This talk will be focused on key mechanisms responsible for Liquid Metal Embrittlement of Zn coated AHSS, making use of some of the key results that were presented during the Galvatech’2021 remote conference.
The four required conditions that must be met for LME to occur will be discussed: the presence of a liquid phase in contact with the solid, the presence of high energy grains boundaries at the solid surface for the GB complexion reaction to occur (giving a liquid like mechanical behaviour to the wetted GB), the presence of an applied tensile stress to trigger the GB opening, and the required deformation rate allowing GB to open before the Fe-Zn reaction can occur.
The role of steel chemistry will be discussed through the way it can decrease the Fe-Zn mutual solubilities and promote LME.
Possible differences between LME assessment through either Gleeble testing either spot welding will be highlighted.
Best Paper Winner Jean-Michel Mataigne, ArcelorMittal Global R&D, will present highlights from his Galvatech 2021 paper "Comparative Assessment of GI And GA Coated AHSS LME Sensitivity During Spot Welding". Selected highlights from other Galvatech 2021 automotive applications papers will also be summarized.
Each session will start with the 20 minute lecture, followed by a 20 minute panel discussion. This will be followed by 10 minutes of general discussion and a short break before beginning the next session.
Automotive, GalvanIzed (GI), GalvAnnealed (GA), Liquid Metal Embrittlement (LME), spot welding, zinc-coated Advanced High Strength Steels (AHSS)