Study Of Armour-Piercing Mechanism And Adiabatic Shear Banding Characteristic

45steel targets, 30CrMnMo steel targets and 25SiMnMo steel targets were penetrated respectively to study failure forms and microstructures near penetrated holes of targets by launching small diameter 93W and 35CrMnSi projectiles with navy 37 gun and φ14.5mm normal gun. Characteristics and causes of formation of adiabatic shear bands(ASBs) were investigated. Meanwhile, characteristic of failure on the heads of residual projectiles and influencing factors were also studied.There were no ASBs near penetrated holes for 45 steel targets. It is shown that ASBs did not occur in the initial stages of launching and process of plugging. A small quantity of ASBs distributing sparsely occurred in the stable penetrating because of enough strain for 30CrMnMo steel targets. Cracks propagated along ASBs because of micro-cracks and micro-pores resulting from non-homogenous deformation in ASBs. The performance of targets was deteriorated. The critical shearing strain forming the ASBs is about 0.47 and the critical temperature is about 391°C. There was a great quantity of ASBs after penetrating 25SiMnMo steel targets. The ASBs distributing reticularly, which resulted in falling of fragments from the surface of penetrated holes, were very wide while plugging destroying just began. All of ASBs above propogated along an angle of about 45° with penetrating direction or its right-about. Their direction was approximately consistent with direction of slip lines in static.There was a great quantity of ASBs and micro-cracks on the 35CrMnSi residua projectiles after penetrating 45 steel targets. The heads of 93W residual projectiles without ASBs were just like "mushroom head" after penetrating 45 steel targets and they were sharp after penetrating 30CrMnMo steel targets.The reason was studied by EET (the Empirical Electron Theory of Solids and Molecules)and theory of dislocation.The dynamic destroyed process of 93W projectiles penetrating 30CrMnMo steel targets was numerical simulated by MCA method.