著者

黒田 雅利 島崎 智憲 岩本 達也 秋田 貢一 小林 祐次 水野 悠太

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.72, no.3, pp.154-160, 2023-03-15 (Released:2023-03-20)

参考文献数

13

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In order to develop the technique to predict the surface characteristics of fatigue specimens of austenitic stainless steels by controlling finishing processing of lathe turning and shot peening, the applicability of the response surface models formerly created by the present authors using experimental design of experiments approaches to the fatigue specimens with different types and/or rolling conditions of austenitic stainless steels have been investigated. The conclusive remarks could be summarized as follows: (1) The predicted surface residual stress obtained by the response surface model of the lathe turning created for the round bars of SUS304 agreed with the observed surface residual stress of the fatigue specimen of SUS316. (2) The response surface model of the shot peening created for the flat plate of SUS316 was applicable to the prediction of the surface roughness RSm, the surface hardness and the surface residual stress of the fatigue specimen of SUS316 in spite of the different processing of the shot peening and the rolling conditions of the material.

著者

下羽 悠一 石川 徹朗 大谷 眞一 秋田 貢一

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.55, no.12, pp.1139-1145, 2006 (Released:2006-12-20)

参考文献数

8

被引用文献数

3 4

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The X-ray stress measurement based on sin2ψ method has been widely adopted. This technique is not entirely efficient, because it is necessary to measure each diffraction profile one after other at five and more incident X-ray angles. On the other hand, stress measurement based on cosα method was proposed using X-ray film as detector. In this method, the stresses are determined from Debye-ring obtained at a single X-ray incident angle with high efficiency. However, it has the problem in this accuracy on stress determination. In this study, a new stress analyzer with sixteen position sensitive proportional counters (PSPC) radially arranged for incidence X-ray was developed. We examined to determine the plane stress components by multi-regression analysis using sixteen diffraction angles on a Debye-ring. As a result, stress components of σx and τxy were measured with sufficient accuracy. However, a stress of σy had large dispersion, because of low strain sensitivity in the y direction. Moreover, it was clarified that σy had pseud-multicollinearity on multi-regression analysis. The accuracy of σy value itself could not be improved, though an analysis to eliminate an effect of pseud-multicollinearity was carried out. In this paper, we proposed the new method to determine the components using two Debye rings obtained by X-ray incidences in both x and y directions. We tried to measure the residual stress components in the butt welded joint using the method. As a result, it was confirmed that the stresses, σx and σy, were obtained in the sufficient accuracy, and that the shear stress, τxy, was arising near the bond in the welds.

著者

黒田 雅利 釜谷 昌幸 山田 輝明 秋田 貢一

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.852, pp.17-00072-17-00072, 2017 (Released:2017-08-25)

参考文献数

13

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In order to assess the fatigue damage of austenitic stainless steels by electron backscatter diffraction (EBSD) method more simply and easily, it should be more preferable to use a commercially available general-purpose EBSD analysis software rather than to employ an in-house developed EBSD analysis programme. In the present study, EBSD measurement was performed for Type 316 austenitic stainless steels subjected to cyclic loading, and the applicability of the EBSD parameter relevant to the pattern quality, which could be obtained by the commercial software, to the fatigue damage assessment was discussed by comparing the other EBSD parameter of the averaged local misorientation (Mave), which could be calculated by the in-house developed programme. As a result, the EBSD parameter relevant to the pattern quality, which signified the full width at half maximum (FWHM) of the histogram distribution of the image quality (IQ), was saturated at the beginning stage of the fatigue cycles, while Mave was increased monotonically with the cycles. This suggested that the FWHM of IQ could be useful to detect the initial stage of the fatigue damage, while Mave was suitable for the quantitative evaluation of the fatigue damage. XRD measurement was also carried out for the same samples employed in the EBSD measurement, and the XRD data was compared with the EBSD data to discuss the crystallographic mechanism of the change in the FWHM of IQ. As a result, it was found that the FWHM of the (111) XRD peak correlated well with the FWHM of IQ. Because the (111) plane in fcc metal such as austenitic stainless steel was most preferable for slip system, this implied that the change in the distribution of the pattern quality generated by the fatigue loading could be due to the slip deformation.