Grain Refiner Addition in Powder

Physical-Chemical Mechanism of Action

Grain refiners like silicon or aluminum react in the molten pool and promote rapid solidification of the metal. They tie up oxygen and prevent grain coarsening.

Metallurgical Relevance & Risks in Welding

A fine-grained structure increases the toughness and crack resistance of the weld. Without grain refiners, the grain can coarsen, resulting in poor toughness and an increased risk of hot cracking.

Shop Practice & Operating Instructions

Use powders with grain refiners for fast welding processes. Make sure the melt time is short (approx. 1-2 seconds) and cooling is fast (t8/5 < 5 s). This prevents large grain formation and leads to a crack-resistant weld.