Silicon Bronze and Stainless Steel 1

[dik]

Is there a problem with using silicon bronze and 316L stainless steel nuts and bolts. Any citations?

Thanks, Dik

 

[TomDOT]

You have to define conditions and timeframe. Inside my office for a week, there will be no problem. Gulf of Mexico in the splash zone with a design life of 100 years? I expect there to be a problem. Your bronze is likely to be something like a quarter volt more negative than passivated 316L

http://www.corrosionist.com/Galvanic_Series_of_Metal_in_Seawater.htm

 

[TVP]

Start with this document:

http://www.nickelinstitute.org/Tech...cticalGuidetoUsingMarineFasteners_10045_.aspx

 

[dik]

Corrosive mining area NaCl and KCl... normal humidity and rain, exposure indoors and outside.

I thought there might be a galvanic corrosion issue... probably best to go with stainless throughout, except for 'galling' issues in tightening stainless against stainless...

Dik

 

[TVP]

Based on that environment, I would be concerned with crevice corrosion. Type 316 (A4 ISO 3506-1 and -2) may not be adequate. Since the galvanic difference is not that large, you might be able to get away with this dissimilar joint, but it would be difficult to extrapolate any kind of short-term lab test into a meaningful long-term field exposure.

 

[CoryPad]

Silicon bronze not likely to be great for this application. For continuous exposure to chloride environments, Monel 400 or K-500 are some copper containing alloys that are used.

 

[EdStainless]

If you want to stay Cu based then Al brass or NiAL Bronze would be better options.
I agree with the crevice corrosion risk with 316.
Can you find hardware in 2205? That might be a good option.
Exposed to rain is better than under cover, at least it will get rinsed once in a while.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[dik]

Thanks very much, gentlemen... I've looked into Monel fasteners and if available, will use these.

Dik