Austenitic Grain Growth Model
A time- and temperature-dependent equation used to predict the coarsening of austenitic grains in the overheated zone of the weld joint.
Grain growth in austenite depends on heat input and holding time at high temperature. The hotter and longer you keep the heat zone in the weld area, the coarser the grains become. Coarse grains in austenite make the steel more brittle and crack-sensitive after cooling, especially when hard microstructures form. In practice, this means: keep heat input as low as possible and weld quickly so the heat zone doesn't stay at high temperature unnecessarily long. When welding thick plates or needing high heat, watch the cooling and proper joint preparation. In the end, what matters is that the microstructure stays fine and tough, not that you meet some formula.