My go-to as well. Pre-war steel.

it's not about pre-war. it's about pre-trinity-nuclear tests. which means uncontaminated by atmospheric radioactive isotopes. it happened at the end of ww-ii but that is not the point.

Yes, however it's also an accepted name for it

> Low-background steel, also known as pre-war steel and pre-atomic steel, is any steel produced prior to the detonation of the first nuclear bombs in the 1940s and 1950s.

https://en.wikipedia.org/wiki/Low-background_steel

It's an important distinction because a lot of ships were sunk during WWII.