5XXX alüminyum alaşımları üzerine uygulanacak fosfatlama işlemi ve organik kaplamalar ile cass testi ve çevrimsel korozyon direncini artıran proses geliştirilmesi
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Dosyalar
Tarih
2021
Yazarlar
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Yayıncı
BTÜ, Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Son yıllarda teknolojinin de gelişmesiyle birlikte başta otomotiv sektörü olmak üzere bir çok farklı sektörde ağır çelik malzemeler yerine daha hafif, daha dayanıklı ve daha tasarruflu metaller tercih sebebi olmaya başladı. Çünkü ağırlık çelik malzemelerin kullanımından dolayı özellikle otomotiv sektöründe çok fazla yakıt tüketimine buna bağlı olarak da maliyetlerin artmasına sebep olmaktadır. Hafif metal olarak alümiyum metali, hem doğada çok bulunmasından, hem yüksek korozyon dayanımları sağlamasından hem de alaşım halde şekillendirilebilmesinden dolayı en çok tercih edilenlerin başında gelmektedir. Çeliğe göre üçte bir daha hafif olan alüminyum metali ve alaşımlarının kullanıldığı araçlarda, daha iyi motor performansı ve yol tutuculuğunun yanında, titreşim ve gürültü gibi olumsuz durumlar en aza indirgenebilmektedir. İlerleyen yıllarda alüminyumun çelik malzemelerin yerine geçerek bir çok sektörde performansı yüksek araçlar üretilmesi hedeflenmektedir. Bu tez çalışmasında, otomotiv endüstrisinde en çok tercih edilen, magnezyum katkısıyla yüksek mukavemet ve yüksek korozyon direnci sağlayabilen 5XXX dövme alüminyum alaşımlarından, 5005 ve 5754 serileri seçilerek, metal yüzeyinde korozyon oluşumunu önleyecek farklı çalışmalar yapılmıştır. 1 mm et kalınlığında 150x100 mm boyutlarındaki plakalar üzerinde yapılan çalışmalarda, destek sağlanan proje kapsamında çok fazla deneme ve tekrar olduğundan dolayı Taguchi deneysel tasarımıyla belirlenen çalışma değerleri göz önünde bulundurulmuştur. 5005 ve 5754 tipi her bir alüminyum alaşımlı plaka türü için, 3'er adet plaka üzerine 5 farklı fosfat kaplama işlemi yapılmıştır. Fosfat kaplama işleminde özellikle fosfatlama ve aktivasyon süresiyle banyo içerisindeki toplam flor değerine dikkat edilmiştir. Fosfat kaplanmış plakaların bir sonraki kaplama işlemleri öncesi taramalı elektron mikroskobu olan SEM cihazı ile fosfat kristal yapıları incelendi. Bu aşamada metal yüzeyde olan fosfat kristallerinin boyutları ve örtücülükleri gözlemlendi. Sonrasında fosfat kaplanmış her plaka üzerine ayrı ayrı kataforez kaplama, çinko lamelli kaplama ve toz boya kaplamaları yapıldı. Bu kaplama işlemleri sonrası plakalara ön değerlendirme için kuru yapışma ve nem direnci gibi ön performans testleri uygulandı. Yapılan değerlendirmeler sonucu ön performans testlerini geçen çalışmaların çevrimsel korozyon testleri ve CASS testleri yani bakırla hızlandırılmış asetik asit tuzu püskürtme testleri başlatıldı. Tüm bu testler otomotiv sektöründe geçerliliği olan Renault 47-01-000-E ve Volksvogen DBL 7391 kaplama standartlarına uygun olacak şekilde başlatıldı ve test sonrası değerlendirmeler bu standartlara uygun olacak şekilde yapıldı.
