TIG yöntemiyle yüzeyi sertleştirilen AISI 4340 çeliğinin mikroyapısının incelenmesi

Bu çalışmada, AISI 4340 çeliğinin yüzeyi gaz tungsten ark (TIG veya GTA) tekniği kullanılarak WC tozu ile modifiye 'edildi. Kaplanan malzemelerin mikroyapılarında üretim parametrelerine bağlı olarak, farklı biçim ve oranlarda WC, W2C fazlarıyla birlikte, ötektik katılaşma ürünü tespit edildi. Sertlik değerleri yapıdaki mevcut faz ve karbürlerin varlığından dolayı önemli ölçüde yükseldi. Mikrosertlik değerleri üst tabaka kalınlığı boyunca 1000-1200 HV arasında değişim gösterirken ara yüzeye doğru gidildikçe sertlik değerlerinde bir azalma (650-800 HV) görüldü. En yüksek sertlik (1184 HV) 1.209 mm/s üretim hızında 0.5 g/s toz yedirme değerinde ve 13.9 kJ/cm enerji girdisi ile üretilen kaplama malzemesinden elde edildi.

Microstructural investigation of AISI 4340 steel hardfaced by TIG process

In this study, AISI 4340 steel surface was modified with WC alloying powder by using a gas tungsten arc (TIG or GTA) process. The results obtained from microstructural investigations indicate that the dendritic solidification resulting from eutectic reaction was observed in the modified layers together with the formation of WC and W2C carbides at different shapes and rates. Hardness values of the coating increased because of existing phase and carbides in the microstructure. While the hardness values of materials with surface modification done by WC coatings changed between 1000-1200 HV, it decreased down to values between 650-800 HV in interface regions. The maximum hardness measured 1184 HV the coating which was produced at high heat input and low powder content 13.9 kJ/cm, and 0.5 g/s, respectively.

