Analysis of the Causes of Cracks in a Thick-Walled Bush Made of Die-Cast Aluminum Bronze

Open access

Abstract

For the die casting conditions of aluminium bronzes assumed based on the literature data, a thick-walled bush was cast, made of complex aluminium bronze (Cu-Al-Fe-Ni-Cr). After the cast was removed from the mould, cracks were observed inside it. In order to identify the stage in the technological production process at which, potentially, the formation of stresses damaging the continuity of the microstructure created in the cast was possible (hot cracking and/or cold cracking), a computer simulation was performed. The article presents the results of the computer simulation of the process of casting the material into the gravity die as well as solidifying and cooling of the cast in the shape of a thick-walled bush. The simulation was performed with the use of the MAGMA5 program and by application of the CuAl10Ni5,5Fe4,5 alloy from the MAGMA5 program database. The results were compared with the location of the defects identified in the actual cast. As a result of the simulation of the die-casting process of this bush, potential regions were identified where significant principal stresses accumulate, which can cause local hot and cold cracking. Until now, no research has been made of die-cast aluminium bronzes with a Cr addition. Correlating the results of the computer simulation validated by the analysis of the actual cast made it possible to clearly determine the critical regions in the cast exposed to cracking and point to the causes of its occurrence. Proposals of changes in the bush die casting process were elaborated, in order to avoid hot tearing and cold cracking. The article discusses the results of preliminary tests being a prologue to the optimization of the die-casting process parameters of complex aluminium bronze thick-walled bushs.

[1] Pisarek, B. (2013). Aluminium Bronze Containing Cr, Mo and/or W with High Resistance to Wear. Łódź: Scientific Bulletin of the Lodz University of Technology No. 1141, Wydawnictwo Politechniki Łódzkiej. (in Polish).

[2] Pisarek, B.P. (2013). Model of Cu-Al-Fe-Ni Bronze Crystallization. Archives of Foundry Engineering. 13(3), 72-79.

[3] Just, P. & Pisarek, B.P. (2014). Feeding and Cooling and Time of Thermal Treatment of a Massive Bush Made of the Complex Aluminum Bronze Cast by the Lost Foam. Archives of Foundry Engineering. 14(4), 39-44.

[4] Pacyniak, T. (2013). Method of full-mold. Selected aspects. Łódź, Wydawnictwo Politechniki Łódzkiej. (in Polish).

[5] Górny, Z. & Lech Z. (1975). Die-casting non-ferrous alloys. Warszawa: WNT. (in Polish).

[6] Pisarek, B. (2011). Simulation of volumetric shrinkage Sv and surface shrinkage Svp. Pietrowski S. (Eds.), Wysokojakościowe Technologie Odlewnicze, Materiały i Odlewy. (167-208), Katowice - Gliwice, PAN.

[7] Górny, Z., Kluska-Nawarecka, S. & Połcik, H. (2003). Simulation of solidification of BA1032 aluminum bronze with experimental verification. Archives of Foundry. 3(9), 140-147. (in Polish).

[8] Fajkiel, A., Dudek, P., Walczak, W. & Zawadzki P. (2007). Improvement of quality of a gravity die casting made from aluminum bronze be application of numerical simulation. Archives of Foundry Engineering. 7(2), 11-14.

[9] Chojecki, A., Burbiełko, A. & Telejko, I. (2005). Formation of Hot Tears in High Strength Al-Cu Alloys. Archives of Foundry. 5(15), 53-59.

[10] Pokorny, M., Monroe, C., Beckermann, C., Bichler, L. & Ravindran, C. (2008). Prediction of Hot Tear Formation in a Magnesium Alloy Permanent Mold Casting. International Journal of Metalcasting. Fall 08, 41-53.

[11] Norouzi, S., Shams, A., Farhangi, H. & Darvish, A. (2009). The temperature range in the simulation of residual stress and hot tearing during investment casting. International Scholarly and Scientific Research & Innovation. 3(10), 558-564.

[12] D’Elia, F., Ravindran, C., Sediako, D., Kainer, K.U. & Hort, N. (2014) Hot tearing mechanisms of B206 aluminum–copper alloy. Materials and Design. 64, 44-55.

[13] Dong, S., Iwata, Y., Sugiyama, Y. & Iwahori, H. (2010). Cold Crack Criterion for ADC12 Aluminum Alloy Die Casting. Materials Transactions. 51(2), 371-376.

[14] Lalpoor, M., Eskin, D.G. & Katgerman, L. (2010). Cold Cracking Development in AA7050 Direct Chill–Cast Billets under Various Casting Conditions. Metallurgical And Materials Transactions. A 41a, 2425-2434.

[15] Lalpoor, M., Eskin, D.G., Ruvalcaba, D., Fjǽr, H.G., Ten Cate, A., Ontijt, N. & Katgerman, L. (2011). Cold cracking in DC-cast high strength aluminum alloy ingots: An intrinsic problem intensified by casting process parameters. Materials Science and Engineering. A 528, 2831-2842

Archives of Foundry Engineering

The Journal of Polish Academy of Sciences

Journal Information


CiteScore 2016: 0.42

SCImago Journal Rank (SJR) 2016: 0.192
Source Normalized Impact per Paper (SNIP) 2016: 0.316

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 166 166 11
PDF Downloads 63 63 6