THE MICROSTRUCTURE OF 20MnSiNb STEEL AND ITS EFFECT ON YEILD BEHAVIOR

Metallographic observation and transmission electron microscopy analysis were applied in investigating the effect of microstructure of 20MnSiNb steel on its yield behavior. And the effect of Nb in the steel was investigated. The results show that the existing of bainite in the steel leads to the disappearance of the yield stage. And the precipitation of Nb has the effect of precipitation hardening and grain refinement.