Welding on Galvanized Plates

[JohnRwals]

Hello!

This is a typical detail used for the connection of precast concrete double tees.
I wonder if 3/8" loose plate should/can be galvanized.
In my opinion, this galvanized finish will be burnt completely due to high welding temperature
and relatively small plate size.
And, touchup finish like ZRC will be required after welding is done on galvanized plates.
Is it meaningful/worthwhile to use small galvanized plates in this connection?

-JRW

 

[dauwerda]

I agree with your concerns. No, it would not be practical to use galvanized plates here.

 

[dik]

From my notes:

-IF WELDING OF HDG STEEL IS REQUIRED, REMOVE ALL GALVANIZING FROM AREAS TO BE WELDED TO PROVIDE 1" MIN BASE METAL AROUND ALL WELDS. WORK SHALL BE DONE IN ACCORD WITH AWS RECOMMENDATION WZC. PROVIDE VENTILATION AS REQUIRED. CLEAN FINISHED WELD AND TOUCH UP WITH TWO COATS OF ZINC RICH PRIMER. PRIMER SHALL OVERLAP EXIST GALVANISING BY 1/2" MIN.
-CONFIRM TOPCOAT, IF APPLIED TO HDG, IS COMPATIBLE WITH HDG MATERIAL.

as an added caution welding galvanised surfaces is a health danger... need good ventilation and/or tanks.


-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[dauwerda]

As the max plate width is 1-3/8" wide with a weld on each side, it looks like DIK's notes also agree that they should not be galvanized.

 

[dik]

dauwerda, I concur... I should have added a note to the effect galv protection, that to do it properly, it needs space and is a lot of work. There is no reason it should be HDG in the first place. You should grind off HDG, rather than burn it off... dangerous to your health. Even grinding has some risks.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[desertfox]

Galvanised plate shouldn't be welded because the fumes that are given off are quite toxic.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[Once20036]

Isn't grinding required due to the fumes that are created?
When precast is being erected, it's typically in an outdoor environment and I think those fumes pose little risk.

My last precast job proposed galvanized plate welded to a galvanized embed for a similar situation.
I`m sure they didn't dip this steel just so they could grind it off in the field & I did not take any exception to their proposed detail.

 

[desertfox]

I won’t be welding the galvanised plates so it doesn’t really matter to me however this section on safety issues of welding galvanised steel might be of interest

4. Health issues regarding welding galvanized steel

Other than the material issues, there are also health risks that operators may encounter. To learn more about these hazards, read more below.

Metal fume fever

When welding galvanized steel, the zinc coating easily vaporises. This will form zinc oxide fumes that will mix with the air. This gas may give short-term effects to your health which is also known as “metal fume fever”. Welders may experience flu-like symptoms once they inhale the fumes. These may include nausea, headaches, high fever, shivers and thirst. The symptoms will usually go away within 48 hours of exposure.

Long term health concerns

There is a small lead content on the galvanized coating. When welding, this lead will vaporise and form lead oxide fumes. These gases can cause long-term health problems such as lung and brain cancer and even complications in the nervous system. Thus, it is crucial to wear the proper safety equipment to avoid these health problems.

Safety gear and proper training

From the safety concerns mentioned above, it all boils down to the lack of welder safety training. It is vital that the welder is well-trained. They should keep the welding shield and welder’s face out of the fumes. The welder should also be in a proper position so that the clean airflow is maximised. Apart from that, this will prevent the oxidized dust from gathering inside the welder’s shield.

For safety purposes, the welder should be provided with a high-quality mask. They should also be fully trained on the safety measures when in terms of welding.

I took this section posted above from this website:-

https://www.cmac.com.au/blog/5-things-to-welding-galvanized-steel-safely

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[dik]

Thanks for the link, fox... it's an excellent link. I've been aware of this issue for years/decades. That's why I raised it.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Brad805]

My nephew is a pipeline welder and it is pretty common in that industry to use the 3M Mask nowadays. I was chatting with him and he said after using for 1d he was sold on it. He could tell when he got home how much better he felt.

 

[dik]

a mask may not be adequate.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Brad805]

That mask supplies fresh air to you. You are not breathing the fumes.

 

[dik]

Thanks brad... I was thinking of a facemask, like for Covid...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Brad805]

Ahh, I am not sure too many bought $4k mask for covid. I have a cheaper version to spray Urethane finishes. Urethane is very bad to spray. They work very well.

 

[dik]

like my standard eMail signature...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JohnRwals]

Fume/health is different issue.
Generally we can weld HDG'd plates whenever we need to as long as we can take safety rule.
In this specific case, steel plates are so small/narrow that HDG'd plates do not make sense
because HDG finish will be lost and another touchup finish will be required.
-JRW

 

[XR250]

At this point, don't most welders know the risks of welding galv.? Do we need to be telling them?
Do we instruct framers to wear ear protection?

 

[desertfox]

If everyone followed the safety rules without being told then we wouldn’t need health and safety executives, further if most welders know the risk, then what about the rest of them?

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein