Resistance spot welding method

Patent metadata

Field	Value
Publication number	US-2016144451-A1
Application number	US-201414902985-A
Country	US
Kind code	A1
Filing date	Jun 26, 2014
Priority date	Jul 11, 2013
Publication date	May 26, 2016
Grant date	—

Abstract

A resistance spot welding method including: a pulsation process of clamping a sheet assembly of two or more overlapped steel sheets including at least one high tensile steel sheet using a pair of welding electrodes that are connected to a spot welding power source employing an inverter direct current method, and performing plural repetitions of current passing and current pass stopping, while pressing the steel sheets with the welding electrodes; and a continuous current pass process in which, after the pulsation process, current is passed continuously for a longer period of time than a maximum current pass time of the pulsation process, while pressing the steel sheets with the welding electrodes.

First claim

1 . A resistance spot welding method comprising:
a pulsation process of clamping a sheet assembly of two or more overlapping steel sheets including at least one high-tensile steel sheet using a pair of welding electrodes that are connected to a spot welding power source employing an inverter direct current method, and performing a plurality of repetitions of current passing and current pass stopping, while pressing the steel sheets with the welding electrodes; and a continuous current passing process in which, after the pulsation process, current is passed continuously for a longer period of time than a maximum current passing time of the pulsation process, while pressing the steel sheets with the welding electrodes.

2 . The resistance spot welding method of claim 1 , wherein, in the pulsation process, current passing times in the current passes are each from 10 milliseconds to 60 milliseconds.

3 . The resistance spot welding method of claim 1 , wherein, in the pulsation process, current pass stop times between adjacent current passes are each from 10 milliseconds to 60 milliseconds.

4 . The resistance spot welding method of claim 1 , wherein, in the pulsation process, a final current pass stop time between a final current pass and the continuous current passing process is from 10 milliseconds to 120 milliseconds.

5 . The resistance spot welding method of claim 2 , wherein, a current value of the current passes in the pulsation process is from 7.0 kA to 14.0 kA.

6 . The resistance spot welding method of claim 2 , wherein a current pass time in the continuous current passing process is from 100 milliseconds to 500 milliseconds.

7 . The resistance spot welding method of claim 6 , wherein the current value of a current pass in the continuous current passing process is from 5.0 kA to 12.0 kA.

8 . The resistance spot welding method of claim 7 , wherein a maximum current value in the continuous current passing process is a maximum current value in the pulsation process or lower.

9 . The resistance spot welding method of claim 1 , wherein the high-tensile steel sheet is a hot stamped steel sheet having a surface covered with a zinc-based skin or an aluminum-based skin.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Fujimoto Hiroki
• Dikawa Hatsuhiko
• Yamanaka Shintaro

Classifications

• B23K11/115 Primary

  by means of two electrodes placed opposite one another on both sides of the welded parts · CPC title

• B23K11/24

  Electric supply or control circuits therefor · CPC title

• B23K11/245 Primary

  using a stepping counter in synchronism with the welding pulses · CPC title

• B23K11/11

  Spot welding · CPC title

• B23K11/16

  taking account of the properties of the material to be welded · CPC title