铸铁中适宜的氮含量范围极窄,氮量太低会使铸件的强度和硬度降到极限值;反之,氮量太高会使铸件产生气孔。随着铸造生严的发展,增加了向铸件内带进过多氮的机会,影响了铸件的质量。氮的来源有:废钢料、增碳剂、砂型和砂芯粘接剂、回用树脂砂及 Suitable range of nitrogen content in cast iron is very narrow, too low a nitrogen content will make the strength and hardness of castings down to the limit value; conversely, too much nitrogen will make the castings produce porosity. With the strict development of casting, casting has increased the chance of bringing too much nitrogen, affecting the quality of castings. Nitrogen sources are: scrap materials, carbon agent, sand and sand core adhesive, resin sand and reuse