Electric urns with drinking water
Electric urns with drinking water
(OP)
Please help me to clarify this
why electric urns didn't crack when exposed to boiled drinking water around 80-100C, i heard that it will be contained with XX ppm of chloride.
Electric urns made from SS304 , that's all we know . and normally from manufacturing process it will definitely have a residual stress.
Thanks
N.
why electric urns didn't crack when exposed to boiled drinking water around 80-100C, i heard that it will be contained with XX ppm of chloride.
Electric urns made from SS304 , that's all we know . and normally from manufacturing process it will definitely have a residual stress.
Thanks
N.





RE: Electric urns with drinking water
The other issue is that even though the urns have fairly high residual stress it mostly results from them being formed and stretched, so the residual stresses are in the opposite direction making them mostly compressive. Add to this the flexibility of the urns and you can see why cracking failures are rare. In commercial kitchens they do happen from time to time with larger heavier equipment.
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P.E. Metallurgy, Plymouth Tube
RE: Electric urns with drinking water
Chloride SCC depends on a lot of things. It's not merely a matter of having chloride in solution, having residual stress and operating above 60 C.
Chloride stress cracks tend to start at chloride pits. You pretty much need pitting conditions for SCC to initiate.
If the surface is flushed and the passive layer allowed to "heal" between exposures, the likelihood of pitting and hence SCC reduces quite a bit, which may explain at least partially why the food equipment handles it so well. Food prep equipment also tends to have good surface prep, especially relative to ordinary stainless pipe.