Effect Of Shot Peening On Surface Integrity

Author:  Katsuji Tosha
Source:  Conf Proc: ICSP-10 Tokyo, Japan 2008
Doc ID:  2008056
Year of Publication:  2008
ABSTRACT This paper describes influences of factors such as size and velocity of particle, and thickness, hardness and crystal phase of work material on surface integrity. Hardness, residual stress and crystal transformation of zone affected by shot peening are examined for a medium carbon steel (C:O.45%, 180HV) and an austenitic stainless steel (SUS304, 210HV). The following results were shown in this paper: (1) Hardness distributions are divided into three types, which are work hardening, non-hardening and work softening ones. (2) Residual stress distributions are divided into two types, which are S-type and C-type. (3) As residual stress induced by the resistance of non affected layer, residual stress on the peened surface shows size effect of the thickness of work material. (4) The ratio of the critical thickness to the depth of workhardened layer is about 5. (5) Strain-induced transformation happens with shot peening. (6) The optimum affected-layer ratio (ratio of the depth of work-hardened layer to the thickness of material), which is called "sweet zone", is from 0.3 to 0.4.

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