The strengthening mechanism of effect of vanadium on structure and properties of hot rolled rebar (0. 21 〜 0. 23C

1. 33 ~ 1. 50Mn) has been studied by alloying using V-N and ferrovanadium alloy. Results showed that the mechanical properties of 0. 06V rebar were up to the requirement of HRB400 grade and HRB500 grade rebar with alloying respectively by using ferrovanadium alloy and V-N alloy； with same vanadium content

the ratio of precipitates in rebar aloyed by V-N alloy was by 83% ~ 110% more than that alloyed by ferrovanadium. The precipitate strengthen effect in rebar alloyed by V-N was stronger than that in rebar alloyed by ferrovanadium alloy

and main precipitate was V( CN) with less VC. The structure of rebar alloyed by V-N alloy was finer and the steel rebar had plenty of free nitrogen with obviously age- ing phenomena.