Role of Methanol on Pitting of Type 316 Stainless Steel

CORROSION ◽  
2005 ◽  
Vol 61 (12) ◽  
pp. 1136-1144 ◽  
Author(s):  
T. Ramgopal ◽  
S. Amancherla
Author(s):  
Ryosuke Fujikawa ◽  
Shigeki Abe ◽  
Takao Nakamura ◽  
Masayuki Kamaya

This study was aimed at investigating the role of crack initiation and growth rate on the fatigue life reduction by environmental effect. First, crack length and the number of cracks were observed on the inner surface of specimens after fatigue test in PWR environment and air. Next, incubation time was deduced by inverse analysis. Third, statistical crack initiation and growth behavior was simulated by a Monte Carlo model. The influence of multiple crack interaction and coalescence to the fatigue life were discussed. It was revealed that environmental effect enhanced crack initiation and accelerated crack growth. Moreover, coalescence of cracks was estimated to influence fatigue life of 316 stainless steel in PWR environment.


2018 ◽  
Author(s):  
Pawan Tyagi ◽  
Tobias Goulet ◽  
Christopher Riso ◽  
Kate Klein ◽  
Francisco Garcia-Moreno

Improving surface finishing is the critical step in the application of an additively manufactured (AM) component. This paper provides insights into the electropolishing route for the surface improvement of the AM component made up of 316 stainless steel with >6% carbon. We have discussed the Taguchi design of experiment-based process optimization to understand the role of various process parameters. Profilometry and scanning electron microscopy were performed to study the electropolished and unpolished areas of the AM components. Optical profilometry provided an estimate of the amount of material to be removed to achieve shining and smooth AM surface. Optical profilometry also provided analysis of several roughness parameters on the electropolished surface. Electropolishing was effective in reducing the surface roughness below ~0.1 µm RMS. This sub µm RMS roughness makes an AM component suitable for major engineering applications. SEM showed distinctively different microstructure on the electropolished surface. We also conducted water contact angle study and spectroscopic reflectance study on electropolished and unpolished AM component surface. Our study revealed that electropolishing is a highly promising route for improving the surface finishing of AM components.


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