Description
It is well known that outer diameter change of SUS 304 coil springs appear as expansion while size change of hard drawn high carbon steel springs appear as contraction at low temperature tempering after spring forming. It has been cleared in this study that coil springs of stainless steel wire having a two phase structure mixed with and phase show a very slight dimensional change which was unknown property until now. These characteristics were caused by different residual stress in neighboring and phase.
