STEEL TUBE EXCELLENT IN HYDROFORMING WORKABILITY

Title:

STEEL TUBE EXCELLENT IN HYDROFORMING WORKABILITY

Document Type and Number:

Japanese Patent JP3450744

Kind Code:

B2

Abstract:

PROBLEM TO BE SOLVED: To prevent the generation of a buckling caused by compression loads at the time of working in a steel tube, to increase its strength and to make excellent its productivity by allowing the tensile strength in the axial direction and the elongation in the circumferential direction of a steel tube worked by applying pressure to the inside surface and to be pushed in the axial direction of the tube to satisfy a specified relation.
SOLUTION: The tensile strength in the axial direction and the elongation in the circumferential direction of the tube satisfy the relation expressed in the inequality, (tensile strength in the axial direction (N(mm2)-180) × (elongation in the circumferential direction (%) -15)≥2,000. The tensile strength is the one obtd. by applying an arc-shaped test piece extracted from the axial direction to a tensile test, and as to the elongation in the circumferential direction of the tube, the one obtd. by expanding the steel tube and applying a test piece of 10 mm width and 50 mm GL extracted in the circumferential direction of the tube to a tensile test is adopted. The steel tube excellent in hydroforming workability is the one capable of sufficiently exhibiting elongation characteristics in the circumferential direction of the tube while maintaining the properties of withstanding compression loads in the axial direction of the tube at the time of working, in which tensile strength in the axial direction and elongation in the circumferential direction of the steel are balanced, and both satisfy prescribed relation. In the case it is applied to the production of automotive structural parts, the production cost thereof is reduced.

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Inventors:

Keisuke Ichiryu
Saburo Inoue
Masayasu Kojima
Kazutoshi Kunishige

Application Number:

JP10196299A

Publication Date:

September 29, 2003

Filing Date:

April 09, 1999

Export Citation:

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Assignee:

Sumitomo Steel Pipe Co., Ltd.

International Classes:

B21D26/033; B21D26/043; C22C38/00; (IPC1-7): B21D26/02; C22C38/00

Domestic Patent References:

JP10175027A
JP10176220A

Attorney, Agent or Firm:

Terutada Houe

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