Nitrogen solid solution hardening
Nitrogen solid-solution strengthening increases the strength of metals by introducing nitrogen atoms into the crystal lattice, which pins dislocations under load.
Physicochemical Mechanism of Action
Nitrogen solid-solution hardening occurs when nitrogen atoms are dissolved into the metal. These atoms sit in the crystal lattice and strain it elastically. This prevents the movement of dislocations under mechanical load, which increases strength.
Metallurgical Relevance & Risks in Welding
If the nitrogen content is too high, the structure can become too hard and prone to cracking. This leads to hot cracks and reduces the toughness of the material. It is important to control the nitrogen content during welding.
Workshop Practice & Action Guidelines
To achieve nitrogen solid-solution hardening, the melting process should be carried out at low temperature and with slow cooling. Use appropriate welding methods like TIG welding with argon-shielded nitrogen gas. Make sure the weld does not cool too quickly (t8/5 > 20 s) to ensure a homogeneous hardness distribution.