Nitride-Forming Additive
Nitride-forming additives like titanium or silicon reduce grain growth in the heat-affected zone by forming stable nitrides, which improves toughness.
Physicochemical Mechanism of Action
Nitride-forming additive reacts with the base material and forms stable nitrides. These compounds slow down grain growth because they restrict the diffusion of atoms in the crystal lattice.
Metallurgical Relevance & Risks in Welding
A too high content of nitride-forming additive can lead to increased hardness and grain size, which impairs the toughness and formability of the material. In addition, hot cracking can occur if the material cools too quickly.
Workshop Practice & Instructions
Use nitride-forming additive in the filler metal in small amounts (e.g., 0.1 to 0.5 % titanium). Make sure the material cools slowly to avoid hot cracking. The exact amount and cooling pattern depend on the specific material and welding process.