The effect of inoculation decreases with holding time. For that reason, many foundries place part of the inoculant addition in the pouring stream, in the mold or immediately before pouring rather than relying only on an early ladle addition.
Late inoculation can support graphite nucleation in thin sections and sharp corners where cooling is fastest. It may reduce chill tendency and improve machinability, but the result still depends on melt quality, temperature, sulfur, treatment history and casting geometry.
Practical controls
- Use a particle size that dissolves within the available contact time
- Control addition rate to avoid untreated metal or undissolved particles
- Keep the alloy dry and minimize excessive fines
- Track pouring delay and compare chill or thermal-analysis results
See Hyborton’s foundry inoculant range and provide the addition method when requesting a quotation.