___

  • [1] Selvan, J.S., Subramanian, K., Nath, A.K., "Effect of laser surface hardening on EN 18 (AISI 5135) steel", Journal of Materials Processing Technology,Vol.91, pp.29-36, 1999. [2]Hidouci, A., Pelletier, J.M., Ducoin, F., Dezert, D., Guerjouma, R., "Microstructural and mechanical characteristics of laser coatings", Surface and Coatings Technology, Vol.123, pp. 17-23, 2000. [3]Wulin, S., Beidi, Z., Changsheng, X., Wie, H., Kun, C, "Cracking susceptibility of a laser- clad layer as related to the melting properties of the cladding alloy", Surface and Coatings Technology, Vol.115, pp.270-272, 1999. [4] Tusek, J., Suban, M., "High-productivity multiple submerged-arc welding and cladding with metal-powder addition", Journal of Materials Processing Technology, pp.207-213, 2003. [5] Modenesi, J.P., Apolinârio, R.E., Pereira, M.I., "TIG welding with single-component fluxes", Journal of Materials Processing Technology, Vol.99, pp. 260-265, 2000. [6] Molinari, A., Tesi, B., Bacci, T., Marcu, T., "Plasma nitriding and nitrocarburising of sintered Fe-Cr-Mo and Fe-Cr-Mo-C alloys", Surface and Coatings Technology, Vol.140, pp. 251-255, 2001. [7] Zhong, M., Liu, W., Yao, K., Goussain, K., Cecile Mayer, J.C., AhimBecker C, "Microstructural evolution in high power laser cladding of Stellite 6-WC layers", Surface and Coatings Technology, Vol.157, pp. 128-137, 2002. [8] Lu, X.D., Wang, H.M., "Microstructure and dry sliding wear properties of laser clad Mo2Ni3Si/NiSi metal silicide composite coatings", Journal of Alloys and Compounds, basımda, 2003. [9] Berns, H., Fischer, A., "Microstructure of Fe-Cr-C hardfacing alloys with alloys with additions of Nb, Ti, B", Materials Characterization, Vol.39, pp.499-527, 1997. [10] Deuis R. L., Yellup, J. M., Subramanian, C., "Metal-matrix composite coatings by PTA surfacing", Composites Science and Technology, Vol.58, pp.299-309, 1998. [11] Kim, H. J., Yoon, B. H., Lee, C. H., "Wear performance of the Fe-based alloy coatings produced by plasma transferred arc weld- surfacing process", Wear, Vol. 249, pp. 846-852, 2002. [12] Prchlik, L., Sampath, S., Gutleber, J., Bancke, G., Ruff,A. W., "Friction and wear properties of WC-Co and M0-M02C based functionally graded materials", Wear, Vol. 249, pp.1103-1115, 2001. [13] Kathuria, Y.P., "Some aspects of laser surface cladding in the turbine industry", Surface Coatings and Technology, Vol.132, pp. 262-269, 2000. [14] Korkut, M.H., Yılmaz, O., Buytoz, S., "Effect of aging on the microstructure and toughness of the interface zone of a gas tungsten arc (GTA) synthesized Fe-Cr-Si-Mo-C coated low carbon steel", Surface and Coatings Technology, Vol.157, pp.5-13, 2002. [15] Esteve, J., Zambrano, U, G., Rincon, C., Martinez, E., Galindo, H., Prieto, P., "Mechanical and tribological properties of tungsten carbide sputtered coatings", Thin Solid Films, Vol.373, pp.282-286, 2000. [16] Rincon, C., Romero, J., Esteve, J., Martinez, E., Lousa, A., "Effects of carbon incorporation in tungsten carbide films deposited by r.f. magnetron sputtering: single layers and multilayers", Surface and Coatings Technology, Vol.163-164, pp.386-391, 2003. [17] Lou D., Hellman, J., Luhulima, D., Liimatainen, J., Lindroos, V.K., "Interactions between tungsten carbide (WC) particulates and metal matrix in WC-reinforced composites", Materials Science and Engineering , Vol.A340, pp. 155-162, 2003. [18] Yang, Y., Man, U. H. C, "Microstructure evolution of laser clad layers of WC-Co alloy powders", Surface and Coatings Technology, Vol.132, pp. 130-136, 2000. [19] Mateos, J., Cuetos, J. M., Fernandez, E., Vijande, R., "Tribological behaviour of plasma-sprayed WC coatings with and without laser remelting", Wear, Vol.239, pp.274-281, 2000. [20] Wu, P., Zhou, C. Z., Tang, X. N., "Microstructural characterization and wear behavior of laser cladded nickel-based and tungsten carbide composite coatings", Surface and Coatings Technology, Vol.166, pp.84-88, 2003. [21] Khedkar, J., Khanna, A.S., Gupt, K.M., "Tribological behaviour of plasma and laser coated steels", Wear, Vol.205, pp.220-227, 1997. [22] Mridha S., Ong H.S., Poh L.S., Cheang P., "Intermetallic coating produced by TIG surface melting", Journal of Materials Processing Technology, Vol.113, pp.516-520, 2001. [23] Pujar, M. G., Dayal, R. K., Gill, T. P. S., Malhotra, S. N., "Microstructural evaluation of molybdenum-containing stainless steel weld metals by a potentiostatic etching technique", Journal of Materials Science, Vol.33, pp.2691-2700, 1998. [24] Raynor, G.V., Rivlin, V.G., "Phase equilibria in iron ternary alloys", The Institute of Metals, 1988. [25] Zhou, R., Jiang, D., Lu, D., "The effect of volume fraction of WC particles on erosion resistance of WC reinforced iron matrix surface composites", Wear, Vol.255, pp.134-138, 2003. [26] Oh, EL, Lee, S., Jung, J.Y., Ahn, S., "Correlation of microstructure with the wear resistance and fracture toughness of duocast materials composed of high- chromium white cast iron and low- chromium steel", Metallurgical and Materials Transactions, Vol.32A, No.3, pp.515-523, 2001. [27] Zhua, Y.C., Ding, C.X., Yukimurac, K., Xiao, D., Struttd, P.R., "Deposition and characterization of nanostructured WC-Co coating", Ceramics International, Vol.27, pp.669-674, 2001.