Summary for galvanized vs cold rolled Discussion
Galvanized vs cold rolled is the core tradeoff in this thread: Davies Wakefield asks for advantages and disadvantages of cold rolled, phosphatized, and painted steel versus galvanized, phosphatized, and painted steel, especially for paint adhesion, weldability, environmental concerns, health risks, and coating durability. The answer says that when galvanizing is improperly performed, it can cause paint adhesion problems, but when it is properly done, adhesion is not an issue. It also notes that powder coating on a properly prepared substrate is a good and widely used finish. If severe scratching is unlikely and ordinary service life is enough, the responder says there may be no need to galvanize. However, for severe scratching and decades of tough exposure, galvanizing is described as the best, if not the only, choice because it is sacrificial. The combination of galvanizing plus paint or powder is identified as a duplex system.
I am trying to put together a list of advantages and disadvantages of cold rolled, phosphatized, and painted steel over galvanized, phosphatized, and painted steel. I am trying to get as much information as possible about paint adhesion, weldability, environmental problems with galvanized, health risks and durability of the coating. Can you help me.
Davies Wakefield
– Two Rivers, Wisconsin
When improperly performed, galvanization can lead to paint adhesion problems, Davies, but when properly done, adhesion isn’t an issue.
Powder coating on a properly prepared substrate is a good and very widely used finish. If severe scratching is unlikely, and reasonable life is good enough, you probably have no need to galvanize. But galvanizing is a sacrificial coating, and if you need something that will hold up despite severe scratching, and that will endure decades of tough exposure, galvanizing is your best if not your only choice. Galvanizing plus paint or powder is called a “duplex system”.
Good luck with it.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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Q. How can we differentiate CR & GA Sheets visually? Is there any method to check?
Arnold Bharathi
– Chennai, India
October 5, 2012