Grand Design - rusting steel special?

Called CORTEN steel, often used on shipping containers, which for some reason are then painted anyway.

Thanks. I'm not looking for any, just satisfying my curiosity.

Yep, been around for a long time now.

The steel was

Ah, that explains this...

Cheers

Aluminium is similar to iron in the periodic table. It oxidises very fast, but the oxide layer bonds strongly to the underlying aluminium and prevents further corrosion.

Iron oxide doesn't do that. It tends to crumble off, allowing further corrosion.

The point is that Weathering steel or Corten steel, as Andy Burns highlighted, is an alloy where the rust layer is stable. I hadn't heard of that.

Cheers

Apparently a salty atmosphere can cause the layer to never stabilise and rust away, hence why shipping containers are painted, wonder why the bother using corten steel in the first place?

It's a sort of clever and much cheaper variant of stainless steel, which is also protected by a thin, protective oxide layer. The original story of 18-8 is quite interesting, it was an experimental melt made by Harry Brearley when looking for better materials for rifle barrels. It was no good for that and apparently stacked outside with other failures to await recycling. That was when its "stainless" properties were discovered.

One wonders whether a bit of serendipity was involved in Corten too, if someone thought "That oxide looks quite nice, perhaps it could be a feature".

possibly this place, very near to my work in Lewes, East sussex?

I walk past this building a couple of times a week. FWIW, although I am by no means averse to industrial finishes like this, I find its appearance on this house pretty uninspiring. It simply looks like rusty fencing, sadly.

J^n

Interesting stats:

Property Weathering steel-clad new-build Bedrooms 5 Bathrooms 3 Project started December 2014 Project finished September 2015 Size of house 257sqm Plot cost £350,000 Build cost £700,000

So, £270 per sq ft. As a new-build there's no VAT. So, that price is around 50% higher psf than a less grand design.

Compare that one's £270 psf to this one:

Which cost £92 psf.

And this, in Manchester:

I much prefer that to the Lewes house.

Think I will have to go and see how this is surviving then

Judging from the stains on the edging, it's still rusting. The description implies they went for the corten look, without using actual corten ...

"the exterior consists of four separate pieces that were made from mild steel, rusted and then coated in a special oil to protect it from the elements."

There is a overpass near the Toyota Factory in Derbyshire that has an unpainted appearance. I asked the Highways agency why it had been left to rust and they replied (some years ago now) tha tthe steel was special and it protected itself with an oxide layer.

https://www.google.co.uk/maps/@52.8659867,-1.5687995,3a,75y,288.16h,101.23t/data=!3m6!1e1!3m4!1sZUnvPm_WQhjjBrnNDSKdzA!2e0!7i13312!8i6656

DerbyBorn wrote in news:XnsA6245FB0BA254TrainJPlantntlworldc@81.171.92.222:

That seems a proper application for the stuff, it's a bridge so doesn't need to look pretty, if it saves on painting it every few years, all to the good, if it means the steel can be easily inspected to spot any problems before they become major, even better ...

Even with quality control (it is obviously not fundamental to their culture ) they still mange to screw things up:

"The durability of COR-TEN did not live up to expectations, with rust holes appearing in the railcars. Painting may have contributed to the problem, a s painted weathering steel is no more corrosion-resistant than conventional steel, because the protective patina will not form in time to prevent corr osion over a localized area of attack such as a small paint failure."