Metallurgical Aspects of Hot Rolling of Heavy Plates from Continuously-cast Slabs

Abstract

Significance of hot rolling to produce heavy plates from continuously-cast slabs with low carbon and low alloying elements is analyzed from metallurgical point of view, special attention being paid to the influence of solidification structure on the mechanical properties of plates. The major conclusions are as follows ; a) Brittle fracture characteristics (vTrs) is not affected by microsegregation existing in either columnar dendrites or equiaxed grains. b) The appropriate reduction ratio in terms of mechanical properties in the thru-thickness direction is approximately 1.5-3, depending on the rolling shape factor which is a function of slab thickness, radius of rolls, and reduction per pass. c) Some elements such as S, P, Mn, N, and C are detected by an Auger electron microscope on the surface of center porosities which can be annihilated by hot rolling. Based upon the results it is suggested that combination of fine initial austenite grain, large rolling shape factor, and low total reduction ratio is a sufficient condition to procure sound mechanical properties of heavy plates manufactured from continuously-cast slabs.