Lost foam casting (LFC) is a green precision casting process categorized as a near net forming technology. Yet, despite its popularity, it still suffers from some technological problems, such as poor filling ability of the castings, coarse and non-dense microstructure, low mechanical properties for the Al and Mg LFC processes, and defective carburization for the low carbon steel LFC process. These drawbacks restrict the development and widespread application of the LFC process. To solve these problems, the present study developed several novel LFC technologies, namely, LFC technologies under vacuum and low pressure, vibration solidification, and pressure solidification conditions; expendable shell casting techno- logy; and preparation technology of bimetallic castings based on the LFC process. The results showed that the LFC under vacuum and low pressure evidently improved the filling ability and solved the oxidization problem of the alloys, which is suitable for producing complex and thin-wall castings. The vibration and pressure solidifications increased the compactness of the castings and refined the microstructure, significantly improving the mechanical properties of the castings. The expendable shell casting technology could solve the pore, carburization, and inclusion defects of the traditional LFC method, obtaining castings with acceptable surface quality. Moreover, the Al/Mg and Al/Al bimetallic castings with acceptable metallurgical bonding were successfully fabricated using the LFC process. These proposed novel LFC technologies can solve the current technological issues and promote the technological progress of the LFC process.
Huang N, Ye S, Fan Z. Principle and Control of Lost Foam Casting. Wuhan: Huazhong University of Science and Technology Press, 2004
2
Huang T, Huang N, Lv Z. Lost Foam Casting Technology. Beijing: Mechanical Industry Press, 2004
3
Charchi A, Rezaei M, Hossainpour S, et al.Numerical simulation of heat transfer and fluid flow of molten metal in MMA–St copolymer lost foam casting process. Journal of Materials Processing Technology, 2010, 210(14): 2071–2080 doi:10.1016/j.jmatprotec.2010.07.028
4
Liu Z, Hu J, Wang Q, et al.Evaluation of the effect of vacuum on mold filling in the magnesium EPC process. Journal of Materials Processing Technology, 2002, 120(1–3): 94–100 https://doi.org/10.1016/S0924-0136(01)01085-8
5
Geffroy P, Lakehal M, Goñi J, et al.Thermal and mechanical behaviour of grey cast iron and ductile iron castings using magnetic molding and lost foam processes. Journal of Materials Processing Technology, 2009, 209(8): 4103–4111 https://doi.org/10.1016/j.jmatprotec.2008.10.002
6
Shayegh J, Hossainpour S, Rezaei M, et al.Developing a new 2D model for heat transfer and foam degradation in EPS lost foam casting (LFC) process. International Communications in Heat and Mass Transfer, 2010, 37(9): 1396–1402 https://doi.org/10.1016/j.icheatmasstransfer.2010.07.015
7
Liu X, Bhavnani S H, Overfelt R A. Simulation of EPS foam decomposition in the lost foam casting process. Journal of Materials Processing Technology, 2007, 182(1–3): 333–342 https://doi.org/10.1016/j.jmatprotec.2006.08.023
8
Sands M, Shivkumar S. EPS bead fusion effects on fold defect formation in lost foam casting of aluminum alloys. Journal of Materials Science, 2006, 41(8): 2373–2379 https://doi.org/10.1007/s10853-006-7077-7
9
Shin S R, Lee Z H, Cho G S, et al.Hydrogen gas pick-up mechanism of Al-alloy melt during lost foam casting. Journal of Materials Science, 2004, 39(5): 1563–1569 https://doi.org/10.1023/B:JMSC.0000016152.96919.6c
10
Fan Z, Jiang W, Liu F, et al.. Status quo and development trend of lost foam casting technology. China Foundry, 2014, 11(4): 296–307
11
Fan Z, Dong X, Huang N, et al.China Patent, ZL02115638.7, 2002-12-04 (in Chinese)
12
Fan Z, Ji S. Low pressure lost foam process for casting magnesium alloys. Materials Science and Technology, 2005, 21(6): 727–734 https://doi.org/10.1179/174328405X43199
13
Li J, Zhao Z, Fan Z, et al.. Study on typical hole defects in AZ91D magnesium alloy prepared by low pressure lost foam casting. China Foundry, 2013, 10(4): 232–236 https://doi.org/10.3969/j.issn.1672-6421.2013.04.006
14
Zhao Z. Study on microstructures and mechanical properties of aluminum (magnesium) alloy under vibration and pressure in lost foam casting process. Dissertation for the Doctoral Degree. Wuhan: Huazhong University of Science and Technology, 2010
15
Zhao Z, Fan Z, Jiang W, et al.Microstructural evolution of Mg9AlZnY alloy with vibration in lost foam casting during semi-solid isothermal heat treatment. Transactions of Nonferrous Metals Society of China, 2010, 20(Suppl3): s768–s773 https://doi.org/10.1016/S1003-6326(10)60579-1
16
Zhao Z, Fan Z, Dong X, et al.. Influence of mechanical vibration on the solidification of a lost foam cast 356 alloy. China Foundry, 2010, 7(1): 24–29
17
Fan Z, Li J, Tian X, et al.China Patent, CN200710168429.1, 2008-05-21
18
Jiang W, Chen X, Wang B, et al. Effects of vibration frequency on microstructure, mechanical properties and fracture behavior of A356 aluminum alloy obtained by expendable pattern shell casting. International Journal of Advanced Manufacturing Technology, 2016, 83(1–4): 167–175 https://doi.org/10.1007/s00170-015-7586-0
19
Xiao B. Characteristics of microstructure and properties of cast iron produced by lost foam casting with vibration. Dissertation for the Doctoral Degree. Wuhan: Huazhong University of Science and Technology, 2013 https://doi.org/10.7666/d.D608931
20
Xiao B, Fan Z, Jiang W, et al.Microstructure and mechanical properties of ductile cast iron in lost foam casting with vibration. Journal of Iron and Steel Research International, 2014, 21(11): 1049–1054 https://doi.org/10.1016/S1006-706X(14)60182-5
21
Zou W, Zhang Z, Yang H, et al.Effect of vibration frequency on microstructure and performance of high chromium cast iron prepared by lost foam casting. China Foundry, 2016, 13(4): 248–255 https://doi.org/10.1007/s41230-016-6037-3
22
Fan Z, Zhao Z, Tang B, et al.China Patent, CN200810197390.0, 2009-03-25
23
Zhao Z, Fan Z, Tang B, et al.Influence of pressure solidification on AZ91D magnesium alloy feeding in lost foam casting process. International Journal of Cast Metals Research, 2011, 24(1): 13–21 https://doi.org/10.1179/136404610X12816241546537
24
Jiang W, Fan Z, Liu D, et al.Effects of process parameters on internal quality of castings during novel casting. Materials and Manufacturing Processes, 2012, 28(1): 48–55 https://doi.org/10.1080/10426914.2012.681414
25
Ridder S D, Kou S, Mehrabian R. Effect of fluid flow on macrosegregation in axi-symmetric ingots. Metallurgical Transactions B, 1981, 12(3): 435–447
Jiang W, Fan Z, Liao D, et al.A new shell casting process based on expendable pattern with vacuum and low-pressure casting for aluminum and magnesium alloys. International Journal of Advanced Manufacturing Technology, 2010, 51(1–4): 25–34 https://doi.org/10.1007/s00170-010-2596-4
28
Jiang W, Fan Z, Chen X, et al.Combined effects of mechanical vibration and wall thickness on microstructure and mechanical properties of A356 aluminum alloy produced by expendable pattern shell casting. Materials Science and Engineering A, 2014, 619(12): 228–237 https://doi.org/10.1016/j.msea.2014.09.102
29
