RESISTANCE SPOT WELDING METHOD

WIPO Patent Application WO/2023/008263

A1

The purpose of the present invention is to provide a resistance spot welding method. In the resistance spot welding method according to the present invention, the carbon equivalent of a high strength galvanized steel sheet used for plate assembly is 0.20% or higher and the tensile strength is 780 MPa or higher. In a first electrification step, when a current value at the beginning of electrification is denoted as Is, a current value at the end of the electrification is denoted as If, and the thickness of a thinnest steel plate of superimposed steel plates is denoted as t, a welding part having a nugget diameter of 3.0 √tmm to 4.5 √tmm is formed while the electrification is performed so that the current value If at the end of the electrification satisfies If>Is. In a second electrification step, a cooling step for maintaining a non-electrification state during 10 ms or more and less than 160 ms, and an electrification step for performing electrification with a current value Ip that is at least the current value If at the end of electrification during 20 ms or more and less than 200 ms are repeated.

KAWABE NAO (JP)
SAWANISHI CHIKAUMI (JP)
TAKASHIMA KATSUTOSHI (JP)
TANIGUCHI KOICHI (JP)
MATSUDA HIROSHI (JP)
YAMAGISHI DAIKI (JP)

PCT/JP2022/028107

February 02, 2023

July 19, 2022

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JFE STEEL CORP (JP)

B23K11/24; B23K11/11; B23K11/16

WO2019124464A1	2019-06-27
WO2020059804A1	2020-03-26
WO2015049998A1	2015-04-09
WO2019124467A1	2019-06-27

JP2021079416A	2021-05-27
JP2003103377A	2003-04-08
JP2003236676A	2003-08-26
JP2017047476A	2017-03-09
JP2012187639A	2012-10-04

KUMASAKA Akira et al. (JP)

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