Technology has always challenged the natural order. People say nature has elements. Our work is to explore and put them to fair use. Galvanized metals are a miracle of the present day. Metal tends to oxidize and corrode due to the presence of Oxygen in the air. It can ruin these items or make them unstable and dangerous.
So, what is metal galvanization? Metal galvanization is adding a protective layer of zinc on a ferrous metal surface, such as steel, to protect it from rusting. But, to use them in any industrial process, the metal needs to be welded together. So, how do you weld galvanized metal?
Table of Contents
- 1 Is It Dangerous to Weld a Galvanized Metal?
- 2 How Can You Weld A Galvanized Metal?
- 3 Preparation Before Welding
- 4 The Risks
- 5 Precautions to Take While Welding Galvanized Steel
- 6 How to Prevent Corrosion When Welding Galvanized Metal
- 7 Conclusion
Is It Dangerous to Weld a Galvanized Metal?
Galvanized metal, such as steel, has a zinc coating on it to prevent corrosion. As you heat it, it emits toxic fumes that can be extremely dangerous for your health. Hence, welding galvanized steel can be a dangerous task. This article will help you know the best way to weld galvanized steel to keep you or your colleagues from these risks.
How Can You Weld A Galvanized Metal?
Galvanized metals like steel can be welded in a similar approach to uncoated steel if it’s adequately prepared. If you attempt to weld it away with the galvanizing layer from the welding area, the weld pool pops and blows out, making it a safety hazard to anybody around.
Although the warmth from the arc may burn off the zinc layer quickly, the weld generated could have problems like porosity, a disappointing bead, lack of fusion, and an excessive amount of spatter. Despite burning the zinc off, porosity is practically inevitable and can be mainly dependent on the zinc coating’s thickness.
Preparation Before Welding
1. Remove the Zinc Coating from the Welding Area
The ideal method to weld galvanized steel is to eliminate the zinc coating, no matter which welding procedure you are likely to use. You can use a grinder or a sheet of 220-grit sandpaper or a grinder on a low setting to remove the zinc coating. But removing the zinc layer also means that it loses the protection.
It usually means that you will have to incorporate two tasks: removing the zinc layer and respraying the weld seam following the weld. It will help to recover the lost rust resistance. In some cases, respraying or painting is done even if one did not remove the zinc coat before the process.
Removing the zinc layer has other benefits too. It reduces the amount of spatter produced and also the amount of cleanup work. In short, removing the zinc layer helps to minimize the reworking tasks and also lowers the cost.
2. Place The Two Pieces Together
Now that you have removed the zinc coating place your two pieces of metal on your work surface and arrange them in your desired way. If you lay the pieces on the floor, avoid welding on a combustible surface.
You should not have to hold the pieces together as you weld. Instead, you can use a welding clamp to hold them together. If you are welding a hole or split to shut it off, then place your bit back on your work surface so the opening faces up.
3. Pick the Right Welder
A standard arc welder is the best choice for welding galvanized steel. Arc welders are versatile. With the alternating currents, It creates a good arc that melts the flux quickly. But since it makes splatter, it is better to work outside.
4. Select the Welding Rod
The welding rod that you would choose should complement the size of the metal. Bigger rods weld a larger area than a smaller rod. There is no-specific galvanized steel material that you should use. So, you can use anything available in the market.
The Risks
Welding regular steel and galvanized steel are two different things. Several risks are associated with the latter. The problem is that the zinc coating around the galvanized steel has a shallow vaporization temperature compared to regular steel.
And since you aim to melt the steel itself, the zinc coating does not stand a chance against the welding arc’s high temperature. Consequently, the zinc vaporizes quickly, reacts almost instantly with the air’s oxygen, and becomes zinc oxide. Zinc Oxide is itself not a toxic gas. It can cause some temporary effects, though. Such as,
Fumes Fever
According to UFDA, 15 mg/day of zinc is vital for appropriate health in humans. Zinc is also a necessary micronutrient for plant and animal life. Too much zinc, though, can result in a temporary disease called “metal fume fever.”
Inhaling Zinc Oxide can cause flu-like symptoms and make you ill temporarily. It usually goes within 48 hours of the exposure. Symptoms of metal fever fumes include nausea, headaches, high fever, thirst, and shivers.
Long-term Problem
Most zinc used in galvanization has a natural lead composition of about 0.5%. It vaporizes with the zinc during welding and then mixes with oxygen, forming the lead oxide. Lead oxide, unlike zinc oxide, is extremely toxic and can cause more severe health problems, including kidney dysfunction and even cancer.
Precautions to Take While Welding Galvanized Steel
By now, you have understood the risks of welding galvanized metal, such as steel. Despite being such a risky job, you still can avoid the dangers by following these precautions:
1. Wear Masks
The best way to avoid the risks of welding galvanized steel is to prevent fumes. Therefore, you should wear a good welding helmet with a respirator and a mask designed for welding metal. Also, consider wearing proper aprons and gloves to protect your hands and clothes.
2. Use A Fume Extractor
The best decision is to weld outside. But if you can’t, make sure you have enough windows into the place where you are welding. If you plan to weld in your workshop, it will help keep a fume extractor 2–3 feet away from the specific location. It will extract the fume away and ensure a safe breathing atmosphere.
3. Don’t Expose Your Skin.
Fumes are not the only risk factors of welding. You should cover up your skin with proper clothing to avoid exposure to UV and Infrared rays. Avoid wearing anything like slapped pants, unbuttoned shirts, or a jacket with an open pocket.
4. Prepare the Surface
Previously we have already talked about the ill-effect of welding a galvanized metal. And we have also mentioned how it affects our health if we don’t remove the coating before welding. Hence, it would help if you prepared the welding area by eliminating the layer before starting the process. It will cause less Zinc vapourization, providing you a safer atmosphere with breathable air.
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How to Prevent Corrosion When Welding Galvanized Metal
The sole motive of galvanizing is resisting corrosion. But to weld safely, you have to remove the zinc layer, exposing those areas to corrosion. Hence, it becomes an issue with welding galvanized steel. The only way to fix this problem is re-galvanizing it after the weld is complete.
Although this process is time-consuming, it can be pretty useful to maintain the metal’s resistance integrity. The method also requires utmost attention and technique. So, the welders should know the safety rules and regulations to protect themselves from the threat of toxic fumes.
You can use paints rich in elemental zinc that will efficiently recover full corrosion protection to the weld areas. They can be found in either spray cans or containers and are suitable for spray or brush applications.
You can apply them to the weld after sandblasting or wire brushing to remove all welding splatter, followed by wiping the weld clean with a rag. Thus, the metal will regain the corrosion resistance successfully.
Conclusion
As a welder, you must know that welding is a risky job. One can only protect himself when he knows the danger. In welding, there are many of them. It is why you require practice and dedication to become a successful welder.
While welding metals are the most engaging job in a welder’s life, welding galvanized steels are one of the dangerous ones. And it is not only because of the flames or fumes but because some people take it lightly. A welder’s job is to know it all and act accordingly.
By now, you have known how to weld galvanized metal and its risks. Now before you perform it, we want you to follow the safety precautions to save yourself from any danger. That said, we hope to see you again with the same peaceful smile.