Influence of Various Manufacturing Techniques on Seismic Performance of High Strength Rebars

Comprehensive seisimic performance of grade 400 MPa rebars manufactured by V-N microalloying,QST and fine-grained process routines was experimentally evaluated according to increasingly accepted earthquake resistant evaluation index based on high strain low cycle fatigue behavior. Vanadium microalloyed rebar shows clear advantage over QST and fine-grained processed rebar in terms of high strain low cycle fatigue life and cyclic toughness,weldability,strain aging sensibility and FATT as well. TEM photos reveal formation of dislocation cells with thicker wall and high density dislocation during cyclic loading which results in deformation energy dissipation due to the existence of fine dispersed V(C,N) particles,consequently facilitated uniform plastic deformation and leads to highest cyclic toughness value of V microalloying rebar.