High-quality black-and-white photographs of large old machines and tools

[Jon]

Inside a high-pressure steam drum.

Fullsize image: https://diqn32j8nouaz.cloudfront.net...m_fullsize.jpg

[mlochala]

Looks very dusty in there.

[12bolts]

That will be the oxide layer. Steam strips every last molecule of preservative from the surface of the steel. But the hot dry environment prevents corrosion forming. So you just get that thin layer of oxide that forms very quickly when the system is depressurized and moisture forms on the surface. A bit like degreasing steel with acid. If you dont apply something to the surface rust will form in minutes