含硅量超过7％的合金,长期都是采用NaF, Nacl, Kcl和Na_3AlF粉状混合物进行变质处理。工艺过程需要切碎,压入等手续,变质剂的用量一般为2％-3％。大部分钠未被合金吸收而作为渣子被清除掉。变质后合金液的钠不断烧损而失去变质效果,因此,变质后的金属液必须在短时间内(即30-45分钟)浇注完毕。对于砂型零件是比较容易做到的。对于金属型铸件则比较困难,这就需要进行补充变质处理或者少熔化金属尽量做到短时间内浇注完毕。 Alloys containing more than 7% silicon have long been decontaminated by powder mixtures of NaF, Nacl, KCl and Na_3AlF. Process needs to shredding, pressing and other procedures, the amount of modifier is generally 2% -3%. Most of the sodium is not absorbed by the alloy and is removed as a slag. Metamorphism of the alloy liquid sodium loss of continuous loss of metamorphic effect, therefore, the deterioration of the liquid metal must be in a short period of time (ie, 30-45 minutes) pouring completed. For the sand parts is relatively easy to do. For the metal castings is more difficult, which requires additional modification or less molten metal as far as possible to achieve a short period of pouring is completed.