Foundry methods of influencing the structure formation of castings and crystallization process of aluminum alloys in sand molds

Шрифт:
179

https://doi.org/10.15407/steelcast2021.04.036

Met. litʹe Ukr., 2021, Tom 29, №4, P. 36-43

P.B. Kaliuzhnyi, PhD (Engin.), Senior Researcher, e-mail: kpb.ptima@gmail.com, https://orcid.org/0000-0002-1111-4826
V.S. Doroshenko, Dr. Sci. (Engin.), Senior Research Scientist, Leading Researcher, e-mail: doro55v@gmail.com, https://orcid.org/0000-0002-0070-5663

Physico-technological Institute of Metals and Alloys of the NAS of Ukraine (Kyiv, Ukraine)

Received 07.08.2021

UDK 621.74.041

The constant growth of requirements for the quality and properties of cast aluminum alloys contributes to the increasing use in foundry technology of physical methods of external influence on the process of casting formation. Of particular interest is the casting in sand molds, as the most versatile way to obtain shaped castings with complex geometry. In this regard, the article analyzes the modern foundry methods of influencing the structure of castings and crystallization process of aluminum alloys in sand molds. The introduction of additive technologies in foundry production has prompted the study of the influence of the geometry of sand molds made by 3D printing on the process of casting formation. It is determined that the use of skeletal, ribbed shell or multilayer molds allows to control the processes of casting solidification. A fundamentally new foundry method is ablation casting, the essence of which is to erode sand by water jets and rapid cooling of the solidifying casting. The study of this method shows that the rapid cooling of the casting by water jets contributes to the refinement of the microstructure components of aluminum alloys, and, accordingly, the increasing of their mechanical properties. Methods of increasing the properties of aluminum alloys during lost foam casting are becoming widespread. Thus, the application of pressure on the solidifying metal contributes to the refinement of the microstructure of aluminum alloys and increase their strength, ductility and hardness, reducing the porosity of castings. The use of vibration contributes not only to the refinement of microstructural components, but also to changes of their morphology. Mechanical vibration significantly increases the mechanical properties and density of aluminum alloys during lost foam casting. The use of aerodynamic cooling at the stage of casting solidification shows that in the aluminum alloy the size of dendritic cells decreases by 1.5–1.8 times, the size of eutectic silicon decreases by 1.3–1.6 times and the length iron intermetallic needles decreases by 1.4–1.8 times compared to castings obtained by traditional lost foam casting technology. The latter methods are the most promising for controlling the process of metal crystallization during lost foam casting, as the most universal method of manufacturing complex cast parts from aluminum alloys.

Keywords: Aluminum alloy, sand mold, cooling rate, 3D printing, aerodynamic cooling, lost foam casting.

