Low-Temperature Recrystallization of Submicrocrystalline Structure of Armco Iron and 30G2R Steel

摘要

The low-temperature recrystallization of armco iron and steel 30G2R with submicrocrystalline (SMC) structure produced by severe plastic deformation has been studied. The low-temperature recrystallization in the heat-treated structural steel occurs simultaneously over the whole volume of material according to the kinetics of normal growth, which was earlier shown for iron with a purity of 99.97 pencent and a quenched steel. Carbide particles retained after deformation in the steel studied do not change the kinetics and activation energy for the low-temperature recrystallization of SMC structure in this structural steel. In armco iron, not all micro-crystallites are able to simultaneously grow upon heating to the recrystallization temperature because of pinning of some boundaries with impurities (mainly with carbon). The formation of thermoactivated recrystallization nuclei was found, which resulted in a nonmonotonic change in the hardness and average grain size upon isothermal holding at the start temperature of recrystallization of armco iron with the SMC structure.