Table 1 - uploaded by Rungsiya Sukhon
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Relation of relative permeability of 304 and 316 at a low magnetic field strength and various cold reductions.
Source publication
The OIML R 111-1 requirements on magnetic properties such as the volumetric magnetic susceptibility (χ) and the magnetization of weights used in legal metrology. So far, these requirements cannot met by weights produced locally in Thailand. This research, therefore, aims to study manufacturing processes that may influence the magnetic properties. I...
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Citations
... Unlike with relative permeability, air cannot be used as a zero Fe% reference point since the magnetic susceptibility of pure austenite is much higher compared to air. The values of relative magnetic permeability µr for fully annealed austenitic steels found in the literature vary typically between 1.003 and 1.009 (Chinzei, Kikinis and Jolesz, 2006;Sukhon et al., 2010). ...
Austenitic stainless steels are commonly used in harsh environments, where corrosion resistance and structural integrity at elevated temperatures are essential to be maintained. Hence, many nuclear energy reactor components are made of austenitic materials, where safety relies on the material's microstructure. Since paramagnetic austenite is prone to transformation into ferromagnetic bcc/bct α' martensite, magnetic and electromagnetic methods are often used to characterize the respective volume fractions. At elevated temperatures, the amount of the deformation-induced α' martensite is substantially reduced and difficult to detect, which possess some unique challenges for magnetic methods. Within this paper a possibility of detecting α' martensite below 0.1% volume is described. As an investigation tool, magnetic force imaging was chosen, as it provides spatially resolved information on magnetic susceptibility, which can be further interpreted as the density of ferrite and α' martensite. The results show that the main obstacle in the reliable estimation of small quantities of α' is calibration. The second problem is the inhomogeneous distribution of α' martensite and possibly a very small grain size, which has magnetic properties more similar to paramagnetism, rather than ferromagnetism.
... Childress et al. [5] have examined the changes of the crystal structure of 304 stainless steel caused by heat treatment at 800°C, showed that magnetic bcc crystal structure was changed to non magnetic fcc crystal structure. Sukhon et al. [6] on 2010, have studied on the changes of magnetic properties on 304 and 316L stainless steel caused by their manufacturing process. ...
The changes in the value of magnetic susceptibility of SS 304 due to heat treatment effect were examined in this research to observed its possibility to be used as material for OIML weight standards. Five samples of 100 g from SS 304 were prepared and their magnetic susceptibiity were measured based on the Bureau International des Poids et Mesures method following different heat treatment to each sample. Heating temperature points were selected at 800 and 1,100 °C, each of them followed by slow and rapid cooling method. Change in the value of magnetic suceptibility was confirmed with X-ray diffraction (XRD) method to examine the change in the amount of ferrite on each sample. The initial value of magnetic susceptibility measured on the sample without heat treatment was (0.0064 ± 0.0007), and the lowest value obtained from the different samples was (0.0040 ± 0.0004) measured on the sample with heat treatment at 800 °C. The lowest magnetic susceptibility value obtained in this research met the requirement of the international recommendation and the measured change of the value of magnetic susceptibility was consistent with the amount of ferrite that contained in the sample obtained based on XRD pattern.
