Filed under: Top Forging Questions
Learn how forgings create improved properties as Rob Mayer discusses the unique advantages of refined microstructures in our finished components. Also discover how controlled deformation, inherent to forging, provides grain flow properties that increase directional strength.
One of the primary benefits of forging is the recrystallization that occurs from the strain energy, the shearing forces that go through the cross-section during deformation. There are several different types of recrystallization. There is static recrystallization. That will occur during just a simple thermal process, but what the forging process then adds is with this strain energy, with the shearing forces that are going on, we’re in a sense breaking up the structure.
It’s almost like creating tiny little pieces. You’re making it reform into all these little grains, and those little fine grains are what give you the impact toughness and the fatigue properties that are so important to parts and service.
A benefit of the impression die forging, especially when we take bar stock, which has been rolled so that the grain structure is longitudinal down the length of the bar, is that then when we form this part, we can make that grain structure go around the bends of the part, or go out into areas that need additional support. It’s like the grain of wood, as I think anybody who’s handled wood knows, that trying to cut across the grain, the material is a lot tougher.
Well, the same thing happens with forged products when we’ve been able to control that grain structure, so that it flows down, say, the length of the part or through the areas that need additional strength.
And one of the things that forging gives you is almost like a trifecta, to use sports terms, it’s crushing out the bad guys. It’s smoothing the playing field. It’s creating a directionality of the strength of the parts. All those things together, it’s something that forging does that other processes just don’t do.