scholarly journals Sn-Aided Joining of Cast Aluminum and Steel Through a Compound Casting Process

Author(s):  
Aina Opsal Bakke ◽  
Arne Nordmark ◽  
Lars Arnberg ◽  
Yanjun Li

AbstractObtaining a strong bond between aluminum and steel is challenging due to poor wettability between aluminum melt and steel and brittle intermetallic phases forming in the interface. In this research, a novel coating method, namely hot dipping of Sn, has been developed to treat the steel insert surfaces. Results show that without preheating the mold or Sn-coated insert, a thin, crack-free, and continuous metallurgical bonding layer was achieved in the A356 aluminum/steel compound castings. Intermetallic structures forming in the interface have been characterized in detail. The Sn-coating layer completely melted and mixed with the liquid aluminum during the casting process. The reaction layer at the aluminum/steel interface is composed of ternary Al–Fe–Si particles and a thin layer of binary Al5Fe2 phase with thickness less than 1 µm. A small fraction of dispersed Sn-rich particles was observed distributing in the reaction layer and adjacent to eutectic Si particles in the A356 alloy. A sessile drop wetting test showed that Sn-coated steel substrates can be well wetted by aluminum melt. The improved wettability between A356 alloy melt and steel was attributed to the penetration and breaking of the aluminum oxide layer at the surface of the aluminum droplets by liquid Sn. Graphic Abstract

2020 ◽  
Vol XVII (2) ◽  
pp. 23-33
Author(s):  
Faisal Hafeez ◽  
Salman Hussain ◽  
Wasim Ahmad ◽  
Mirza Jahanzaib

This paper presents the study to investigate the effects of binder ratio, in-gate length and pouring height on hardness, surface roughness and casting defects of sand casting process. Taguchi methodology with L9 orthogonal array was employed to design the experimentation. Sand casting of six blade impeller using A356 alloy was performed and empirical models for all the above response measures were formulated. Confirmatory tests and analysis of variance results confirmed the accuracy of the model. Binder ratio was found to be the most significant parameter affecting casting surface defects and surface roughness. This was followed by pouring height and in-gate length.


Author(s):  
Williams S. Ebhota ◽  
Akhil S. Karun ◽  
Freddie L. Inambao

The study investigates the application of centrifugal casting process in the production of a complex shape component, Pelton turbine bucket. The bucket materials examined were functionally graded aluminium A356 alloy and A356-10%SiCp composite. A permanent mould for the casting of the bucket was designed with a Solidworks software and fabricated by the combination of CNC machining and welding. Oil hardening non-shrinking die steel (OHNS) was chosen for the mould material. The OHNS was heat treated and a hardness of 432 BHN was obtained. The mould was put into use, the buckets of A356 Alloy and A356-10%SiCp composite were cast, cut and machined into specimens. Some of the specimens were given T6 heat treatment and the specimens were prepared according to the designed investigations. The micrographs of A356-10%SiCp composite shows more concentration of SiCp particles at the inner periphery of the bucket. The maximum hardness of As-Cast A356 and A356-10%SiCp composite were 60 BRN and 95BRN respectively, recorded at the inner periphery of the bucket. And these values appreciated to 98BRN and 122BRN for A356 alloy and A356-10%SiCp composite respectively after heat treatment. The prediction curves of the ultimate tensile stress and yield tensile stress show the same trend as the hardness curves.


2016 ◽  
Vol 93 ◽  
pp. 518-528 ◽  
Author(s):  
Su-ling Lu ◽  
Fu-ren Xiao ◽  
Zhi-hong Guo ◽  
Li-juan Wang ◽  
Han-yun Li ◽  
...  

2021 ◽  
Vol 95 ◽  
pp. 29-37
Author(s):  
Bach Dao Hong ◽  
◽  
Trung Trinh Van

AA3003 aluminum alloy made from raw scrap materials that have the advantage of economical use, but hottearing often occurs in the product billets of the direct chill casting process. This study used ANOVA analysis method for determination of chemical composition of AA3003 aluminum billet products to show influence of chemical composition on hot-tearing ability. The evaluation of the microstructure and chemical composition distribution of the elements by optical and scanning electron microscopes combined with energy dispersive spectroscopy showed the existence of impurities such as Cu, Zn, Fe, Pb exceeding the allowable limit in aluminum billets, especially at grain boundary, which can be the main reason for the hot-tearing of cast aluminum billets.


2019 ◽  
Vol 265 ◽  
pp. 112-121 ◽  
Author(s):  
Guangyu Li ◽  
Wenchao Yang ◽  
Wenming Jiang ◽  
Feng Guan ◽  
Haixiao Jiang ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 598 ◽  
Author(s):  
Kashif Ishfaq ◽  
Muhammad Asad Ali ◽  
Naveed Ahmad ◽  
Sadaf Zahoor ◽  
Abdulrahman M. Al-Ahmari ◽  
...  

Sand-casting is a well established primary process for manufacturing various parts of A356 alloy. However, the quality of the casting is adversely affected by the change in the magnitude of the control variables. For instance, a larger magnitude of pouring velocity induces a drop effect and a lower velocity increases the likelihood of cold-shut and mis-run types of defects. Similarly, a high pouring temperature causes the formation of hot tears, whereas a low temperature is a source of premature solidification. Likewise, a higher moisture content yields microcracks (due to gas shrinkages) in the casting and a lower moisture content results in the poor strength of the mold. Therefore, the appropriate selection of control variables is essential to ensure quality manufactured products. The empirical relations could provide valuable guidance in this regard. Additionally, although the casting process was optimized for A356 alloy, it was mostly done for a single response. Therefore, this paper aimed to formulate empirical relations for the contradictory responses, i.e., hardness, ultimate tensile strength and surface roughness, using the response surface methodology. The experimental results were comprehensively analyzed using statistical and scanning electron microscopic analyses. Optimized parameters were proposed and validated to achieve castings with high hardness (84.5 HB) and strength (153.5 MPa) with minimum roughness (5.8 µm).


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