With the development of technology in recent years, lighter, more durable and more economical metals have started to be preferred instead of heavy steel materials in many different sectors, especially in the automotive sector. Because of the use of heavy steel materials, it causes a lot of fuel consumption, especially in the automotive sector, and therefore an increase in costs. As a light metal, aluminum metal is one of the most preferred ones because it is found in nature, provides high corrosion resistance and can be shaped as an alloy. In vehicles using aluminum metal and alloys that are one-third lighter than steel, adverse situations such as vibration and noise can be minimized in addition to better engine performance and road holding. In the following years, it is aimed to produce high performance vehicles in many sectors by replacing aluminum with steel materials. In this thesis study, the 5005 and 5754 series were selected from 5XXX forged aluminum alloys, which are the most preferred in the automotive industry, which can provide high strength and high corrosion resistance with magnesium additive, and different studies have been carried out to prevent corrosion on the metal surface. In the studies performed on 1 mm wall thickness and 150x100 mm sized plates, the working values determined by the Taguchi experimental design were taken into consideration as there were too many trials and repetitions within the scope of the project supported. For each type of aluminum alloy plate type 5005 and 5754, 5 different phosphate coating processes were made on 3 plates. In the phosphate coating process, particular attention was paid to the phosphating and activation time and the total fluorine value in the bath. Phosphate crystal structures were examined with a scanning electron microscope SEM device before the next coating processes of the phosphate coated plates. At this stage, the size and hiding power of the phosphate crystals on the metal surface were observed. Afterwards, cataphoresis coating, zinc flake coating and powder paint coatings were applied on each phosphate coated plate. After these coating processes, preliminary performance tests such as dry adhesion and humidity resistance were applied to the plates for preliminary evaluation. As a result of the evaluations, cyclic corrosion tests and CASS tests, namely copper accelerated acetic acid salt spray tests, were initiated for the studies that passed the pre-performance tests. All these tests were initiated in accordance with the Renault 47-01-000-E and Volksvogen DBL 7391 coating standards, which are valid in the automotive industry, and post-test evaluations were made in accordance with these standards.
With the development of technology in recent years, lighter, more durable and more economical metals have started to be preferred instead of heavy steel materials in many different sectors, especially in the automotive sector. Because of the use of heavy steel materials, it causes a lot of fuel consumption, especially in the automotive sector, and therefore an increase in costs. As a light metal, aluminum metal is one of the most preferred ones because it is found in nature, provides high corrosion resistance and can be shaped as an alloy. In vehicles using aluminum metal and alloys that are one-third lighter than steel, adverse situations such as vibration and noise can be minimized in addition to better engine performance and road holding. In the following years, it is aimed to produce high performance vehicles in many sectors by replacing aluminum with steel materials. In this thesis study, the 5005 and 5754 series were selected from 5XXX forged aluminum alloys, which are the most preferred in the automotive industry, which can provide high strength and high corrosion resistance with magnesium additive, and different studies have been carried out to prevent corrosion on the metal surface. In the studies performed on 1 mm wall thickness and 150x100 mm sized plates, the working values determined by the Taguchi experimental design were taken into consideration as there were too many trials and repetitions within the scope of the project supported. For each type of aluminum alloy plate type 5005 and 5754, 5 different phosphate coating processes were made on 3 plates. In the phosphate coating process, particular attention was paid to the phosphating and activation time and the total fluorine value in the bath. Phosphate crystal structures were examined with a scanning electron microscope SEM device before the next coating processes of the phosphate coated plates. At this stage, the size and hiding power of the phosphate crystals on the metal surface were observed. Afterwards, cataphoresis coating, zinc flake coating and powder paint coatings were applied on each phosphate coated plate. After these coating processes, preliminary performance tests such as dry adhesion and humidity resistance were applied to the plates for preliminary evaluation. As a result of the evaluations, cyclic corrosion tests and CASS tests, namely copper accelerated acetic acid salt spray tests, were initiated for the studies that passed the pre-performance tests. All these tests were initiated in accordance with the Renault 47-01-000-E and Volksvogen DBL 7391 coating standards, which are valid in the automotive industry, and post-test evaluations were made in accordance with these standards.
Açıklama
Anahtar Kelimeler
Kimya, Chemistry