REFERENCES

1. Shangguan, H., Kang, J., Deng, C., Hu, Y., Huang, T. (2017). 3D-printed shell-truss sand mold for aluminum castings. Journal of Materials Processing Technology, vol. 250, pp. 247–253, doi: https://doi.org/10.1016/j.jmatprotec.2017.05.010
2. Kang, J., Wang, J., Shangguan, H., Zheng, L., Deng, C., Hu, Y., Yi, J. (2020). Modeling and Simulation of the Casting Process with Skeletal Sand Mold. Materials, vol. 13, no. 7, 1596, doi: https://doi.org/10.3390/ma13071596
3. Shangguan, H.L., Kang, J.W., Yi, J.H., Deng, C.Y., Hu, Y.Y., Huang, T. (2018). Controlled cooling of an aluminum alloy casting based on 3D printed rib reinforced shell mold. China Foundry, vol. 15, no. 3, pp. 210–215, doi: https://doi.org/10.1007/s41230- 018-7252-x
4. Deng, C., Kang, J., Shangguan, H. et al. (2018). Insulation effect of air cavity in sand mold using 3D printing technology. China Foundry, vol. 15, no. 1, pp. 37–43, doi: https://doi.org/10.1007/s41230-018-7243-y
5. Deng, C., Kang, J., Shangguan, H., Hu, Y., Huang, T., Liu, Z. (2018). Effects of hollow structures in sand mold manufactured using 3D printing technology. Journal of Materials Processing Technology, vol. 255, pp. 516–523, doi: https://doi.org/10.1016/j. jmatprotec.2017.12.031
6. Wang, J., Zheng, L., Kang, J., Hu, Y. (2020). Study on the Directional Solidification Process of an Aluminum Alloy Bar in Multishell Mold Being Gradually Immersed in Water. Materials, vol. 13, 2197, doi: https://doi.org/10.3390/ma13092197
7. Grassi, J., Campbell, J., Hartlieb, M., Major, F. (2009). The Ablation Casting Process. Materials Science Forum, vol. 618, pp. 591–594, doi: https://doi.org/10.4028/www.scientific.net/msf.618-619.591
8. Bohlooli, V., Shabani Mahalli, M., Boutorabi, S.M.A. (2013). Effect of ablation casting on microstructure and casting properties of A356 aluminium casting alloy. Acta Metallgica Sinica, vol. 26, no. 1, pp. 85–91, doi: https://doi.org/10.1007/s40195-012- 0092-6
9. Dudek, P., Fajkiel, A., Reguła, T. (2014). The Research on the Ablation Casting Technology for Aluminium Alloys. Solid State Phenomena, vol. 223, pp. 70–77, doi: https://doi.org/10.4028/www.scientific.net/ssp.223.70  
10. Tiryakioğlu, M., Grassi, J. (2016). On the Properties and Performance of Ablation Cast Components. In Shape Casting: 6th International Symposium. Springer, Cham, pp. 93–100, doi: https://doi.org/10.1007/978-3-319-48166-1_12
11. Taghipourian, M., Mohammadaliha, M., Boutorabi, S.M., Mirdamadi, S.H. (2016). The effect of waterjet beginning time on the microstructure and mechanical properties of A356 aluminum alloy during the ablation casting process. Journal of Materials Processing Technology, vol. 238, pp. 89–95, doi: https://doi.org/10.1016/j.jmatprotec.2016.05.004
12. Weiss, D., Grassi, J., Schultz, B., Rohatgi, P. (2011). Testing the Limits of Ablation. Modern Casting, vol. 101, no. 12, pp. 26–29.
13. Weiss, D., Grassi, J., Schultz, B., Rohatgi, P. (2011). Ablation of Hybrid Metal Matrix Composites. AFS Proceedings. Transactions of the American Foundry Society, vol. 119, pp. 35–41.
14. Niakan, A.A., Idris, M.H., Karimian, M., Ourdjini, A. (2012). Effect of Pressure on Structure and Properties of Lost Foam Casting of Al-11Si Cast Alloy. Applied Mechanics and Materials, vol. 110–116, pp. 639–643, doi: https://doi.org/10.4028/www. scientific.net/AMM.110-116.639
15. Kang, B., Kim, Y., Kim, K., Cho, G., Choe, K., Lee, K. (2007). Density and Mechanical Properties of Aluminum Lost Foam Casting by Pressurization during Solidification. J. Mater. Sci. Technol, vol. 23, iss. 6, pp. 828–832.
16. Zhao, Z., Fan, Z., Dong, X., Tang, B., Pan, D., Li, J. (2010). Influence of mechanical vibration on the solidification of a lost foam cast 356 alloy. China Foundry, vol. 7, pp. 24–29.
17. Jiang, W., Chen, X., Wang, B., Fan, Z, Wu, H. (2016). Effects of vibration frequency on microstructure, mechanical properties, and fracture behavior of A356 aluminum alloy obtained by expendable pattern shell casting. The International Journal of Advanced Manufacturing Technology, vol. 83, pp. 167–175, doi: https://doi.org/10.1007/s00170-015-7586-0
18. Zhao, Z., Fan, T. (2014). Influence on the Microstructures and Properties of A356 with Vibration Pressure in Lost Form Casting. Applied Mechanics and Materials, vol. 685, pp. 7–10, https://doi.org/10.4028/www.scientific.net/AMM.685.7
19. Doroshenko, V.S. (2014). Increasing the hardness of the metal of the casting by cooling it in an evacuated sand form with a gaseous, liquid refrigerant and the movement of sand particles. Casting of Ukraine, no. 4, pp. 13–22 [in Russian].
20. Acar, S., Guler, K.A. (2021). A Preliminary Study Upon the Applicability of the Direct Water Cooling with the Lost Foam Casting Process. International Journal of Metalcasting, vol. 15, no. 1, pp. 88–97, doi: https://doi.org/10.1007/s40962-020-00420-7
21. . Kaliuzhnyi, P. (2020). Influence of Sand Fluidization on Structure and Properties of Aluminum Lost Foam Casting. Archives of Foundry Engineering, vol. 20, no. 1, pp. 122–126, doi: 10.24425/afe.2020.131293