THE INFLUENCE OF DIFFERENT GRAIN SIZES ON WORKHARDENING BEHAVIOUR OF 316L AUSTENITIC STAINLESS STEEL
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2020-07-10
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info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, farklı tane boyutunun deforme edilmiş AISI 316L östenitik paslanmaz çeliğin çalışma sertleşmesi davranışına ve mekanik özelliklere etkisi araştırılmıştır. 1100 °C’de farklı sürelerde (20 dk, 40 dk, 60 dk, 160 dk, 240 dk, 260 dk) tavlama işlemi yapılmıştır. Tavlama işlemine tabi tutulmuş numunelerin mikroyapı analizleri yapılarak optimum parametrelerin 60 dk, 160 dk ve 260 dk tavlana numunelerde olduğu tespit edilmiştir. Bu numuneler 1x10-3 s-1 gerinim oranında ve 25 °C, 500 °C ve 800 °C sıcaklıklarda soğuk, ılık ve sıcak deformasyon işlemine tabi tutulmuştur. Her test sonrası gerilme-gerinim diyagramları elde edilerek, bu diyagramlardan farklı sıcaklıklarda çekme testine tabi tutulan her numune için maksimum çekme dayanımı, akma dayanımı (% 3), uzama (%) ve çalışma sertleşmesi üsteli belirlenmiştir. Sonuçlar, tüm numunelerin mukavemet ve çalışma sertleşmesi üstelinin artan test sıcaklığı ile azaldığını, ancak kaba taneli numunelerde mukavemet ve çalışma sertleşmesi üstelindeki düşmenin ince taneli numunelere kıyasla daha az olduğunu göstermiştir. Bunun nedeni, kaba taneli numunelerde dislokasyon ve çözünen atomların etkileşimi nedeniyle ortaya çıkan ve 500 °C veya 800 °C’de belirgin testere dişi davranışın oluşmasına neden olan dinamik deformasyon yaşlanmasıdır.
In this study, the effects of the different grain sizes on workhardening behavior and mechanical properties of deformed AISI 316L austenitic stainless steel were investigated. Heat treatment was carried out at 1100 °C for different times (20 min, 40 min, 60 min, 160 min, 240 min, 260 min.). The microstructure analysis of the samples subjected to heat treatment were done and optimum parameters were determined as 60 min, 160 min. and 260 min. These samples were cold, warm and hot deformed at 25 °C, 500 °C and 800 °C for the strain rate of 1x10-3 s-1. Stress and strain diagrams were obtained after each test and maximum tensile strength, yield strength (3%), elongation (%) and workhardening index were determined for each sample subjected to tensile test at different temperatures. The results showed that strength and workhardening index of all samples decreased with increasing test temperature, however decrement in strength and workhardening index is more less in coarse grained samples compared to the finer grained samples. This is due to dynamic strain ageing occured in the coarse grained samples which showed more pronounced serrated behaviour after testing at 500oC or 800oC due to interaction of mobile dislocations and solute atoms."
In this study, the effects of the different grain sizes on workhardening behavior and mechanical properties of deformed AISI 316L austenitic stainless steel were investigated. Heat treatment was carried out at 1100 °C for different times (20 min, 40 min, 60 min, 160 min, 240 min, 260 min.). The microstructure analysis of the samples subjected to heat treatment were done and optimum parameters were determined as 60 min, 160 min. and 260 min. These samples were cold, warm and hot deformed at 25 °C, 500 °C and 800 °C for the strain rate of 1x10-3 s-1. Stress and strain diagrams were obtained after each test and maximum tensile strength, yield strength (3%), elongation (%) and workhardening index were determined for each sample subjected to tensile test at different temperatures. The results showed that strength and workhardening index of all samples decreased with increasing test temperature, however decrement in strength and workhardening index is more less in coarse grained samples compared to the finer grained samples. This is due to dynamic strain ageing occured in the coarse grained samples which showed more pronounced serrated behaviour after testing at 500oC or 800oC due to interaction of mobile dislocations and solute atoms."
Açıklama
Anahtar Kelimeler
Östenitik paslanmaz çelik, soğuk, ılık ve sıcak deformasyon, tane boyutu, çalışma sertleşmesi., Stainless steel, cold, warm and hot deformation, grain size, workhardening.
