低Mg球化剂在汽车球铁件生产中的应用

Application of Low-Mg Nodularizing Alloy in Productin of Automotive Nodular Iron Castings

采用w（Mg）量为7％～9％的球化剂生产汽车球铁件,为确保浇注温度,出铁温度为1 550℃以上,采用冲入法进行球化处理,反应剧烈,Mg吸收率只有30％～40％,铁液温度降低严重.改用w（Mg）量4％～4.5％的球化剂,出铁温度降低20～30℃,试验结果显示：球化反应平稳,Mg吸收率提高到50％～60％,球化剂的加入量减少了0.2％,孕育剂加入量从1.0％降为0.7％,覆盖剂加入量从1.5％降为1.3％,回炉料加入量从40％增加到60％,降低了生产成本.

Originally the nodularizing alloy containing 7%-9% Mg had been used for production of automotive nodular iron castings. In order to ensure the pouring temperature,the tapping temperature was enhanced up to 1 550 9C ,and the pour-over process was adopted for nodularizing. As the result,the nodularizing reaction was violent,the recovery rate of Mg was only 30%- 40% ,the temperature drop of the iron melt was serious. Therefore,the nodularizing alloy was changed to the low-Mg type containing 4%~4.5% Mg,tapping temperature also decreased by 20-30℃. The test result showed that the nodularizing reaction became smooth,the recovery rate of Mg was increased to 50%-60% so that the adding amount of the nodularizing alloy was reduced by 0.2% ,the inoculant amount reduced from 1.0% to 0.7% ,the nodularizer-covering agent was reduced from 1.5% to 1.3%,the usage amount of the returned iron charge was increased from 40% to 60% that led to the cost reduction.