Microstructural Forging Refinement
The targeted transformation of the as-built microstructure through thermomechanical post-treatment or hot working to achieve fine-grained, isotropic properties. This significantly increases toughness values.
Forging refinement is refining the grain through hot forming. You forge the material in a specific temperature range, thereby breaking up and rebuilding the coarse cast or rolled structure. The result is a finer, more uniform structure that becomes tougher. In welding, this is important because the heat input can coarsen the structure again. So when you weld a forged part, you quickly get coarse grain in the heat-affected zone. This makes the material more brittle and prone to cracking. To fix that, you often need to do a heat treatment after welding or re-form the part in a controlled way. But be careful: it's a delicate touch, wrong temperatures make everything worse. When in doubt, stick to the material manufacturer's specs.