Carbon Steel Coil Spring 1) Material: 62Si2MnA, 65Mn, SK3,SK4, SK5 ... , SUS301,304 2) Thickness: 0.1-3.0mm 3) Width: 3-80mm Carbon Steel ... , electrical machine ,start-up machine,etc.),constant force spring for door ,windows ,electric fans ,machines of lift ... for various kinds of carbon and stainless steel products and supplies high elastic and heat treatment ...