already rusting.. shame :(
Comes pre-rusted from the yard.
That is a special steel. The oxidation layer is very thin and hard and protects the rest of the structure. Does not need painting. Many highway bridges are made out of it.
CorTen is a trade name for a steel alloy material originally produced by United States Steel.The very last thing you want to do is have to paint thousands of miles of picket fence every few years. Even Tom Sawyer's friends would catch on quickly.
Corten is a weathering steel. This material is a corrosion resistant steel, that left uncoated develops an outer layer patina. This patina protects the steel from additional corrosion. It is a high strength steel alloy, and it is used where higher strength and longer life cycle material are desired. Especially in situations where untreated alloys are desired. Alternately spelled as Cor 10.
As Cor-Ten became more popular over the years other producing mills began to develop their own atmospheric corrosion resistant weathering steels. ASTM stepped in and created what is considered equivalent specifications to Cor-Ten® in most applications.
The applicable equivalent ASTM specifications are ASTM A588, A242, A606-4, A847 and A709-50W, which Central Steel Service supplies in various products including, sheet, coil, plate, steel flats, angles, channels, pipe & tube.
It was either that or the avocado green.
The rust acts like a protective coating on steel structures and impedes more rusting inside the steel, because to oxidize iron (which is rust) it needs oxygen and the rust coating acts like a wall!