All forming angle iron, regardless of scale, involves some kind of plastic deformation. Material expansion occurs on the outside surface of the bent angle, compression on the inside, and you need to know how to deal with both. The limits of material ductility will be the controlling factor for the minimum bend radius.
The strains associated with the plastic deformation when cold forming can cause the material to strain-harden. This can change the material’s mechanical properties in the area of the bend, where plastic deformation is occurring. At this point, ductility and resistance to fracture will need to be considered.
When bending thick angle iron, you need to abide by a minimum inside bend radius. This will minimize the effects of strain hardening and cracking at the bend.