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Pre Galvanized Sheet instead of Hot Dip Galvanizing

We are using Cold Rolled Sheet steel for Making Cable trays and send for hot dip galvanizing. Since we are using Pre-galvanized sheets for Cable trunkings, why can't we use pre galvanised (as per ASTM A653) Steel Sheets for Trays? I want to know the corrosive resistance strengths of Hot Dip Galvanized Sheets & Pre galvanized Sheets.

K.Sundara Rajan
- Dubai
2005

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Who said you can't, K? The principal difference is simply that the pre galvanized sheet won't be coated at the sheared edges.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

Can you please clarify the difference between Hot Dip Galvanized & Pre Galvanized

Sajeevan K.V
Technical Assistant - UAE
2007

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There may be a difference, but not necessarily. "Pre galvanized" just means that the material was galvanized as a sheet before it was formed into a product. Usually this will mean that when the item is sheared out of the sheet, or holes are punched into it, that there will be no galvanizing on those sheared and punched edges so they will be more prone to rusting. Those sheared edges may be rolled so they are not exposed (picture the sheet metal on an automobile, where you see no rough metal edges on your trunk lid or hood because they have been 'rolled under' and are inside the trunk and under the hood).

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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Thanks Ted, It means a lot to me, hence I am reviewing MTS for cable trays.

Wilfredo H. Meneses
- Doha, Qatar
February 28, 2012