Microstructure and Wear Behaviour of 17-4 Precipitation Hardening Stainless Steel with Various Ti Content
- PDF / 3,604,897 Bytes
- 8 Pages / 594 x 792 pts Page_size
- 106 Downloads / 218 Views
SINTERED METALS AND ALLOYS MICROSTRUCTURE AND WEAR BEHAVIOUR OF 17-4 PRECIPITATION HARDENING STAINLESS STEEL WITH VARIOUS Ti CONTENT Dursun Ozyurek,1,2 Ender Nalcacioglu,1 and Kerim Cetinkaya1 UDC 669.018.298.3 In this study, the wear behaviour of aged 17-4 PH SS (precipitation hardening stainless steel) that contains 0.5, 1, 1.5, and 2% of Ti was examined. The mixed elemental powders (in wt.%: 17 Cr, 4 Cu, 4 Ni, 1 Mn, 1 Si, 0.3 Nb, 0.07 C, and Fe remaining) were cold-pressed (800 MPa), and the pre-formed 17-4 PH SS green compacts were sintered at 1300°C for 60 min in a 0.1 Pa vacuum and at 4 °C/min heating rate and cooled down in furnace to room temperature. Alloys with different amounts of titanium were aged at 480°C for 1, 4, and 8 h. Scanning electron microscopy, X-ray diffraction analysis, and density and hardness measurements were employed to characterize the aged alloys. The pin-on-disc apparatus was used for wear testing. The wear testing was performed under the sliding speed of 0.8 m/sec, two various loads (of 30 and 45 N), and at five different sliding distances of 600, 1200, 1800, 2400, and 3000 m. Research results showed that in 17-4 PH SS, the weight loss and density decreases with a higher titanium content, while their hardness increase. Thus, a higher amount of Ti addition contributes to lower weight losses. The friction coefficient shows the highest value in the samples containing 0.5% Ti and the lowest in the alloy containing 2% Ti. M23C6 and M3C carbides are formed in the microstructure of the material, as expected. From the SEM images of worn surfaces, the adhesive and oxidative wear mechanisms were determined as dominant. Due to the choice of composition with the highest hardness and corresponding sintering conditions, the wear resistance of alloys can be increased significantly. Keywords: 17-4 PH stainless steel, heat treatment, microstructure, hardness, wear.
INTRODUCTION The stainless steel is quite widely applied in industrial practices to increase the service life of the parts used and to achieve maximum possible energy conservation. In particular, the 17-4 alloy is one of the most preferable precipitation-hardening (PH) stainless steel (SS) for this purpose. These steels are used in the chemical industry, power plants, light water reactors, and pressurized water reactors due to their high strength, excellent corrosion resistance, and producibility [1–4]. This alloy is martensitic stainless steel strengthened by solid solution and aging
1Karabuk 2To
University, Technology Faculty, Karabuk, Turkey. whom correspondence should be addressed; e-mail: [email protected].
Published in Poroshkova Metallurgiya, Vol. 59, Nos. 7–8 (534), pp. 39–48, 2020. Original article submitted January 20, 2020. 386
1068-1302/20/0708-0386 2020 Springer Science+Business Media, LLC
process and reinforced with precipitation of copper-rich phases in the martensitic matrix [5]. The precipitation of the second phase in this steel begins with the formation of copper-rich body-centred cubic (bcc) precipitate
Data Loading...
