The Effect of retained austenite and carbide distribution on the wear resistance of bearing steel

Özgeneci, Zeren
This study aims to investigate the effect of the amount of retained austenite and undissolved carbides on the wear resistance of the heat treated bearing steels. As inner and outer ring material 100Cr6 steel grade was used. The specimens were austenitized in the range 800°C to 1000°C, and then, quenched to room temperature in oil to produce a hard martensitic phase. A composite microstructure of undissolved carbides, martensite and retained austenite were observed in hardened steel specimens. It was seen that the amount of undissolved carbides decreases but the amount of retained austenite increases with an increase in austenitization temperature. The amount of retained austenite in all the samples were in the range of 10% to 58% in as-quenched condition. Four different tempering stages were applied to as-quenched samples: The first group and second group specimens were tempered at 180°C and at 235°C, respectively. The third group was double tempered at 190°C, and then, at 170°C. In the fourth group, a subzero treatment at -120°C was applied to the as-quenched specimen before tempering at 170°C. In all tempering operations, the tempering time was 90 minutes. The selection of different combinations of tempering yielded specimens having a very large range of retained austenite content (0%-26%) and hardness values (58 HRC-67 HRC). The highest amount of retained austenite was obtained in the samples tempered at 180°C. On the other hand the lowest amount of retained austenite was obtained in the samples sub-zero treated (-120°C) and tempered at 170°C. For this reason, the wear tests of bearings under contaminated lubrication was prepared from these steel components. It was found that maximum bearing service life time under contaminated lubrication was obtained after an austenitization treatment at 900°C and tempering at 180°C having a hardness of 63 HRC and a retained austenite content of 12%. 


The effect of double austenitization on the microstructure and toughness of AISI M2 high speed steel
Ögel, Bilgehan (1998-06-01)
In this study, the effect of double austenitization on microstructure and toughness of AISI M2 high speed steel was investigated. For double austenitization treatment, the specimens, which are hardened initially at 1220 degrees C and quenched in air, were hardened for a second time in the temperature range 1150 - 1050 degrees C. For comparison purposes, another set of specimens is austenitized singly in the temperature range 1150 - 1050 degrees C. Tempering process was carried out between 500 - 640 degrees ...
The Effects of heat treatment on microstructure, hardness and fatigue behavior of (AMS5659) 15-5 precipitation hardenable stainless steel
Gören, Şahin; Gürbüz, Rıza; Department of Metallurgical and Materials Engineering (2018)
In this study, effects of heat treatment parameters on microstructure, hardness and fatigue behavior of 15-5 precipitation hardenable stainless steels have been examined. Heat treatments have been conducted in three different steps homogenization, solutionizing and aging treatment at different temperatures and times. Microstructural analysis in terms of grain size and chemical composition analysis have been performed by optical and scanning electron microscope (SEM). Then, hardness measurements were applied...
Investigating the Effects of Repair Welding on Microstructure, Mechanical Properties, and Corrosion Behavior of IN-939 Superalloy
Mashhuriazar, Amirhossein; Badihehaghdam, Mohammadhassan; Gür, Cemil Hakan; Ertürk, Murat Tolga; Batıgün, Caner; Tirkeş, Süha; Sajuri, Zainuddin; Omidvar, Hamid (2022-11-01)
This study aimed to investigate the effects of tungsten inert gas (TIG) repair welding on microstructure, mechanical properties, and corrosion resistance of Inconel 939. After welding with Inconel 625 filler under argon atmosphere, the microstructure, hardness, tensile strength, and corrosion resistance of the specimens were analyzed. The results showed that the hardness value and corrosion resistance decreased in the heat-affected zone and particularly in the fusion zone. These changes were attributed to a...
The effect of tempering on susceptibility to stress corrosion cracking of AISI 4140 steel in 33% sodium hydroxide at 80 degrees C
Sarioglu, F (2001-09-30)
The stress corrosion cracking (SCC) behaviour of low alloy steel AISI 4140 was investigated in 33% sodium hydroxide solution at 80 degreesC under freely corroding conditions. Tempering temperatures of 450, 500, 550, 600 and 650 degreesC were used to produce a range of micro structures and strength levels. The relation between the crack growth rate and the stress intensity factor was obtained by constant displacement rate tests conducted on pre-cracked compact tension specimens. The crack growth behaviour an...
Effects of current density, coating thickness, temperature, pH and particle concentration on internal stress during Ni-MoS2 electrocodeposition
Guler, E. Saraloglu; Karakaya, İshak; KONCA, ERKAN (2014-02-01)
Internal stress in plated deposits has been a common problem that may affect the functionality of coatings. Electrodeposition parameters and insoluble particles modify the characteristics and the level of internal stress of coatings. The influence of the electrocodeposition parameters and their interaction effects on the internal stress during the electrodeposition of Ni and Ni-MoS2 composite coatings were studied by fractional factorial design. The parameters studied and their ranges were: MoS2 particle co...
Citation Formats
Z. Özgeneci, “The Effect of retained austenite and carbide distribution on the wear resistance of bearing steel,” M.S. - Master of Science, Middle East Technical University, 2017.