A method for producing extra-thick steel plates by two-dimensional deformation of continuous casting slabs

Abstract

The invention provides a method of producing a super-thick steel plate through two-dimensional deformation of a continuous casting billet. In the method, the continuous casting billet being 300 mm in thickness is employed for producing the super-thick steel plate being less than 245 mm in thickness, wherein the total reduction rate in the thickness direction of both forging and rolling is not less than 18.3%. The continuous casting billet is forged through a technology including both the thickness direction and the width direction, wherein the technology includes following steps: (1) forging the continuous casting billet in the width direction; (2) when one-time forging and pressing amount is 90-200 mm, forging the continuous casting billet in the thickness direction with the one-time forging and pressing amount being not less than 35 mm; (3) slowly cooling the forged continuous casting billet; and (4) rolling the forged continuous casting billet at the temperature of 1100-1250 DEG C, wherein the beginning temperature is more than 1050 DEG C, the slowly cooling temperature after rolling is not less than 400 DEG C and the slowly cooling time is not less than 24 h. The method achieves production of the super-thick steel plate being less than 245 mm in thickness at a low compression ratio with the continuous casting billet, so that the range of specification of steel plate production with the continuous casting billet is enlarged. Under a fixed edge cutting amount, the lower limit of width specification of a steel plate finish product can be reduced by 380 mm. The method increases yield of the super-thick steel plate, reduces production cost and can reach more than 90% in defect detection qualified rate.

Description

Technical field [0001] The invention belongs to the field of metal material pressure processing, and particularly relates to a method for producing an extra-thick steel plate of 245 mm or less by two-dimensional deformation of a 300 mm continuous casting billet. Background technique [0002] In recent years, with the rapid development of my country's heavy industry, transportation, and national defense modernization, the energy, transportation, construction, shipbuilding, machinery manufacturing and other industries have increasingly demanded extra-thick steel plates. On the basis of the existing thickness specifications, the extra-thick steel plate puts forward higher requirements on the internal quality of the steel plate, which is reflected in the increasingly stringent requirements for the performance and flaw detection level of the steel plate. At the same time, the increase in the production enterprises and capabilities of extra-thick steel plates has made competition in th...

AI Technical Summary

Problems solved by technology

At present, three production processes are widely used in the production of extra-thick plates: one is the direct rolling of continuous casting slabs. This method is limited by the compression ratio and the thickness of continuous casting slabs. The general product thickness is less than 200mm, and the thickness ranges from 100 to 200mm. Performance pass rate and flaw detection rate are not high

The second is to use steel ingots for direct rolling. Generally, the thickness of the steel plate produced is more than 150mm. This method can increase the thickness of the finished steel plate and increase the compression ratio, but the production cost is significantly higher than that of the continuous casting slab.

The third method uses steel ingots to be rolled after processing (including forging, secondary blanking, electroslag remelting, etc.), and this method will also significantly increase production costs

However, the above production methods for extra-thick steel plates all have a common defect, that is, the production cost is relatively high, which is unbearable for thick plate manufacturers.

[0004] To sum up, the current production method of extra-thick steel plate (thickness above 100mm) cannot achieve the goal of low cost and high pass rate, and the width of the produced steel plate is limited by the billet specification. Edge trimming, low finished product rate, and inflexible production methods