Shunda has been handling steel heat treat process for 18 years since 2002 and has several Patents for Invention which are the guiders of our superior quality steel strips.

Roller Shutter Spring and spring strip steel
1. Material: C75, C67, 65Mn, 50#, C75Cr1, C75s.
2. Finish: Black; Grey blue; Polished Blue

3. Edge: Both round edges 

4. Hardness:43-49HRC as customer's requirements 

5.Thickness:  1.2mm, 1.25m, 1.3mm, 1.4mm, 1.5mm, 1.6mm

6. Width:  45mm, 50mm, 55mm, 60mm

7. Strength of extension: ≥1450 Mpa

8. Percentage elongation : ≥ 4.5 %