Monitoring the microstructural changes during tempering of quenched SAE 5140 steel by magnetic barkhausen noise

Davut, Kemal
Gür, Cemil Hakan
The aim of this work is to characterize the microstructures of quenched and tempered steels non-destructively by a diverse set of parameters of the Magnetic Barkhausen Noise method (MBN fingerprint, frequency spectra, pulse height distribution, root-mean-square, and total number of pulses). Identical specimens from a SAE 5140 steel bar were prepared. All specimens were austenitized at 860 degrees C for 30 minutes and water-quenched identically. The quenched specimens were then tempered at various temperatures between 200 degrees C and 600 degrees C. The microstructures were characterized by metallographic examinations and hardness measurements. Pulse height distributions, noise signal envelopes and frequency spectra were used to evaluate Barkhausen activity. The results show that as the tempering temperature increases, the Barkhausen activity increases due to the enhancement of domain wall displacement with softening of the martensite. An excellent correlation was found between Barkhausen parameters and hardness values.


Monitoring the Microstructural Evolution in Spheroidized Steels by Magnetic Barkhausen Noise Measurements
DAVUT, Kemal; Gür, Cemil Hakan (Springer Science and Business Media LLC, 2010-12-01)
The aim of this study is to monitor nondestructively the degree of spheroidization in steels by Magnetic Barkhausen Noise (MBN) method. Various series of specimens consisting of either lamellar pearlite or partially/completely spheroidized carbides were produced from AISI 1060 steel by appropriate heat treatments. All specimens were characterized by metallographic examinations, hardness and MBN measurements. The results show that MBN signals are very sensitive to the variations in the microstructure caused ...
Characterization of dual-phase steels using magnetic barkhausen noise technique
KAPLAN, MÜCAHİT; Gür, Cemil Hakan; Erdogan, METEHAN (Springer Science and Business Media LLC, 2007-12-01)
The aim of this work is to nondestructively characterize the dual phase steels using the Magnetic Barkhausen Noise (MBN) method. By quenching of AISI 8620 steel specimens having two different starting microstructures, from various intercritical annealing temperatures (ICAT) in the ferrite-austenite region, the microstructures consisting of different volume fractions of martensite with morphological variations have been obtained. The microstructures were first conventionally characterized by metallographical...
Investigation of the variations in microstructure and mechanical properties of dual-matrix ductile iron by Magnetic Barkhausen Noise analysis
Gür, Cemil Hakan; Erdogan, Mehmet (Informa UK Limited, 2008-01-01)
The variations in the microstructure and tensile properties of dual-matrix ductile irons have been investigated non-destructively by Magnetic Barkhausen Noise (MBN) method. Specimens have been intercritically austenitised at 795 degrees C and 815 degrees C for 20 minutes, and then oil-quenched to obtain different martensite volume fractions. Two specimens, namely as-cast and oil-quenched from 900 degrees C, were prepared for comparison purpose. To investigate the effect of tempering, some specimens were tem...
Processing forced vibration test records of structural systems using the analytic signal
Çelik, Ozan Cem (SAGE Publications, 2020-09-01)
This article presents the use of the analytic signal procedure for processing the large volume of structural vibration data recorded in forced vibration tests. The analytic signal facilitates the computationally laborious task of extracting the steady-state amplitude for each response measure of interest from the recorded accelerations throughout the building at each operated frequency of the forced vibration source. The implementation of the signal processing procedure introduced here is illustrated in der...
Comparison of magnetic Barkhausen noise and ultrasonic velocity measurements for microstructure evaluation of SAE 1040 and SAE 4140 steels
Gür, Cemil Hakan; Çam, İbrahim (Elsevier BV, 2007-05-01)
The aim of this study is to compare the performance of magnetic Barkhausen noise and ultrasonic methods for the evaluation of the microstructure of commercial steels. Following the austenitization of the specimens made of SAE 1040 and SAE 4140, various heat treatments were carried out to obtain microstructures consisting of martensite, tempered martensite, fine pearlite-ferrite, and coarse pearlite-ferrite. The microstructures were initially characterized by SEM investigation and hardness measurements. The ...
Citation Formats
K. Davut and C. H. Gür, “Monitoring the microstructural changes during tempering of quenched SAE 5140 steel by magnetic barkhausen noise,” JOURNAL OF NONDESTRUCTIVE EVALUATION, pp. 107–113, 2007, Accessed: 00, 2020. [Online]. Available: