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Number of results: 8
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Abstract

The article presents the results of the research on the influence of the shape of reaction chamber on spheroidisation of cast iron produced with use of the inmold method. The amounts of nodular graphite precipitates in castings produced with the use of different reaction chambers have been compared.

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Authors and Affiliations

P. Just
T. Pacyniak
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Abstract

Small additions of Cr, Mo and W to aluminium-iron-nickel bronze are mostly located in phases κi (i=II; III; IV),and next in phase α

(in the matrix) and phase γ2. They raise the temperature of the phase transformations in aluminium bronzes as well as the casts’ abrasive

and adhesive wear resistance. The paper presents a selection of feeding elements and thermal treatment times which guarantees structure

stability, for a cast of a massive bush working at an elevated temperature (650–750°C) made by means of the lost foam technology out of

composite aluminium bronze. So far, there have been no analyses of the phenomena characteristic to the examined bronze which

accompany the process of its solidification during gasification of the EPS pattern. There are also no guidelines for designing risers and

steel internal chill for casts made of this bronze. The work identifies the type and location of the existing defects in the mould’s cast. It also

proposes a solution to the manner of its feeding and cooling which compensates the significant volume contraction of bronze and

effectively removes the formed gases from the area of mould solidification. Another important aspect of the performed research was

establishing the duration time of bronze annealing at the temperature of 750°C which guarantees stabilization of the changes in the bronze

microstructure – stabilization of the changes in the bronze HB hardness.

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Authors and Affiliations

P. Just
B.P. Pisarek
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Abstract

The study discusses the issues connected with the production of thin-walled ceramic slurry in the replicast cs technology. In the ceramic mould production process, a special role is played by the liquid ceramic slurry used to produce the first layer of the mould. The study examines selected technological properties of liquid ceramic slurries used to produce moulds in the replicas cs technology. The ceramic slurries for the tests were prepared based on the binders Ludox Px30 and Sizol 030, enriched with Refracourse flour. The wettability of the pattern's surface by the liquid ceramic slurry and the dependence of the apparent viscosity on the ceramic flour content in the mixture were determined. The wettability of the pattern surface by the liquid ceramic slurry was determined based on the measurement of the wetting angle. The angle was determined by means of an analysis of the computer image obtained with the use of a CDC camera.

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Authors and Affiliations

R. Kaczorowski
T. Pacyniak
P. Just
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Abstract

The paper presents the optimization of master alloy amount for the high nodular graphite yield (80-90%) in cast iron obtain in lost foam process. The influence of the gating system configuration and the shape of the reaction chamber, the degree of spheroidisation cast iron was examined. Research has shown that the, optimal of master alloy amount of 1.5% by mass on casting iron. The degree of spheroidisation is also influenced by the gating system configuration. The best spheroidisation effect was obtained for liquid cast iron was fed into the reaction chamber from the bottom and discharged from the top.
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Authors and Affiliations

P. Just
T. Pacyniak
R. Kaczorowski
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Abstract

The current work presents and describes the test bench for analyzing the lost foam process, especially measuring of the pressure of gases in the gas gap and continuous measuring of the rate of rise of the bath level when pouring the liquid metal into the mould. A series of preliminary research was carried out on the bench which was aimed at determining the influence of the basic parameters of the process, i.e. the density of the styrofoam pattern, thickness of the refractory coating applied on the pattern, kind of the alloy and the temperature of pouring on the mould cavity by the liquid metal and the pressure of gases in the gas gap.

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Authors and Affiliations

R. Kaczorowski
T. Pacyniak
P. Just
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Abstract

The paper presents the results of research related to the possibility of inoculation of the AZ91 magnesium alloy casted into ceramic moulds by gadolinium. Effects of gadolinium content (0.1–0.6 wt%) on microstructure of the AZ91 alloy under as-cast state were investigated. The influence of the inoculator on the formation of the microstructure investigated by means of the thermal and derivative analysis by analysing the thermal effects arising during the alloy crystallization resulting from the phases formed. The degree of fragmentation of the microstructure of the tested alloys was assessed by means of the light microscopy studies and an image analysis with statistical analysis was performed. Conducted analyses have aimed at examining on the effect of inoculation of the gadolinium on the differences between the grain diameters and average size of each type of grain by way of measuring their perimeters of all phases, preliminary αMg and eutectics αMg+γ(Mg17Al12) in the prepared examined material.
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Bibliography

