Nondestructive evaluation of the effects of carburizing process parameters on microstructure and residual stress state of SAE 9310 steel via magnetic Barkhausen noise method

Yıldırım, Zafer
Carburizing is a surface treatment process applied for improving the surface hardness, wear resistance, and also fatigue life of some critical aerospace and automotive components, such as gears, bearings, and bushings. It consists of carbon diffusion into low-C steels in the austenitized condition which results in a carbon gradient along with the depth, then followed by quenching, sub-zero treatment, and tempering. In a carburized component, a strong and wear-resistant surface layer (the case) with compressive residual stress, as well as hardness and residual stress gradients from the case to the core is expected. Residual stresses, which are critical for the performance and stability of the engineering components, are defined as the self-equilibrating elastic stresses in a component in the absence of external stresses, created during manufacturing. In carburized components, the C-gradient affects the phase transformations on cooling and, thus, the final patterns of the microstructure and the residual stress. Besides, depending on the carbon content, carburized steels may contain retained austenite up to 10%, which affects the magnitude and the depth profile of the residual stress, and also, the dimensional stability of the part. Controlling the success of the carburizing process is vital to satisfy the design requirements and to guarantee safety with expected performance and lifetime. This necessitates practical, reliable, and time- and cost-effective non-destructive evaluation methods by the manufacturers. The aim of this thesis is to determine non-destructively the effects of the parameters of the carburizing process chain on microstructure, hardness, and residual stress state by using the Magnetic Barkhausen Noise (MBN) method. In the experimental part, a series of SAE 9310 steel specimens having different microstructure and residual stress states were prepared by altering the cooling rate (air-cooling, quenching), the carburizing time (3h, 6h), the cryogenic treatment temperature (-25°C, -75°C, -100°C), and the tempering temperature (150°C, 300°C). The specimens were systematically characterized through metallographic investigations, hardness measurements, measurements of retained-austenite and residual stress by the XRD method, and MBN measurements. The results show that a good correlation exists between the results obtained by conventional methods and the parameters derived from the MBN signals.


Comparison of Nondesturctive Stress Measurement Techiques for Determinatuion of Residual Stresses in the Heat Treated Steels
Hizli, Huseyin; Gür, Cemil Hakan (MATERIALS RESEARCH FORUM LLC, 105 SPRINGDALE LN, MILLERSVILLE, PA 17551 USA; 2018-09-14)
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 of the variations in surface residual stress distributions in the carburized 19CrNi5H steels by means of non-destructive and semi-destructive measurement techniques, Magnetic Barkhausen...
Nondestructive Characterization of Microstructures of Heat-Treated Steels by Magnetic Barkhausen Noise Technique
Gür, Cemil Hakan (2017-01-01)
Optimization and control of the microstructure is important for improving the properties of steel components. Development of non-destructive techniques for microstructure characterization is a critical task. Magnetic Barkhausen Noise (MBN) technique is a promising and challenging non-destructive technique for automated evaluation of microstructures in steel components in a fast and reliable manner. This paper presents the results of MBN measurements for microstructure characterization of the quenched and te...
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...
Gür, Cemil Hakan; Yelbay, Hasan İlker; Çam, İbrahim (2010-06-11)
Residual stresses have significant inflences on the service performance of the welded components. Various studies have been continuing to develop nondestructive methods for determination of residual stresses with portable equipment and short measurement time, as an alternative to the existing techniques such as X-ray diffraction. This study aims to investigate the applicability of Magnetic Barkhausen Noise method on predicting surface residual stresses in the welded steel plates.
Comparison of Electronic Speckle Laser Interferometry Hole-Drilling and X-ray Diffraction Techniques for Determination of Residual Stresses in the Heat Treated Steels
HIZLI, HÜSEYİN; Gür, Cemil Hakan (2017-06-01)
Carburizing is widely used to improve wear resistance and fatigue life of high duty machine parts. Fatigue performance of the carburized components is greatly dependent on the residual stress state in the surface layer. The aim of this paper is to measure the depth profiles of residual stresses in the carburized steels by electronic speckle laser interferometry (ESPI) assisted hole-drilling, and to compare the results with those measured by X-ray diffraction technique. To comprehend the differences in the r...
Citation Formats
Z. Yıldırım, “Nondestructive evaluation of the effects of carburizing process parameters on microstructure and residual stress state of SAE 9310 steel via magnetic Barkhausen noise method,” M.S. - Master of Science, Middle East Technical University, 2022.