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1. (WO2018163017) RESISTANCE SPOT WELDING METHOD FOR JOINING ZINC COATED STEEL SHEETS

Pub. No.:    WO/2018/163017    International Application No.:    PCT/IB2018/051239
Publication Date: Fri Sep 14 01:59:59 CEST 2018 International Filing Date: Wed Feb 28 00:59:59 CET 2018
IPC: B23K 11/11
C23C 2/06
C22C 38/02
C22C 38/06
C22C 38/18
C22C 38/22
C22C 38/24
C22C 38/26
C22C 38/28
C22C 38/32
C22C 38/44
C22C 38/46
C22C 38/48
C22C 38/50
C22C 38/58
Applicants: ARCELORMITTAL
UNIVERSITE DE NANTES
Inventors: MUSIK, Céline
ZHU, Kangying
HUIN, Didier
MATAIGNE, Jean-Michel
PERLADE, Astrid
FRAPPIER, Renaud
Title: RESISTANCE SPOT WELDING METHOD FOR JOINING ZINC COATED STEEL SHEETS
Abstract:
A method for resistance spot welding comprising the following successive steps: - providing at least two steel sheets with thickness (th) comprised between 0.5 and 3mm, at least one of the sheets being a zinc or zinc-alloy coated steel sheet (A) with a tensile strength (TS) higher than 800 MPa and a total elongation (TEL) such as (TS)x(TEL)>14000MPa%, wherein the composition of the steel substrate of (A) contains, in weight: 0.05% ≤ C ≤ 0.4%, 0.3% ≤ Mn ≤ 8%, 0.010% ≤ Al ≤3%, 0.010% ≤ Si ≤ 2.09%, with 0.5% ≤ (Si+Al) ≤ 3.5%, 0.001% ≤ Cr ≤ 1.0%, 0.001% ≤ Mo ≤ 0.5% and optionally: 0.005% ≤ Nb ≤0.1%, 0.005% ≤ V ≤ 0.2%, 0.005% ≤ Ti ≤ 0.1%, 0.0003% ≤ B ≤ 0.005%, 0.001% ≤ Ni ≤ 1.0%, the remainder being Fe and unavoidable impurities, - performing resistance spot welding of the at least two steel sheets for producing a weld with an indentation depth (IDepth) on the surface of said steel sheet (A) such as: 100 µm ≤ (IDepth) ≤ 18.68 (Znsol)- 55.1, wherein (IDepth) is in micrometers and wherein Znsol is the solubility of Zn in the steel of sheet (A) at 750°C, in weight %.