Abstract: This paper has originally established two bunch of elastoplastic expressions for the open-ended thick-walled cylinder of the ideal plastic material using Mises yield Condition of the elliptic parametric equation for σz=0 and the twelve polygonal yield Condition, and further studied the applicable range of these expressions, as well as presumed on the famous Lode's experiment to prove these expressions more comformable to reality, in particular these expressions from the twelve polygonal yield condition are more convenient for application[1].

Key words: Austenite reverted transformation (ART), Mechanical properties, Microstructure, Product of strength and ductility (Rm×A), Automotive steel