Stainless steel

[Lan123]

Would a type 316 valve welded to a type 304 stainless steel pipe lead to the corrosion of the 304 pipe? Application is clean water. If so what is the best way to protect the pipe without changing the pipe material.

Thanks is advance.

 

[bimr]

Do you have a picture?

 

[rconner]

If all materials in contact end up in the same passive state, and the weld is compatible as well (and also not "sensitized", where I assume it may contact an electrolyte), I guess the risk of dissimilar metal corrosion could be rather low as both materials at are quite close together on most galvanic series charts. That being said, this may be difficult to achieve in the field and in all conceivable conditions, particularly in the weld area and if any stagnation/sedimentation and/or "cervices" exist. While you might get more specialized assistance on the materials/"Corrosion" forum, from a practical standpoint it should be realized presumably "clean" water that may contact the weld area may not always be at the same concentrations, or as as clean, as a grab analysis might seem, and SS systems in general have probably been most vulnerable in weld areas.

 

[weldstan]

316 valves are commonly used in 304 pipe systems in your service. For the most part, this is due to valve manufacturers' preference and stocking practice.