Method for producing low-carbon steel or low-alloy steel plate having submicron crystal grain

Abstract

The invention discloses a method for producing low-carbon steel or low-alloy steel plate having submicron crystal grain which comprises the steps of, subjecting the raw steel billets to austenizing treatment above Ac3 temperature, hot-rolling at the temperature of over Ar3, fast cooling after rolling, performing warm-rolling or cold rolling at the temperature range from 600 deg. C. to room temperature, direct cooling or roll bending after rolling.

Description

technical field [0001] The invention relates to a method for manufacturing low-carbon steel or low-alloy steel plate, in particular to low-carbon steel or low-alloy steel with submicron grains (that is, grain diameters within the range of 1.0 μm to 0.1 μm). Background technique [0002] Low carbon steel and low alloy steel are the most widely used steel grades in the application field of steel materials. In order to improve the strength of steel, it is common practice to add alloying elements such as Mn and Si or perform controlled rolling, controlled cooling, heat treatment, etc., or add microalloying elements such as Nb and V. However, for steel, it is not only required to have high strength, high toughness and other good comprehensive properties, but also to consider resource conservation (less alloy elements) and sustainable use (easy to recycle). Grain refinement is one of the few effective means. However, most of the existing manufacturing methods for industrialized ...

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Problems solved by technology

However, when the matrix phase grains are so fine (average size below 0.2 μm), the Achilles’ heel—plastic instability, which has only a small work hardening effect after yielding—results in low uniform tensile elongation. rate and high yield strength ratio (the ratio of yield strength to tensile strength is often higher than 0.9) [Jingtianfu et al. Journal of Materials Science Letters, 16(1997): 485, Tsuji et al. Scr.Mater., 46(2002): 305 ]

Therefore, iron and steel materials with too fine matrix phase grains are not only difficult or expensive to manufacture, but also have serious defects and application limitations.

To sum up, among the existing methods for preparing various submicron grain steels, some do not have large-scale industrial production; some have insurmountable difficulties in the implementation of large-scale industrial production, such as the manufacturing process is too complicated, the equipment The process requirements are too high, and there are certain requirements for the thickness of the original blank, so it stays in the non-production stage

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