Steel vs Aluminum - Debunking 4 Common Misconceptions
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- เผยแพร่เมื่อ 2 ต.ค. 2024
- Aluminum and steel are some of the most common metals in the world, yet they are often misunderstood when it comes to strength and corrosion capabilities. In this video we review the following misconceptions:
00:06 - Steel is not stronger than aluminum
01:15 - Strength per weight
03:04 - Aluminum can corrode
04:11 - Steel can resist corrosion
If you like these steel and aluminum facts, let us know and we’d be happy to share more!
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References:
[1] European Committee for Standardization, Eurocode 3: Design of Steel Structures, 1993 (2005).
[2] CSA Group, S157-17 - Strength Design in Aluminum, 2017.
[3] M. C. J. H. P. Sensharma, "Effect of Welded Properties on Aluminum Structures," 2010.
[4] J. Davis, "Aluminum and Aluminum Alloys," 2001.
[5] Canadian Institute of Steel Construction, Handbook of Steel Construction 11th ed., 2016 (2017).
As an electrician I've seen many aluminum wires corrode into dust. To be fair copper will also do this in very humid conditions, but aluminum is way worse. That's why we don't use it in romex any more, just doesn't hold up and becomes a safety hazard.
At work we are often avoid aluminum because of the following issues:
-Dissimilar metal corrosion with steel fasteners
-The need (or precieved need) for helicoil inserts
-Difficulty in welding, the strongest AL alloys are often only weldable by friction stir welding which is a non-starter
-Fatiuge limits for vibrating structures and structures loaded to a high percentage of their yield strength
-High strength aluminum alloys are harder to procure and have longer lead times
-Some alloys are prone to stress corrosion cracking.
When I was a kid and in school I had a real affinity for aluminum but when I had to start designing stuff steel grew on me fast.
Hey,
I’m doing a caravan
The base chasis is steel, so I was thinking to use aluminium for structural wall and roof frame connecting it to steel base chasis,
Does welding make it weaker? Use brackets instead or
Fastners are no good?
@@sagarshrestha9444 5000 series Aluminium-Alloys have a good corrosion resistance, are fairly easy to weld (given the correct tools) and don't lose a lot of strength during welding.
But welding thin Aluminium sheet metal is really a pain, so maybe consider riveting? There are suitable sealants for the joints, so it'll be watertight. We used SikaFlex in the shop I worked at, but that's a Swiss product and probably veeery expensive...
there are many other disadvantages to aluminium the man neglected to mention such as cost and strength per unit volume.
because main reason why steel is often chosen for construction is that, while more massive, also takes up a LOT less space than aluminium.
another thing is flexibility and toughness, you can hit a steel I beam with a forklift and it's not gonna budge and at worst you're tearing the bolts out of the concrete floor before the beam takes significant damage.
you do that with aluminium there'll be a huge gash torn into it, with extremely sharp edges all around it.
Great video, the only slight issue is the over simplification with the yield strength of stainless steels, those with a yield in the 200 MPA range are the very low end of the range such as 409, and most are far stronger, 304 is 240MPA, 316 is 290MPA, 303 is 415MPA yield strength and 301 has a field strength of 945MPA, you made the effort to show difference with differ types of aluminium, I think it would have been interesting to see the same with the different types of stainless.
Sorry, but you are comparing the 0,2% yield strengths of type 303, 304 and 316 in the annealed condition to type 301 in the cold rolled "full hard" condition. Not exactly a fair comparison.
There are nitrogen-alloyed (nitrogen-strengthened) stainless steels that can surpass 800 MPa 0,2% yield strength without cold work strengthening and exceed 1500 MPa with cold work. PH 13-8 Mo stainless steel will attain 1400+ MPa yield strength in the H950 aged condition. Maraging steels (MAR 250, 300 and 350) are technically not stainless steel, but MAR350 can even attain higher values for yield.
u guys are dorks (i love you both dearly)
Yes, more please. I'm so puzzled. Stainless steel is very hard to cut and drill but apparently it's weaker structurally. I'd like to understand this better.
chromium fucks it up 😂
And there is different types of strength.
The reason many stainless steels tend to be difficult to cut and machine is due to the tough, gummy nature of the material. The toughness creates high cutting forces, which in turn promote work hardening (anyone who has had to drill stainless steel with a hand held drill has likely encountered this). The "gumminess" of the material makes it difficult to get good chip control when machining.
@@ferrumignis Correct
I observe they are brittle and crack easily and not as ductile as ordinary steel. I think that is why they are not used in car bodies because they cannot be stamped into shape without cracking ?
