Metallographic examination and analysis are conducted for the cracks of different kind of grey iron.The results are showed, there are existing some thermal crack which caused by cubical-expansion.

• 摘要通过对不同类型灰铸铁件中的裂纹进行金相检验和分析，认为，该类铸件中存在一种由于体积膨胀而造成的热裂纹。