wroughtn_harv
Super Member
Welding Galvanized Steel -- Safely
ｩ Sperko Engineering Services, Inc.,1999,
Welding of Galvanized Products
Welding of galvanized steel is done almost exactly the same way as welding of the bare steel of the same composition; the
same welding processes, volts, amps, travel speed, etc. can be used with little modification when the switch is made from
uncoated steel to galvanized steel -- unless the zinc coating is unusually thick.
The difference between welding galvanized steel and welding uncoated steel is a result of the low vaporization temperature of
the zinc coating. Zinc melts at about 900ｰF and vaporizes at about 1650ｰF. Since steel melts at approximately 2,750ｰF and
the welding arc temperature is 15,000 to 20,000ｰF, the zinc that is near the weld does not stand a chance -- it's vaporized!
By the time the weld pool freezes, the zinc is gone. This has two immediate consequences:
The vaporized zinc increases the volume of welding smoke and fumes.
The zinc at and near any welds is actually burned off by the heat of the arc, removing the protective zinc coating.
Zinc Fumes -- A Safety Hazard?
When zinc vapor mixes with the oxygen in the air, it reacts instantly to become zinc oxide. This is the same white powder
that you see on some noses at the beach and the slopes. Zinc oxide is non-toxic and non carcinogenic. Extensive research1
into the effects of zinc oxide fumes has been done, and although breathing those fumes will cause welders to think that they
have the flu in a bad way, there are no long-term health effects. Zinc oxide that is inhaled is simply absorbed and eliminated
by the body without complications or chronic effects. Current research2 on zinc oxide fumes is concentrated in establishing
the mechanism by which zinc oxide causes "metal fume fever," how its effects are self-limiting and why zinc oxide fume
effects ameliorate after the first day of exposure even though the welder may continue to be exposed to zinc during subsequent
days ("Monday-morning fever"). Other research3 is being done using zinc oxide fumes together with various drugs which
results in a synergetic effect for treatment of cancer and AIDS. Another area of research is use of zinc compounds as the active
ingredients in throat lozengers that are recognized as significantly effective in reducing the duration and intensity of the
common cold.
Typical 杜etal fume fever begins about 4 hours after exposure, and full recovery occurs within 48 hours. The symptoms
include fever, chills, thirst, headache and nausea. All of these symptoms, pain and suffering, as well as lost work (and play)
time, can be avoided entirely by simply not inhaling the zinc oxide fumes. This can easily be done using any of the
methods described later.
Unlike other heavy metals, such as copper, lead and mercury, zinc is an essential micro nutrient. Zinc is essential to the
proper growth of plants and animals. Zinc forms part of the enzyme system that regulates biological processes throughout the
body. As shown on any multi-vitamin/mineral bottle, the recommended minimum adult intake is 15 mg/day.
1Walsh, Sandstead, Prasad, Newberne and Fraker, Environmental Health Perspectives, Volume 102, Supplement 2,
June 1994, 5-46. Provides summary plus 471 references.
2 Kuschner,D'Alessandro, et. al., Pulmonary Responses to Purified Zinc Oxide Fumes, Journal of Investigative
Medicine, 1995:43:371-378.
3Robert Sabin, Zinc Activated Profile, COPE, March/April 1995: 16,17
Welding Galvanized Steel
If you're going to weld galvanized please read the whole thing here.
http://www.sperkoengineering.com/html/articles/WeldingGalvanized.pdf
I've been welding galvanized materials for forty plus years now. I've had fume sickness a couple of times. However, I've had friends that have been sickened for days from walking in while I was welding some galvanized materials. I see it as more about individual tolerance than poisonous gases. I can't take cigarette smoke for very long but I can weld all day long without any problems.
My father is eighty four and he welded galvanized materials most of his life. He was a gate man at a chainlink fence company. He taught me to weld by welding up sixteen gauge galvanized fence tubing.
If you're going to weld galvanized do it in intelligent manner. But don't avoid it because you're worried about poisoning yourself.
