Jfe Steel Corporation

Jfs Steel Corporation

Takayuki Futatsuka

Kentaro Sato

Tomohiro Sakaidani

Takeshi Fujita

Yoshiyasu Kawasaki

Yoshihiko Ono

Katsutoshi Takashima

Yuji Yamasaki

Yasunobu Nagataki

Shimpei Yoshioka

Shinsuke Komine

Hideaki Kobiki

Hiroshi Matsuda

Yoshimasa Funakawa

Tatsuya Nakagaito

Saiji Matsuoka

Yuki Toji

Hideyuki Kimura

Shusaku Takagi

Kazuhiko Higai

Yoshikiyo Tamai

Eiichi Shiraishi

Takaaki Hira

Katsumi Nakajima

Takashi Iwama

Yutaka Awajiya

Kayo Tokieda

Muneka Iwasawa

Youiti Komatu

Kazunari Yoshitomi

Yukiko Hata

A strain state of a bending outside surface of a test specimen is photographed by use of a camera without falling out of focus during a bending test. A bending test facility for a metal sheet material for an automobile body includes a supporting member that supports two supported portions of a flat test specimen formed of the metal sheet material for an automobile body, a punch for performing a bending test in which an area between the two supported portions of the test specimen is pressed from an opposite side to the supporting member so that the test specimen is bent to be deformed, and a camera for photographing, from the side of the supporting member, a bending outside surface of the test specimen during the bending test using the punch, with relative positions of the punch and the camera during the bending test being fixed.

Bending test facility and bending test method for metal sheet material for automobile body and bending performance evaluation method using the bending test facility

A collision performance evaluation test with few variations in test results with high accuracy in which a complicated phenomenon that actually occurs can be reproduced in a simple manner by considering the history of deformation in both the press forming and a collision. A collision performance evaluation test method for a metal sheet material for an automobile body is characterized in that a press working apparatus first forms a flat test specimen made of a metal sheet material to be tested into a V shape by primary bending, a bending test apparatus then deforms, by secondary bending, the test specimen formed by the primary bending in a direction intersecting with the primary bending direction, and a bending load and a bending stroke for the test specimen during the secondary bending deformation are recorded and evaluated.

Method and facility for collision performance evaluation test for metal sheet material for automobile body

A high strength steel sheet has a yield-point elongation of 1% or greater and a tensile strength of 980 MPa or greater. The high strength steel sheet has a specific chemical composition and microstructure. A ratio of retained austenite grains adjoining a retained austenite grain having a different crystal orientation to total retained austenite grains is 0.60 or greater, the ferrite has an average grain size of 5.0 μm or less, and the retained austenite has an average grain size of 2.0 μm or less. A value obtained by dividing a volume fraction Vγa by a volume fraction Vγb is 0.40 or greater, where the volume fraction Vγa is a volume fraction of retained austenite in a fractured portion of a tensile test specimen after a warm tensile test at 150° C., and the volume fraction Vγb is a volume fraction of retained austenite before the warm tensile test at 150° C.

High strength steel sheet, impact absorbing member, and method for manufacturing high strength steel sheet

A translation control and rotation control mechanism support jig for supporting a front end portion of an automobile body part includes a pair of support members, a rotary box having an L-shaped plate, a rotary shaft pin, a compression pin, and a connection plate. The translation control mechanism includes a support plate, a slide guide, an automobile body part securing disk, a translation plate, and a compression pin. Energy-absorbing members are disposed in an arcuate guide groove on a side surface of the rotary box and a linear guide groove arranged on the support plate or the translation plate. A collision punch collides at a test speed with the L-shaped plate of the rotary box. The compression pin deforms the energy-absorbing members to apply torque opposite to a rotation direction and a reaction force in an opposite direction to a translation direction.

Collision performance evaluation test method and apparatus for automobile body part

A collision resistance performance of a structural member is effectively improved while suppressing an unnecessary increase in mass of the structural member. The structural member includes a hollow member and a tension member. The hollow member forms a closed cross-sectional shape by a top sheet portion, a pair of sidewall portions each continuous to each side of the top sheet portion in a width direction, and a bottom sheet portion arranged to face the top sheet portion. The tension member is formed by a metal sheet extending along the width direction of the top sheet portion and being thinner than the sheet thickness of the hollow member, and connects inner surfaces of the pair of sidewall portions facing each other to each other to restrain the distance between the pair of sidewall portions from increasing.

Structural member for vehicle

A hot-pressed member having excellent bending collapsibility, a method for manufacturing the same, and a method for manufacturing a steel sheet for the hot-pressed member. The hot-pressed member includes a steel sheet as a base material, the steel sheet having a specified chemical composition. The hot-pressed member has a microstructure in which a martensite microstructure is present in a volume fraction of 70% or greater, and a number density of inclusions having a longest diameter of 25 &#x3bc;m or greater is 0.02/mmor less. The hot-pressed member has a tensile strength of 1.8 GPa or greater.

