Un painted SS 304 Versus Painted SS 304 Versus Galvanized Low Alloy St
Un painted SS 304 Versus Painted SS 304 Versus Galvanized Low Alloy St
(OP)
Conditions: Offshore Marine Humid 50 Dec C
Item: Non pressure but in Support/semi loaded (Spring Holder, or Actuator assembly Tie Rods, Fasteners in Instruments)Tie rods, Bolting material (Studs and Nuts)
Material under Discussion:
1) SS 304 (Solution Annealed) A 193 B 8,
2) SS 304 Painted,
3) Uncoated Low Alloy Steel (A 193 B7 (A 320 L7) grades)
4) Galvanized Low Alloy Steel (A 193 B7 ( A 320 L7)grades)
A) Amongst the above 4, which is the better choice
B) What corrosion test should one conduct to find out the suitability of the material (is B 117 salt spray, suitable test)
C) are there Published Salt Spray test data for the above grades, link or references requested, any NACE or EFC publications?
Thanks in advance
Item: Non pressure but in Support/semi loaded (Spring Holder, or Actuator assembly Tie Rods, Fasteners in Instruments)Tie rods, Bolting material (Studs and Nuts)
Material under Discussion:
1) SS 304 (Solution Annealed) A 193 B 8,
2) SS 304 Painted,
3) Uncoated Low Alloy Steel (A 193 B7 (A 320 L7) grades)
4) Galvanized Low Alloy Steel (A 193 B7 ( A 320 L7)grades)
A) Amongst the above 4, which is the better choice
B) What corrosion test should one conduct to find out the suitability of the material (is B 117 salt spray, suitable test)
C) are there Published Salt Spray test data for the above grades, link or references requested, any NACE or EFC publications?
Thanks in advance





RE: Un painted SS 304 Versus Painted SS 304 Versus Galvanized Low Alloy St
1) this is suitable, but you need to control pitting and SCC
2) a coating might help with pitting and SCC, but coating defects will still allow some of each
3) is completely unsuitable - the corrosion would be severe
4) will provide short life - DNV has data that shows corrosion rate to be 5 to 15 micrometers of zinc per year
B 117 is suitable only with correlation to your environment.
Yes, there are many NACE documents on this subject, but check DNV also.
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.