Production system and method of low-yield-ratio hot-rolled high-strength anti-seismic reinforcing steel bars

Abstract

The invention provides a production system and method of low-yield-ratio hot-rolled high-strength anti-seismic reinforcing steel bars. The method includes the steps that a heating furnace, a rough rolling unit, a pair of truncate scissors, an intermediate rolling unit, a post-intermediate-rolling water cooling device, another pair of truncate scissors, a finish rolling unit front section, a finish rolling water cooling device, a finish rolling unit rear section, a post-finish-rolling water cooling device, multi-lengths flying shears and a cooling bed are sequentially arranged in the rolling direction; rolling of a re-crystallization area is achieved by precisely controlling rolling temperature, austenite grains are refined, the rolling temperature of a critical austenitic area and ferrite re-crystallization area is precisely controlled through water cooling and a recovery section, deformation induced ferrite phase change and two-phase district ferrite phase change are achieved, perlitic transformation and little bainite transformation are achieved through after-rolling water cooling, strength, plasticity and toughness of the ribbed bars can be remarkably improved, and the ribbed bars have a low yield ratio and good plasticity, toughness, anti-seismic performance and welding performance. Meanwhile, the rolling fault rate is reduced through high-temperature rolling of a rough rolling area and an intermediate rolling area and production efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy hot rolling, and in particular relates to a production system and method for hot-rolling high-strength anti-seismic steel bars with low yield ratio. Background technique [0002] With the rapid development of the construction industry, large-scale infrastructure and urbanization construction requires a large number of construction steel bars, especially ribbed steel bars, so the application of ribbed steel bars is increasing. For large high-rise buildings and long-span public buildings, give priority to the use of 500MPa grade steel bars, and increase the production and application ratio of 500MPa grade steel bars year by year; carry out research and development on the application technology of 600MPa grade steel bars. For earthquake-prone areas, high-strength earthquake-resistant steel bars with high yield ratio and high uniform elongation should be used emphatically. [0003] ...

AI Technical Summary

Problems solved by technology

Both the patent application CN101185938A and the Australian patent 9419292.9 can obtain fine-grained steel through strain-induced phase transformation, but the yield ratio of the product produced by the patent 9419292.9 is too high to be practical, and it is mostly aimed at plates

CN101185938A The problem is that the billet heating temperature is low, and the rough rolling temperature is low, which greatly increases the equipment load and reduces the service life of equipment such as rolling mills and shears

The structure of the product obtained by this process is generally tempered martensite + tempered sorbite + ferrite + pearlite. Although the mechanical properties of the product are high, the tendency of stress corrosion cracking is relatively large, the strength ratio is low, and the shock resistance Poor performance, poor welding performance, relatively poor construction adaptability

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