Why is lead added to the galvanizing bath?
Lead is not purposely added to galvanizing baths, rather it is an impurity in zinc. Different types of zinc have different levels of lead. The specified lead maximums for the various types of zinc can be found in ASTM B6.
Lead does have the beneficial effect of decreasing the surface tension of zinc, which allows it to flow off the steel easier as it is being removed from the kettle. This creates thinner galvanized coatings that have less runs and drips. Bismuth is sometimes added to galvanizing baths to achieve the same effect as lead has when types of zinc are used that have very low levels of lead.
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Galvanized wire seems to develop white spots right out of the kettle. A way to correct the problem has been to increase water flow at the quenching stage. Would welcome ideas on how to prevent these white spots that often are called water spots.
Hi Tommy, assistance with galvanizing process details is available to AGA members only. To become a member: https://galvanizeit.org/about-aga/become-a-member
Hi, Do you know about any lead free galvanizing? if yes how is it done? Thanks
Hi Harry, All zinc grades contain a small amount of lead, because lead is found in most natural deposits of zinc. Some galvanizers utilize high grade and special high grade zinc ingots which have very low lead content (<0.003 or <0.03%) and are acceptable for most low-lead applications.
We had change the zinc cattle with additon of new zinc but we suffer under the problem of zinc pimples and rough surface which can't overcome yet after 7 days could anyone suggest something then plz contact me on my mail
Hi Ajay, We have a guideline for reducing dross pimples which is available to AGA members: https://galvanizeit.org/members/guidelines-notes/dross-pimples-on-finished-product