Farklı Martenzit Hacim Oranlarında Kırılma Tokluğu Değerlerinin İncelenmesi

Yıl 2020, , 277 - 282, 01.06.2020

Mehmet Fatih Aycan

https://doi.org/10.2339/politeknik.520142

Cited By: 1

Öz

Bu
çalışmada AISI 4140 ve AISI 4340 çeliklerde martenzit hacim oranlarının sertlik
ve kırılma tokluğu üzerindeki etkisi incelenmiştir. Çeliklerin ara kritik
sıcaklık aralıkları belirlenerek üçer farklı sıcaklıkta su verme işlemi,
ardından görüntü işleme yöntemi ile içyapı görüntüleri üzerinde her koşul için
martenzit hacim oranı belirlenmiştir. Ara kritik sıcaklığın artmasıyla
martenzit hacim oranları artış göstermiştir. Numunelere sertlik ve kırılma
tokluğu testleri uygulanmış, martenzit miktarının artmasıyla numunelerin
sertlikleri artarken kırılma tokluğunun azaldığı belirlenmiştir. AISI 4340’ın,
AISI 4140’a göre daha yüksek sertlik değerlerine sahip olmasına rağmen daha
düşük kırılma tokluk değerlerine sahip olduğu görülmüştür. 

Anahtar Kelimeler

AISI 4140, AISI 4340, martenzit hacim oranı, mekanik özellikler

Investigation on Fracture Toughness Values for Various Martensite Volume Fractions

Öz

In this study the effect of martensite volume fraction
on hardness and fracture toughness properties of AISI 4140 and AISI 4340 steels
were investigated. After determining of intercritical boundary temperatures for
steels, the water quenching processes were performed at three intercritical
annealing temperatures. The martensite volume fractions were determined from
microstructure images for each condition by using image processing method. The
martensite volume fraction increased with increasing intercritical temperature.
The hardness and fracture toughness tests were conducted on the specimens.
Increasing of martensite content increased the hardness values whereas
decreased the fracture toughness values. Although AISI 4340 had higher hardness
than AISI 4140, it had lower fracture toughness properties.

Anahtar Kelimeler

AISI 4140, AISI 4340, martensite volume fraction, mechanical properties

Kaynakça

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