INFLUENCE OF GAS NITRIDING ON FATIGUE PERFORMANCE OF AUSTENITIC STAINLESS-STEEL TYPE AISI 304: PARAMETRIC STUDY AND OPTIMIZATION

M. J. AL- Arofi; Farag M. Shuaeib; A. AL- Khatib; Muftah T. Abujelala

doi:10.66411/jer.v9i9.168

Authors

M. J. AL-Arofi Mechanical Engineering Dept., Faculty of Engineering, Garyounis University, Benghazi, Libya (GSPLAJ) Author
Farag M. Shuaeib Mechanical Engineering Dept., Faculty of Engineering, Garyounis University, Benghazi, Libya (GSPLAJ) Author
A. AL-Khatib Mechanical Engineering Dept., Faculty of Engineering, Garyounis University, Benghazi, Libya (GSPLAJ) Author
Muftah T. Abujelala Mechanical Engineering Dept., Faculty of Engineering, Garyounis University, Benghazi, Libya (GSPLAJ) Author

DOI:

https://doi.org/10.66411/jer.v9i9.168

Keywords:

Fatigue, Stainless steel, Gas nitriding, Ammonia, Response surface, Optimization

Abstract

The aim of the present work is to investigate the fatigue performance of an austenitic stainless steel material type AISI 304 after subjecting it to a conventional gas nitriding process throughout temperature range of 400 - 600^o C, nitriding time of 10 - 50 hrs and ammonia (NH3) flow rate of 100 - 600 litre/hr. Previous work on this subject was performed using the classical method of changing one factor at a time. This old method requires many specimens and extensive experimental work which is both costly and time consuming. Furthermore, the classical method is not capable of detecting the interaction effects between the factors and also cannot perform experimental optimization. Previous drawbacks are tackled by using the response surface methodology (RSM) in the design of experiments using statistical methods. Accordingly, RSM design of experiment is created; samples were prepared and gas nitrided according to the design of experiment set up. Fatigue tests were performed on an Avery-Denison fatigue testing machine at a stress ratio R = -1. After analyzing the results, it is found that the fatigue strength of the tested specimens has improved to 318 MPa which represents an extent of 27% by gas nitriding as compared with un-nitrided specimens (250 MPa). Optimum settings for the gas nitriding time, flow rate and temperature factors to obtain the maximum fatigue strength were 540^oC, 40 hrs, and 400 liter/hr ammonia gas respectively

References

[1] T. Bell, "Surface Engineering of Austenitic Stainless Steel", Journal of Surface Engineering, Vol. 18 No. 6, pp 415-422, (202). DOI: https://doi.org/10.1179/026708402225006268

[2] Michel J. Korwin, Christopher D. Morawski, George J. Tymowskie, and Witold K Liliental, "Design of Nitrided and Nitrocarborized Materials", in Metrological Design Handbook, Chap.14, edited by George E. Totten, Kiyoshi Funtani, and Lin Xie, Marccl Deker Inc, (USA), (2004).

[3] G. G. Garrett and D. L. Marriott, "Engineering Applications of Fracture analysis", 3rd ed, John Wiley & Sons Singapore (1991).

[4] Thelning, K-E., "Steel and its Heat Treatment", Bofors Handbook, Butterworth, London, Chap.6, (1975).

[5] The ASM (American Society for Metals), 1991, “Heat Treating Handbook”, (Ohio, USA), vol.04.

[6] The ASM (American Society for Metals), 1994, “Surface Engineering Handbook”, (Ohio, USA), vol.05.

[7] The ASM (American Society for Metals), 2004, “Metallography and Microstructures Handbook”, (Ohio, USA), vol.09.

[8] The ASM (American Society for Metals), "Fatigue and Fracture Handbook", vol. 19, (Ohio, USA), (1996).

[9] Lakhtin, Yu.M. and Kohen, Ya. D. "Structure and Strength of Nitrided Alloys", Metallurgical, Moscow, chap.1, 2 & 7, in Russian (1982).

[10] George E. Dieter and David Bacon, "Mechanical Metallurgy", 3rd, SI Metric edition, (McGraw-Hill Book Company, London). Chap.12, (1991).

[11] K. Hussain, A. Tauqir, A. ul Haq, A.Q. Khan, "Influence of gas nitriding on fatigue resistance of maraging steel", International Journal of Fatigue, 21 163- 168, (1999). DOI: https://doi.org/10.1016/S0142-1123(98)00063-2

[12] Menthe, A. Bulak, J. Olfe, A. Zimmermann, K.-T. Rie, "Improvement of the mechanical properties of austenitic stainless steel after plasma nitriding", Surface and Coatings Technology, vol. 133 - 1134, p. 259 – 263 (2000). DOI: https://doi.org/10.1016/S0257-8972(00)00930-0

[13] J. Bielawski, J. Baranowska, K. Szczecinski, Microstructure and properties of layers on chromium steel, Surface & Coatings Technology, 6572-6577, (2006). DOI: https://doi.org/10.1016/j.surfcoat.2005.11.037

[14] 12 MINITAB Statistical Software versions 13 User Guide II, USA, (2003).