Deformation Behavior of Fe-3 percent Si Steel at High Temperatures

摘要

Deformation behavior of a Fe-3 percent Si steelwith ultrafine MnS inhibitors was studied in the temperaturerange 500-1000 deg C. The steel exhibits a threshold behavior.Analysis in terms of threshold stress shown that there were twocharacteristic modes of deformation behavior in the power-lawcreep regime. At temperatures 500-700 deg C the value of thestress exponent, n, is equal to 6, and the true activation energyfor plastic deformation, Q, linearly increases from 170 kJ/mol tovalue closed to 239 kJ/mol with temperature rise. Attemperatures above 700 deg C the stress exponent is about 4,and the true activation energy for plastic deformation is about240 kJ/mol. Two temperature dependencies of normalizedthreshold stress differed by a value of the energy term, Q_o,were found in these two temperature intervals. The value Q_ois about 55 and 39 kJ/mol in an intermediate and hightemperature range, respectively. Operating deformationmechanisms in two temperature regions are discussed.