Abstract: A heat treatment operation can be executed, suppressing a wave-shaped deformation at a non heat-treatment region of an article to be heat treated. To an elongated-shaped article to be heat treated to which a raised portion extending in the longitudinal direction is formed, a hardening region, as a heat-treated region defined to extend in a longitudinal direction at a part of the raised portion, and a non-hardening region, as a non-heat-treated region defined to extend in the longitudinal direction at flange portion, and other parts of the raised portion are arranged side by side in a width direction orthogonal to the longitudinal direction. The flange portion is clamped by a first and a second clamp, arranged in the longitudinal direction, and one first clamp is a tight clamp for holding fixedly the flange portion and a plurality of second clamps are loose clamps for clamping loosely the flange portion, allowing the article to be heat treated to be convex on the side of the heated hardening region.

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 (10) being a press formed article has an intermediate top portion (11) which extends in a longitudinal direction of the center pillar (10), and two blade portions (12) which are both bent in the same direction from both sides of the intermediate top portion (11), in which hardening regions (Q) are provided on both sides of the intermediate top portion (11), extending over the intermediate top portion (11) and the blade portions (12). 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 (10).

Abstract: A heat treatment operation can be executed, suppressing a wave-shaped deformation at a non heat-treatment region of an article to be heat treated. To an elongated-shaped article to be heat treated (10) to which a raised portion (11) extending in the longitudinal direction is formed, a hardening region as being a heat-treated region defined to be extended in a longitudinal direction at a part of the raised portion (11) and a non-hardening region as being non heat-treated region defined to be extended in the longitudinal direction at flange portion (13) and other parts of the raised portion (11) are arranged side by side in a width direction orthogonal to the longitudinal direction.

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 (10) being a press formed article has an intermediate top portion (11) which extends in a longitudinal direction of the center pillar (10), and two blade portions (12) which are both bent toward the same side from both sides of the intermediate top portion (11), in which hardening regions (Q) are provided on both sides of the intermediate top portion (11), extending over the intermediate top portion (11) and the blade portions (12). These hardening regions (Q) hardened by the induction hardening apparatus are regions in the form, widening toward the end, which continuously expands from the upper portion to the lower portion of the center pillar (10).