Investigation of the effects of aluminum addition and austempering heat treatment on wear behavior of ductile cast irons

Öz

Ductile cast irons, which do not contain aluminum (Al) and contain 3 wt.% Al, were produced by the sand mold casting method. After production, the samples kept in the austenite field at 900 ° C for 90 min were rapidly cooled to 300 ° C and held at this temperature for 60 min. Optical microscope, SEM, EDS, and ball-on-disc type wear devices were used to examine the effect of austempering on the microstructure and wear properties of the cast irons. It was determined that as the amount of Al increased, the ferrite ratio and the amount of graphite in the matrix increased, whereas the nodularity of the graphite deteriorated. Alloying with Al provided higher hardness and better wear resistance. After austempering, retained austenite and bainitic ferrite matrix structure were obtained. It was observed that the amount of bainite formed after austempering decreased in the sample containing 3% Al. It was determined that abrasive and adhesive wear was predominant on wear surfaces of the samples. While alloying with 3% Al increased the wear resistance, austempering process gave better results in the wear resistance of the unalloyed sample.

Anahtar Kelimeler

• Austempering
• Ductile cast iron
• Wear
• Aluminum
• Alloying

Küresel grafitli dökme demirlerin aşınma davranışına alüminyum ilavesinin ve östemperleme ısıl işleminin etkilerinin incelenmesi

Öz

Alüminyum (Al) içermeyen ve ağırlıkça %3 Al içeren küresel grafitli dökme demirler kum kalıba döküm yöntemiyle üretilmiştir. Üretim sonrası, 900 °C’de 90 dk süreyle östenit sahada tutulan numuneler, 300 °C’ye hızla soğutulmuş ve bu sıcaklıkta 60 dk boyunca bekletilmiştir. Yapılan östemperleme işleminin, dökme demirlerin mikroyapı ve aşınma özelliklerine etkisinin incelenmesi amacıyla, optik mikroskop, SEM, sertlik ve disk üzeri bilya tipi aşındırma cihazları kullanılmıştır. Al miktarı arttıkça, matristeki ferrit oranı ve grafit miktarının arttığı, buna karşılık grafitlerin küreselliğinin bozulduğu belirlenmiştir. Al ile alaşımlandırma, malzemeye daha yüksek sertlik ve daha iyi aşınma dayanımı kazandırmıştır. Östemperleme sonrası numunelerde, kalıntı östenit ve beynitik ferrit matris yapısı elde edilmiştir. %3 Al içeren numunede, östemperleme sonrası oluşan ferrit miktarının arttığı görülmüştür. Numunelerin aşınma yüzeylerinde abrazif ve adhezif aşınmanın dominant karakterde olduğu belirlenmiştir. %3 Al ile alaşımlama aşınma direncini artırırken, östemperleme işlemi alaşımsız numunenin aşınma dayanımında daha iyi sonuç vermiştir.

Anahtar Kelimeler

• Östemperleme
• Küresel grafitli dökme demir
• Aşınma
• Alüminyum
• Alaşımlama

Teşekkür

Yazar, dökme demirlerin tedariği sürecindeki yardımlarından ötürü, Yük. Müh. Açelya Sandıkoğlu’na teşekkür eder.

Kaynakça

1. K. A, Kasvayee, E. Ghassemali, I. L. Svensson, J. Olofsson ve A. E. W. Jarfors, Characterization and modeling of the mechanical behavior of high silicon ductile iron. Materials Science and Engineering A, 708, 159–170, 2017. https://doi.org/10.1016/j.msea.2017. 09.115
2. A. Vicente, J. R. Sartori Moreno, T. F. Santos, D. C. R. Espinosa ve J. A. S. Tenório, Nucleation and growth of graphite particles in ductile cast iron. Journal of Alloys and Compounds, 775, 1230–1234, 2019. https://doi.org/10.1016/j.jallcom.2018.10.136
3. K. Odum ve M. Soshi, Surface Formation Study Using a 3-D Explicit Finite Element Model of Machining of Gray Cast Iron. Procedia CIRP, 45, 111–114, 2016. https://doi.org/10.1016/J.PROCIR.2016.02.168.
4. A. O. Adebayo, O. O. Ajibola, A. F. Owa, S. G. Borisade, K. K. Alaneme ve A. Oyetunji, Charaterisation and dry sliding wear behaviour of 2.29  aluminium-alloyed ductile iron. Materials Today: Proceedings, 38, 1152-1158, 2021. https://doi.org/ 10.1016/j.matpr.2020.07.138.
5. A. R. Kiani-Rashid ve D. V. Edmonds, Microstructural characteristics of Al-alloyed austempered ductile irons. Journal of Alloys and Compounds, 477, 391-398, 2009. https://doi.org/10.1016/j.jallcom.2008.10.038.
6. A. R. Kiani-Rashid, Influence of austenitising conditions and aluminium content on microstructure and properties of ductile irons. Journal of Alloys and Compounds, 470, 323-327, 2009. https://doi.org/ 10.1016/j.jallcom.2008.02.070
7. C. Labrecque ve M. Gagné, Ductile Iron: Fifty years of continuous development. Can Metall Q, 37, 343–378, 1998. https://doi.org/10.1179/cmq.1998.37.5.343.
8. M. S. Soiński, P. Kordas, K. Skurka ve A. Jakubus, Investigations of Ferritic Nodular Cast Iron Containing about 5-6% Aluminium. Arch Foundry Eng, 16, 141-146, 2016. https://doi.org/10.1515/afe-2016-0099.

