Not particularly foundry, but more metal manufacture. I've seen several videos on extruding aluminum, brass or copper through a die to extrude a (hot) cilindrical block to a strip, tube, profile, etc. But steel is still old fashioned rolled with complex profiled rolls to make rebar, i beam, angle irons or seamless tubes (Mannesmann-Vallourec). Why does the steel industry not use the same method: i.e. heating a cilidrical strand section obtained by continuous casting to just below the melting point and then squeezing it through a die like they do with copper or aluminum ?
At least one company is doing it: https://www.hoeschsep.com/wp-content/uploads/2017/05/Gesamtprospekt-HSEP-EN.pdf I'd imagine the process would be very hard on dies and require even larger hydraulic rams than currently used.
Many years ago my dad did some wiring on a machine that they were going to use to extrude chrome molly. The mens room was adjacent to the extruder so they had a 2" piece of armor plating on the wall, just in case. Never heard about how it worked out.
It's called continuous casting in the steel industry and is quite common. For instance steel t-posts are continuous cast to near shape then hot rolled to final shape. Steel does not lend itself to direct casting (extrusion). Cast steel properties generally improve with hot rolling resulting in grain refinement. Rolled beams are of superior quality over cast beams and are less likely to fracture or fail through fatigue loads. So the blooms are rolled from an ingot and then into desired shape. A cast billet will also be rolled to finished shape but the cast shape may resemble the final product.
