EFFECT OF GRAIN REFINMENT ON MECHANICAL PROPERTIES OF MICROALLOYED STEELS

Abstract

Notation d-grain size; μm SD-standard deviation YS-yield strength; MPa TS-tensile strength; MPa YS/TS-yield ratio T-temperature; o C T R-reheating temperature; o C T D-deformation temperature; o C A R3-austenite-ferrite transformation start temperature; o C ITT-impact transition temperature; o C CR-cooling rate; K/s, o C/s σ' 0-the Peierls-Nabarro stress; MPa σ ss-solid solution strengthening; MPa σ p-precipitation strengthening; MPa σ g-grain boundary strengthening; MPa σ sg-subgrain strengthening; MPa σ d-dislocation strengthening; MPa σ t-texture strengthening; MPa UFF-ultra fine ferrite UFG-ultra fine-grained x-distance from the origin on the cross section of the specimen after rolling; mm HVs-Vickers hardness near the surface layer of rolled specimen HVo-Vickers hardness in the middle layer of rolled specimen 88