Parameters Optimization Of Hot-rolled Large Size H-beam In The Controlled Cooling Process

Controlled cooling was applied to make the mechanical properties of Q235 steel reach the performance of the alloy steel, and to reduce the residual stress occurring in the process of controlled cooling. The influence of different cooling rate on the phase transition temperature was analyzed by GLEEBLE-3500 thermal simulator experiment. The research object is the large H section steel of Q235. The growing up and recrystallization of austenitic grain was contolled in the process of controlled cooling, so was the cooling rate. The desired phase change organization was achieved by refining the grain size and precipitation strengthening. Comprehensive mechanical properties of H steel were improved.The fully coupled three-dimensional finite element model of heat transfer and deformation was established, according to the basic theory of heat transfer and finite element analysis. Simulation analysis research of hot-rolled h-beam rolling in controlled cooling process was conducted. Because of the cooling degree of different parts in the process of H-beam is not the same, different convective heat transfer coefficients were applied in water cooling phase. The real water cooling process was simulated, and three different kinds of controlled cooling scheme were put forward. To obtain properly controlled cooling time, numerical simulation of temperature field was conduct, and smal er difference of section temperature was achieved.The change of the stress/strain field of H-beam in three kinds of controlled cooling scheme was simulated by ANSYS finite element analysis software. The influence of temperature change on the stress in temperature field and the biggest deformation degree in the process of cooling were analyzed.The cooling parameters of H-beam were optimized by combining finite element analysis and genetic algorithm. The section of H-beam is homogeneity, and comprehensive mechanical properties were improved.