[1] Wang, Y.N. & Huang, J.C. (2007). The role of twinning and untwining in yielding behavior in hot-extruded Mg-Al-Zn. Alloy Acta Materialia. 55(3), 897-905. DOI: 10.1016/ j.actamat.2006.09.010.
[2] Yu, Zhang et. al (2017). Effects of samarium addition on as-cast microstructure, grain fragmentation and mechanical properties of Mg-6Zn-0.4Zr magnesium alloy. Journal of Rare Earths. 167(1), 31-33. DOI: 10.1016/S1002-0721(17)60939-6.
[3] Cao, F.Y, Song, G.L. & Atrens, A. (2016). Corrosion and passivation of magnesium alloys. Corrosion Science, 111(10), 835-845. DOI: 10.1016/j.corsci.2016.05.041.
[4] Mao, X., Yi, Y., Huang, S. & He, H. (2019). Bulging limit of AZ31B magnesium alloy tubes in hydroforming with internal and external pressure. The International Journal of Advanced Manufacturing Technology. 101, 2509-2517. DOI: https://doi.org/10.1007/s00170-018-3076-5.
[5] Władysiak, R. & Kozuń, A. (2015). Structure of AlSi20 alloy in heat treated die casting. Archives of Foundry Engineering.15(1), 113-118. DOI: 10.1515/afe-2015-0021.
[6] Rapiejko, C., Pisarek, B. & Pacyniak, T. (2017). Effect of intensive cooling of alloy AZ91 with a chromium addition on the microstructure and mechanical properties of the casting. Archives of Metallurgy and Materials. 62(4), 2199-2204. DOI: 10.1515/amm-2017-0324.
[7] Zhao, H.L., Guan, S.K. & Zheng, F.Y. (2007). Effects of Sr and B addition on microstructure and mechanical properties of AZ91 magnesium alloy. Journal of Materials Research. 22, 2423-2428. DOI: 10.1557/jmr.2007.0331.
[8] Bonnah, R.C., Fu, Y. & Hao, H. (2019). Microstructure and mechanical properties ofAZ91 magnesium alloy with minor additions of Sm, Si and Ca elements. China Foundry. 16(5), 319-325. DOI: 10.1007/s41230-019-9067-9.
[9] Jafari, H. & Amiryavari, P. (2016). The effects of zirconium and beryllium on microstructure evolution, mechanical properties and corrosion behaviour of as-cast AZ63 alloy. Materials Science & Engineering A. 654, 161-168 DOI: 10.1016/j.msea.2015.12.034.
[10] Boby, A., Ravikumar, K.K., Pillai, U.T.S. & Pai, B.C. (2013). Effect of antimony and yttrium addition on the high temperature properties of AZ91 magnesium alloy. Procedia Engineering 55. 355(5), 98-102. DOI: 10.1016/j.proeng. 2013.03.226.
[11] Huang, W., Yang, X., Mukai, T. & Sakai, T. (2019). Effect of yttrium addition on the hot deformation behaviors and microstructure development of magnesium alloy. Journal of Alloys and Compounds. 786, 118-125. DOI: 10.1016/ j.jallcom.2019.01.269.
[12] Pourbahari, B., Mirzadeh, H., Emamy, M. & Roumina, R. (2018). Enhanced ductility of afine-grained Mg-Gd-Al-Zn magnesium alloy by hot extrusion. Advanced Engineering Materials. 20, 1701171. DOI: 10.1002/adem.201701171.
[13] Tardif, S., Tremblay, R. & Dubé, D. (2010). Influence of cerium on the microstructure and mechanical properties of ZA104 and ZA104 + 0.3Ca magnesium alloys. Material Science and Engineering A. 527, 7519-7529. DOI: 10.1016/j.msea.2010.08.082.
[14] Wang, X.J. et al. (2018). What is going on in magnesium alloys? Journal of Materials Science & Technology. 34(2), 245-247. DOI: 10.1016/j.jmst.2017.07.019.
[15] Nan, J. et. al (2016) Effect of neodymium, gadolinium addition on microstructure and mechanical properties of AZ80 magnesium alloy. Journal of Rare Earths. 34(6), 632-637. DOI: 10.1016/S1002-0721(16)60072-8.
[16] Miao, Y., Yaohui, L., Jiaan, L. & Yulai, S. (2014). Corrosion and mechanical properties of AM50 magnesium alloy after being modified by 1 wt.% rare earth element gadolinium. Journal of Rare Earth. 723, 558-563. DOI: 10.1016/S1002-0721(14)60108-3.
[17] Mingbo, Y., Caiyuan, Q., Fusheng, P. & Tao, Z. (2011). Comparison of effects of cerium, yttrium and gadolinium additions on as-cast microstructure and mechanical properties of Mg-3Sn-1Mn magnesium alloy. Journal of Rare Earths. 29(6), 550-557. DOI: 10.1016/S1002-0721(10)60496-6.
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[19] Pietrowski, S. & Rapiejko, C. (2011). Temperature and microstructure characteristics of silumin casting AlSi9 made with investment casting method. Archives of Foundry Engineering. 11(3), 177-186.
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[21] Rapiejko, C., Pisarek, B, Czekaj, E. & Pacyniak, T. (2014). Analysis of AM60 and AZ91 Alloy Crystallisation in ceramic moulds by thermal derivative analisys (TDA). Archive of Metallurgy and Materials. 59(4) DOI: 10.2478/amm-2014-0246.
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Authors and Affiliations

C. Rapiejko
1
ORCID: ORCID
D. Mikusek
1
P. Just
1
T. Pacyniak
1
ORCID: ORCID

  1. Lodz University of Technology, Department of Materials Engineering and Production Systems, ul. Stefanowskiego 1, 90-924 Łódź, Poland
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Abstract

The paper presents the effect of manganese on the crystallization process, microstructure and selected properties: cast iron hardness as well as ferrite and pearlite microhardness. The compacted graphite was obtained by Inmold technology. The lack of significant effect on the temperature of the eutectic transformation was demonstrated. On the other hand, a significant reduction in the eutectoid transformation temperature with increasing manganese concentration has been shown. The effect of manganese on microstructure of cast iron with compacted graphite considering casting wall thickness was investigated and described. The nomograms describing the microstructure of compacted graphite iron versus manganese concentration were developed. The effect of manganese on the hardness of cast iron and microhardness of ferrite and pearlite were given.

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Authors and Affiliations

Grzegorz Gumienny
ORCID: ORCID
B. Kurowska
ORCID: ORCID
P. Just

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