Modares Mechanical Engineering

Modares Mechanical Engineering

Effect of Micro structure on Acoustic Softening of CK45 Steel

Authors
Mirdavood Hoseini 1
Maghsoud Shalvandi 2
Aydin Salimiasl 3
1 Student
2 Manufacturing Department-Faculty of Mechanical Engineering - University of Tabriz
3 Mechanical engineering faculty of payame noor, tabriz
Abstract
Vibration waves with frequencies greater than 20 kHz, known as ultrasonic vibrations, are used in many manufacturing and engineering processes. This paper studies the occurrence of acoustic softening in steel specimens with three different microstructures. For this purpose, specimens with bainite and martensitic microstructures were created by Austempering and Quench heat treatments. The final dimensions of these specimens were obtained with Modal finite element analysis using ANSYS software so that the resonance frequency of the specimen is equal to the resonance frequency of transducer. Given that ultrasonic vibration induces a tension called vibrational stress to the crystal, this stress causes movement of dislocations and reduces the yield strength of specimens. In this paper 55 w / cm2 ultrasonic vibration, 18%, 12% and 8% yield strengths of specimens are reduced with ferrite- perlite, bainite and martensitic microstructure. Due to the absorption of vibrational energy by dislocation, the metal forming of these materials takes place with less energy. Also, in this paper, a numerical model for acoustic softening was investigated and it was found that there is a good correlation between numerical modeling and experimental e results.
Keywords
Ultrasonic Vibration
tensile test
Acoustic Softening
Microstructure

Subjects

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Modares Mechanical Engineering
Volume 18, Issue 9
December 2018
Pages 33-39