C channel choose material correctly

1.Pre-Galvanised products are very suitable for extended exposure in dry, normal or mildly corrosive environments, but are not typically used outdoors. It has a thickness equal to about one-third that of Hot Dip Galvanised products.

2.Hot Dip Galvanised products are immersed in molten zinc resulting in all surfaces, being completely coated. The most important advantage is the coating thickness, which provides dual protection against corrosion through an overall barrier coating and then a secondary defence of the zinc, which can protect the steel by galvanic action.
Hot Dip Galvanised products are recommended for prolonged outdoor exposure and will offer protection for years in most outdoor or industrial environments.

3.Stainless Steel Grade 304 is a durable material, resistant to many corrosive environments, suitable for use in manufacturing applications. This product is used typically throughout Brewing and Dairy plants.

4.Stainless Steel Grade 316 is a member of the chromium nickel family of austenitic stainless steels, with the addition of 2% molybdenum for improved corrosion resistance. It is particularly resistant to corrosion in chloride environments.
Grade 316 is used where corrosion resistance and long lasting service life is important. Some typical applications of Grade 316 are food and chemical manufacturing plants, marine environments and polluted atmospheres.