High-strength steel rolling method

Abstract

The invention belongs to the field of steel and iron smelting, and particularly relates to a high-strength steel rolling method. The rolling process comprises rough milling process and finish rolling process, and comprises the following steps that (1) the press-down amount of two passes of rough rolling is 35-40mm, and the press-down rate of the last pass of rough rolling is controlled within 25%-28%; (2) the thickness of an intermediate billet between rough milling and finish rolling is adjusted to 54-57mm; (3) in the finish rolling process, the finish rolling temperature is controlled to 960-1050 DEG C, more deformation of the finish rolling area occurs below the Tnr temperature, and an ideal F+B tissue is obtained. The rolling method has the advantages that the pass press-down amounts of a rough rolling machine are reasonably distributed, the thickness of the intermediate billet is controlled, the finish rolling temperature is strictly controlled, and the mechanical property of high-strength steel products is guaranteed; the impact toughness of the high-strength steel products is greatly improved, the difficult problem of property of the high-strength steel products is solved, and the market occupation rate is increased.

Description

technical field [0001] The invention belongs to the field of iron and steel smelting, in particular to a rolling method of high-strength steel. Background technique [0002] Thick-gauge high-strength steel products produced by the steel industry frequently have the problem of inconsistent impact energy. The technical conditions require that the impact energy at -20°C is greater than 47J. In actual inspections, there are often substandard situations. The high brittle transition temperature of steel is caused by -20°C. The main reasons for low-temperature impact failure are: first, the thickness of the steel plate is thicker, the deformation of the finish rolling is small, the rolling control is difficult, and the grain refinement and uniformity are poor; the second is that the main strengthening mechanism of this steel is the precipitation strengthening of TiC, and the precipitation strengthening improves While increasing the strength, the ductile-brittle transition temperatu...

AI Technical Summary

Problems solved by technology

At the same time, from the perspective of the structure, the phenomenon of uneven grains is more obvious, mainly because the content of hardenability-enhancing elements is low, resulting in uneven cooling of the surface and the core.

Through the analysis of the metallographic structure, it is found that the unevenness of the grains of thick-gauge high-strength steel products with different impact energy is very obvious, especially the difference between the surface and the core structure is relatively large, the surface structure is fine, and the core structure is relatively thick. Structure is extremely detrimental to impact performance

[0003] This problem can be partially solved by adding alloying elements such as Mo and Cr to improve hardenability, but these two alloying elements are expensive. In view of the current poor steel market situation, adding these two elements It will bring about a substantial increase in cost, which is not conducive to the occupation of the market by high-strength steel products of enterprises