TIG Yöntemiyle Yüzeyi Sertleştirilen AISI 4340 Çeliğinin Mikroyapısının İncelenmesi

Yıl 2005, Cilt: 18 Sayı: 1, 44 - 60, 30.06.2005

Soner Buytoz , Mustafa Ulutan , M. Mustafa Yıldırım

Öz

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.

Anahtar Kelimeler

TIG yöntemi, yüzey modifikasyonu, dendrit, M7C3

Microstructural Investigation Of AISI 4340 Steel Hardfaced By TIG Process

Öz

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.

Anahtar Kelimeler

TIG method, surface modification, dendrite, M7C3

Kaynakça

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