Yüksek Alaşımlı Beyaz Dökme Demirde Titanyum Katkısının Mikroyapı ve Sertlik Üzerine Etkisi

Yüksek alaşımlı beyaz dökme demir malzemeler yüksek aşınma dayanımından dolayı çimento, beton ve madencilik sektörlerinde geniş bir kullanım alanına sahiptir. Bu çalışmada, yüksek alaşımlı beyaz dökme demir malzemelerde titanyum katkısının mikroyapı ve sertlik özelliklerine etkisi incelenmiştir. Bu amaçla, döküm malzemeler % 0.5, % 1 % 1.5 ve % 2 oranlarında titanyum içerecek şekilde indüksiyon ocağında ergitilerek alaşımlandırılmış ve metal kalıba dökülerek şekillendirilmiştir. Farklı oranlarda titanyum içeren numunelere 850 ˚C’ de 5 saat süreyle tavlama yapılarak havada sertleştirilmiş ve devamında 250 ˚C’ de 4 saat süreyle temperleme işlemi uygulanmıştır. Döküm konumundaki ve ısıl işlem uygulanmış numunelerde ışık mikroskobu ve elektron mikroskobu (SEM) ile mikroyapı incelemeleri yapılmıştır. Artan titanyum oranı ve ısıl işlem koşullarına bağlı olarak malzemelerin mikroyapı ve sertlik özelliklerinde meydana gelen değişimler karşılaştırmalı olarak incelenmiştir.

Anahtar Kelimeler:

Dökme Demir, Titanyum, Isıl İşlem, Mikroyapı, Sertlik

The Effect of Titanium on Microstructure and Hardness in High Alloy White Cast Iron

High alloy white cast iron materials are widely used in cement, concrete and mining industries due to high wear resistance. In this study, the effect of titanium on microstructure and hardness properties in white cast iron materials was investigated. For this purpose, cast materials were alloyed by melting at in induction furnace to include titanium with the rates of % 0, % 0.5, % 0.1, % 1.5, % 2 and were formed by casting into the metal mould. Specimens with different contents of titanium were applied hardening on air after heat treatment at 850 ˚C for 5 hours and tempered at 250 ˚C for 4 hours. Microstructure of cast and heat treated specimens were investigated by using light microscope and scanning electron microscope (SEM). In the microstructure investigations, it was observed that titanium has a significant effect on carbide morphology. It was seen that the hardness of the material with heat treatment increases significantly according to the casting condition. Also it was observed that highest hardness values were obtained with the specimens that include %1 Ti.

Keywords:

Cast Iron, Titanium, Heat Treatment, Microstructure, Hardness,

PDF

___

[1] Y.P. Wang, D.Y. Li, L. Parent and H. Tian, “Improving The Wear Resistance of White Cast Iron Using a New Concept”, Wear, vol. 273, pp. 1623-1628, 2011.
[2] K.S. Al-Rubaie and M. Pohl, “ Heat Treatment and Two –Body Abrasion of Ni-Hard 4”, Wear, vol. 312, pp. 21-28, 2014.
[3] M. Mohammadnezhad, V. Javaheri, M. Shamanian, M. Naseri and M. Bahrami, “Effects of Vanadium Addition on Microstructure, Mechanical Properties and Wear Resistance of Ni-Hard 4 White Cast Iron”, Materials and Design, vol. 49, pp. 888-893, 2013.
[4] C. Scandian, C. Boher, J.D.B. de Mello and F. Rezai-Aria, “Effect of Molybdenum and Chromium Contents in Sliding Wear of High-Chromium White Cast Iron : The Relationship Between Microstructure and Wear”, Wear, vol. 267, pp. 401-408, 2009.
[5] M. Çöl, F.G. Koç, H. Öktem and D. Kır, “The Role of Boron Content in High Alloy White Cast Iron (Ni-Hard 4) on Microstructure, Mechanical Properties and Wear Resistance”, Wear, vol. 348-349, pp. 158-165, 2016.
[6] Y. Lv, Y. Sun, J. Zhao, G. Yu, J. Shen and S. Hu, “Effect of Tungsten on Microstructure and Properties of High Chromium Cast Iron”, Materials and Design, vol. 39, pp. 303-308, 2012.
[7] P. La, F. Wei, S. Hu, C. Li and Y. Wei, “White Cast Iron With a Nano-Eutectic Microstructure and High Tensile Strength and Considerable Ductility Prepared by an Aluminothermic Reaction Casting”, Materials Science and Engineering A, vol.561, pp. 317-320, 2013.
[8] A. B. Jacuinde, R. Correa, J. G. Quezada and C. Maldonado, “Effect of Titanium on The As-Cast Microstructure of a 16% Chromium White Iron”, Materials Science and Engineering A, vol. 398, pp. 297-308, 2005.
[9] M. B. Alamdarlo and V. N. Najafabadi, “Investigating The Effect of Titanium Addition on The Microstructure and Mechanical Properties of Ni-Hard 4 Cast Iron”, Journal of Modern Processes in Manufacturing and Production, vol. 5, pp. 17-27, 2016.
[10] X. Wu, J. Xing, H. Fu and X. Zhi, “Effect of Titanium on The Morphology of Primary M7C3 Carbides in Hypereutectic High Chromium White Iron”, Materials Science and Engineering A, vol. 457, pp. 180-185, 2007.