Aluminum-Zinc Precipitation Alloy

AlZnMg is a precipitation-hardening alloy. You don't get strength just by quenching, but by a subsequent heat treatment – that's called aging. When you have to weld it, heat input is crucial, otherwise you lose hardness in the weld area and it stays soft. For welding, it's best to use a matching filler and cool the part controlled after welding. With thin sheets, be careful not to burn through, and with thick parts, avoid too much heat build-up.