The Effect Of Peening Shot Size On The Performance Of Carbon Steel Springs

Author:  Bird, G. and Saynor, D.
Source:  Springs, October 1986
Doc ID:  1986091
Year of Publication:  1986
Abstract:  
The effect of shot peening on the properties of helical compression springs of various materials and wire sizes, using cast steel shot sizes between S70 and S550, was examined. The springs, made from wire to BS 1408 and BS 2803 materials, were shot peened in a Wheelabrator 'Tumblast' machine. With each shot size used, the intensity of peening was determined. After the springs had been shot peened, they were stress relieved and prestressed before carrying out stress relaxation and fatigue tests. In the stress relaxation tests, the shot peened springs relaxed more than the unpeened ones--the larger the size of shot used, the greater the relaxation. In the fatigue tests, shot peening was shown to improve the endurance limit of all the springs, the improvement being most marked with the smaller shot sizes. In general, the largest increases was obtained when the shot size was less than a quarter of the wire dia. Descriptors: Carbon steels-- Mechanical properties; Helical springs-- Mechanical properties; Stress relaxation-- Deformation effects; Fatigue limit-- Deformation effects; Shot peening