The Development of New Type Almen Strip for Measurement of Peening Intensity on Hard Shot Peening

• Published in: Transaction of Japan Society of Spring Engineers Vol. 1992; no. 37; pp. 53 - 57
• Main Authors: WATANABE, Yoshihiro, HASEGAWA, Norihiko, NAMIKI, Kunio, HATANO, Atsumi
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Society of Spring Engineers 31.03.1992; Japan Science and Technology Agency
• ISSN: 0385-6917; 1348-1479
• DOI: 10.5346/trbane.1992.53

As the fatigue strength of high hardness materials is mainly ruled by residual stress, it is essential to give compressive residual stress on surface layer to enhance the fatigue durability. For this reason, “hard shot peenig” characterized by its larger shot injecting energy with arc height higher than 0.6mmA has become of major interest lately. This process leads to an increase in fatigue strength by 25% compared to conventional peening process. Here, the arc height indicating peening intensity is ordinary measured by Almen strip A type, hardness of which is HRC 44 to 50. However, in hard shot peening, it has been pointed out that this strip is not proper as an index of peening effect, because the arc height measured by A strip is not in good correspondence to surface residual stress. Based on this background, the new type strip suitable for hard shot peening, conventional C type strip and high hard trial strip with hardness of HRC 60 were studied. Using these strips, the relation between residual stress and arc height measured by these strips were investigated. And it was concluded that the arc height measured by high hard trial strip was in good agreement with the maximum compressive stress and the magnitude of stressed layer.