Some features of silumins inoculation with strontium

The Sr-modified alloys must be refined due to them superheating up to 800-850°C, caused by increasing in gas saturation. The use up to 40% scrap in the charge material induces Sr accumulation in Al alloys. The Sr losses during refining and remelting are investigated as compared with the use of standard Na-containing modifier. It is shown that the complete uptake of Sr and minimum gas saturation of silumins (AK12) occur by using Al+5% Sr master alloy at 720-730°C for 0.05-0.07% Sr content in alloy. An influence of Sr on shrinkage processes, especially for large-sized thick-walled castings must be taken into account when introducing Sr in place of Na.