Rolling production method for improving toughness of steel on line

Abstract

The invention discloses a rolling production method for improving the toughness of steel on line. A continuous casting billet is taken as a raw material. The rolling production method sequentially comprises the following working procedures of billet heating, descaling, rough rolling, continuous rolling, through-water cooling, finish rolling through a bar reducing and sizing mill and cooling through a cooling bed, and finally a finished product bar is obtained; wherein a rolled material subjected to continuous rolling is subjected to through-water cooling to 650-850 DEG C, after through-water cooling, the rolled material is subjected to self-tempering to obtain the finish rolling temperature of the bar reducing and sizing mill, the finish rolling temperature is 500-700 DEG C, and the temperature of the bar on the cooling bed is 480-650 DEG C. According to the method, KOCKS rolling is adopted for finish rolling of the bar reducing and sizing mill, proeutectoid ferrite in a non-required form is eliminated by controlling the finish rolling temperature and the cooling temperature after rolling, the toughness of the steel is improved, and the grain size, hardness and mechanical performance of the non-quenched and tempered steel can be controlled by adopting the rapid cooling technology after rolling.

Description

technical field [0001] The invention belongs to the field of special steel production and processing in the metallurgical industry, and relates to a rolling process, in particular to a method for improving the toughness of steel. Background technique [0002] In recent years, with the rapid development of my country's economy, my country's automobile manufacturing industry and machinery manufacturing industry have developed rapidly. In this context, the amount and variety of non-quenched and tempered steel are also increasing. also gradually increased. Non-quenched and tempered steel has better mechanical properties, more uniform hardness from the center to the edge, longer fatigue life, and greatly reduces manufacturing costs. It is widely used in the production of high-strength rods and shafts. However, due to the high final rolling temperature (generally 800-850°C) of non-quenched and tempered steel, the austenite grain size tends to be coarse, and it is easy to form pro-...

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Problems solved by technology

[0005] According to the literature search, in the prior art, for improving the toughness of steel, most iron and steel enterprises only improve the impact toughness of steel through the heat treatment process of quenched and tempered steel. At present, no research on hot-rolled steel has been found to improve the toughness of steel. There is also no relevant technical report on improving the toughness of steel by studying the rapid cooling of steel after rolling.

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