Undercooled Structure
The undercooled structure forms by rapid cooling below the equilibrium temperature and shows fine grains or non-equilibrium phases. It increases hardness but can also lead to cracking.
Physical-Chemical Mechanism of Action
The undercooled structure forms during rapid cooling below the equilibrium temperature. This results in non-equilibrium phases or fine grain on a micro level.
Metallurgical Relevance & Risks in Welding
The undercooled structure increases the hardness of the weld, which can lead to cracking. It can also affect durability and mechanical properties.
Workshop Practice & Instructions
To achieve an optimal undercooled structure, pay attention to correct cooling times and temperature profiles. Use suitable welding methods such as gas welding or TIG welding for high-hardness steels. If necessary, post-weld heat treatment (PWHT) can be applied to coarsen the grain and reduce hardness.