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2022.10.25
Here we are going to present B390 aluminum composition, properties, and how to select an aluminum alloy for die casting.
Alloy B390 is a type of aluminum alloy used for the casting process, B390 aluminum is also known as SC174B and A23900, the ASTM SC174B is its name in older literature, A23900 is UNS number, and B390 (ANSI/AA B390.0) is designated by Aluminum Association.
When it comes to its uses, Alloy B390 was developed for automotive engine blocks, it is also a great material to make die cast valve bodies and sleeve-less piston housings.
Compared to other aluminum alloys, B390 has a high percentage of silicon and copper, which gives it a higher strength, casting fluidity, and lower melting temperature, but the corrosion resistance and weldability have been decreased at the same time.
– Al: 72.7 to 79.6%
– Si: 16 to 18%
– Cu: 4.0 to 5.0%
– Zn: 0 to 1.5%
– Fe: 0 to 1.3%
– Mg: 0.45 to 0.65%
– Mn: 0 to 0.5%
– Ni: 0 to 0.1%
– Ti: 0 to 0.1%
– Residuals: 0 to 0.2%
Mechanical Properties of Alloy B390
– Elongation at Break: 0.88%
– Fatigue Strength: 170 MPa
– Shear Modulus: 29 GPa
– Poisson’s Ratio: 0.33
– Ultimate Tensile Strength: 320 MPa
– Yield Tensile Strength: 250 MPa
Thermal & Physical Properties of Alloy B390
– Latent Heat of Fusion: 640 J/g
– Mechanical Maximum Temperature: 170 °C
– Melting Point: 580 °C
– Thermal Conductivity: 130 W/m-K
– Thermal Expansion: 20 µm/m-K
– Density:2.8 g/cm^3
Aluminum die-casting alloys have a specific gravity of approximately 2.75 g/cm^3, which makes them among the lightweight structural metals. The vast majority of die castings manufactured worldwide are made from aluminum alloys. Six essential elements comprise the die cast aluminum alloy system: silicon, copper, magnesium, iron, manganese, and zinc. Each component influences the alloy in a manner that is both independent and interactive.
When selecting an alloy for die casting, it is necessary to analyze not only the material’s chemical composition and physical and mechanical properties but also the alloy’s inherent characteristics and how these characteristics influence the die casting process, as well as any necessary machining and final surface finishing. This table contains a variety of die castings as well as other characteristics that are normally considered when selecting an aluminum alloy for a certain application.
The commercially available aluminum die casting alloys have machining properties that vary to some degree, but the group as a whole is superior to iron, steel, and titanium. Die casting alloys are in some ways superior to wrought and gravity cast alloys with the same chemical composition because of the quick solidification rate of the die casting process. The machinability of A380 alloy is much greater than typical. Alloy 518’s machinability is among the best, and magnesium, which comprises the majority of the alloying elements, is the key constituent. Alloy B390, which has the highest silicon concentration and the highest proportion of silicon-free constituent, is the least in terms of machining characteristics.
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