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Process to determine life time of galvanized steel

April 7, 2009

Dear sir,

I work in a hot dip galvanizing plant and I would like to know if there is any cost effective and accurate way of determining the lifetime of galvanized steel?

Please advice and would appreciate a quick response.

Iresha Ranasinghe
Trainee chemist - Sapugaskanda, Colombo, Sri Lanka.

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April 9, 2009

The life expectancy of galv is dependent on many factors.
The environment and the thickness of the zinc are the most important.
For a fixed environment, the life expectancy is proportional to the thickness. Double the thickness will double the life.

As to environment, the most important factor is the sulfur level. Mostly coming from car exhaust and industrial pollution, this forms acid rains and is corrosive to the zinc.

Have a look at this site.
http://www.hdg.org.uk/126_Corrosion_Maps.php
for an idea of life expectancy in the UK. That doesn't mean it works for other countries, some of which have their own similar maps.
The UK map is based on actual data from hundreds of samples.

Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK