Effects of Solidification Cooling Rate and Heat Treatment on Impact Properties of Heavy-Walled Pearlitic Spheroidal Graphite Iron Castings

Abstract

  To evaluate and improve the toughness of heavy-walled pearlitic spheroidal graphite iron castings, Charpy impact tests were conducted on specimens with casting modulus of 1.25 to 5 cm and different solidification cooling rates to simulate actual products. As a result, the absorbed energy in the transition region and ductile region tended to decrease as the solidification cooling rate decreased in the as-cast material. The impact transition temperature was higher than room temperature. However, after normalizing, the absorbed energy in the transition region improved and the impact transition temperature shifted to a lower temperature, suggesting that improving the matrix structure is effective for improving the impact properties of heavy-walled pearlitic spheroidal graphite iron castings.