Secondary graphitization annealing is often used to obtain 100% ferrite matrix in the production of ductile iron. The volume expansion of pearlite will occur during secondary graphitization annealing. So far, whether this expansion can affect the micro-shrinkage porosity between the austenite rings surrounding the graphite nodule during solidification has not attracted people's attention, while micro-shrinkage porosity is one of the primary factors affecting the impact toughness of ductile iron at ultra-low temperature. Aiming at the problem of whether the secondary graphitization of ductile iron affects the micro-shrinkage porosity, the secondary graphitization annealing of pearlitic ductile iron is carried out, and the effect of secondary graphitization expansion on micro-shrinkage porosity was studied. The metallographic microstructures and micro-shrinkage porosity are observed by Axiovert200MAT metallographic microscope and MLA250 (FEIQuanta) scanning electron microscope. The maximum length of micro-shrinkage porosity is measured by Nano Measurer 1.2 and the maximum area is measured by Photoshop software. The results show that the volume expansion rates of ductile iron and gray cast iron after secondary graphitization annealing are about 1.2% and 1.4%, respectively. After secondary graphitization annealing, the size and quantity of micro-shrinkage porosity of ductile iron decrease. It indicates that the expansion after secondary graphitization of cast iron will help to repaire micro-shrinkage porosity.
Published in | Advances in Materials (Volume 11, Issue 3) |
DOI | 10.11648/j.am.20221103.13 |
Page(s) | 69-76 |
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This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
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Copyright © The Author(s), 2022. Published by Science Publishing Group |
Ductile Iron, Gray Cast Iron, Secondary Graphitization, Expansion Rate, Micro-shrinkage Porosity
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APA Style
Shuying Chen, Qingchun Li, Jiajian Song, Ming Sun, Haiqing Sun, et al. (2022). Effect of Secondary Graphitization Expansion on Micro-shrinkage Porosity of Ductile Iron. Advances in Materials, 11(3), 69-76. https://doi.org/10.11648/j.am.20221103.13
ACS Style
Shuying Chen; Qingchun Li; Jiajian Song; Ming Sun; Haiqing Sun, et al. Effect of Secondary Graphitization Expansion on Micro-shrinkage Porosity of Ductile Iron. Adv. Mater. 2022, 11(3), 69-76. doi: 10.11648/j.am.20221103.13
@article{10.11648/j.am.20221103.13, author = {Shuying Chen and Qingchun Li and Jiajian Song and Ming Sun and Haiqing Sun and Guowei Chang}, title = {Effect of Secondary Graphitization Expansion on Micro-shrinkage Porosity of Ductile Iron}, journal = {Advances in Materials}, volume = {11}, number = {3}, pages = {69-76}, doi = {10.11648/j.am.20221103.13}, url = {https://doi.org/10.11648/j.am.20221103.13}, eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.am.20221103.13}, abstract = {Secondary graphitization annealing is often used to obtain 100% ferrite matrix in the production of ductile iron. The volume expansion of pearlite will occur during secondary graphitization annealing. So far, whether this expansion can affect the micro-shrinkage porosity between the austenite rings surrounding the graphite nodule during solidification has not attracted people's attention, while micro-shrinkage porosity is one of the primary factors affecting the impact toughness of ductile iron at ultra-low temperature. Aiming at the problem of whether the secondary graphitization of ductile iron affects the micro-shrinkage porosity, the secondary graphitization annealing of pearlitic ductile iron is carried out, and the effect of secondary graphitization expansion on micro-shrinkage porosity was studied. The metallographic microstructures and micro-shrinkage porosity are observed by Axiovert200MAT metallographic microscope and MLA250 (FEIQuanta) scanning electron microscope. The maximum length of micro-shrinkage porosity is measured by Nano Measurer 1.2 and the maximum area is measured by Photoshop software. The results show that the volume expansion rates of ductile iron and gray cast iron after secondary graphitization annealing are about 1.2% and 1.4%, respectively. After secondary graphitization annealing, the size and quantity of micro-shrinkage porosity of ductile iron decrease. It indicates that the expansion after secondary graphitization of cast iron will help to repaire micro-shrinkage porosity.}, year = {2022} }
TY - JOUR T1 - Effect of Secondary Graphitization Expansion on Micro-shrinkage Porosity of Ductile Iron AU - Shuying Chen AU - Qingchun Li AU - Jiajian Song AU - Ming Sun AU - Haiqing Sun AU - Guowei Chang Y1 - 2022/08/09 PY - 2022 N1 - https://doi.org/10.11648/j.am.20221103.13 DO - 10.11648/j.am.20221103.13 T2 - Advances in Materials JF - Advances in Materials JO - Advances in Materials SP - 69 EP - 76 PB - Science Publishing Group SN - 2327-252X UR - https://doi.org/10.11648/j.am.20221103.13 AB - Secondary graphitization annealing is often used to obtain 100% ferrite matrix in the production of ductile iron. The volume expansion of pearlite will occur during secondary graphitization annealing. So far, whether this expansion can affect the micro-shrinkage porosity between the austenite rings surrounding the graphite nodule during solidification has not attracted people's attention, while micro-shrinkage porosity is one of the primary factors affecting the impact toughness of ductile iron at ultra-low temperature. Aiming at the problem of whether the secondary graphitization of ductile iron affects the micro-shrinkage porosity, the secondary graphitization annealing of pearlitic ductile iron is carried out, and the effect of secondary graphitization expansion on micro-shrinkage porosity was studied. The metallographic microstructures and micro-shrinkage porosity are observed by Axiovert200MAT metallographic microscope and MLA250 (FEIQuanta) scanning electron microscope. The maximum length of micro-shrinkage porosity is measured by Nano Measurer 1.2 and the maximum area is measured by Photoshop software. The results show that the volume expansion rates of ductile iron and gray cast iron after secondary graphitization annealing are about 1.2% and 1.4%, respectively. After secondary graphitization annealing, the size and quantity of micro-shrinkage porosity of ductile iron decrease. It indicates that the expansion after secondary graphitization of cast iron will help to repaire micro-shrinkage porosity. VL - 11 IS - 3 ER -