ALUMINIUM ALLOY WITH INCREASED RESISTANCE AND LOW QUENCH SENSITIVITY

摘要

The alloy comprises aluminum metal with production contaminants which individually constitute not more than 0.05 wt% and in total not more than 0.15 wt%. Other metals included in the alloy are 4.6-5.2 wt% Zn; 2.6-3.0 wt% Mg; 0.1-0.2 wt% Cu; 0.05-0.2 wt% Zr; not more than 0.05 wt% Mn; not more than 0.05 wt% Cr; not more than 0.15 wt% Fe; not more than 0.15 wt% Si; not more than 0.10 wt% Ti. Preferred amounts of the metals are: 4.6 wt% Zn; 2.6-2.8 wt% Mg; 0.10-0.15 wt% Cu; 0.08-0.18 wt% Zr; not more than 0.03 wt% Mn; not more than 0.02 wt% Cr; not more than 0.12 wt% Fe; not more than 0.12 wt% Si; not more than 0.05 wt%Ti. Independent claims are included for: a) a process for manufacturing plates up to 300 mm thick in the claimed alloy in which: A) the alloy is extruded to form bars not less than 300 mm thick; B) the bars are heated at not more than 20 degrees C/hr from 170-410 degrees C to 470-490 degrees C; C) the bars are homogenized for 10-14 hrs at 470-490 degrees C; D) bars are hot rolled to form plates; E) the plates are cooled to 400-410 degrees C to not more than 100 degrees C; F) plates are cooled to room temperature; G) plates are hardened: b) a similar process in which hot rolling to form plates is omitted and the final hardened bars are used as plates.