Very nice video. As a mechanical engineer, I think you did a great job touching on all of the major points. I would love to see more videos of this quality.
I will say that the only critical point missing is temperature vs strength.
Good video, would love to see one on electrochemical corrosion and pairing of different materials.
Nice topic! It's clear the contrast between materials
depending to what it would be use to and take advantagr of it particular properties
That was our goal, thanks for the comment Emilio!
Aluminium also suffers from Hydro Aluminium Oxide (HAO) under certain conditions. HAO turns affected areas or spots into soft powder which can penetrate the metal and cause failure. This is mostly seen in marine enviornments.
Great video as usual; I appreciated the differentiation between the different types of steel alloys and their strengths!
Idk what your field of specialty is, but I really liked how you mentioned the extremely weak welded aluminum. It would be nice to have a whole video dedicated to the effects of welding on different types of metals. I've heard that welding makes steel stronger for some applications, but I've asked about weldable 80ksi steel and they said I was a fool bc welding makes it weaker
Thanks Matthew,
Yes, welding certainly could be a video topic of its own. We've added this to our roster of potential future videos.
Cheers!
Not an engineer, but a welder, what exact type of 80Ksi steel exactly are you looking to weld? almost all are weldable, some creep resistant Chrome-Moly alloys need careful pre and post heat to avoid cracking but don't end up weaker at all when done correctly.
If you know exactly what alloy of 80Ksi steel you are looking to weld I can probably point you towards a few good resources on how to weld it.
I'd never heard of weathering steel (nor the chemistry of oxide layers). Very interesting.
Corten steel was big in the 70's here in California especially for the guard rails on the freeways and some tech buildings. out of fashion for years (or maybe painted). It has a nice simple even brown rust tone, earthy color.
Nice video but should also discuss the area under the stress strain diagram for aluminium and steel i.e. steel has much greater resilience than alumimium.
When fatigue life is considered, things get even worse for aluminium.
As a mechanical designer, give me steel any day of the week!
I love the looks of weathered steel.
I'd like to answer some of the questions here about Weathering Steel. I work with it.
Weathering Steel is more known as Corten steel.
Corten is a carbon steel with an added 0.5% to 1.0% of Chrome, and Nickel, and Copper (each). Think of it as a low percentage stainless steel with an added copper. See why it is rust resistant? The copper helps in creating the corten patina with helps to prevent further rusting.
Corten steel, Or CorTen, or Cor-Ten steel. Short for *COR*rosion resistant - *TEN*sile strength. CorTen trademark is owned by US Steel who invented it in 1933. Therefor, people use Weathering Steel to avoid using the trade name.
US Steel is in Pittsburgh PA. Home of the Steelers. And now you know why it's called Steelers. 😁
Cheers!
Some other huge differences are strength based on heat (steel wins) and cold embrittlement (not sure on the properties of aluminum here). Also, fatigue strength is huge and steel would win on this one as well (that is why aluminum can't be used in house wiring - bend it a few times and it breaks; copper can be bent many times more before that happens). I have read that even aluminum power lines often have a steel cable in the core for extra strength (and since electric primarily flows on the outsides of the conductor). Because of fatigue, I am very wary of aluminum for many critical structural purposes. Because of steel rust, galvanizing, etc. is a must in my opinion. (Disclaimer: I majored in mechanical engineering in college, but never got a job in it, so I understand and love engineering, but am not a real engineer and certainly not a materials scientist.)
HV power lines actually use a mixture of steel and alumium, since they have to use fairly pure alumium for high electrical conductivity, and steel is cheaper and better than alumium alloys for structural reinforcement (less creep) The stronger alloys of alumium are not as conductive, so they are only normally used in special case power lines where corrosion of the steel reinforcement might be an issue.
Also, the current only uses a potion of the surface (skin effect) so the core of the conductor can be used for strength and the outer surface can be optimized for conducting current.
Very nice video, really learned something
As a constructive critisim, the thumbnail didnt look as profesional as the whole video, it has amazing animations and the thumbnail was kinda misleading to tue Quality of the video
Keep it up!
Hi Vicente,
Thank you for the feedback, we will keep working on making better thumbnails.
Cheers!
One small nitpick the aircraft component shown when speaking of aluminium use in aircraft was a fan assembly, these are usually made out of titanium alloys.
What a noob, no mention of Aluminium fatigue.
Great video, thanks.
Thanks for the comment!