9. A. O. Adebayo, K. K. Alaneme ve A. Oyetunji, Corrosion Evaluation Of Austempered Aluminium-Alloyed Ductile Irons In Well Water And 0.5M NaCl Solution. Journal of Chemical Technology and Metallurgy, 56, 180-193, 2021.
10. A. R. K. Rashid ve D. V. Edmonds, Oxidation behaviour of Al-alloyed ductile cast irons at elevated temperature. Surface and Interface Analysis, 36, 1011-1013, 2004. https://doi.org/10.1002/sia.1825
11. E. Aguado, M. Ferrer, P. Larrañaga, D. M. Stefanescu ve R. Suárez, The Effect of the Substitution of Silicon by Aluminum on the Properties of Lamellar Graphite Iron. International Journal of Metalcasting, 13, 536-545, 2019. https://doi.org/10.1007/s40962-018-00303-y.
12. D. Franzen, P. Weiß, B. Pustal ve A. Bührig-Polaczek. Modification of Silicon Microsegregation in Solid-Solution-Strengthened Ductile Iron by Alloying with Aluminum. International Journal of Metalcasting, 14, 1105-1114, 2020. https://doi.org/10.1007/s40962-020-00412-7
13. H. R. Erfanian-Naziftoosi, N. Haghdadi ve A. R. Kiani-Rashid, The effect of isothermal heat treatment time on the microstructure and properties of 2.11% Al austempered ductile iron. Journal of Materials Engineering and Performance, 21, 1785-1792, 2012. https://doi.org/10.1007/s11665-011-0086-y.
14. A. S. Benam, Effect of alloying elements on austempered ductile iron (ADI) properties and its process: Review. China Foundry, 12, 54–70, 2015.
15. U. R. Kattner ve B. P Burton, Phase diagrams of binary iron alloys. ASM International, Chicago, 1993.
16. M. M. Khalvan ve M. Divandari, Microstructure of spheroidal graphite aluminum-alloyed cast irons (SGAACI) containing up to 7.5 wt% produced via in-mold process. International Journal of Metalcasting, 15, 271–280, 2021. https://doi.org/10.1007/s40962-020-00461-y.
17. J. D. Lemm, A. R. Warmuth, S. R. Pearson ve P. H. Shipway, The influence of surface hardness on the fretting wear of steel pairs-Its role in debris retention in the contact. Tribology International, 81, 258-266, 2014. https://doi.org/10.1016/j.triboint.2014.09.003.
18. J. Li, Y. Lu, H. Zhang ve L. Xin, Effect of grain size and hardness on fretting wear behavior of Inconel 600 alloys. Tribology International, 81, 215-222, 2015. https://doi.org/10.1016/j.triboint.2014.08.005.
19. G. K. Goh, L. Lim, M. Rahman ve S. Lim, Effect of grain size on wear behaviour of alumina cutting tools. Wear, 206, 24-32, 1997. https://doi.org/10.1016/ S0043-1648(97)00002-1
20. A. K. Jha, B. K. Prasad, O. P. Modi, S. Das ve A. H. Yegneswaran, Correlating microstructural features and mechanical properties with abrasion resistance of a high strength low alloy steel. Wear, 54, 120-128, 2003. https://doi.org/10.1016/S0043-1648(02)00309-5
21. A. M. Kirk, P. H. Shipway, W. Sun ve C. J. Bennett, Debris development in fretting contacts – Debris particles and debris beds. Tribology International, 149, 105592, 2020. https://doi.org/10.1016/ j.triboint.2019.01.051