Geleneksel ve SiC Toz Katkılı Yüksek Darbe Enerjili Elektriksel Kıvılcımla İşlenmiş Dubleks Çelik Yüzeylerin İncelenmesi

Yıl 2016, Cilt: 6 Sayı: 1, 111 - 120, 01.01.2016

Bülent Ekmekci

Öz

Bu çalışmada dubleks çift fazlı çelik numuneler, su ve hidro-karbon bazlı dielektrik sıvılarda, toz katkısız ve SiC toz katkısı kullanılarak elektriksel kıvılcım yöntemi ile işlenmiştir. İşlenen yüzeyler elektron mikroskobisi, x-ışını kırınım kristalografisi ile incelenmiş ve yüzey topografisi ile ilgili sonuçlar karşılaştırmalı biçimde irdelenmiştir. Elde edilen bulgular; bu yöntemle işlenmiş ferritik dubleks çeliklerle benzer mikro çatlak ağ yapılarının farklı dielektrik ortamlarda oluştuğunu göstermiştir. Dubleks çeliklerin yapısında bulunan ferritik taneler hidro-karbon bazlı dielektrik sıvıda kalıntı östenite dönüşmekte ve yeniden katılaşan katmanda taneler arası dönüşüm gerilmelerini düşürmektedir. Ancak, dielektrik sıvı olarak su kullanıldığında, östenitleşme azalmakta ve yeniden katılaşan katmanda taneler arası dönüşüm gerilmeleri yükselmektedir

Anahtar Kelimeler

Çift fazlı çelik, Elektriksel kıvılcım ile işleme, Yeniden katılaşma

Investigation of Duplex Steel Surfaces in Conventional and SiC Powder Mixed Electrical Discharge Machining Using High Pulse Energy

Öz

Duplex steel samples were electrical discharge machined using non-additive and SiC powder additives in water and hydrocarbon based dielectric liquid. Machined surfaces were examined using scanning electron microscopy, x-ray diffraction crystallography and the results regarding the surface topography were discussed in a comparative manner. If the findings were compared with ferritic steel, duplex steel surfaces would exhibit similar micro-cracks network on the surface but in different dielectric media. Ferritic grains in the structure of duplex steel is transformed to retained austenite when using hydrocarbon based dielectric liquid during machining which reduces the intergranular transformational stresses in the re-solidified layer. However, austenitization decreases when water is used as dielectric liquid and transformational stresses increase in the re-solidified layer.

Anahtar Kelimeler

Dual phase steel, Electrical discharge machining, Re-solidification

Kaynakça

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