Non destructive Characterization of Prior Austenite Structure of AISI D2 Tool Steel by Magnetic Barkhausen Noise Technique

2015-06-18
Davut, Kemal
Kılıçlı, Volkan
Murathan, Ömer Faruk
Şimşir, Caner
Heat treatment operations of steels usually start with austenitization. The properties of the heat treated products, therefore, are strongly influenced by the prior austenite grain structure. The present study aims at investigating the possibility of using magnetic Barkhausen noise (MBN) technique to evaluate the prior austenitic grain structure. For that purpose air quenched AISI D2 cold work tool steel samples were used. In order to obtain samples having different prior austenitic structure, the samples were austenitized between 1000 ⁰C and 1150 ⁰C for 30 minutes. Afterwards all the samples were air quenched. Formation of the desired microstructures was ensured by metallographic examinations. The Barkhausen activity of the samples were evaluated by MBN fingerprints and the root-mean-square value of the noise signal. The results show that with increasing prior austenite grain size, the Barkhausen activity increases due to the enhancement of domain wall displacement. This enhancement is mainly caused by the reduction of prior austenite grain boundary area per unit volume. Apart from the martensitic matrix, the prior austenite grain boundaries act as an additional obstacle to domain wall motion; due to the presence of non-magnetic precipitates at these regions. Moreover; the increase of austenite grain size is accomplished by higher austenitizing temperatures; which in turn reduces the density of alloy carbides by dissolving them. Since the alloy carbides can also restrict domain wall motion, lower density alloy carbides also contribute to higher MBN response of the samples austenitized at a higher temperature. The results indicate that the MBN technique, with a proper calibration, can non-destructively characterize the prior austenitic structure of tool steels.
11th Int Conf on Barkhausen Noise Micromagnetic Testing (ICBM 11), (18 - 20 Haziran 2015)

Suggestions

Sensitivity Analysis of Distortion of Carburized Steel Shafts Using Computer Simulations
Yazır, Büşra; Evcil, Elif; Yıldız, Seçil; Davut, Kemal; Şimşir, Caner (null; 2016-12-01)
Carburizing and subsequent quenching heat treatments are commonly used industrial processes to improve the properties and performance of steel shafts. Undesired dimensional and shape changes (distortion) related to these treatments are still the most frequent reason for expensive and time consuming corrective operations, low performance during service and even product rejection. The major aim of this study is to identify the suitable control parameters for subsequent optimization of the carburized quenching...
Electrochemical production of molybdenum refractory metal powders
Akpınar, Bengisu; Karakaya, İshak; Department of Metallurgical and Materials Engineering (2019)
Molybdenum (Mo) is a refractory metal and mostly used as an alloying agent in cast iron, steels and superalloys to enhance hardenability, strength, toughness and corrosion resistance. It also finds other uses either in the form of a pure metal or an element in, for example, lubricants and catalysts. Traditional metal production methods are not suitable for molybdenum because pure molybdenum has a very high melting point and tends to be oxidized at low temperatures. Hydrogen reduction of molybdenum oxide is ...
Nanowires assembled from iron manganite nanoparticles: Synthesis, characterization, and investigation of electrocatalytic properties for water oxidation reaction
Çetin, Asude; Önal, Ahmet Muhtar; Nalbant Esentürk, Emren (Cambridge University Press (CUP), 2019-09-30)
The development of stable and effective earth-abundant metal oxide electrocatalysts is very crucial to improve competence of water electrolysis. In this study, iron manganite (FeMnO3) nanomaterials were synthesized as an affordable electrocatalyst for water oxidation reactions. The structural and chemical properties of FeMnO3 nanomaterials were studied by transmission electron microscopy, scanning electron microscopy, energydispersive X-ray, X-ray diffraction, X-ray photoelectron spectroscopy, inductively c...
Compressive strength development of calcium aluminate cement-GGBFS blends
Kirca, Onder; Yaman, İsmail Özgür; Tokyay, Mustafa (2013-01-01)
The compressive strength development of calcium aluminate cement (CAC) and ground granulated blast furnace slag (GGBFS) blends that were subjected to different curing regimes are investigated. The blends had GGBFS/CAC ratios between 0% and 80%, by mass. Mortar specimens, prepared with a water:binder:sand ratio of 1:2:6, were subjected to seven different curing regimes and the compressive strengths were monitored up to 210 days. In order to understand the effect of temperature on compressive strength develop...
Non-fickian moisture absorption in polymers coated with a thin nanocomposite layer
Altan, Altan; Altan, M. Cengiz; Guloglu, GÖRKEM EĞEMEN; Güloğlu, Görkem Eğemen (2014-01-01)
Moisture absorption in polymers and polymeric composites is well known to lead to significant degradation in mechanical properties. Most epoxy based composites may absorb 2 to 5 wt.% moisture when they are subjected to humid environments. Moisture absorption in polymers has been often characterized with Fickian or various non-Fickian models to describe the time-dependent absorption phenomena. Previous experiments have shown that dispersing moderate amounts of nanoclay in an epoxy resin can: (i) reduce the t...
Citation Formats
K. Davut, V. Kılıçlı, Ö. F. Murathan, and C. Şimşir, “Non destructive Characterization of Prior Austenite Structure of AISI D2 Tool Steel by Magnetic Barkhausen Noise Technique,” presented at the 11th Int Conf on Barkhausen Noise Micromagnetic Testing (ICBM 11), (18 - 20 Haziran 2015), İzmir, Türkiye, 2015, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/85598.