Nicely put together video! 👌
Try titanium aluminum alloy 75/25 for maximum strength .
Coincedently the weight to elastic modulas ratio of steel and aluminum as nearly equal.
A curious coincidence indeed!
thanks for the comment :)
Why, obviously, you use titanium, as Hollywood makes it utterly immortal and far stronger.
Despite the fact that titanium is between aluminum and iron in strength and alloys only modify the base behavior, it's magic or something.
Still, for steel protection, I tend to like either nitride finishes or phosphate based finishes, but they're surface treatments.
All lies within the chemistry, specifically, applied chemistry within the field of metallurgy. Not a mystic art, but a complex field of science.
Science, the vast field engineers depend upon.
Deny that, deny the existence of skyscrapers and the car you drive.
Awesome stuff 😎. Thanks 👍🏿
Glad you enjoyed it
Good post, I feel more informed.
Good to hear! Thanks William
great video.
yes please do get in depth into the topics.
It's always fun to learn or fresh up
Great video! Question, can I add a piece of aluminum to steel to act as an sacrificial anode to protect it from rusting? How would I go about doing this?
k they're right next to each other in the series so you might not get good effect but al sticks to steel from galling so you could thread the two together & torque the heck out of it, or you could rivet it on (most pop rivets are al) or if you've got the capability: explosive welding! jk explosive welding is super cool but idk anyone who could do it at home, lol.
So hi, machinist of 10 years here (the guy on the floor who actually does the part-making). Just wanna say that Aluminum is butter and Steel is rock. That is all, have fun!
Moooore!
Why we dont use aluminium for rebar etc.?
Aloha stadium was supposed to use a weathering steel. Someone cut corners and the stadium ended up being like the Golden Gate bridge needing paint.
Cost considerations?
Good question--we are currently developing our next video with some considerations of strength to cost ratios. Stay tuned for that!
I've always thought of rust as iron reacting to oxygen, essentially burning very slowly.
you need to increase audio recording volume
Steel has on big advantage, relaibility.
Aluminium has creep, slow deformation under normaly calculated load.
It flows like plastic.
There is no material cost efective and recycleble like steel.
And yes, aluminium has corosion too, high strenght aloys esp.
Why it is widely used for motorcycles frame and sports car?
TIL: "Weathering Steel".
As a bloke from Sheffield: Stainless is the *only* steel though ;-)
Can you talk more about anodizing and other sacrificial or functional layers.
Maybe even something about magnetic differences in metals , and how they are degaussed.
Great Video! It would be great if you could do a full series on materials. Especially yield and strength in a simple formula so the home builder can explore the correct material for the job. The natural guess id to go on the heavy side because there is no quick way to calculate acceptable load bearing properties
I believe a factor in the corrosion-resistance of aluminum is that aluminum oxide adheres to aluminum metal, whereas the same is not true of iron. The rust flaking off exposes fresh iron surface to corrosion.
I worked for a large airplane company for years, corrosion prevention is a huge part of the assembly of airplanes.
Ever came across SS304, SS301..?
In. Those aluminum power lines running down your street has a steel wire running down the middle of the wire bundle
Thank you.
Thanks, need more info on this subject. Good to know.
thanks
Steel is remarkably complex... I feel you should have provided more examples of extreme steels of different kinds used in corrosive, high strength, impact, etc.
Thanks for the feedback. You're definitely right about the complexity--we had a long lost of properties that didn't make it in this video
disagree, I think the presenter did a good job of drawing a line beyond which more info would have only added clutter
👍🏻👍🏻
Which ia better aluminium and metal...?
4:25 search for crevice corrosion or crevice oxidation
Nice video. Doesn't most stainless steel also include Nickel?
Hi Tom,
Yes, common stainless steels such as SS304 (also known as 18/8 stainless) include 18% chromium and 8% nickel.
Thanks for your comment!
Keep up the good work. Thanks for the video.
Weathering steel.
a What's the material composition?
b Roof. Is it suitable?
Thank you.
Very informative video
but feathers are lighter than steel.
7000 forged aluminum is seldom seen in many applications, it's usually 6000 series.
Noice, now we want more
keep it bro
great video 👍
Nice Channel
Thanks for the visit!
One more thing about aluminium, the material gets stronger with falling temperatures, unlike steel which gets brittle.
I was not aware about this.
Any link to more detailed info?
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Thank you
well not really. Why compare precipitation aging aluminum alloys and not put in martensite aging steel alloys that go WAY beyond 2000 Mpa? 😂😂😂