Chilling Effect of Inoculation on the Microstructure and Hardness Property of Hypo-Eutectic Grey Cast Iron

Abstract

The influence of varied weight percent of inoculant (ferrosilicon) on the microstructure and hardness property of hypo- eutectic grey cast iron was investigated. Four sets of chill wedge samples were produced using two chill wedge wooden patterns (W3.5 and W4). The first set, the control samples W3.5 and W4 were uninoculated. The second, third and fourth sets were inoculated with 1.0wt.%, 1.5wt.% and 2wt.% ferrosilicon respectively to give inoculated samples W3.5 and W4. Wedge test was conducted on the samples at the four different points (1, 2, 3 and 4) in accordance with ASTM A367. From the results, microstructures of the control and the inoculated samples were differently influenced by the varied percentage of the inoculant at the four designated points 1, 2, 3 and 4. The average hardness property of the inoculated samples decreases with increasing ferrosilicon addition. Samples W3.5 and W4 with 1.0wt.% ferrosilicon revealed high hardness property at chill zone, and hardness property of W3.5 was high relative to sample W4 with the values of 34.9 HRA and 30.6 HRA respectively. Similarly, the control samples showed the highest hardness property at the chill zone. Sample W3.5 revealed high hardness value of 33.0 HRA relative to sample W4 of 26.8 HRA at the chill zone.