Title:
HOLLOW MEMBER AND METHOD FOR MANUFACTURING HOLLOW MEMBER
Document Type and Number:
WIPO Patent Application WO/2023/248452
Kind Code:
A1
Abstract:
According to the present invention, a hollow member has a circumferential hardness difference section in at least a portion in the longitudinal direction along the center axis thereof. When viewing the circumferential hardness difference section in a cross-section perpendicular to the center axis, a thickness difference, derived by subtracting the minimum value of the thickness in the circumferential direction of the cross-section from the maximum value of the thickness, is no more than 20% of an average value of the thickness over the entire circumference of the cross-section. Furthermore, when the average of the integral of the Vicker's hardness over the entire circumference of the cross-section is used as a hardness threshold, the cross-section includes: a low-strength range in which the Vicker's hardness in the circumferential direction is no more than the hardness threshold; and a high-strength range in which the Vicker's hardness in the circumferential direction exceeds the hardness threshold.
Inventors:
SHIMAZAKI NASA (JP)
MATSUBAYASHI RYOTA (JP)
MATSUBAYASHI RYOTA (JP)
Application Number:
PCT/JP2022/025223
Publication Date:
December 28, 2023
Filing Date:
June 24, 2022
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
B21C37/06; B21D22/28
Domestic Patent References:
| WO2016133156A1 | 2016-08-25 | |||
| WO2016104706A1 | 2016-06-30 | |||
| WO2017154481A1 | 2017-09-14 |
Foreign References:
| JP2009131881A | 2009-06-18 | |||
| JP2009136897A | 2009-06-25 | |||
| JP2006272350A | 2006-10-12 | |||
| JP2002102959A | 2002-04-09 |
Attorney, Agent or Firm:
MATSUNUMA Yasushi et al. (JP)
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