| 摘要 |
A steel bar which, in a section perpendicular to its longitudinal axis, possesses a microstructure consisting of at least two concentric zones, where the peripheral zone comprises tempered martensite and untempered bainite, and the central zone, or core, consists of untempered bainite and a mixt. of untempered ferrite and pearlite. The peripheral zone may itself be surrounded by a layer of pure, tempered martensite and the central zone may consist mainly of untempered ferrite and pearlite. The term bar applies to any type of steel bar, whether the steel is killed, semi-killed, or rimming steel. Wire rod or bar is used e.g. for reinforcing concrete it possesses good weldability. The bars have high mechanical props. in relation to their low content of alloying elements and are therefore low in cost. |
