A q420c-grade hot-rolled angle steel and its preparation method based on machine learning

Abstract

The invention discloses a Q420C grade hot-rolled angle steel and a preparation method based on machine learning. The alloy composition is adjusted and the rolling process is optimized through a GRA-ELM performance-component optimization model, so that the hot-rolled angle steel has ferrite at room temperature. and pearlite tissue structure. The V microalloying process is used to precipitate fine and dispersed V (C, N) refined structure in the steel, and the final large-sized angle steel has good strength and impact resistance, and its yield strength is ≥ 420MPa and tensile strength ≥ 570MPa , elongation ≥ 22%, and the average longitudinal V-notch impact energy at 0 °C is more than 123J. The invention reasonably reduces the amount of vanadium and the cost per ton of steel through the machine learning algorithm. Through reasonable alloy composition design, heating system optimization and rolling process research, large-scale hot-rolled equal-edge angle steel that meets various performance requirements is developed. , the cost is low and the preparation process is simple.

Description

technical field [0001] The invention belongs to the technical field of angle steel manufacturing, and in particular relates to a Q420C grade hot-rolled angle steel and a machine learning-based preparation method thereof. Background technique [0002] Angle steel is widely used in various building structures and engineering structures, such as beams, bridges, transmission towers, lifting and transportation machinery, ships, etc. But for many years, most of the angle steels produced in my country are small-sized angle steels of Q235 and Q345. The strength grade of the steel is low, and there are few optional types, especially the lack of large-sized angle steels. At the same time, with the increasing demand for global energy and resources, it has become an important development trend of the iron and steel industry to realize the alloy reduction and cost reduction of iron and steel materials. Therefore, the development of large-scale angle steel with low cost but excellent com...

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Problems solved by technology

[0003] Chinese patent application CN201710705303.7 discloses a Q345 grade hot-rolled weather-resistant large-scale angle steel for iron towers and its preparation method. The yield strength level of the weather-resistant angle steel is only 345MPa, including 5 specifications: ∠180*180*12, ∠180*180*16, ∠200*200*16, ∠200*200*20 and ∠200*200*24 have low yield strength and angle steel specifications, which cannot meet the growing needs

[0004] Chinese patent application CN201610138492.4 discloses a low-temperature-resistant hot-rolled angle steel and its preparation method. V microalloying elements are added to the angle steel alloy system to improve the structure and performance of the material. The content is V: 0.04-0.06%. The yield strength level of weather-resistant angle steel is only 345MPa, its wall thickness is about 18mm, and its edge width is 180mm. Similarly, its yield strength and angle steel specifications are low, which cannot meet the growing needs

However, when processing data in the early stage, theoretical screening and correlation analysis were not carried out, and only standardized processing was performed. Secondly, SVM is relatively more suitable for small sample data, and the effect of using large sample data is relatively poor.

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