H.Özkan GÜLSOY, Lütfi YAKUT, Semih ÖZBEY

Nb İlavesi ve Sinter Şartlarının Toz Enjeksiyon Kalıplama ile Üretilmiş AISI- 420 Martenzitik Paslanmaz Çelikler Üzerine Etkisi : Mikroyapısal, Mekanik ve Korozyon Özellikler

Bu araştırma makalesinde, Toz Enjeksiyon Kalıplama metodu kullanılarak üretilmiş AISI-420 martenzitik paslanmaz çeliklerin mikroyapısal, mekanik ve korozyon özellikleri üzerine Nb ilavesinin ve sinterleme şartlarının etkisi incelenmiştir. Gaz atomizasyonu ile üretilmiş önalaşımlı AISI-420 paslanmaz çelik tozlar polimerik bağlayıcılar ile karıştırılarak besleme stoğu oluşturulmuş ve enjeksiyon kalıplama metodu kullanılarak şekillendirme işlemleri gerçekleştirilmiştir. Kalıplama işlemi sonrasında, solvent ve ısıl bağlayıcı giderme işlemleri uygulanarak kullanılan bağlayıcıların büyük bir kısmı yapıdan uzaklaştırılmıştır. Bağlayıcısı giderilmiş numuneler 1250-1350 oC sıcaklık aralığında H2 ve Ar atmosferi altında sinterlenmiştir. Nihai özelliklerin eldesi için numuneler sinterleme sonrasında ısıl işlemlere tabi tutulmuştur. Isıl işlem görmüş numunelerin yoğunlukları Arşimet prensibine göre ölçülmüştür. Mikroyapısal gelişimlerin belirlenmesi için metalografik prosedürler; mekanik özelliklerin belirlenmesi için çekme testi ve sertlik ölçümleri; korozyon dirençlerinin tespiti için potansiyometrik ölçümler gerçekleştirilmiştir. Nihai numunelerin %99 kısmi yoğunluk değerlerine ulaştığı, Nb ilavesinin tüm mekanik ve korozyon özelliklerini geliştirdiği gözlemlenmiştir. Buna ilave olarak H2 sinterleme atmosferinde sinterlenen numunelerin en iyi özellikleri sergilediği görülmştür.

The Effect of Nb Addition and Sintering Conditions on AISI-420 Martensitic Stainless Steels Produced by Powder Injection Molding: Microstructural, Mechanical and Corrosion Properties

In this research article, the effect of Nb addition and sintering conditions on the microstructural, mechanical and corrosion properties of AISI-420 martensitic stainless steels produced by Powder Injection Molding method was investigated. The feedstock was formed by mixing the alloyed AISI-420 stainless steel powders produced by gas atomization with polymeric binders and shaping processes were carried out using the injection molding method. After the molding process, solvent and thermal binder removal processes were applied and most of the binders used were removed from the structure. The debinded samples were sintered under H2 and Ar atmosphere in the temperature range of 1250-1350 oC. Samples were subjected to heat treatment after sintering in order to obtain the final properties. Densities of heat-treated samples were measured according to Archimedes principle. Metallographic procedures for determining microstructural developments; tensile testing and hardness measurements to determine mechanical properties; potentiometric measurements were carried out to determine corrosion resistance. It was observed that the final samples reached 99% relative density values, and Nb addition improved all mechanical and corrosion properties. In addition, samples sintered in an H2 sintering atmosphere were found to exhibit the best properties.

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