Grain Growth Anisotropy
The directional alignment of crystallites along the temperature gradient leads to uneven growth rates and different mechanical properties in different directions.
Physico-Chemical Mechanism of Action
Grain growth anisotropy arises when crystallites grow during cooling in a temperature gradient. They align with the maximum temperature change and therefore grow unevenly in different directions.
Metallurgical Relevance & Risks in Welding
This anisotropy can lead to different mechanical properties within a weld, impairing strength and toughness. It increases susceptibility to cracks and hot cracking, especially when the material is under stress.
Workshop Practice & instructions
To minimize grain growth anisotropy, ensure uniform cooling of the weld. Use a controlled cooling process and avoid rapid cooling steps. For high-temperature-resistant steels, anisotropy can be reduced by careful selection of the welding process and materials.