Study of Fatigue in AISI 4340 Steel with Different Microstructural Conditions, Submitted to a Surface Treatment of Shot Peening

Abstract:

The AISI 4340 steel has been largely employed for structural purposes, which requires resistance levels with yield strength above 1400 MPa and it attains high levels of resistance in dual phase, bainitic or martensitic microstructural conditions. The samples of AISI 4340 steel with different microstructural conditions (martensitic, bainitic and ferritic/perlitic) have been submitted to fatigue tests on push-pull mode. Subsequently, the new specimens underwent a shot peening surface treatment and new fatigue tests. The results have been discussed in comparison to the three microstructural conditions studied and they were related to a microstructural characterization. The results have showed that a shot peening treatment is not always beneficial to fatigue life, since there is a relationship between the compressive stresses developed on the surface and its roughness formed due to the deformations. Under the three microstructural above studied it was noticed a strong fatigue life reduction in the martensitic condition because such microstructure is considered less ductile.

• Periodical: Materials Science Forum (Volume 869)
• Pages: 503-507
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.869.503
• Online since: August 2016
• Authors: Carlos Eduardo Molento de Moraes*, Carlos Antonio Reis Pereira Baptista, Marcelo Augusto dos Santos Torres, Maria da Penha Cindra Fonseca, Antonio Jorge Abdalla
• Keywords: AISI 4340 Steel, Fatigue, Microstructural Characterization, Shot Peening

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