Abstract
Tensile properties of high Cr-Fe alloys with small amounts of C and N were investigated after the heat-treatments in the temperature range from 800 to 1200°C followed by air cooling (A.C.) or water quenching (W.Q.). The yield strength, σy, and the tensile strength, σB, showed considerable scattering with heat treatments even when the same condition of annealing was used.
However, Δσy defined as the difference between σy of A.G. specimens and σy of W.Q. ones where those specimens were heated at a time in a furnace, was uniquely determined by the annealing temperature. Δσy was primarily explained by the difference between the Ky·d-1/2 term of Hall-Petch eq. for A.C. specimens and that for W.Q. ones, but some part of Δσy explained by the difference in the friction term, was present. Small difference in contents of C and N significantly affected the responces of ductility and of grain size in these alloys to the change in annealing temperature.
