Hülya DURMUŞ, Canser GÜL, Fatma Gizem ÇAKIR

Farklı Menevişleme Sıcaklıklarının 51CrV4 Çeliğinin Mekanik Özelliklerine Etkilerinin İncelenmesi

Otomotiv ve makine endüstrilerinde, yorulma dayanımı yüksek olan birçok parçanın imalatında; yüksek mukavemetleri, yüksek darbe dayanımları ve mükemmel yorulma performansları nedeniyle 51CrV4 çelikleri tercih edilmektedir. Isıl işlem uygulanabilir ve sertleştirilebilir çelik grubunda yer alırlar. Yapılan bu çalışmada tavlama ve yağda soğutma yapıldıktan sonra farklı iki sıcaklıkta menevişleme işlemi uygulanan 51CrV4 çeliği numuneler incelenmiştir. Farklı sıcaklıkta işlem gören numunelerin, morfolojilerinde ve mekanik özelliklerindeki değişim incelenmiştir. Menevişleme işleminin aşınma dayanımı üzerine olan etkileri tartışılmıştır. Çalışmanın sonucunda ferritik matris içinde karbür çökeltilerinden oluşan ve beynitik yapı içeren iki farklı mikroyapıya ulaşılmıştır. Kesit ve yüzeyden alınan sertlik ölçümlerinde belirgin bir farklılık gözlemlenmemiştir. Buna rağmen, yapılan çekme, çentik darbe ve kuru kum kauçuk aşınma testleri sonucunda numune grupları arasında belirgin farklılıklar gözlemlenmiş ve en uygun menevişleme sıcaklığının 315 °C olduğu sonucuna varılmıştır.

Investigation into Effects of Different Tempering Temperatures on Mechanical Properties of 51CrV4 Steel

In the automotive and machinery industries; 51CrV4 steels are preferred due to their high strength, high impact strength, and excellent fatigue performance for the manufacturing of fatigue sensitive parts. They are included in the group of heat treatable and hardenable steels. In this study, samples of 51CrV4 steel tempered at two different temperatures after annealing and oil cooling were examined. The changes in the morphology and mechanical properties of the samples processed at different temperatures were analyzed. The effects of tempering on wear resistance were discussed. As a result of the study, two different microstructures consisting of carbide sediments in the ferritic matrix and containing a bainitic structure were reached. No significant difference was observed in the hardness measurements taken from the section and the surface. However, as a result of the tensile, charpy impact, and dry sand rubber wheel abrasion tests, significant differences were observed between the sample groups and it was concluded that the most suitable tempering temperature was 315 ° C.

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