1.blue tempered spring for rolling shutter 2.CK67,AISI 1065,1070 ... Blue Tempered spring steel strip for rolling shutter doorHeat treatment is carried out mainly for reducing sheet thickness, improving surface ... client’s requestForms: Coils, Sheets, stripsApplications: Springs for shutter doorRaw Material: Baosteel CK67,CK75, SAE1065,SAE1070 CS60, ... lbs, 2727 kgs blue tempered spring for rolling shutter