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Title: Relaxation Of Shot Peening Residual Stresses Of The Steel 42 Crmo 4 By Tensile Or Compressive Deformation
Author: Hanagarth, Vohringer, Macherauch
Source: Conf Proc: ICSP-4, (p.327-336)
Publication year 1990
Document number: 1990058
Number of pages: 9
Abstract:
The relaxation behaviour of shot peening residual stresses of the steel 42 CrMo 4 (A1S1 4140) in a quenched and tempered state was investigated in uniaxial tension and
compression tests, respectively. After deformation to given strain values, residual stresses were determined in the unloaded state by X-ray measurements. In compression
tests, the relaxation of shot peening induced compressive residual stresses in the surface layers starts at the stress value +__-400 N/mm+². On the other hand, the
relaxation of shot peening induced tensile residual stresses in the core region starts at the relatively large tensile stress value +__ 1150 N/mm+². Thus, the relaxation
behaviour of shot peening residual stresses is completely different at compressive and tensile loading. The combination of deformation tests and X-ray measurements allows
the determination of the surface yield strength of shot peened specimens, thereby taking into account the fact that when superimposing the surface residual stress and a
critical compressive loading stress, residual stress relaxation starts. A modelling of the relaxation behaviour caused by uniaxial and biaxial residual stress states,
respectively, will be presented. In the shot peened state, a surface yield strength value results, which is 25 % smaller than that obtained in the unpeened condition. This
finding will be analyzed and discussed, thereby considering results which were determined recently in analogous experiments with shot peened A1CuMg 2 and TiA16V4.
Descriptors: Residual stress-relaxation; Tensile loading; Compressive loading; Surface yield strength; Workhardening; Worksoftening; Half width; Bauschinger-effect
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