Single Boride Layer (Fe2B) Formation of Borided AISI M2 High-Speed Steel

Abstract

In this study, AISI M2 High-Speed Steel was borided by a pack-boriding method. Samples were borided in the atmospheric controlled furnace at 900 to 1100 C for 2 to 6h. For the boriding heat treatment, AISI 316 stainless steel crucible and a powder mixture with the trade name EKABOR 2 as the boriding agent were used. After the boriding treatment, samples were metallographically prepared. A scanning electron microscope (SEM) and integrated EDX (Energy Dispersive X-Ray Analysis) unit were used for the microstructure and chemical analysis examinations. As a result of SEM (BE) and EDX examinations, only a single-phase (Fe2B) boride layer is formed on the material surface, unlike many other types of steel. After microscopic examinations, the sample’s hardnesses were measured with the help of the Vickers indenter by 100g. As a result of the experimental studies, it was determined that AISI M2 high-speed steel can be borided, and the thickness of the boride layer increases with the increase in boriding temperature and time. In addition, it has been determined that the boride layer is approximately 5 times harder than the matrix metal.

Keywords

• AISI M2
• pack boriding
• Ekabor 2
• boride layer
• Fe2B phase
• hardness

Borlanmış AISI M2 Yüksek Hız Çeliğinde Tek Fazlı (Fe2B) Borür Tabakası Oluşumu

Öz

Bu çalışmada AISI M2 Yüksek Hız Çeliği kutu-borlama yöntemi ile borlanmıştır. Numuneler atmosferik kontrollü fırında 900 ila 1100 C'de 2 ila 6 saat süreyle borlanmıştır. Borlama ısıl işlemi için AISI 316 paslanmaz çelik pota ve borlama maddesi olarak ticari ismi EKABOR 2 olan toz karışımı kullanılmıştır. Borlama işleminden sonra numuneler metalografik olarak hazırlanmıştır. Mikroyapı ve kimyasal analiz incelemeleri için taramalı elektron mikroskobu (SEM) ve entegre EDX (Energy Dispersive X-Ray Analysis) ünitesi kullanılmıştır. SEM (BEI) ve EDX incelemeleri sonucunda, diğer birçok çelik türünden farklı olarak malzeme yüzeyinde sadece tek fazlı (Fe2B) borür tabakası oluşmuştur. Mikroskobik incelemelerden sonra numunenin sertliğini ölçmek için Vickers indenteri yardımıyla 100 gr. ağırlık kullanılmıştır. Deneysel çalışmalar sonucunda, AISI M2 yüksek hız çeliğinin borlanabileceği, borlama sıcaklığı ve süresinin artmasıyla borür tabakasının kalınlığının arttığı tespit edilmiştir. Ayrıca borür tabakasının matris metalden yaklaşık 5 kat daha sert olduğu tespit edilmiştir.

Anahtar Kelimeler

• AISI M2
• kutu borlama
• Ekabor 2
• borür tabakası
• Fe2B fazı
• sertlik

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