SUS304 corrosion by high levels of Chloride content in water
SUS304 corrosion by high levels of Chloride content in water
(OP)
How to avoid corrosion of SUS304 (stainless steel) by higher levels of Chloride content in the water (200mg/Liter) while it comes to Solar Hot Water systems in specific.





RE: SUS304 corrosion by high levels of Chloride content in water
304 is unsuitable for warm chloride solutions; 316 may also be unsuitable depending upon T & [NaCl]. Probably need to use a duplex stainless steel. See
Saltwater corrosion engineering Forum
304 vs 316 for below waterline marine applications on boats
thread307-178690
Some info on duplex stainless steels:
http://
RE: SUS304 corrosion by high levels of Chloride content in water
I have some curves based on experience, basically if you can keep the pH up (7.5-8.5) with 304 you can handle close to 200ppm total Cl in solution. This is a pitting limit.
The problem is that if you have crevices then crevice corrosion will start at lower levels.
The other problem is that chloride stress corrosion cracking is a real risk.
Moving to 316 will not get you better pitting resistance (at this pH and temp) and the CSCC will still be a risk.
You may want to look at lean duplex grades. Both LDX2101 and AL-2003 will give you plenty of CSCC resistance. The LDX2101 has pitting resistance slightly better than 304. The AL-2003 is better than 316. In the case of the duplex grades the data indicates that higher alloy content results in higher pitting resistance under these conditions.
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