The Effect of Ni Content on the Microstructure and Mechanical Properties of Heat Resistant Ductile Iron with Heavy Section
The medium-silicon molybdenum ductile iron exhibits good mechanical and heat-resistant properties, making it suitable for preparing various large-scale heat-resistant castings. This study investigated the influence of Ni content on the microstructure, mechanical properties and oxidation resistance...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Harbin University of Science and Technology Publications
2023-08-01
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| Series: | Journal of Harbin University of Science and Technology |
| Subjects: | |
| Online Access: | https://hlgxb.hrbust.edu.cn/#/digest?ArticleID=2227 |
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| Summary: | The medium-silicon molybdenum ductile iron exhibits good mechanical and heat-resistant properties, making it suitable for preparing various large-scale heat-resistant castings. This study investigated the influence of Ni content on the microstructure, mechanical properties and oxidation resistance of the medium-silicon molybdenum ductile iron using optical microscopy, scanning electron microscopy, tensile testing machine, and Brinell hardness tester. The results indicated that with the increase of Ni content, the size of graphite nodules in as-cast ductile iron decreased, while the number of graphite nodules increased slightly. Ni can promote the formation of pearlite in the matrix of ductile iron, resulting in a 20% increase in pearlite content when the Ni content increased from 0% to 1. 9% . The mechanical tests showed that the addition of Ni can significantly improve the strength and hardness of the medium- silicon molybdenum ductile iron but reduced its plasticity. When the Ni content was 1. 9% , the ductile iron had the highest strength and hardness, with a tensile strength, hardness, and elongation of 618 MPa, 218 HBW, and 12. 0% , respectively. However, the oxidation resistance test showed that adding Ni was detrimental to the heat resistance performance. As the Ni content increased, the thickness of the oxidation film gradually increased. The thickness of the oxidation film was 55. 66 μm for the sample without Ni and increased to 341. 41 μm when the Ni content was 1. 9% , a difference of 285. 75 μm.
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| ISSN: | 1007-2683 |