The chemical composition of steel will drastically change the outcome of the steel being galvanized.
Galvanized steel with higher silicon content will appear dark gray in color, matted and as result the coating will become brittle. The ideal composition of steel should consists of less than 0.25% carbon, 0.05% phosphorous and manganese of less than 1.3%.
As mentioned above the ideal silicon content should range between 0-0.04% or 0.15-0.25%. Materials galvanized properly should appear shiny with a spangled pattern covering their surface.
The Life Expectancy of Galvanized Steel
The metallurgical bond galvanizing provides, gives it an advantage over other coatings should materials get damaged during transport, assembly or regular wear and tear. Life expectancy of galvanized steel can be in excess of 50+ years. It is not uncommon for galvanized steel to last from 20 to 25 years in the most severe urban and coastal environments.