ESD Tekniği ile WC Kaplanmış AISI 1010 Çelik Sacların Nokta Kaynağı

Öz

Değişik yöntemlerle yapılan yüzey kaplamaları, metalik ve metalik olmayan malzemelerin yüzey özelliklerini değiştirmekte ve aşınma direnci gibi özellikleri iyileştirmektedir. Sert bir fazla yüzey kaplama sonucunda, yüzey aşınmaya karşı korunmakta ancak ark ve yüksek enerjili kaynaklı birleştirmede sorun çıkabilmektedir. Kaplama tabakasının genel özelliklerinin, kaynak işlemi sonrasında nasıl değiştiğinin yanında, kaynaklı birleştirmenin mekanik özellikleri de önemlidir. Bu çalışmada, sabit akım, farklı frekans ve voltajlarda AISI 1010 çeliği üzerine ESD yöntemi ile tungsten karbür (WC) kaplama işlemi yapılmış ve daha sonra iki aynı özellikteki numune, sabit akım ve baskı kuvvetinde nokta kaynağı ile birleştirilmiştir. Kaynak bölgesini ortaya çıkarmak için numuneler ikiye bölünmüştür, daha sonra kalıba alınarak ve klasik metalografik işlemler uygulanmıştır. Metalografik işlemler sonrasında kaynak bölgesinde oluşan içyapıları incelemek için optik mikroskop ve Elektron Mikroskopisi ile görüntüler alınmıştır. Sonuçlar, WC kaplı çelik sacların kaynak bölgesinde bölgesel alaşımlamaya sebep olduğunu ve bu nedenle mikro yapılarda ciddi değişiklikler olduğunu göstermiştir.

Anahtar Kelimeler

• AISI 1010
• Düşük Karbonlu Çelik
• Nokta direnç kaynağı
• Elektro-Kıvılcım Biriktirme (ESD)
• Tungsten Karbür (WC) kaplama

Spot Welding of AISI 1010 Steel Sheets Coated with WC by ESD Technique

Abstract

Surface coatings made with different methods change the surface properties of metallic and non-metallic materials and improve properties such as wear resistance. As a result of a hard surface coating, the surface is protected against wear, but problems may arise in arc and high-energy welded joints. Besides how the general properties of the coating layer change after the welding process, the mechanical properties of the welded joint are also important. In this study, tungsten carbide (WC) coating was carried out on AISI 1010 steel by ESD method at constant current using different frequencies and voltages and later two identical specimens were joined by spot welding at constant current and pressure. In order to reveal the welding zone, the samples were sliced into two, and then moulded and classical metallographic processes were applied. After metallographic processes, images were taken with an optical microscope and Electron microscopy to examine the microstructures formed in the weld zone. The results show that WC coated steel sheets cause localized alloying in the weld zone and therefore drastic changes in microstructures.

Keywords

• AISI 1010 steel
• Low carbon steel
• Spot resistance welding
• Electro-Spark Deposition (ESD)
• Tungsten Carbide (WC) Coating

References

1. Agarwal, A., Dahotre, N.B., Pulse Electrode Deposition of Super hard Boride Coatings on Ferrous Alloy. Surface and Coatings Technology 106(2-3), 242-250, 1998.
2. Chen, Z., Zhou, Y. H., Surface modification of resistance welding electrode by electro-spark deposited composite coatings: Part I. Coating characterization. Surface and Coatings Technology 201(3-4), 1503-1510, 2006.
3. Cheng, L., Xiang, X., Shi-jie, D., TiB2/Ni coatings on surface of copper alloy electrode prepared by electrospark deposition. Transactions of Nonferrous Metals Society of China 21(2), 317-321, 2011.
4. Emre, H. E., Kaçar, R., Resistance spot weldability of galvanize coated and uncoated trip steels. Metals 6(12), 299, 2016.
5. Emre, H.E., Bozkurt, B., Effect of Cr-Ni coated Cu-Cr-Zr electrodes on the mechanical properties and failure modes of TRIP800 spot weldments. Engineering Failure Analysis 110, 104439, 2020.
6. Frangini, A., Masci, S., Di Bartolomeo, A., Cr7C3-based cermet coating deposited on stainless steel by electrospark process: structural characteristics and corrosion behavior. Surface and Coating Technology 149(2-3), 279-286, 2002.
7. Gedeon, S. A., Eagar, T. W., Resistance spot welding of galvanized steel: Part I. Material Variations and Process Modifications. Metallurgical and Materials Transactions B 17, 879-885, 1986.
8. Jiao, Z., Peterkin, S., Felix, L., Liang, R., Oliveira, J. P., Schell, N., Zhou, Y., Surface Modification of 304 Stainless Steel by Electro-Spark Deposition. Journal of Materials Engineering and Performance 27, 4799-4809, 2018.

