Cast steel, or forged steel or crucible steel. All terms used often incorrectly to talk about old well made edge tool steel. Forged or cast steel has been heated red hot then hammered, turned then hammered again. What this does is change the nature of the steel. Like rice particles steel has a structure that is oval and long . Hammer it when hot and these particles come together and get into alignment. This gives you a finer grain structure to the steel
So what? Well the more this is done the better the steel gets the harder it becomes and the finest edge it will hold . Look at Japanese sword makers for the zenith of this skill. You get a blade that holds its edge longer and takes a finer edge . Makes A2 steel look very dull.
Get it now they are not being made any more.