Structure And Performance Controlled And Predicted Of Third Grade Rebar In 20MnSi

This research was supported by the Education Committee of Hebei province. The main purpose of this work was to enhance the classification of 20MnSi-rebar from second to third grade by means of cooling control after rolling. Compared with the production of micro-alloyed rebar in third grade, this method was better advanced in technology, more economic, lower in energy consumption and environment pollution.Presently, the research is yet limited to the experiential stage of testable rolling, measurement, re-testable rolling and re-measurement. The period of testable rolling is long, the consumption is expensive, and the eligibility rate is low because of unsteady production.As we know, the inner structure of hot rolling rebar must be controlled, if its properties are to be controlled. In this paper, the whole process of structure changing is simulated by computer on the basis that the kind of steel is not changed and the target is that the structure and property of third grade rebar are controlled through controlling the cooling parameters.The conclusions are as follow:To the different spec of 20MnSi rebar, the temperature field of water cooling is analyzed and simulated by computer, the temperature-distributing curve is obtained after rolling and heat treatment. The result is agreed with the test value.Aimed at the cooling nozzle setting, The heat transfer coefficient modal is developed for fitted the site cooling equipment. After it is used in the simulation and prediction of temperature field, the calculated result is agreed with the test value.Through the computer simulation of changed structure field on super-cooling austenite, the distribution of changed structure content on rebar section is obtained, the finial and the best changed structure content is gained.The predicted tissue and structure are basically agreed with the measurement result through metallurgical micro-observation.