High Quality Aluminum Circle for Traffic Signs:
Specification: 
Alloy: 1070-1200, 3003 
Temper: H1X/H2X/O 
Thickness: 0.15mm~4.0mm 
Diameter: 20mm - 1250mm 
Feature: 
Low anisotropy, which facilitates deep drawing 
Strong mechanical properties 
High and homogeneous heat diffusion 
Ability to be enameled, covered by PTFE (or others), anodized 
Good reflectivity 
High strength-to-weight ratio 
Durability and resistance to corrosion 
https://www.jdgroupchina.com/aluminum-circle/aluminium-circle-for-road-sign/aluminum-circle-for-traffic-sign.html