ｩ Sperko Engineering Services, Inc.,1999,
Welding of Galvanized Products
Welding of galvanized steel is done almost exactly the same way as welding of the bare steel of the same composition; the
same welding processes, volts, amps, travel speed, etc. can be used with little modification when the switch is made from
uncoated steel to galvanized steel -- unless the zinc coating is unusually thick.
The difference between welding galvanized steel and welding uncoated steel is a result of the low vaporization temperature of
the zinc coating. Zinc melts at about 900ｰF and vaporizes at about 1650ｰF. Since steel melts at approximately 2,750ｰF and
the welding arc temperature is 15,000 to 20,000ｰF, the zinc that is near the weld does not stand a chance -- it's vaporized!
By the time the weld pool freezes, the zinc is gone. This has two immediate consequences:
The vaporized zinc increases the volume of welding smoke and fumes.
The zinc at and near any welds is actually burned off by the heat of the arc, removing the protective zinc coating.
Zinc Fumes -- A Safety Hazard?
When zinc vapor mixes with the oxygen in the air, it reacts instantly to become zinc oxide. This is the same white powder
that you see on some noses at the beach and the slopes. Zinc oxide is non-toxic and non carcinogenic. Extensive research1
into the effects of zinc oxide fumes has been done, and although breathing those fumes will cause welders to think that they
have the flu in a bad way, there are no long-term health effects. Zinc oxide that is inhaled is simply absorbed and eliminated
by the body without complications or chronic effects. Current research2 on zinc oxide fumes is concentrated in establishing
the mechanism by which zinc oxide causes "metal fume fever," how its effects are self-limiting and why zinc oxide fume
effects ameliorate after the first day of exposure even though the welder may continue to be exposed to zinc during subsequent
days ("Monday-morning fever"). Other research3 is being done using zinc oxide fumes together with various drugs which
results in a synergetic effect for treatment of cancer and AIDS. Another area of research is use of zinc compounds as the active
ingredients in throat lozengers that are recognized as significantly effective in reducing the duration and intensity of the
common cold.
Typical 杜etal fume fever begins about 4 hours after exposure, and full recovery occurs within 48 hours. The symptoms
include fever, chills, thirst, headache and nausea. All of these symptoms, pain and suffering, as well as lost work (and play)
time, can be avoided entirely by simply not inhaling the zinc oxide fumes. This can easily be done using any of the
methods described later.
Unlike other heavy metals, such as copper, lead and mercury, zinc is an essential micro nutrient. Zinc is essential to the
proper growth of plants and animals. Zinc forms part of the enzyme system that regulates biological processes throughout the
body. As shown on any multi-vitamin/mineral bottle, the recommended minimum adult intake is 15 mg/day.
1Walsh, Sandstead, Prasad, Newberne and Fraker, Environmental Health Perspectives, Volume 102, Supplement 2,
June 1994, 5-46. Provides summary plus 471 references.
2 Kuschner,D'Alessandro, et. al., Pulmonary Responses to Purified Zinc Oxide Fumes, Journal of Investigative
Medicine, 1995:43:371-378.
3Robert Sabin, Zinc Activated Profile, COPE, March/April 1995: 16,17
Welding Galvanized Steel
If you're going to weld galvanized please read the whole thing here.
http://www.sperkoengineering.com/html/articles/WeldingGalvanized.pdf
I've been welding galvanized materials for forty plus years now. I've had fume sickness a couple of times. However, I've had friends that have been sickened for days from walking in while I was welding some galvanized materials. I see it as more about individual tolerance than poisonous gases. I can't take cigarette smoke for very long but I can weld all day long without any problems.
My father is eighty four and he welded galvanized materials most of his life. He was a gate man at a chainlink fence company. He taught me to weld by welding up sixteen gauge galvanized fence tubing.
If you're going to weld galvanized do it in intelligent manner. But don't avoid it because you're worried about poisoning yourself.