Liao D, Fan Z, Jiang W, et al.Study on the surface roughness of ceramic shells and castings in the ceramic shell casting process based on expandable pattern. Journal of Materials Processing Technology, 2011, 211(9): 1465–1470 https://doi.org/10.1016/j.jmatprotec.2011.03.021
30
Jiang W, Fan Z, Liu D, et al.Influence of process parameters on filling ability of A356 aluminium alloy in expendable pattern shell casting with vacuum and low pressure. International Journal of Cast Metals Research, 2012, 25(1): 47–52 https://doi.org/10.1179/1743133611Y.0000000014
31
Jiang W, Fan Z, Liu D, et al.Influence of gas flowrate on filling ability and internal quality of A356 aluminum alloy castings fabricated using the expendable pattern shell casting with vacuum and low pressure. International Journal of Advanced Manufacturing Technology, 2013, 67(9–12): 2459–2468 https://doi.org/10.1007/s00170-012-4663-5
32
Jiang W, Fan Z, Liao D, et al.Investigation of microstructures and mechanical properties of A356 aluminum alloy produced by expendable pattern shell casting process with vacuum and low pressure. Materials & Design, 2011, 32(2): 926–934 https://doi.org/10.1016/j.matdes.2010.08.015
33
Emami S M, Divandari M, Hajjari E, et al.Comparison between conventional and lost foam compound casting of Al/Mg light metals. International Journal of Cast Metals Research, 2013, 26(1): 43–50 https://doi.org/10.1179/1743133612Y.0000000037
34
Guler K A, Kisasoz A, Karaaslan A. Investigation of lost foam casted aluminum bimetal microstructures. Materials Testing, 2014, 56(9): 737–740 https://doi.org/10.3139/120.110625
35
Guler K A, Kisasoz A, Karaaslan A. Fabrication of Al/Mg bimetal compound casting by lost foam technique and liquid-solid process. Materials Testing, 2014, 56(9): 700–702 https://doi.org/10.3139/120.110624
36
Divandari M, Vahid Golpayegani A R. Study of Al/Cu rich phases formed in A356 alloy by inserting Cu wire in pattern in LFC process. Materials & Design, 2009, 30(8): 3279–3285 https://doi.org/10.1016/j.matdes.2009.01.008
37
Mehdi Hejazi M, Divandari M, Taghaddos E. Effect of copper insert on the microstructure of gray iron produced via lost foam casting. Materials & Design, 2009, 30(4): 1085–1092 https://doi.org/10.1016/j.matdes.2008.06.032
38
Choe K H, Park K S, Kang B H, et al.. Study of the interface between steel insert and aluminum casting in EFC. Journal of Materials Science and Technology, 2008, 24(1): 60–64
39
Xiao X, Ye S, Yin W, et al.HCWCI/carbon steel bimetal liner by liquid-liquid compound lost foam casting. Journal of Iron and Steel Research International, 2012, 19(10): 13–19 https://doi.org/10.1016/S1006-706X(12)60145-9
40
Xiao X, Ye S, Yin W, et al.. High Cr white cast iron/carbon steel bimetal liner by lost foam casting with liquid-liquid composite process. China Foundry, 2012, 9(2): 136–142
41
Jiang W, Li G, Fan Z, et al.Investigation on the interface characteristics of Al/Mg bimetallic castings processed by lost foam casting. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 2016, 47(5): 2462–2470 https://doi.org/10.1007/s11661-016-3395-9
42
Jiang W, Fan Z, Li G, et al.Effects of melt-to-solid insert volume ratio on the microstructures and mechanical properties of Al/Mg bimetallic castings produced by lost foam casting. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 2016, 47(12): 6487–6497 https://doi.org/10.1007/s11661-016-3788-9
43
Li G, Jiang W, Fan Z, et al.Effects of pouring temperature on microstructure, mechanical properties, and fracture behavior of Al/Mg bimetallic composites produced by lost foam casting process. International Journal of Advanced Manufacturing Technology, 2017, 91(1–4): 1355–1368 https://doi.org/10.1007/s00170-016-9810-y
