Hadde merdanelerinin ESD yöntemi ile yüzey modifikasyonu ve aşınma davranışlarının optimize edilmesi
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Tarih
2024
Yazarlar
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Yayıncı
Necmettin Erbakan Üniversitesi, Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada Elektro Spark Deposition yöntemi ile WC/Co kaplamalar hadde merdanelerinin ana malzemesi olan küresel grafitli dökme demirler (GGG-60) üzerine biriktirilmiştir. Yüksek çalışma şartlarına bağlı olarak zamanla aşınma dirençleri düşen hadde merdanelerinin yüzeyinde oluşturulacak kaplamalar ile hem yüzey kaliteleri hem de aşınma davranışlarının iyileştirilmesi çalışmanın ana konusunu oluşturmaktadır. Optimum kaplama parametreleri Taguchi deneyi ile 132 V ve 1230 Hz olarak belirlenmiştir. Varyans, Doğruluk ve Regrasyon analizleri ile elde edilen sonuçların kararlılık seviyesi artırılmaya çalışılmıştır. Deneysel numunelere ısıl işlem uygulanmış, 4 farklı varyasyonda sonuçlar karşılaştırılmıştır. Kaplamaların tribolojik performansları aşınma testi ile belirlenmiştir. Mekanik özellikler ise çekme ve üç nokta eğme testi ile incelenmiştir. Kaplama karakterizasyonuna (element ve bileşik dağılımlarına) SEM/EDS ve XRD ile bakılmıştır. Kaplamaların yüzey pürüzlülüğü 2D profilometre ile ölçülmüştür. Mikro sertlik ölçümleri sonucu altlık numunenin yüzey sertlik değeri 270 ± 5.6 HV0,2' den 1330 ± 12.5 HV0,2 ye yükseldi. İlk duruma göre yüzey sertlik değeri 5 kat arttı. Kaplamalar içerisinde W2C, W ve WC1-x ara fazların varlığına rastlandı. Bu da kaplama içerisinde oluşan dekarbürizasyon oluşma ihtimalini artırmıştır. Isıl işlem görmüş kaplamalı numunelerde WC oranı diğer kaplamalara göre daha fazla hesaplanmıştır. Bu durum hem mikrosertlik değerini, hem de aşınma direncini olumlu yönde etkilemiştir. SEM/EDS sonuçları da bu durumu destekler niteliktedir. Kaplama ve ısıl işlem aşınma direncini 5 kat artırırken sürtünme katsayısını ise 2,13 kat düşürdü. Çekme testinde maksimum gerilme 778 ± 29 MPa, üç nokta eğme testinde maksimum gerilme 1588 ± 8 MPa olarak hesaplandı. Deneysel ortamda kullanılan hadde merdanesine WC/Co kaplamalar başarılı bir şekilde uygulandı. SEM/EDS görüntülerinde kaplamalı bölgede W, Fe, C, Co ve Al elementlerine, kaplamasız bölgede ise Fe, C, ve Al elementlerin varlığına rastlandı. Yapılan literatür çalışmaları sonucu bir hadde merdanesinin kaplanması ve deneysel yönden incelenmesi çalışmanın özgünlüğünü oluşturmaktadır.
In this study, WC/Co coatings were coated on spheroidal graphite cast irons (GGG-60), which is the main material of rolling rolls, by Electro Spark Deposition method. The main subject of the study is to improve both surface quality and wear behavior with the coatings to be formed on the surface of the rolling rolls, whose wear resistance decreases over time due to high working conditions. The optimum coating parameters were determined as 132 V and 1230 Hz by Taguchi experiment. An attempt was made to increase the stability level of the results obtained through Variance, Accuracy and Regression analyses. Heat treatment was applied to the experimental samples, and the results were compared in 4 different variations. The tribological performances of the coatings were determined by the abrasion test. The mechanical effects were investigated by tensile test and three point bending test. Coating characterization (element and compound distributions) was examined by SEM/EDS and XRD. The surface roughness of the coatings was measured with a 2D profilometer. As a result of microhardness measurements, the surface hardness value of the substrate sample increased from 270 ± 5.6 HV0,2 to 1330 ± 12.5 HV0,2. Compared to the first case, the surface hardness value increased 5 times. The presence of W2C, W and WC1-x interphases was found within the coatings. This increased the possibility of decarburization occurring in the coating. WC ratio was calculated more in heat treated coated samples compared to other coatings. This had a positive effect on both the microhardness value and the wear resistance. SEM/EDS results also support this situation. Coating and heat treatment reduced the wear resistance by 5 times and the friction coefficient by 2.13 times.The maximum stress was calculated as 778 ± 29 MPa in the tensile test, and the maximum stress was calculated as 1588 ± 8 MPa in the three-point bending test. WC/Co coatings were successfully applied to a rolling roll used in the experimental environment. In the SEM/EDS images, the presence of W, Fe, C, Co and Al elements in the coated region and Fe, C, and Al elements in the uncoated region were found. As a result of the literature studies, the coating of a rolling roll and its experimental examination constitute the originality of the study.
In this study, WC/Co coatings were coated on spheroidal graphite cast irons (GGG-60), which is the main material of rolling rolls, by Electro Spark Deposition method. The main subject of the study is to improve both surface quality and wear behavior with the coatings to be formed on the surface of the rolling rolls, whose wear resistance decreases over time due to high working conditions. The optimum coating parameters were determined as 132 V and 1230 Hz by Taguchi experiment. An attempt was made to increase the stability level of the results obtained through Variance, Accuracy and Regression analyses. Heat treatment was applied to the experimental samples, and the results were compared in 4 different variations. The tribological performances of the coatings were determined by the abrasion test. The mechanical effects were investigated by tensile test and three point bending test. Coating characterization (element and compound distributions) was examined by SEM/EDS and XRD. The surface roughness of the coatings was measured with a 2D profilometer. As a result of microhardness measurements, the surface hardness value of the substrate sample increased from 270 ± 5.6 HV0,2 to 1330 ± 12.5 HV0,2. Compared to the first case, the surface hardness value increased 5 times. The presence of W2C, W and WC1-x interphases was found within the coatings. This increased the possibility of decarburization occurring in the coating. WC ratio was calculated more in heat treated coated samples compared to other coatings. This had a positive effect on both the microhardness value and the wear resistance. SEM/EDS results also support this situation. Coating and heat treatment reduced the wear resistance by 5 times and the friction coefficient by 2.13 times.The maximum stress was calculated as 778 ± 29 MPa in the tensile test, and the maximum stress was calculated as 1588 ± 8 MPa in the three-point bending test. WC/Co coatings were successfully applied to a rolling roll used in the experimental environment. In the SEM/EDS images, the presence of W, Fe, C, Co and Al elements in the coated region and Fe, C, and Al elements in the uncoated region were found. As a result of the literature studies, the coating of a rolling roll and its experimental examination constitute the originality of the study.
Açıklama
Doktora Tezi
Anahtar Kelimeler
Elektro Kıvılcım Biriktirme, Hadde Merdaneleri, Kaplama, Coating, Electro Spark Deposition, Rolling Rolls, WC-Co
Kaynak
WoS Q Değeri
Scopus Q Değeri
Cilt
Sayı
Künye
Buğday, M. (2024). Hadde merdanelerinin ESD yöntemi ile yüzey modifikasyonu ve aşınma davranışlarının optimize edilmesi. (Yayımlanmamış doktora tezi). Necmettin Erbakan Üniversitesi, Fen Bilimleri Enstitüsü Makine Mühendisliği Anabilim Dalı, Konya.
