Lattice expansion by foreign atoms

Physical-Chemical Mechanism of Action

Foreign atoms like silicon or vanadium incorporate into the metal lattice and expand it. This leads to a denser atomic arrangement, which increases mechanical strength.

Metallurgical Relevance & Risks in Welding

Excessive lattice expansion can alter the microstructure and lead to steel that is too hard. This increases susceptibility to cracking and fracture. Insufficient incorporation of foreign atoms can result in a weld that is too soft, reducing its mechanical strength.

Workshop Practice & Action Guidelines

Ensure that alloying atoms are added in the correct proportion to the metal. For steels with silicon: keep Si content between 0.4% and 0.7%. Monitor melting time and temperature to achieve optimal lattice expansion.