A Computer Based Simulation And Prediction Of Microstructure And Property Evolution Of The Controlled Cooling On Finishing Rolled 72A High-carbon Steel

The high-speed wire production in the high speed wire mill has good economic benefits. It is one of the hottest researches in our research fields to study the affect that the technology impacts on the microstructure and property in the hot rolling production.This paper mainly study on technological parameters impacting on property of the wire by controlled cooling in the stelmor conveyor. Firstly, the study signification, some research methods in and abroad and the prediction model of the property are introduced. Then, with the theory of under-cooled austenite and thermal simulation tests, CCT curve about 72A steel is drawn and the mathematical model of the curve is established. According to the P.C.Campbell's microstructure model and by using data from the SEM observations, interlamellar spacing model of the pearlite is established. Combined with the production data, a temperature drop of air-cooled model is built. In conjunction with the P.C.Campbell performance model and using production data, a regression model in which the error within±20MPa is checked by using production data is built. Combined the temperature drop caused by Air-cool and the temperature raise caused by latent heat during phase-changing, a workpiece actual temperature model is established. Finally, with the model built above and the layout of the equipments, one kind of application software is developed by using Excel VBA. In the software, the input data contains laying head temperature, level state of the fans, diameter of the wire steel, and entrance speed of the first moving conveyor, and the output data consists of the start and end temperature during phase-changing, the start and end time during phase-changing, interlamellar space, tensile strength as well as actual temperature-time curve of the workpiece. The software provides a platform for us to simulate and analyze the producing technology.By using the software application, we analyze the technology, and the result shows: entrance speed of the first moving conveyor impacting on the performance is not obvious; Decreasing diameter of the wire steel and increasing the cooling speed of the fans will increase the tensile strength; Decreasing the laying head temperature properly will increase the tensile strength and get smaller grain size.