B-pillar with tailored properties

Abstract

A dimensionally stable B-pillar for an automotive vehicle including tailored material properties is provided. The B-pillar includes at least one localized soft zone surrounded by a hard zone. The hard zone typically has a yield strength of 950 MPa to 1700 MPa; a tensile strength of 1200 MPa to 2100 MPa; and an elongation of greater than 4%. The soft zones each have a yield strength of 340 MPa to 780 MPa; a tensile strength of 400 MPa to 980 MPa; and an elongation of greater than 10%. The microstructure of the hard zone is martensite, and the microstructure of the soft zones is tempered martensite, ferrite pearlite bainite, ferrite pearlite austenite, ferrite pearlite, ferrite bainite, cementite austenite, and/or cementite bainite. The soft zones of the B-pillar are manufactured with a slow cooling step, which can be conducted in air outside of the dies.

Dependencies are inferred from the claim text.