Application of acoustic emission to monitor bainitic and martensitic transformation

Woźniak, T. Z.; Rożniatowski, K.; Ranachowski, Z.

doi:10.4149/km_2011_5_319

Cited by 4 publications

(3 citation statements)

References 26 publications

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“…During phase transformations, acoustic effects are generated as a result of dynamic triggering of cumulated energy. Due to the non-invasive method of measuring acoustic emission, it is possible to monitor transformation processes in steel [8][9][10][11]. As a result of changes in the tested object, elastic waves are propagated.…”

Section: Introductionmentioning

confidence: 99%

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Bulletin of the Polish Academy of Sciences: Technical Sciences

Trafarski,

Łazarska,

Ranachowski

2021

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of acoustic emission during heat treatment processes show that this method is the source of relevant information about the phenomena occurring in the processed material [6,7,11,12]. Measurement of acoustic emission signals is performed using the passive method. The apparatus used has no influence on the tested object. Registered signals are related only to the acoustic effects occurring in the material under study [13]. Sources of acoustic emission in metals are [3,5,[14][15][16][17][18][19][20][21]: dislocation motion due to plastic deformation, formation of twins, phase transitions of the displacive type, micro and macro cracks. Acoustic emission is a method of obtaining new information about phenomena occurring during phase changes. The applied research techniques may be used in the industry to test large samples in the future. Monitoring of heat treatment processes is vitally important for the utility values of finished industrial products. By tracking the breakdown kinetics of supercooled austenite, processes can be regulated and improved. New solutions and technologies in this aspect are still being searched for. MATERIALS AND METHODS Research materialThe samples were prepared from 27MnCrB5-2 steel. Samples were taken and prepared from one steel rod. Cylindrical specimens with diameters of 22 mm and height of 25 mm were made. The chemical composition of 27MnCrB5-2 steel is presented in Table 1.The steel subjected to the tests is used in the automotive industry for fasteners of machine parts. The fasteners are heat treated to improve the properties of the material from which they are made. During the tests, the continuous cooling process was performed on the samples.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Bulletin of the Polish Academy of Sciences: Technical Sciences

Trafarski,

Łazarska,

Ranachowski

2021

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“…Bhadeshia [12,13] showed that the kinetics of bainitic transformation is controlled by a nucleation rate. Research related to the kinetics of bainitic transformation were also carried out by T.Z.Woźniak [14][15][16], who proposed a model of transformation mechanism to separate C-curves.…”

Section: Introductionmentioning

confidence: 99%

The Application of Acoustic Emission and Artificial Neural Networks in an Analysis of Kinetics in the Phase Transformation of Tool Steel During Austempering

Łazarska

Woźniak

Ranachowski

et al. 2017

Archives of Metallurgy and Materials

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During the course of the study it involved tool steel C105U was used. The steel was austempered at temperatures of 130°C, 160°C and 180°C respectively. Methods of acoustic emission (AE) were used to investigate the resulting effects associated with transformations and a large number of AE events were registered. Neural networks were applied to analyse these phenomena. In the tested signal, three groups of events were identified of: high, medium and low energy. The average spectral characteristics enabled the power of the signal spectrum to be determined. After completing the process, the results were compiled in the form of diagrams of the relationship of the AE incidence frequency as a function of time. Based on the results, it was found that in the austempering of tool steel, in the first stage of transformation midrib morphology is formed. Midrib is a twinned thin plate martensite. In the 2nd stage of transformation, the intensity of the generation of medium energy events indicates the occurrence of bainite initialised by martensite. The obtained graphic of AE characteristics of tool steel austempering allow conclusions to be drawn about the kinetics and the mechanism of this transformation.

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