Publication: Eklemeli imalat ile üretilen Inconel 718 parçalarının ezerek parlatma yöntemiyle yüzey iyileştirme sürecinin modellenmesi ve deneysel doğrulanması
Abstract
Inconel 718 gibi süper alaşım malzemeler, yüksek sıcaklıklarda mukavemetlerini korumaları, ısı iletim katsayılarının düşük olması, pekleşme kabiliyetlerinin olması gibi sebeplerden dolayı geleneksel yöntemlerle imalat süreçleri zor ve maliyetli olan malzemelerdir. Ayrıca, havacılık endüstrisinde özellikle uçak motorlarında kullanılan parçaların karmaşık geometrili ve bazı durumlarda ince olmaları bu paçaların geleneksel yöntemlerle üretimini daha da zorlaştırmakta ve üretim maliyetlerinin arttırmaktadır. Tüm bunlar dikkate alındığında, Eklemeli İmalat (Eİ) teknolojisi diğer birçok endüstride olduğu gibi havacılık endüstrisinde de geleneksel yöntemlerle kıyaslandığında önemli üstünlüklere sahip ve tercih edilebilir bir yöntem olmaktadır. Günümüzde birçok Eİ yöntemi mevcut olmasına karşın Lazerle Toz Yatağında Füzyon (LTYF) yöntemi diğer Eİ yöntemlerine kıyasla çok daha yaygın kullanılan bir yöntemdir. Ancak LTYF yöntemi ile metalik parçaların imalatında karşılaşılan en önemli sorunların başında ısıl gerilmeler, çarpılmalar ve üretilen parçaların çok yüksek yüzey pürüzlülükleri gelmektedir. Bu çalışmada, sonlu elemanlar yönteminde LTYF ile üretilen Inconel 718 alaşım malzemesine ısıl işlemin, ezerek parlatmanın ve ısıl işlem görmüş haline ezerek parlatmanın etkisi ortaya konmuştur. Bu ikincil işlemlerin deneysel doğrulaması yapılmış. İkincil işlemlerden sonra, parçaların yüzey kalitesinin arttığı ve mekanik özelliklerinde gelişmelerin olduğu gözlemlenmiştir. İkincil işlemlerden sonra sonlu elemanlar yöntemiyle ve ampirik yaklaşımla analiz edilen kalıntı gerilme değerleri karşılaştırılmış ve sonuçların birbiriyle uyuştuğu sonucuna varılmıştır.
Super-alloy materials such as Inconel 718 are materials that are difficult and costly to manufacture with traditional methods for reasons such as maintaining their strength at high temperatures, low heat transfer coefficients and hardening capabilities. In addition, the fact that the parts used in the aviation industry, especially in aircraft engines, have a complex geometry and in some cases, makes it difficult to manufacture these trophies by traditional methods and increases production costs. Considering all these, additive manufacturing technology is considered as a preferred method in the aviation industry, as in many other industries that has significant advantages over traditional methods. Although there are many additive manufacturing methods available today, Laser Powder Bed Fusion (LTYF) method is a much more widely used method compared to other additive manufacturing methods. However, the most important problems encountered with the manufacturing of metallic parts with LTYF method are thermal stresses, distortions and very high surface roughness of the produced parts. In this study, the effects of heat treatment, roller burnishing and roller burnishing in the heat treated state on Inconel 718 alloy material produced with LTYF in the finite element method were revealed. Experimental validation of these post-processesing has been done. After post-processing, it was observed that the surface quality of the parts increased and there were improvements in their mechanical properties. After the post-processing, the residual stress values analyzed with the finite element method and the empirical approach were compared and it was concluded that the results agree with each other.
Super-alloy materials such as Inconel 718 are materials that are difficult and costly to manufacture with traditional methods for reasons such as maintaining their strength at high temperatures, low heat transfer coefficients and hardening capabilities. In addition, the fact that the parts used in the aviation industry, especially in aircraft engines, have a complex geometry and in some cases, makes it difficult to manufacture these trophies by traditional methods and increases production costs. Considering all these, additive manufacturing technology is considered as a preferred method in the aviation industry, as in many other industries that has significant advantages over traditional methods. Although there are many additive manufacturing methods available today, Laser Powder Bed Fusion (LTYF) method is a much more widely used method compared to other additive manufacturing methods. However, the most important problems encountered with the manufacturing of metallic parts with LTYF method are thermal stresses, distortions and very high surface roughness of the produced parts. In this study, the effects of heat treatment, roller burnishing and roller burnishing in the heat treated state on Inconel 718 alloy material produced with LTYF in the finite element method were revealed. Experimental validation of these post-processesing has been done. After post-processing, it was observed that the surface quality of the parts increased and there were improvements in their mechanical properties. After the post-processing, the residual stress values analyzed with the finite element method and the empirical approach were compared and it was concluded that the results agree with each other.