engleski

Mathematical Modeling and Computer Simulation of Non-monotonic Quenching

Numerical modeling of phase transformations and hardness distribution in non-monotonic quenched steel specimen was developed based on the results of simple experimental test i.e. Jominy test. Differences between the cooling curves of investigated steel specimen and cooling curves of Jominy specimen were taken in the account in the model. The hardness in specimen points was estimated by the conversion of cooling time results to hardness by using both, the relation between cooling time and distance from the quenched end of Jominy specimen, and by using the Jominy hardenability curve. The cooling curves at the specimen points was predicted by numerical modeling of cooling by using the finite volume method. Besides characteristic cooling times, t8/5, it takes into account the history of cooling. Developed method was compared with methods of simulation of as- quenched hardness based on characteristic cooling times from 800 to 500 °C, t8/5 without taking in account history of cooling. Moreover developed model was compared by methods that are based on continuous cooling transformation (CCT) diagram and isothermal transformation (IT) diagram by using Scheil’s additivity rule. Developed numerical model for computer simulation of quenching was also experimentally verified. Limitations of proposed numerical model were found out as well. It has been shown that proposed numerical model can be successfully applied for purposes of simulation of interrupted quenching of carbon and low alloyed steel specimens.

numerical modelling ; steel ; quenching

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