Transient Nucleate Boiling and Its Use for Thermomechanical Technologies Development

Abstract

In the paper high temperature and low temperature intensive thermomechanical treatment is discussed. It is based on recently discovered new three physical principles that belong to the transient nucleate boiling process taking place in cold fluids. Such processes are considered in conditions when any film boiling during quenching in cold fluids is completely absent. That makes nucleate boiling very intensive, i.e. . The discoveries are used for direct quenching articles after forgings. The first is intensive high-temperature thermo-mechanical treatment (HTTMT). It is used for low and middle-carbon alloy steels. Forged steel parts are intensively quenched with a cooling interruption at the proper time to form surface compression residual stresses and fine bainitic microstructure at the core that increases radically surface life of forgings. The second method includes high-temperature and low temperature intensive thermo - mechanical treatment (LTTMT) of high carbon alloy steels with delaying martensitic transformation to make low-temperature thermo - mechanical treatment (LTTMT) possible. Then, after high temperature and low-temperature thermomechanical treatment, the steel goes to immediate tempering to create highly strengthened fine bainitic microstructure throughout the section of the steel part. A modified method of cooling time calculation, suitable for any size and form of steel part, is widely discussed in this paper.