9. Kayalı, Y., Talaş, Ş., Investigation of Wear and Corrosion Behaviour of AISI 316 L Stainless Steel Coated by ESD Surface Modification. Protection of Metals and Physical Chemistry of Surfaces 55(6), 1148-1153, 2019.
10. Kou, S., Welding Metallurgy, Wiley, Second Edition, 2002.
11. Li, Z.W., Gao, W., Kwok, P., Li, S., He, Y., Electro-spark deposition coatings for high temperature oxidation resistance. High Temperature Materials and Processes 19(6), 443-458, 2000.
12. Liu, J., Wang, R., Qian, Y., Formation of a single-pulse electrospark deposition spot. Surface and Coatings Technology 200(7), 2433-2437, 2005.
13. Luo, P., Dong, S., Xie, Z., Yangli, A., Yang, W., The effects of coating parameters on the quality of TiB2-TiC composite phase coating on the surface of Cu-Cr-Zr alloy electrode. Surface and Coatings Technology 253, 132-138, 2014.
14. Miller, T., Pirolli, L., Deng, F., Ni, C., Teplyakov, A. V., Structurally different interfaces between electrospark-deposited titanium carbonitride and tungsten carbide films on steel. Surface and Coatings Technology 258, 814-821, 2014.
15. Müftüoğlu, F., Keskinel, T., Effect of Coating Thickness on Electrode Life in the Spot Welding of Galvanized Steels. Turkish Journal of Engineering and Environmental Sciences 31(3), 183-187, 2007.
16. Padgurskas, J., Kreivaitis, R., Rukuiža, R., Mihailov, V., Agafii, V., Kriūkienė, R., Baltušnikas, A., Tribological properties of coatings obtained by electro-spark alloying C45 steel surfaces. Surface and Coatings Technology 311, 90-97, 2017.
17. Reynolds, J.L., Holdren, R.L. and Brown, L.E., Electro-Spark Deposition. Advanced Materials and Processes 161(3), 35-37, 2003.
18. Talaş, Ş., Mertgenç, E., Gökçe, B., ESD coating of copper with TiC and TiB2 based ceramic matrix composites. IOP Conference Series-Materials Science and Engineering 146, 012005, 2016.
19. Tang, J., Mechanical and tribological properties of the TiC–TiB2 composite coating deposited on 40Cr-steel by electro spark deposition. Applied Surface Science 365, 202-208, 2016.
20. Tang, S. K., The process fundamentals and parameters of electro-spark deposition, University of Waterloo, Master Thesis (Printed), 2009.
21. Tumuluru, M., The Effect of Coatings on the Resistance Spot Welding Behavior of 780 MPa Dual-Phase Steel. Welding Journal 86, 161-169, 2007.
22. Wang, J. S., Meng, H. M., Yu, H. Y., Fan, Z. S., Sun, D. B., Characterization and wear behavior of WC-0.8 Co coating on cast steel rolls by electro-spark deposition. International Journal of Minerals, Metallurgy and Materials 16(6), 707-713, 2009.
23. Wang, P. Z., Pan, G. S., Zhou, Y., Qu, J. X., Shao, H. S., Accelerated electrospark deposition and the wear behavior of coatings. Journal of Materials Engineering and Performance 6(6), 780-784, 1997.
24. Wei, X., Chen, Z., Zhong, J., Wang, L., Hou, Z., Zhang, Y., Tan, F., Facile preparation of nanocrystalline Fe2B coating by direct electrospark deposition of coarse-grained Fe2B electrode material. Journal of Alloys and Compounds 717, 31-40, 2017.
25. Zou, J., Zhao, Q., Chen, Z., Surface modified long-life electrode for resistance spot welding of Zn- coated steel. Journal of Materials Processing Technology 209, 4141-4146, 2009.