Arcelormittal

Université De Nantes

Céline Musik

Astrid Perlade

Jean-Michel Mataigne

Kangying Zhu

Didier Huin

Christine Kaczynski

Remi Cavallotti

Renaud Frappier

Yacine Benlatreche

Didier Hun

A pre-coated steel substrate coated with: a first pre-coating including titanium, the first coating having a thickness of 40 nm to 1200 nm, optionally, an intermediate pre-coating layer including at least 8% by weight nickel and at least 10% by weight chromium, the rest being iron or an intermediate pre-coating layer including Fe, Ni, Cr and Ti wherein the amount of Ti is above or equal to 5 wt. % and wherein the following equation is satisfied: 8 wt. %<Cr+Ti<40 wt. %, the balance being Fe and Ni, the intermediate pre-coating layer having a thickness between 2 and 30 nm a second pre-coating being a zinc-based coating and the steel substrate including above 0.05 wt. % of Si.

Method for manufacturing an assembly

A method for resistance spot welding comprising the following successive steps: &#x2014;providing at least two steel sheets with thickness (th) comprised between 0.5 and 3 mm, 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)&#xd7;(TEL)&#x3e;14000 MPa %, wherein the composition of the steel substrate of (A) contains, in weight: 0.05%&#x2264;C&#x2264;0.4%, 0.3%&#x2264;Mn&#x2264;8%, 0.010%&#x2264;Al&#x2264;3%, 0.010%&#x2264;Si&#x2264;2.09%, with 0.5%&#x2264;(Si+Al)&#x2264;3.5%, 0.001%&#x2264;Cr&#x2264;1.0%, 0.001%&#x2264;Mo&#x2264;0.5% and optionally: 0.005%&#x2264;Nb&#x2264;0.1%, 0.005%&#x2264;V&#x2264;0.2%, 0.005%&#x2264;Ti&#x2264;0.1%, 0.0003%&#x2264;B&#x2264;0.005%, 0.001%&#x2264;Ni&#x2264;1.0%, the remainder being Fe and unavoidable impurities, &#x2014;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 &#x3bc;m&#x2264;(IDepth)&#x2264;18.68 (Zn)&#x2212;55.1, wherein (IDepth) is in micrometers and wherein Znis the solubility of Zn in the steel of sheet (A) at 750&#xb0; C., in weight %.

Resistance spot welding method for joining zinc coated steel sheets

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Piblange, France

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