NDTnet 1998 Aug, Vol.3 No.8

Abstract

A feature of the present stage of development in engineering is automation which requires on-line control of dimensions and on-line evaluation of the condition of the material. Systematic research studying the surface and near surface layer condition of the workpiece / product material after mechanical and/or heat treatment started some three decades ago. In the beginning researchers were concerned with descriptions of surface integrity by measuring surface roughness, microhardness, residual stresses in the surface layer and quite often also me/allographic analysis. These methods all belong to destructive methods where analysis is made on specially prepared specimens. These methods are time-consuming and suitable only for laboratory analysis. In industrial practice, especially in automotive industry where on-line and total quality control of parts and products are often required, a need has emerged for fast, accurate and reliable methods. Therefore in the last decade, very intensive research has been started in the field of non-destructive evaluation methods and their introduction into automated manufacturing systems. Among numerous non-destructive evaluation methods we can mention the analysis of residual stresses and analysis of properties in the surface layer after various heat treatment procedures based on the Barkhausen effect.

The paper presents a measuring system for detecting the magnetic Barkhausen noise for which research has shown that it is a carrier of information on the properties and changes in ferromagnetic materials. These properties and changes refer to hardness, microstructure, heat treatment, cold deformation, chemical composition and also residual stresses. The reported research investigation is restricted to observations of the relationship between the suitably analysed frequencies of Barkhausen noise signals and different cold deformation of carbon steel.

Keywords: Micromagnetic method, Magnetic Barkhausen Noise, Low Carbon Steel, Cold Deformation, Microstucture Analyisis

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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