Date

2022-2

Author

Shariati, Behdad

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In this thesis, the mechanical properties of old generation ductile iron and new generation SSF materials were compared and investigated by observing cooling behavior. For exploring the thermal analysis, cooling curves were recorded by a temperature scanner to reveal the effect of graphite shape modification by optimum inoculation. Correlations were performed with microstructural features obtained by image analysis and cooling curve analysis. It was observed that inoculation increases the TL and prevents carbide formation in the structure. After inoculation of SSF and old generation DI with 0.5%FeSi, the difference between theoretical eutectic (1152 °C) and the maximum eutectic temperature was measured by thermal analysis. It was found that ΔT changes from 7.4 to -0.8 for SSF and from 4.7 to -0.5 for S.G alloys stand for the increase in eutectic temperature over 1152°C, which is evidence of fully graphite solidification. It was found that the tensile strength decreased from 581 MPa( S.G alloy) to 512 MPa (SSF alloy), but % elongation increased from 10.7(S.G) to 18(SSF) % due to increasing ferrite phase content which is a primary benefit and characteristic of SSF alloy. The tensile strength of DI iron alloys produced in this work was determined to be slightly higher due to the presence of 72 % pearlite compared to 2.13 % in SSF alloys produced. Due to the fully ferritic matrix structure, a 68 % increase in elongation and a 23 % increase in yield strength of SSF alloy compared to DI were achieved in this study.

Subject Keywords

Ductile iron, SSF, mechanical property, solid solution strengthened,

URI

https://hdl.handle.net/11511/96319

Collections

Graduate School of Natural and Applied Sciences, Thesis