Intercrystalline Precipitation Hardening
Intergranular precipitation hardening boosts mechanical strength by embedding nanoscale particles at grain boundaries, which blocks dislocation movement.
Physical-Chemical Mechanism of Action
Intergranular precipitation hardening refers to the embedding of nanoscale particles such as silicon or nitride at the grain boundaries of the metal. These particles create obstacles for dislocation movement of atoms, which increases resistance to movement and thus hardness.
Metallurgical Relevance & Welding Risks
This hardening can be achieved by too rapid cooling or by special additives such as silicon. It improves strength but can also lead to hot cracking if cooling is not controlled. Excessive hardness can make the material brittle and lead to fractures.
Workshop Practice & Action Instructions
To achieve intergranular precipitation hardening, the weld pool process should be controlled. For steels with silicon content, a cooling time of 10 to 20 seconds after welding is recommended. Avoid excessive cooling rates, as these can lead to hot cracking.