Hot-pressed member, method for manufacturing the same, and method for manufacturing steel sheet for hot-pressed member

An object of the present invention is to provide a collision performance evaluation test method and apparatus that achieve a part collision test that satisfactorily reproduces the state of an actual automobile body collision, allow the test to be performed in a high-speed region, and increase the economic rationality of the test. A motion control mechanism formed of a translation control mechanism or a rotation control mechanism is provided in at least one of a support jig that supports one end portion of an automobile body part and a support jig that supports the other end portion of the automobile body part. The motion control mechanism includes a fixed member fixed to a motion restriction member in the support jig and a movable member so connected to the fixed member as to be movable and fixed to the one end portion or the other end portion of the automobile body part. A compression member protruding from one of the fixed member and the movable member toward the other is fit into a guide portion formed in the other one of the fixed member and the movable member so as to extend in the movable direction of the movable member and disposed with an energy-absorbing member therein. The motion of the movable member with respect to the fixed member deforms the energy-absorbing member to apply reaction force in the direction opposite the direction of the motion to the movable member.

Collision performance evaluation test method and collision performance evaluation test apparatus for automobile body part

Disclosed is a hot-pressed steel sheet member having a tensile strength of 1780 MPa or more and excellent bending collapsibility. The hot-pressed steel sheet member includes: a specific chemical composition; a microstructure in which an average grain size of prior austenite grains is 8 &#x3bc;m or less, a volume fraction of martensite is 90% or more, and a solute C content is 25% or less of a total C content; and a tensile strength of 1780 MPa or more.

Hot-pressed steel sheet member and method for producing same

A high-strength hot-dip galvanized steel sheet excellent in formability includes, on the basis of mass percent, 0.05-0.3% C, 1.4% or less (including 0%) Si, 0.08%-3% Mn, 0.003-0.1% P, 0.07% or less S, 0.1-2.5% Al, 0.1-0.5% Cr, and 0.007% or less N, Si+Al&#x2265;0.5%, and the balance being Fe and incidental impurities, wherein the steel sheet has a retained austenite content of 3% or more by volume fraction, a stretch-flange formability &#x3bb;&#x3e;50% and wherein the average aspect ratio (major axis/minor axis) of retained austenite grains is less than 2.5.

High-strength hot-dip galvanized steel sheet excellent in formability and method of producing same

A method of measuring panel stiffness of an automobile part outer panel by pushing an indenter onto a surface of the panel in a pushing direction intersecting the surface under a load to deform the panel and measuring deformation of the panel includes arranging grids in a lattice form to a surface of a site of the panel; arranging markers previously knowing three-dimensional position information on a periphery of the site; pushing the indenter onto the surface of the site under the load and moving the indenter in a direction perpendicular to the pushing direction, during which the grids on the surface deformed by loading of the indenter are simultaneously and repeatedly shot from plural positions by plural cameras; and calculating position information of the grids corresponding to the markers based on the image data to measure change in deformation of the panel associated with movement of the indenter.

Method and apparatus for measuring dynamic panel stiffness of outer panel for automobile parts

A method for manufacturing includes a polygonal shape closed structure part with a bent shape in the longitudinal direction only by press forming. The method uses two metal plates for manufacturing a curvilineal closed structure part and includes a press forming process of forming straight or bent folding lines in the longitudinal direction of the two metal plates at positions corresponding to a polygonal bent shape with a flange formed at least at one of the ends of the width direction of each plate, a process of forming a closed structure by laying the two metal plates to overlap each other flange to flange and end to end for ends without flanges and by welding the portions laid to overlap each other in the longitudinal direction of the metal plates, and a process of forming a polygonal shape closed structure having a bent shape in the longitudinal direction by holding both ends of the closed structure and by compressing it toward its central axis.

Curvilineal closed structure parts and method for manufacturing the same

The invention provides a high strength cold rolled steel sheet comprising ferrite phases and second phases, in which the mean grain size of the ferrite phases is 20 &#x3bc;m or less, the volume fraction of the second phase is 0.1% or more to less than 10%, the absolute value |&#x394;r| of in-plane anisotropy of r value is less than 0.15, and the thickness is 0.4 mm or more. The high strength cold rolled steel sheet of the present invention has a tensile strength of 370 to 590 MPa, and has excellent stretchability, dent resistance, surface precision, secondary working embrittlement, anti-aging, and surface appearance, therefore it is suitable for outer panels of automobile.

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Tokyo, Japan

Takayuki Futatsuka