1.cold drawn spring steel bar 2.Induction treatment 3.SAE9254,SUP12V, 55CR3,SUP9 4. ... strength 5.ECT We has been specializing in cold drawn spring steel bar/coil for over 15 years ,and the engineers is ... using .Now,the product details as follows:1.Spring steel coil or round bar. 2.Steel grade:SUP9,SUP9A,SUP10,SUP7,SUP12,SUP12V,SUP6 ... hot rolled;D200-D1000 by hot forged. Cold drawn spring steel bar