I'm a little confused about different steels and wonder if someone could clarify it because it seems like there are often confusing ways steel is described for frames which seems inaccurate in bikes descriptions.

One thing that often seems confusing is you often read chromoly is better than high tensile steel but chromoly is a high tensile steel according to this wiki page and many other sites that list types of steels.

https://en.wikipedia.org/wiki/Carbon_steel

Also some chinese sites claim their high tensile steel frames have chromium and molybdenum but they still describe them as high tensile steel without mentioning chromoly. Brompton which describes their frames as high tensile steel but on their site also describe them as chromoly too.

Add to that some Chinese manufacturers sell 'high carbon steel frames' and claim these are superior to high tensile steel frames.

When a high tensile steel frame isn't using chromium and molybdenum what elements is it using instead, presumably these are the inferior high tensile steel frames?

Also dare I ask what is better high carbon steel for a frame or a high tensile steel?

It appears high carbon steel can be used for springs and wires and is very strong and can flex for many thousands of operations but is difficult to weld but modern robotic welding and other technology has improved welding of this material.

Where does modern high carbon steel frame manufacture rank compared to classic steels used in frames, better or worse? Is there any solid information out there that compares them for strength and durability?

Why have some of the higher quality steel frame manufacturers like fuji-ta moved from high tensile to high carbon steel for frames?