The Global Cost of Corrosion • Hacker News Board

Re: The Global Cost of Corrosion

#21

Post by jacquesm » Mon, Jul 25, 2022, 5:51 PM UTC

Arrath wrote: post #10

countvonbalzac wrote: post #3

Why aren't bridges and ships made out of stainless steel? Is it too expensive, or not as strong as regular steel?

Cost, primarily. I'm not certain but I believe joins and welds also need further attention to ensure the corrosion protection isn't impaired. Anyway, O&M is the problem for the guy trying to get the next decade's budget approved so if the upkeep is more expensive, hey at least I got this thing built.

Yes, this is called electrochemical cleaning. If you don't do that then the weld will be more vulnerable to oxidization because the protective layer that forms on stainless steel will be damaged and upset by the welding process leaving some of the iron in the steel directly exposed to the environment. This then can cause pitting of the surface, which is the beginning of the end.

For such a process to be effective it has to be done immediately after welding. You can use it to try to repair something that is already rust damaged but in my experience the gain from that is mostly a stay of execution, not a perfect solution.

Re: The Global Cost of Corrosion

#22

Post by ortusdux » Mon, Jul 25, 2022, 5:53 PM UTC

Ekaros wrote: post #19

alex_young wrote: post #15

Earlier quoted context omitted.

IIRC stainless isn't actually rust proof, especially in applications where there is a lot of interaction with odd chemicals and things like sea water, so bridges may not be an ideal use for the product.

I have heard the same. Actually making rusting proof stuff is very hard. Specially if there is any chance of things like acids being involved. Coatings could help, but even then why not just paint regular steel. Now other thing I wonder is how structurally sound some of the stainless alloys are? Do they have similar characteristics to steels now used?

IIRC, Coated rebar can actually fail faster or in less predictable and therefore worse ways. The coating is often damaged during install, but even perfectly coated bar forms cracks eventually. The entire system's galvanic potential is focused on these small exposed areas, causing extremely fast rusting. The coating tends to fail in higher stress areas, which means that not only does the bar fail, it fails in the worst possible locations.

Re: The Global Cost of Corrosion

#23

Post by denimnerd42 » Mon, Jul 25, 2022, 5:54 PM UTC

Arrath wrote: post #12

denimnerd42 wrote: post #7

Earlier quoted context omitted.

There is a steel called Corten where the rust develops a protective layer similar to aluminum and won't rust all the way through. The only issue is it isn't good when exposed to constant water as the rust will wash off and not protect.

Some may also find the rusted patina look less than ideal. Personally I don't mind it at all.

some people use it as an architectural element. they'll build planters, roofs, siding, fences...

Re: The Global Cost of Corrosion

#24

Post by mattkrause » Mon, Jul 25, 2022, 5:55 PM UTC

bilsbie wrote: post #6

This is why I get scared when I see articles about people developing plastic eating bacteria. Sure it is great for reducing waste but it’s a dangerous game to be playing for sure.

Those microbes require very specific conditions: precise pH and osmolarity, high temperature (50-70˚C), long contact times, feedstock that's been literally pulverized, etc.

These probably aren't going to occur anywhere outside of a bioreactor, so our action figures are likely safe...for now!

Re: The Global Cost of Corrosion

#25

Post by elil17 » Mon, Jul 25, 2022, 5:58 PM UTC

countvonbalzac wrote: post #3

Why aren't bridges and ships made out of stainless steel? Is it too expensive, or not as strong as regular steel?

Yes and yes. Stainless is expensive. It's stronger than some types of steel but not as strong as others. It's also difficult to weld. Plus, it's not 100% corrosion resistant - it only offers partial protection.

Re: The Global Cost of Corrosion

#26

Post by fest » Mon, Jul 25, 2022, 5:58 PM UTC

A soviet-era book on machining I recently read stated that up until that point, about 40% of the total steel and cast iron production since 1890 has been lost to corrosion.

Re: The Global Cost of Corrosion

#27

Post by hammock » Mon, Jul 25, 2022, 5:59 PM UTC

hristov wrote: post #8

This is an important issue. People keep talking about recycling, but much more important than recycling is just being able to use a thing for longer before you are even thinking about recycling it. Japanese automakers did the world a great favor when in the 80s and 90s they made much longer lasting cars and made longevity and resale value an important consideration in the purchasing decision. They did this mostly by…

>This is an important issue. People keep talking about recycling, but much more important than recycling is just being able to use a thing for longer before you are even thinking about recycling it.

Reduce, reuse, recycle. In that order

Re: The Global Cost of Corrosion

#28

Post by pygy_ » Mon, Jul 25, 2022, 6:00 PM UTC

HPsquared wrote: post #2

Rust's a Must, by T.R.B. Watson: """ Mighty ships upon the ocean Suffer from severe corrosion Even those that stay at dockside Are rapidly becoming oxide. Alas, that piling in the sea Is mostly FE2O3 And when the ocean meets the shore, You'll find there's FE3O4. 'Cause when the wind is salt and gusty Things are getting awful rusty We can measure it, we can test it We can halt it or arrest it We can gather it and weig…

I have a song about this (in French) sung from the vantage point of near future robots.

https://soundcloud.com/user-876103472/lennui-cest-loxyge-ne

Long story short: screw the meatbags, let's get rid of atmospheric oxygen...

Re: The Global Cost of Corrosion

#29

Post by bradfa » Mon, Jul 25, 2022, 6:04 PM UTC

jacquesm wrote: post #14

hristov wrote: post #8

This is an important issue. People keep talking about recycling, but much more important than recycling is just being able to use a thing for longer before you are even thinking about recycling it. Japanese automakers did the world a great favor when in the 80s and 90s they made much longer lasting cars and made longevity and resale value an important consideration in the purchasing decision. They did this mostly by…

Volvo led the way in this long before Japan got even close to figuring this out. That's why you still see ancient Volvo's drive around in numbers that are just way higher than any other brand.

Are modern Volvos still better than average for corrosion resistance?

Re: The Global Cost of Corrosion

#30

Post by LatteLazy » Mon, Jul 25, 2022, 6:04 PM UTC

jtlienwis wrote: post #4

The environmentalists killed a zinc mine in my state due to pollution concerns. Of course every pound of zinc not mined meant more steel without zinc protection, and hence more rust and more mining of iron ore. Arguments like this were completely lost on them.

Or just mine the zinc elsewhere?!