Rebar is a common name for hot-rolled ribbed steel bars. The grade
of ordinary hot-rolled steel bar is composed of HRB and the minimum
yield point of the grade. H, R, and B are the first letters of the
three words of hot-rolled ribbed steel. Hot-rolled ribbed steel
bars are divided into three grades: Grade II HRB335 (the old grade
is 20MnSi), Grade III HRB400 (the old grades are 20MnSiV, 20MnSiNb,
20Mnti), and Grade IV HRB500.
