Microstructure and Mechanical Properties of V-Alloyed Rebars Subjected to Tempcore Process

Two B400B-R and B500B grade rebars were industrially produced through a Tempcore process. The standard chemical composition of was additionally alloyed with 0.067 wt.% V to enhance its mechanical properties. A set optimized processing parameters applied manufacture two different diameters D20 (Ø 20 mm) D32 32 mm). microstructure -mechanical properties relationships evaluated using optical scanning electron microscopes, hardness, tensile testing. In addition, thermal model developed define the cycle evolution during cooling in quenching & tempering box (QTB) simulate kinetics V(C,N) precipitation. observations showed typical graded consisting ferrite-pearlite core outer tempered martensite ring for both grades diameters. (compared D20) resulted softening (from 160 135 HV10) surface 220 200 as well decreasing yield strength 455 413 MPa) 580 559 MPa). On contrary, an increase hardness 165 175 240 270 HV10), addition 510 537 at almost same level 624–626 MPa are observed compared D20. modeling simulation calculations suggest that manufacturing involves longer time QTB which allow deeper along relatively higher temperature renders faster larger volume fraction precipitates. current study demonstrates full potential V-alloying can be exploited when sufficient equalization is achieved, valid rebars.