Press molding and its high frequency quenching method and its high frequency quenching system

Abstract

A press formed article such as a center pillar or the like for a vehicle having a demanded strength distribution achieved by hardening through induction hardening or the like, and a method and an apparatus for performing induction hardening on the press formed article. The center pillar () being a press formed article has an intermediate top portion () which extends in a longitudinal direction of the center pillar (), and two blade portions () which are both bent in the same direction from both sides of the intermediate top portion (), in which hardening regions (Q) are provided on both sides of the intermediate top portion (), extending over the intermediate top portion () and the blade portions (). These hardening regions (Q) hardened by the induction hardening apparatus are regions in a form which widens toward the end and continuously expand from the upper portion to the lower portion of the center pillar (). Therefore, the ratio between the hardening regions and non-hardening regions changes in the longitudinal direction of the center pillar (), resulting in a demanded strength distribution.