Isıl İşlemin Yüksek Manganlı Çeliklerin Mikroyapısı ve Darbe Direnci Üzerindeki Etkileri

Öz

Yüksek manganlı çelikler, yüksek gerilme koşullarında güvenli bir şekilde çalışabilmenin son derece önemli olduğu madencilik, inşaat, çimento ve metalürji sektörleri başta olmak üzere birçok alanda aşınmaya ve darbeye dayanıklı malzemeler olarak yaygın şekilde kullanılmaktadır. Bu noktada, malzemenin karbon ve manganez oranı, ısıl işlem sonrasında döküm parçanın mikroyapısı üzerinde önemli bir etkiye sahiptir. Bu nedenle ısıl işlem koşullarının malzemenin kimyasal bileşimine göre uygun şekilde belirlenmesi gerekmektedir. Bu çalışmada GX120MnCr18-2 DIN standardına sahip yüksek manganlı çelik numunelere 1030~1100 oC arasındaki çeşitli östenitleme sıcaklıklarında ısıl işlemler uygulanmıştır. Numuneler optik mikroskopta incelenerek SEM/EDS analizleri gerçekleştirilmiştir. Yukarıda bahsi geçen numunelerin darbe dayanımı ve sertlik değerleri sırasıyla TS EN ISO 148-1 ve TS EN 130 6508-1 standartlarına göre yapılan testler ile ölçülmüştür. Bu incelemelerden östenitleme sıcaklığı arttıkça karbür çözünürlüğünün arttığı, darbe dayanımının ise önce arttığı daha sonra azaldığı görülmüştür.

Anahtar Kelimeler

• yüksek manganlı çelik (YMÇ)
• ısıl işlem
• mikroyapısal analiz
• darbe dayanımı

Effects of Heat Treatment on Microstructure and Impact Resistance of High Manganese Steels

Öz

High manganese steels are widely used as wear- and impact-resistant materials in many areas, especially in the mining, construction, cement, and metallurgy sectors, where it is extremely important to be able to work safely in high-stress conditions as well as resistance to abrasion under heavy loading conditions thanks to their unique work-hardening performance. At this point, the carbon and manganese ratio of the material has a considerable influence on the microstructure of the cast part after the heat treatment. Therefore, heat treatment conditions have to be determined appropriately depending on the chemical composition of the material. In this study, heat treatment processes were applied to high manganese steel specimens having GX120MnCr18-2 DIN standard at various austenitizing temperatures between 1030~1100 oC. The specimens were examined under an optical microscope and SEM/EDS analyses were performed. Impact resistance and hardness values of the above-mentioned specimens were measured via the tests performed with TS EN ISO 148-1 and TS EN 130 6508-1 standards, respectively. From these investigations, it was determined that the carbide solubility increased as the austenitizing temperature increased while the impact resistance first increased and then decreased.

Anahtar Kelimeler

• high manganese steel (HMS)
• heat treatment
• microstructural analysis
• impact resistance

Kaynakça

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