The Use of SiC Materials as Inoculants in Gray Cast Iron and Their Effects on Mechanical Properties

Abstract

Gray cast iron is widely used in the automotive and machinery industries due to its excellent castability, high thermal conductivity, and superior vibration damping capacity. However, because of its lamellar graphite structure, it exhibits lower mechanical properties than steel and spheroidal graphite cast iron. Therefore, numerous experimental studies have focused on inoculation treatments to improve graphite morphology and mechanical performance. In this study, the effects of different inoculants on the microstructural and mechanical properties of gray cast iron were investigated. In-stream inoculation was applied during mold filling using high purity green silicon carbide (SiC), metallurgical SiC, and barium-containing FeSi inoculants. Uninoculated and inoculated specimens were evaluated by thermal analysis, optical microstructural examination, and mechanical testing. The thermal analysis results showed that the eutectic temperature, recalescence, and graphitization tendency varied depending on the inoculant used. Microstructural observations revealed that D- and E-type graphite predominated in the uninoculated samples, whereas inoculated samples exhibited A-type graphite and a more homogeneous microstructure. Mechanical test results indicated a reduction in hardness due to the increased ferrite content, while the tensile and yield strengths increased by approximately 10%. The findings demonstrate that the in-stream inoculation process significantly improves graphite morphology, microstructural homogeneity, and mechanical performance of gray cast iron. Furthermore, high-purity green SiC exhibited promising potential as an alternative inoculant to conventional inoculation materials.

Keywords

• Gray cast iron
• SiC
• microstructure
• thermal analysis
• hardness

Supporting Institution

Erkunt Sanayi A.Ş.

Project Number

E24-019

Ethical Statement

This study has been prepared in accordance with the principles of scientific research and publication ethics. All sources used in the research process have been accurately and completely cited, and information taken from other studies has been used with appropriate references. No unethical practices such as plagiarism, data fabrication, falsification, duplicate publication or unjust authorship have been employed at any stage of the study. As the author, I declare that the study is original and has been completed in accordance with ethical rules.

Thanks

This study was supported by Erkunt Sanayi A.Ş. We would like to express our gratitude to the R&D Centre Directorate for their contributions.

SiC Malzemelerin Gri Dökme Demirde Aşılayıcı Olarak Kullanımı ve Mekanik Özelliklere Etkisi

Abstract

Gri dökme demirler, üstün dökülebilirlik, yüksek ısı iletkenliği ve titreşim sönümleme kabiliyeti sayesinde otomotiv ve makine imalat sanayinde yaygın olarak kullanılmaktadır. Ancak lamel grafit yapısı nedeniyle çelik ve küresel grafitli dökme demirlere göre daha düşük mekanik özellikler sergilemektedir. Bu nedenle, grafit morfolojisini iyileştirmek amacıyla aşılama işlemi üzerine birçok deneysel çalışma yürütülmektedir. Bu çalışmada, farklı aşılayıcıların gri dökme demirin mikroyapısal ve mekanik özellikleri üzerindeki etkileri araştırılmıştır. Deneysel çalışmalarda, sıvı metalin kalıba dökümü sırasında akışa aşılama yöntemi uygulanmış; yüksek saflıkta yeşil Silisyum Karbür (SiC), metalürjik SiC ve baryum içeren FeSi aşılayıcıları kullanılmıştır. Aşısız ve aşılanmış numuneler termal analiz, optik mikroyapı incelemeleri ve mekanik testlerle değerlendirilmiştir. Termal analiz sonuçları, ötektik sıcaklık, geri ısınma miktarı ve grafitleşme eğiliminin kullanılan aşılayıcıya bağlı olarak değiştiğini göstermiştir. Mikroyapı incelemelerinde, aşı uygulanmayan numunelerde D ve E tipi grafit yapıları baskın iken, aşılanan numunelerde A tipi grafit oluşumu ve daha homojen bir yapı elde edilmiştir. Mekanik testler sonucunda, artan ferrit oranına bağlı olarak sertlik değerlerinde azalma, buna karşılık çekme ve akma dayanımlarında yaklaşık %10 oranında artış belirlenmiştir. Elde edilen bulgular, akışa aşılama yönteminin grafit morfolojisini iyileştirerek gri dökme demirin mikroyapısal homojenliğini ve mekanik performansını önemli ölçüde geliştirdiğini, özellikle yeşil SiC'nin geleneksel aşılayıcılara alternatif olabilecek potansiyele sahip olduğunu göstermektedir. 

Keywords

• Gri dökme demir
• mikroyapı
• termal analiz
• sertlik.

Supporting Institution

Erkunt Sanayi A.Ş.

Project Number

E24-019

Ethical Statement

Bu çalışma, bilimsel araştırma ve yayın etiği ilkeleri gözetilerek hazırlanmıştır. Araştırma sürecinde kullanılan tüm kaynaklar doğru ve eksiksiz biçimde belirtilmiş, başka çalışmalardan alınan bilgiler ise uygun şekilde atıf yapılarak kullanılmıştır. Çalışmanın hiçbir aşamasında intihal, veri tahrifi, sahtecilik, tekrar yayın veya haksız yazarlık gibi etik dışı uygulamalara yer verilmemiştir. Yazar olarak, çalışmanın özgünlüğünü ve etik kurallara bağlı kalınarak tamamlandığını beyan ederim.

Thanks

Bu çalışma Erkunt Sanayi A.Ş. tarafından desteklenmiştir. Katkılarından dolayı Ar-Ge Merkezi Müdürlüğü’ne teşekkürlerimizi sunarız.

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