| Steels’s organization and performance are influenced by their chemicalcompositions, rolling process and cooling methods. Cooling method after rollingprocess affects the phase transformation of metals, organization, and precipitation ofmicro-alloy elements,thus affects the performance of steels finally. Through the ultrafast cooling after rolling process, we can change the organization of the steel, refinegrains, improve the strength of steel and improve the performance of the steel further.A hot rolling plant has advanced process equipment. In order to improve thestrength of steels under constant composition and reduce production cost, they plan toreplace the roll cooling process by ultra fast cooling project. In this paper, author hasresearched the Q235B and Q345B steel produced by this hot rolling plant, drawn CCTcurves though thermal simulation experiment, provided the cooling system of ultra fastcooling; Two kinds of C-Mn steels, i.e. Q235B and Q345B, were investigated by ultrafast cooling technology in laboratory to find out the influence of ultra fast cooling onmicrostructure etc. Organization uniformity, inclusion, precipitate and properties oftested Q235B and Q345B steels were observed and tensile test as well as fracturemorphology observation were conducted to analyze how to roll Q345B steel by ultrafast cooling with Q235B composition. The results show that it’s possible to produceQ345B steel with Q235B material by ultra fast cooling process.The research of this topic not only has good theoretical significance andinnovativeness, it also close related with the renovation project of hot rolling mill andhas very good practical significance. |
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