Galvanizing Insights Volume 7, Issue 2

Volume 7, Issue 4

  

AGA member galvanizers are required to meet ASTM and ISO specifications of minimum coating thicknesses; imported galvanizers are not.

  

Buyer Beware!

Imported galvanized steel can present avoidable problems

Importing galvanized steel may seem like a bargain up front, but many specifiers and owners are discovering they are getting less than they bargained for.  Over the past six months, the American Galvanizers Association (AGA) has had an influx of concerned callers who have imported galvanized steel.  As the association representing North American after-fabrication hot-dip galvanizers, this is disheartening for many reasons.  Outside the obvious - such as imported galvanized steel takes business away from the North American producers - there is a chain reaction of other concerns for galvanizers and their customers to consider.  All of our member galvanizers, including associate members in foreign countries, adhere to the ASTM and/or ISO standards to ensure a high-quality galvanized coating. To meet the ASTM and ISO specifications, galvanizers are required to meet minimum coating thicknesses.  > MORE

 

 



Q: I just galvanized some material for a job and the customer called me with a complaint that the material has a white powder all over the surface.  What do I do about this?

The material was good when it left the galvanizing plant and then developed some white powdery particles on the surface after it was erected.  Well, there are a number of potential reasons for the white particles on the surface.  One of the first that comes to mind is an excess of aluminum in the galvanizing kettle.  Most galvanizers try to keep their aluminum under 0.005% to help with brightness, but also to limit the formation of aluminum oxide on the surface of the coating (aluminum oxide is a white powdery material.)  Too much aluminum goes to the surface of the coating and will oxidize before the zinc oxide forms, resulting in a thin, white, powdery layer on the surface.  If this happens do nothing, as the coating will eventually form the zinc oxide and hydroxide before forming zinc carbonate.  The white powdery material will gradually disappear.   > MORE

 


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This official publication of the American Galvanizers Association, Inc. (AGA) does not necessarily reflect the view of the board of directors or AGA members. Every effort is made to ensure accuracy. Any errors are strictly accidental and may be corrected in a subsequent issue. This material provides general information only and is not intended as a substitute for competent, professional examination and verification as to suitability and applicability. The publication of the material herein is not intended as a representation or warranty on the part of the AGA. Anyone making use of this information assumes all liability arising from such use. Questions or comments about this publication should be directed to the AGA. Comments and suggestions are encouraged.

Copyright © 2007 American Galvanizers Association. The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. The information provided herein is not intended as a representation or warranty on the part of the AGA. Anyone making use of this information assumes all liability arising from such use.