Preparaton method of low carbon 520 MPa grade composite fortified ultra fine crystal grain band steel

Abstract

The invention relates to a preparation method of a 520MPa grade composite strengthened ultra-fine-grain strip steel, which uses C, Si, Mn, Nb, P, S and Fe as raw materials, undergoes smelting, and is continuously cast into billets and heated, and then controlled Rolling controlled cooling. The billet heating temperature is 1190-1210°C; rolling is controlled in the austenite recrystallization zone, non-recrystallization zone and deformation-induced phase transformation zone, the rough rolling start temperature is 1140-1160°C, and the rough rolling finish temperature is 1040- 1050°C, the thickness of the intermediate billet is 32-45mm, the starting temperature of the finishing rolling is 1000-980°C, the finishing rolling temperature is 790-820°C, water cooling is carried out between the finishing stands, and the cooling rate after rolling is 20-30°C / s, the coiling temperature is 430-470°C, the yield strength of the obtained ultra-fine-grain strip steel is 520-570MPa, and the tensile strength is 620-690Mpa.

Description

Technical field [0001] The invention relates to a preparation method of low-carbon high-strength steel, in particular to a preparation method of low-carbon 520MPa grade composite strengthened ultra-fine grain strip steel. Background technique [0002] At present, iron and steel materials are still the main body of structural materials. However, with the development of society and economy, the steel industry is under increasing pressure to save resources, save energy, and protect the environment. Therefore, it has become a hot spot in the field of iron and steel research to use special processing techniques for traditional iron and steel materials to greatly improve their performance, prolong their service life, and effectively improve resource utilization and recovery. [0003] In 1997 and 1998, Japan and South Korea successively launched a research program on structural materials for the 21st century. The goal is to double the practical strength and structural life of exis...

AI Technical Summary

Problems solved by technology

Whether it is from the mechanical properties of the above-mentioned steel or the metallographic structure of the steel, it can be explained that the tensile strength of the super-SS400 steel obtained in the experiment is still low, and the yield strength is relatively large, which makes the formability in the application poor; The gap in the test mechanical performance data is large, indicating that this technical scheme can improve the process conditions of the existing carbon-manganese steel with a yield strength of 200MPa to 400MPa structural steel, which still needs further research and should be solved.

Images