Determination of residual stress state in SAE/AISI 8620 carburized steel by non-destructive testing methods

Download
2017
Kaleli, Tuğçe
Industrial performance of the carburized steels is mainly dependent on the residual stress state in the carburized layer that is controlled by the process parameters such as carburizing temperature and time. Non-destructive evaluation of the material properties and residual stress state has been gained importance for industrial applications due to its advantages such as measurement speed and complete control possibility of the components by automation. The aim of this thesis is to investigate the efficiency of magnetic Barkhausen noise (MBN) method for determining the residual stresses and monitoring variations in residual stress state in AISI/SAE 8620 steel. For this purpose, MBN measurements were performed to observe residual stress state on a series of samples prepared by changing carburizing time and tempering temperature, and then, the results were compared with those of X-ray diffraction methods. Microstructural examinations and micro hardness values were also investigated to analyze the results of the measurements. Increase in the carburizing time up to critical level caused to increase the compressive residual stresses in the carburized layer that is detected as a reduction in MBN emission. Moreover, it was observed that changing tempering temperature causes the change in the martensite morphology and different stress relaxation levels. A clear relationship has been observed between residual stresses and MBN signals. 

Suggestions

Nondestructive monitoring of the variations in microstructure and residual stress in carburized steels
Hızlı, Hüseyin; Gür, Cemil Hakan; Department of Metallurgical and Materials Engineering (2016)
Service life and performance of the case-hardened machine parts are greatly dependent on the residual stress state in the surface layers which directly affects the fatigue behavior. Recently, all industrial sectors have been requested for a fast and non-destructive determination of residual stress. This study aims to monitor the variations in surface residual stress distributions in the carburized 19CrNi5H steels by means of non-destructive and semi-destructive measurement techniques, Magnetic Barkhausen No...
Measurement of residual stresses in the carburized steels by non destructive techniques
Hızlı, Hüseyin; Kaleli, Tuğçe; Gür, Cemil Hakan (null; 2016-10-01)
Residual stress state on the surface layers has a critical effect on the service performance and fatigue life of the carburized components. Non-destructive determination of residual stress state in a rapid and reliable way has being gained importance for industrial applications. The aim of this study is to investigate the efficiency of the magnetic Barkhausen noise (MBN) method for monitoring the residual stress variations as a function of carburizing process parameters. For this purpose, MBN and XRD measur...
Investigation of the effect of orientation and heat treatment on the stress corrosion cracking susceptibility of 7050 aluminium alloy
Çevik, Gül; Doruk, Mustafa; Department of Metallurgical and Materials Engineering (2004)
In the present work, the effect of variation in specimen orientation and heat treatment on the Stress Corrosion Cracking (SCC) susceptibility of 7050 aluminum alloy was investigated in 3,5% NaCl solution and under freely corroding conditions. For this purpose, Constant Extension Rate Tests (CERT) was performed on precracked Compact Tension (CT) specimens and the Direct Current Potential Drop technique was applied to measure the crack lengths. In addition to crack length versus time curves, the relationship ...
Determination of susceptibility to intergranular corrosion in AISI 304L and 316L type stainless steels by electrochemical reactivation method
Aydoğdu, Gülgün Hamide; Aydınol, Mehmet Kadri; Department of Metallurgical and Materials Engineering (2004)
Austenitic stainless steels have a major problem during solution annealing or welding in the temperature range of 500-800 °C due to the formation of chromium carbide, which causes chromium depleted areas along grain boundaries. This means that the structure has become sensitized to intergranular corrosion. Susceptibility to intergranular corrosion can be determined by means of destructive acid tests or by nondestructive electrochemical potentiokinetic reactivation (EPR) tests. The EPR test, which provides q...
Investigation of the influence of specimen geometry on quench behaviour of steels by X-ray determination of surface residual stresses
Gür, Cemil Hakan (Elsevier BV, 2002-7)
Considerable residual stresses may form during quenching due to the differential cooling and the increase in volume accompanying the phase transformations. The design of a part may be entirely responsible for the formation of residual stresses at a critical level and even cracking during quenching. Furthermore, a certain design may be perfectly safe for one type of steel, or one type cooling conditions, and unsafe for another. In this study, an experimental procedure to investigate the influence of specimen...
Citation Formats
T. Kaleli, “Determination of residual stress state in SAE/AISI 8620 carburized steel by non-destructive testing methods,” M.S. - Master of Science, Middle East Technical University, 2017.