Grain Growth Inhibition by Second-Phase Particles
Zener particles block grain boundaries and prevent uncontrolled coarse grain growth during annealing. This improves the strength and toughness of the steel.
Physico-chemical mechanism of action
Zener particles are finely distributed, insoluble particles in the metal that block grain boundaries. These obstacles prevent grain boundaries from expanding uncontrollably and growing into coarse grains.
Metallurgical relevance & risks in welding
Without Zener particles, coarse grain growth during annealing can lead to a coarsened structure. This makes the steel softer and less tough, leading to cracks and failure. By adding Zener particles, grain growth is controlled, improving mechanical properties.
Workshop practice & action instructions
To create Zener particles, certain additives such as silicon or aluminum can be added to the weld pool. The concentration and addition scheme must be strictly followed. When selecting the steel, ensure that it already contains Zener particles or that they can be generated by additives.