Dynamic Strain-Induced Precipitation
The controlled precipitation of fine particles during plastic deformation at elevated temperatures. It actively blocks dislocation movement, thereby increasing high-temperature strength.
Dynamic strain aging is a phenomenon you mainly have to watch out for in unalloyed and low-alloy steels in the blue brittleness range. Dissolved atoms, especially carbon and nitrogen, diffuse to dislocations during deformation and block them. This leads to a significant increase in strength, but also to a loss of toughness and ductility. In welding, this is relevant because the heat-affected zone can enter this critical temperature range. If the material is under stress there, it can lead to cracks. So pay attention to proper heat management and avoid unnecessary stresses in the component, especially when working with higher preheat temperatures. If the material tends to crack, it helps to control the cooling rate and make the weld clean and without notches.