Preparation process of composite casting blanks for high-toughness thick steel plate

Abstract

The invention discloses a preparation process of composite casting blanks for a high-toughness thick steel plate. The preparation process adopts continuous casting blanks with different furnace numbers, the same steel grades and different carbon contents to compound so as to meet the requirements for overall strength and core toughness, thus the composite continuous casting blanks for an extra-thick steel plate with high surface quality and excellent core impact toughness are obtained. The low carbon design of an inner layer greatly improves the metallurgical quality of the central portion andprovides strong support for improving the toughness of the center and the whole. The high carbon design of an outer layer provides a carbon source for the whole compositions to ensure the whole strength, the uniformity of the compositions is achieved through diffusion, finally the whole compositions with both toughness and strength are obtained, and the occurrence rate of surface cracks is reduced.

Description

technical field [0001] The invention belongs to the technical field of steel plate processing, and in particular relates to a preparation process of a composite cast slab for high-toughness thick steel plate. Background technique [0002] High-toughness Q345 thick steel plates need to be rolled and normalized by thick slabs to ensure performance. When the thickness is large, the composite casting slab can be used. In order to ensure the strength performance, the general C content is designed to be between 0.13-0.20%. However, when the slab is within the design range of the composition, there is a large segregation in the central part. When the carbon content is 0.10-0.15%, the central toughness guarantee ability is better, but this composition area is close to the carbon content range of the peritectic region, and the surface of the slab has high crack sensitivity; the composition is within 0.16-0.22%, the slab The surface crack sensitivity is low, but the central toughnes...

AI Technical Summary

Problems solved by technology

However, when the casting slab is within the design range of the composition, there is a large segregation in the central part

When the carbon content is 0.10-0.15%, the central toughness guarantee ability is better, but this composition area is close to the carbon content range of the peritectic region, and the surface of the slab has high crack sensitivity; the composition is within 0.16-0.22%, the slab Low susceptibility to surface cracks, but low guarantee of central toughness

[0003] The currently published technology for composite billet making of extra-thick steel plates is to use continuous casting billets of the same steel type, same furnace number, and same composition for compounding. However, the composition of the inner and outer layers of the rolled steel plate cannot take into account the crack sensitivity of the surface and the impact toughness of the core; another open similar technology is the technology of stainless steel composite steel plate, and the blank is made of stainless steel plate and carbon steel casting billet It is made by compounding. On the one hand, stainless steel is used to ensure the corrosion resistance, and on the other hand, carbon steel is used to ensure the strength requirements. It belongs to the composite of heterogeneous materials, and the cost is greatly reduced compared with pure stainless steel plates, but the process is relatively complicated and the cost is higher than that of ordinary carbon steel plates. steel or low alloy steel