Causes Analysis on Unqualified Transverse Impact Absorption Energy of B50A789 Steel Large-size Bar

There was a problem of unqualified transverse impact absorption energy in the multi-batch B50A789 steel bars heads in the process of incoming inspection. The causes of unqualified transverse impact absorption energy of bar were analyzed by means of impact test, fracture analysis, metallographic examination, hardness test, chemical composition analysis. The results show that there were lamellar structure and longitudinal banded structure on the fracture surface of large-scale bar impact specimen, and the lamellar structure and longitudinal banded structure of bar head were more significant than that of bar tail, which led to the disqualification of transverse impact absorption energy of bar head.