Welding Steel vs Aluminum: Most Important Differences

Welding is an art form that only its “artists” can ever appreciate to its fullest extent.

But to appreciate it doesn’t just go as deep as how dedicated one must be to express the utmost care in the process.

Because this dedication should go as deep as how you penetrate the metal in welding, and that is one hundred percent!

Before you get started, familiarizing yourself with whatever medium you’ll be using must be included in considering how to go around welding it.

That’s why we’ll be talking about two materials you’ve most likely heard of before: steel and aluminum!

What is Steel?

Steel for welding

There’s a reason why steel is the first metal you’ll be handling in your welding training.

Being a lovechild between carbon and iron makes steel EXTREMELY well-versed to be a common material for construction work.

“Why isn’t iron more common?”

I mean, sure, iron does make its rounds in construction work, too, but only for workshops that have top-quality equipment because this metal DESERVES top quality!

Oh, and it’s really difficult to weld it, so there’s that, too.

So if you only use your usual equipment on it, your eyes might burn out of their sockets first before you could do decent work.

Carbon steel, on the other hand, is the softest, easiest metal to weld (and the cheapest!), which is what you’ll be using a lot when you’re still a new, bright-eyed student in welding school.

Put these two metals together, and you have the middle ground with steel!

What is Aluminum?

Aluminum for welding

From soda cans in vending machines to simple pots, you’ll see this metal pretty much anywhere you go because aluminum is excellent in fabrication!

But does that make it an excellent metal for welding

Read now, and ask questions later!

So, you’ve handled a soda can before, right? One thing you’ll notice is how easy it is to crush once it’s all empty.

And as easy as that is, it only means it’s MUCH, much harder for you to weld it.

Being sensitive and extremely sensitive makes it unable to handle the heat that well.

But what do you use in welding?

That’s right. Heat.

So you can see how this turns out as a problem, right?

If that’s not bad enough, while the aluminum itself can only handle up to 650 degrees Celsius, there’s always a protective layer of oxide in every piece of aluminum.

And because its job is to protect the aluminum, this oxide layer has a melting point of 2, 037 degrees Celsius.

Which is, you know, quite a jump from 650 degrees.

This vast difference between melting points truly makes it harder for welders like you to work on it, but not impossible!

Steel Vs Aluminum: The Comparison

steel vs aluminum for welding

Prep Time

Before you could get started, you’ll first need to have your base metals cleaned up for a neater welding experience.

Well, only for aluminum, anyway.

Because with steel, even when it has dirt or dust staining all over it, you can still start welding on it!

Although, that doesn’t mean you should skip out on cleaning up the steel BEFORE welding since a clean surface ensures having a stronger weld.

While you can neglect cleaning steel without having too much consequence afterward, the same can’t be said for aluminum.

As mentioned earlier, aluminum is protected by an outer oxide layer that has a far higher melting point than aluminum itself.

With that kind of imbalance, it’s obvious WHY you have to get rid of this layer!

And you can do that using an alkaline solution, and a wire brush.

The solution can remove any dirt or grime clinging onto it other than the oxide layer.

Which the wire brush can get to remove with the help of the alkaline (or acid). 

Once you’re sure you got every nook and cranny brushed up, make sure to rinse it AND dry it entirely before you could set down your electrode on it.


The reason why anyone turns to metal for a LOT of things is to maintain that good condition for a long, long time (unlike wood) but recyclable (unlike plastic).

So having aluminum as a soft, sensitive metal does ruin that image, to be honest.

It’s not dense enough for you to be confident in its not-exactly-long lifespan.

But for the little time it has, you can enjoy its strength, even more, when it’s placed in an environment that has a lower melting point AND you’re looking for something lightweight to do the job!

However, you can leave the higher temperatures to steel with its dense, long-lasting material that won’t bend so easily under stress or force.

It does rust like hell, though. 

Aluminum doesn’t have that on top of its other problems because of its oxide layer, so the steel can enjoy its rust all it wants.

welding steel vs aluminum

Bring in the Heat

Finding a welder’s work environment be anything else other than hot is probably rare unless there’s a fully functioning AC going on in the background.

Still, the heat welders handle is no joke.

What’s more with the metals, right?

As mentioned earlier, aluminum is far more sense if you’re going to compare it to steel.

And because it’s sensitive, it has a far better heat transmission than steel does!

In the end, however, heat conduction might be pointless if you’re only supposed to weld it.

Only at a meager 650 degrees Celsius, the aluminum itself will easily melt when you use the same temperature as the one you use for steel.

Heck, by the time you probably go 660 degrees Celsius, there’s going to be a pure aluminum puddle from where a sheet of aluminum was while its layer remains somewhat intact!

Meanwhile, steel’s all macho with its superior 1, 510 degrees Celsius melting point (for stainless steel) or its “lower” melting point of 1, 371 degrees Celsius from carbon steel.

So you can probably already tell which one’s going to survive a sweltering construction site between the two metals.

If aluminum is necessary for the project, then you better be sure to look after it like it’s your baby! Got it?

Final Words

Knowing how to handle different types of metal is a must-have in a life of a welder.

By having this quality, you’ll be aware of how exactly you can go about welding them because, well, metals aren’t built the same!

And acknowledging this fact can help heighten the quality of your weld!

Which is EXTREMELY helpful when you’re going to be working on something as difficult as aluminum.

Once you know how to do it there, welding steel will be as easy as breathing!

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