316L has developed radial cracks; is it a corrosion issue? Pictures attached
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Our company produces 4 reaction kettles. The material is 31603; the medium consists of alkali, isopentanol, and water. The operating temperature is 150 degrees, while the operating pressure ranges from -0.01 to 0.15 Mpa. One of the units is now experiencing the problem shown in the image: there are two pits, and after these pits were smoothed, radiating cracks were detected during dye penetrant testing. What could be the cause? Seek a solution.
If the crack appears outside the weld and its heat-affected zone, the likelihood of alkali embrittlement is high. Alkali embrittlement is related to the original properties of 316L material (such as grain size and heat treatment), the concentration of alkalis, and the operating temperature; thorough inspections should be carried out to eliminate the cracks.
Once metal develops \"alkali embrittlement\", it is difficult to eliminate completely; one can only take necessary measures to slow down its progression. Welding again may lead to widespread cracking in certain areas. It is recommended to carry out repairs from the outside of the reactor after stopping the cracking process. You might want to consult Sorex Industries for advice – I hope this helps.
What can the concentration of the base reach? Concentration and temperature are factors affecting alkali embrittlement
Is the crack shaped like a withered branch? It could be chloride stress corrosion cracking! !