Crystallization Nucleus
A nucleus is a very small, stable crystalline zone from which a new metal lattice forms during cooling. Its formation requires overcoming an energy barrier.
Physicochemical Mechanism of Action
A nucleation seed forms from a liquid metal melt through the random collision of atoms into a stable lattice. This process requires an energy barrier that is overcome by heat exchange during cooling.
Metallurgical Relevance & Welding Risks
The size and number of nucleation seeds influence the structure and properties of the joined steel. Too small or too many seeds can lead to uneven cooling and fine grains, which reduces toughness and hardness. This can cause cracks and damage in the workpiece.
Workshop Practice & Instructions
To control nucleation seeds optimally, it is important to ensure homogeneous cooling of the metal. This can be achieved by choosing the right welding processes and parameters. For high-temperature welding like TIG or MIG, the cooling protection layer should be thinner to ensure uniform cooling.