| 摘要 |
PURPOSE: Low thermal expansion compacted vermicular(CV) graphite cast iron free from chunky graphite in the structure and excellent in castability, mechanical properties and processability is provided, which improves a degree of precision and performance caused by acceleration when applied to a precision machine tool. CONSTITUTION: This low thermal expansion cast iron having a shape factor of graphite of 0.2 to 0.5 and compacted vermicular graphitization rate of 80% or more comprises 2.0 to 3.0% by weight of C, 1.52 to 2.5% by weight of Si, below 1.0% by weight of Mn, below 0.045% by weight of P, below 0.020 by weight of S, 34 to 35% by weight of Ni and 0.012 to 0.023% by weight of Mg.
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