Method for Producing Helical Springs

Author:  J Wienand; G Mier, both of Germany
Source:  US Patent 6,022,427
Doc ID:  2000015
Year of Publication:  2000
Abstract:  
A method of manufacturing helical springs from steel wire. The springs' skin is thermomechanically hardened by shot peening the unstressed springs followed by thermally destressing them, and shot peening them again. The second shot peening is carried out in at least two steps. The method produces springs that are just as strong as conventional but smaller and lighter in weight. The first one of the steps is a rough shot peening with shot that is coarser than in the second one of the steps which is a fine shot peening was shot at a lower speed than in the first step. This increases compression of the wire's surface and polishes the wire's surface.