FERRİTİK DÖKME DEMİRİN ÖSTEMPERLEME ÇALIŞMASININ DEĞERLENDİRİLMESİ

Yıl 2024, , 165 - 171, 30.04.2024

Tanju Teker , Serdar Osman Yılmaz

https://doi.org/10.54365/adyumbd.1438508

Öz

Bu çalışmada, ferritik sfero dökme demirlerin yapısal karakterizasyonuna östemperleme sıcaklıklarının etkisi analiz edilmiştir. Östemperleme, tam bir östenit yapı elde etmek için malzemelerin 900 ºC sıcaklıkta yeterli bir süre östenitlenmesi ve ardından bir aralık sıcaklığında su vermedir. Östemperleme 320, 420 ve 520 ºC' de 1.5 saat süreyle elde edilmiştir. Numunelerin metalurjik karakterizasyonu, optik mikroskopi, enerji dağılımlı spektrometri, X-ışını kırınımı, mikrosertlik kullanılarak belirlendi. Östemperleme sıcaklığı, ferritik sfero dökme demirlerin faz değişimleri üzerinde dikkate değer bir etkiye sahipti. Daha yüksek derecede östemperleme, ausferrit adı verilen daha kaba bir yapı üretti.

Anahtar Kelimeler

Östemperleme, Mikroyapı, Ausferrite, Sertlik.

EVALUATION OF AUSTEMPERING STUDY OF FERRITIC CAST IRON

Öz

In this study, the effect of austempering temperatures on the structural characterization of ferritic spheroid cast irons was analyzed. Austempering was the austenitization of the materials in the temperature of 900 ºC for an adequate period to obtain a complete austenite structure and then quenching to an interval temperature. Subcritical diffusion times were achieved at 320, 420, and 520 ºC ausferrite temperatures for period of 1.5 h. Metallurgical description of samples was defined using optical microscopy, energy dispersive spectrometry, X-ray diffraction, microhardness. The austempering temperature had a remarkable effect on the phase variations of the ferritic ductile cast irons. The higher degree of austempering produced a coarser structure called ausferrite.

Anahtar Kelimeler

Austempering, Microstructure, Ausferrite, Hardness.

Kaynakça

• Chang LC. Carbon content of austenite in austempered ductile iron. Scripta Materialia 1998; 39: 35–38.
• Lawrynowicz Z, Dymski S. Mechanism of bainite transformation in ductile iron ADI. Archives of Foundry Engineering 2006; 6: 171–176.
• Szykowny T. Isothermal eutectoidal transformation in ductile cast iron EN-GJS-500-7. Archives of Foundry 2005; 5: 303–312.
• Dymski S, Giętka T. Influence of gradual austenitizing on chosen properties of ADI. Archives of Foundry Engineering 2008; 8: 185–190.
• Giętka T, Dymski S. Predicting ADI mechanical properties. Archives of Foundry Engineering 2009; 9: 267–274. [6] Nofal AA. Advances in the metallurgy and applications of ADI. Journal of Metallurgical Engineering 2013; 2: 1–18.
• Jianghuai Y, Putatunda SK. Influence of a novel two-step austempering process on the strain-hardening behaviour of austempered ductile cast iron (ADI). Materials Science and Engineering A 2004; 382: 265–279.
• Kiani-Rashid AR. Influence of austenitising conditions and aluminium content on microstructure and properties of ductile irons. Journal of Alloys and Compounds 2009; 470: 323–327.
• Sidjanin L, Rajnovic D, Eric O, Smallma RE. Austempering study of unalloyed and alloyed ductile irons. Materials Science and Technology 2010; 26: 567–571.
• Ramadan M, Fathy N. Influence of semi-solid isothermal heat treatment on microstructure and mechanical properties of ductile cast iron. Journal Minerals and Materials Characterization Engineering 2014; 2: 26–31.
• Mandal D, Ghosh M, Pal J, De PK, Ghosh Chowdhury S, Das SK, Das G. Effect of austempering treatment on microstructure and mechanical properties of high-Si steel. Journal of Materials Science 2009; 44: 1069–1075.
• Ochulor EF, Adeosun SO, Amuda MOH, Balogun SA. Strength characteristics of inoculated and nodularized thin wall ductile iron castings. Journal Minerals and Materials Characterization Engineering 2015; 3: 94–105.
• Qu Y, Xing J, Zhi X, Peng J, Fu H. Effect of cerium on the as-cast microstructure of a hypereutectic high chromium cast iron. Materials Letters 2008; 62: 3024–3027.
• Aranzabal J, Serramoglia G, Rousiere D. Development of a new mixed (ferritic-ausferritic) ductile iron for automotive suspension parts. International Journal of Cast Metals Research 2003; 16: 185–190.
• Rao PP, Putatunda SK. Comparative study of fracture toughness of austempered ductile ırons with upper and lower ausferrite microstructures. Materials Science and Technology 1998; 14: 1257–1265.
• Rao PP, Putatunda SK. Dependence of fracture toughness of austempered ductile ıron on austempering temperature. Metallurgical Materials Transactions A 1998; 29: 3005–3016.
• Erdogan M, Kilicli V, Demir B. Transformation characteristics of ductile iron austempered from intercritical austenitizing temperature ranges. Journal of Materials Science 2009; 44: 1394–1403.
• Yang J, Putatunda SK. Improvement in strength and toughness of austempered ductile cast iron by a novel two-step austempering process. Materials and Design 2004; 25: 219–230
• Benam AS. Effect of alloying elements on austempered ductile iron (ADI) properties and its process: Review. China Foundry 2015; 12: 54–70.
• Erdogan M, Kilicli V, Demir B. The influence of the austenite dispersion on phase transformation during the austempering of ductile cast iron having a dual matrix structure. International Journal of Materials Research 2008; 99, 751–760.