... Spring Steel Strip 1.Material: 65, 70, 75, 85, 65Mn, etc 2.Thickness:0.15mm-2.0mm 3.Width:30mm-355mm Specification of Spring Steel Strip ... for Roller Shutter Doors :1.Material: 65, 70, 75, 85, 65Mn, 55SiMnV, 60Si2MnA, 60Si2CrA, etc.2 ... grey, bright & blue6.Features: The chemical compositions helps spring steel to endure significant bending or twisting and return to ...