Table 1. Casting Parameters Foundry Pouring temperature (°F/ °C)
ZE41A A B C
AZ91D A B D
1436/780 1332/722 1470/798
1436/780 1336/724 1400/760
Cover gas
CO2 CO2 CO2
CO2 CO2
+ SF6 + SF6 + SF6
+ SF6 + SF6
M-134 Flux
Other
Samples obtained
Refined using Mg–Zr master alloy, Ladle poured Fracture bars, Tensile bars Refined using Mg–Zr master alloy, Ladle poured Fracture bars
100% remelted metal, Refined using Mg–Zr master alloy, Ladle poured
Ladle poured Degassed using degassing tablet, Ladle poured
100% virgin metal, Refined and degassed using C2
Cl6
attributed to particle-type Mg–Al–O inclusions in the AZ91D alloy and film- type Mg–O inclusions in the ZE41A alloy on the fracture surfaces of the tensile samples and fracture bars. Te AZ91D castings had very few inclusions, but they were much larger than those in the ZE41A castings. Tis research recognized extensive variability of the inclusion levels in the industry and is a precursor to devel- oping industry standards for melt cleanli- ness in magnesium alloys. Tis will be a major step in enabling improved quality and enhanced use of magnesium alloys in aerospace and automotive industries.
tablets, Poured directly from crucible
Microstructure A representative micrograph from
Foundry A of the grain structures of the ZE41A castings produced toward the start and end of a produc- tion run is shown in Figure 1. Te samples were extracted from tensile mold castings. At the start of pouring, the average grain size of the castings from Foundry A was 22 ± 1 µm and increased to 38 ± 7 by the end of the production run. For Foundry C, at the start of pouring, the average grain size of castings was 27 ± 2 µm and
increased to 32 ± 3 µm by the end of the production run. Te grain struc- tures in Figure 1 were very spherical in shape, especially near the start of the production runs. With the minor grain coarsening toward the end of the production run, the grain struc- ture begins to deviate from its spheri- cal shape. Such a coarsening and devi- ation from spherical grain structure during holding were expected due to zirconium losses, which may occur from reactions with iron crucibles or settling of zirconium particles over time. However, this coarsening is not
Fracture bars, Tensile bars
Fracture bars, Tensile bars Fracture bars,Tensile bars Fracture bars, Tensile bars
INDUSTRY LEADERS) for the processing of aluminum intentensive automotive components
Basketless Heat Treating Systems (BHTS®
SIMPLY...NO BASKETS REQUIRED Reduce energy consumption by 40% • Reduce fl oor space requirements by 30% • Reduce cycle times • Reduce material handling and maintenance costs • Reduce capital costs
To learn more about Can-Eng Furnaces Engineering, Design & Manufacturing capabilities please visit
www.can-eng.com or e-mail Tim Donofrio at
tdonofrio@can-eng.com
P.O. Box 235, Niagara Falls, New York, 14302-0235 | T : 905.356.1327 | F : 905.356.1817 |
WWW.CAN-ENG.COM March 2017 MODERN CASTING | 47
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94