Why don't engineers just use stainless on things like bridges? Surely the initial cost would be offset by reduced maintenance
Why don't engineers just use stainless on things like bridges?
Why don't engineers just use stainless on things like bridges? Surely the initial cost would be offset by reduced maintenance
Among what's probably a mountain of reasons, pavement doesn't exactly adhere to it well.
they already have a better and cheaper structural steel that forms a thin layer of "rust" and then does not corrode further.
Cor Ten steel.
this. the oxide layer protects from further corrosion. it's even trendy to use for external finishes now.
stainless eventually rusts too, OP.
The US Steel building in Pittsburgh is made out of it, built circa 1969. Never had a finish applied, though it did cover the sidewalks around it with red stains for the first few months after construction.
Looks a little evil.
tall buildings are absolutely terrifying
You're such a fricking woman
There are many different types/grades of stainless steel. The ones that actually have the sort of corrosion resistance needed for permanent unprotected outdoor use have higher levels of chromium or other alloy components, which tends to make them less suitable for structural components (less ductile, etc). And for the sort of tonnage you're talking about for a bridge, the price difference is very significant. As in, a 304 stainless h-beam cost 5x as much as a low-carbon steel one in the same dimensions, while having significantly less yield strength.
stainless is also heavier than normal steel.
Which is why galvanizing exists, along with zinc paints and such.
Not correct. To the extent that there is a difference, it’s negligible.
>Why don't engineers just use stainless on things like bridges? Surely the initial cost would be offset by reduced maintenance
It would be easier to use Roman concrete that is apparently self-healing than stainless rebar.
Easiest is to just build out of steel and forget the concrete. When it rusts you sand the spot and paint it. Concrete only takes half the load so you'd have to double the amount of steel and just build everything with painted trusses and H beams
Didn't we have this thread already?
At least once to wit, with the same picture and close, if not exact wording.
we did, and nothing of value came from it
Summer's almost over, it'll get a little better in a couple of weeks. Not a lot, but a little.
>Why don't engineers just
so you're saying you're not an engineer
>Surely the
why would you think you came up with some "totally obvious simple" idea that men who dedicated years of their lives to their profession just overlooked?
https://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
Anon, that's just how you must start a thread to get replies. If you do it without stepping on someone's foot you're 10x likely to just 404 alone.
getting 4bong replies is not a vital need
>surly te exspurts no
Yes many thousands of people whose entire jobs are to build correct infrastructure at the best possible price point will know more about which metal to use than some guy on an anime imageboard who only thinks about one singular aspect of distinction between stainless and non-stainless steel
Why don't engineers just make unbreakable lightbulbs like they did around 1900s? Surely they still have the technology
I would also like to personally apologize for this inexcusably antisemitic remark.
They didn't have unbreakable lightbulbs. The early light bulbs were even worse than modern incandescents in durability and longevity.
Carbon filaments are technically superior, though. Tungsten has a positive temperature coefficient of resistance, causing blown filaments when the inrush current hits a thin spot. Carbon has a negative temperature coefficient, so thin spots produce less heat and the filament has built-in wear leveling. The only problem with early bulbs was their use of natural carbon sources (IIRC bamboo fibers) which have inherent irregularities leading to premature failure.
I’m not sure if that’s true, but it’s somewhat plausible, and good information.
Lol what a homosexualy engineer response.
Why didnt the engineers just_______? Is always answered by the word "budget".
Why don't they just use platinum?
why don't we just have flying cars so we don't need bridges or roads anymore?
>Surely the initial cost would be offset by reduced maintenance
Haha no. Call your local metal distributor and ask him the price difference between several tons of structural vs stainless steel and see how that compares to a few gallons of structural steel primer
Not to mention mechanical properties
It's more expensive than you could imagine. A lot of people do not want to work with stainless. I design water pumps, usually sewerage pumps but sometimes we get specific jobs where the pump has to work in salt water so super duplex has to be used. It's incredibly painful to find anyone who will work on stainless steel. Some guys will just refuse it isn't even worth their time. Trying to have specific parts in a pump manufactured with stainless is the most painful shit I've ever done.
Because there's really no such thing as truly stainless steel. Especially when in contact with salt water. And they do use rust resistant alloys, otherwise bridges would be fricked within weeks rather than decades.
I'm a structural engineer, specializing in marine structures. Stainless steel is a pain in the ass as a building material. Fabricating and welding is fricky, and stainless steel bolts are a nightmare. Sometimes, though, it's what you've got to use. For highly corrosive or sanitary environments, it's OK. Still, just getting the shit made and connected is 5-10 times more costly than carbon steel, material cost notwithstanding.
Welding does indeed suck as it destroys the stainless layer at and near the weld, so you have to treat it to restore its stainless properties or it becomes an easily corrodable weak point..
>stainless layer
stainless steel is an alloy, not a surface treatment
please read about how welding affects stainless steel and most importantly passivation before you post again
>It's this thread again
Thanks for waiting 6 months at least.
Stainless steel is just shitty and expensive unless you need absolutely no rust like if you are handling food.
The issue with rust isn’t that the metal oxidizes. Every piece of metal you see has an oxide layer, but there are many different types of rust/oxidation depending on metal and other factors. The issue comes when the oxidized metal is bigger or smaller than the same non oxidized metal. If the rust swells up enough it will flake off and expose more metal to rust. The cycle continues with more rust flaking off and more metal being exposed to oxygen.
The solution is to compose alloys where the rust will form a protective layer instead of flaking off and corroding the object. This is accomplished by making the oxides form to be about the same size as the unoxidized metal.
I work on a railroad and the steel is all rusty since it is exposed to the elements 24/7 but even our 100 year old unpainted bridges and 70 year old rail show no serious signs of corrosion since the alloys are designed for it. When you leave a can of chili out in the woods and it rusts into nothing it is because the manufacturers didn’t care about rust as a factor.
>"stainless" steel galvanically corrodes over 10 years
>entire region's water table is now contaminated with chromium and thus undrinkable
>nothing personnel, kid