuous casting slab

Authors: Mujun Long; Zhihua Dong; Dengfu Chen; Qi Liao; Youguang Ma

Addresses: College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China ' College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China ' College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China ' College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China ' College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China

Abstract: Solidification during slab continuous casting is of importance to the quality of steel products. Non-uniform cooling often occurs during slab continuous casting, leading to uneven solidification rate at different locations, especially that along the slab width direction. Considering the realistic cooling intensity along all directions, the effect of uneven solidification on steel quality was discussed. Results indicated that, uneven solidification caused by non-uniform cooling would induce defects like shrinkage cavities, segregation and cracks. Due to the uneven solidification, long-narrow solidification ends would form. At the long-narrow solidification ends, high solid phase fraction inhibited the movement of liquid steel and the supplement of solidification shrinkage, leading to serious partial segregation and shrinkage cavities. The irregular solidification end went against the application of dynamic soft reduction technology as well. Furthermore, uneven solidification would lead to high temperature gradient and high thermal stress in the solidified shell, resulting in cracks in the slabs. Defects in the slab, especially the centre macro-segregation and centre shrinkage cavities, were reduced by optimising the spray nozzle arrangement of the continuous caster.

Keywords: uneven solidification; continuous casting; shrinkage cavities; segregation; slab cracks; product quality; steel products; non-uniform cooling; temperature gradient; thermal stress; spray nozzle optimisation.

DOI: 10.1504/IJMPT.2013.058956

International Journal of Materials and Product Technology, 2013 Vol.47 No.1/2/3/4, pp.216 - 232

Received: 09 Jan 2013
Accepted: 20 Aug 2013
Published online: 28 Jun 2014 *

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