| 摘要 |
<p>A method of strengthening ferritic ductile iron castings while maintaining ductility at a high level is disclosed. An iron alloy melt is cast consisting essentially of by weight 3.9-6.0% Si, 3.0-3.5% C, .1-.3% Mn, 0-.35% Mo, at least 1.25% Ni, no greater than .015% S and .06% P, the remainder Fe, the melt having been subjected to a nodularizing agent to form graphite nodules upon solidification. The cast alloy is heat treated to provide a fully ferritic microstructure with 9-14% by volume grpahite, a yield strength of at least 75,000 psi, a tensile strength of at least 95,000 psi, and an elongation of at least 17%.</p> |
