Title:
METHOD FOR MANUFACTURING RESISTANCE SPOT WELDED JOINT
Document Type and Number:
WIPO Patent Application WO/2019/124467
Kind Code:
A1
Abstract:
A method for manufacturing a resistance spot welded joint according to the present invention enables maintaining a nugget diameter stably while suppressing expulsion in spot welding of a steel sheet which has a substance of high electrical resistance on the surface layer. The method for manufacturing the welded joint according to the present invention characterized by being provided with: a preliminary electric conduction step for supplying a DC current Ia(t) (kA) for ta seconds so as to satisfy expressions (1) and (2) while applying pressure to an electrode at 5.5 kN or higher, the electrode having a tip diameter which is set to 8.0 mm or larger and which is a diameter of a circle having an area equal to that of a region obtained by projecting a surface region, having a curvature radius of 40 mm or larger, of a tip surface of the electrode to a surface perpendicular to the direction of pressure application to the electrode; and a main electric conduction step for supplying a DC current while applying pressure to the electrode at 5.0 kN or higher, wherein the current Ia (t) is continuously supplied during 80% or more of said ta.
Inventors:
FURUSAKO SEIJI (JP)
YASUYAMA MASANORI (JP)
YASUYAMA MASANORI (JP)
Application Number:
PCT/JP2018/046887
Publication Date:
June 27, 2019
Filing Date:
December 19, 2018
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
B23K11/11; B23K11/24
Domestic Patent References:
| WO2015170687A1 | 2015-11-12 |
Foreign References:
| JP2017047476A | 2017-03-09 | |||
| JP2010207909A | 2010-09-24 | |||
| JP2004291088A | 2004-10-21 |
Attorney, Agent or Firm:
AOKI, Atsushi et al. (JP)
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