Stress Corrosion Cracking of 304L and 316L Stainless Steels in Salt-Spray Environment

碩士 === 國立臺灣海洋大學 === 材料工程研究所 === 101 === In this work, 304L stainless steel (SS) was subjected to either sensitization treatment at 650℃/10hr or grain-coarsening treatment at 1150℃/1hr before rolling to 20% reduction in thickness. The effects of carbide precipitation and coarse grain size on the stre...

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Bibliographic Details
Main Authors: Yu-Chin Ho, 何昱瑾
Other Authors: Wu Kai
Format: Others
Language:zh-TW
Published: 2013
Online Access:http://ndltd.ncl.edu.tw/handle/38582882853031050766
Description
Summary:碩士 === 國立臺灣海洋大學 === 材料工程研究所 === 101 === In this work, 304L stainless steel (SS) was subjected to either sensitization treatment at 650℃/10hr or grain-coarsening treatment at 1150℃/1hr before rolling to 20% reduction in thickness. The effects of carbide precipitation and coarse grain size on the stress corrosion cracking (SCC) of the specimens were evaluated and compared to the base metal specimen. The susceptibility of distinct specimens to SCC was ranked by determining the maximum and total crack length of the U- bent specimen at 80℃ in a salt-spray environment. The results indicated the effect of grain-coarsening treatment had a minor role on the SCC susceptibility. However, the sensitization before rolling could obviously raise the cracking susceptibility of the specimens in the salt-spray environment. Moreover, the crack path was more likely to change from transgranular to intergranular for the sensitized specimens. It was noted that cracks tended to initiate at the intersection of slip bands in the cold-rolled specimens. The step-wise crack growth in all the specimens was associated with the crack growth along the slip bands or induced martensite therein. Various samples were exposed to the salt-spray environment and periodically measured the weight loss of the samples. The results indicated the cold-rolled and sensitized specimens showed higher weight loss than other specimens. Furthermore, the base metal was more resistant to surface dissolution in the salt-spray condition under the free applied-loading.