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Coastal Urban Furniture: Corrosion Problems

2005

I am working at my End-of-Degree Project, which topic is the improvement of the design of various pieces of urban furniture (street lamps, mailboxes and dustbins). The main problems concerning corrosion appear of course when they are placed near the coast. Now the most employed materials are galvanized steel sheet, aluminium and stainless steel, either PE-powder painted or blank. I would really welcome information related to the following questions:

How could I protect the sharp edges of galvanized steel sheet? I have observed them in the microscope and they appear completely blank, with no traces of Zn or painting. I suggested spraying them with Zn after being cut, but the adhesion of the painting which must be applied later results strongly deteriorated.

Are big pores (up to 90 micrometers in a 100 micrometers-paint layer) inside the painting harmful? Are they avoidable or intrinsic to the power-painting process?

Is anodized Aluminium (AlMg1 or AlMg3) resistant against sea aerosol?

I have seen a plate (1.5 mm thick) made of AISI 430 completely covered with rust stains after 16 months. Which steel should I use? How could I predict the life (meaning through-corrosion) of such a plate?

Which tests (salt spray test, condensation, corrosive gases ) should pass a part to assure a 20-year life without pretty big aesthetic problems (red-rust edges, rust stains bigger than 2 cm, etc) when placed near the coast? How could I compare the test-hours with the real life-years?

Thank you very much for your help.

Ana Ilvarez GarcÌa
Student - San Sebastian, Spain

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Hi Ana,

I can't help you with your questions regarding which materials would be the best for this application, but I can tell you that there is no accelerated corrosion test whose result correlates with real-life performance. The accelerated tests are good for providing information about relative performance.

George Gorecki
- Naperville, Illinois
2005

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I have heard of a test that is said to correlate quite well with outdoors conditions in the Great Lakes area. It was apparently developed for the car industry corrosion testing. It is called SAE J2334. Check it out.

Jean-Pierre Mamin
- Bergamo, Italy
2005

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2005

Thanks, Jean-Pierre.

I have checked it out. It seems to be very interesting.
But I have heard about other tests performed in the Automotive industry, and the sequence is Saltmist + Humidity + Dry phase, instead of Humidity + Saltmist + Dry. Which is the difference? Which effects arise in both cases?

Thank you very much for your help.

Ana Alvarez
- San Sebastian, Spain

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2005

YOU SHOULD TRY
HOT DIP GALVANIZED
THERE ARE NORMS ASTM A123
YOU CAN CONSULT ABOUT THAT
MY COMPANY IS INVOLVED IN FABRICATION OF GRATING STEEL INDUSTRIAL FLOORS SAFETY FENCES AND URBAN FURNITURE

OVER 95% OF THE INDUSTRY USE HOT DIP GALVANIZED
ALUMINIUM BRASS AND STAINLESS STEEL ARE FAIR BUT PRICES ARE 3 TO 10 TIMES HIGHER.

WE PROVIDE ANTIVANDALIC URBAN FURNITURE MADE OF GRATING STEEL HOT DIP GALVANIZED.

PABLO JASIENOVICZ
- ZARTETE, BSAS, ARGENTINA