Sep
26
2007
Moulding methods and materials
Microstructure evolution in Al-7Si-0.3Mg alloy during partial melting and solidification from melt: a comparison
Shankargoud Nyamannavar*, M. Ravi and K. Narayan Prabhu*
Regional Research Laboratory, India , *National Institute o f Technology, India
67th World Foundry Congress
In the present work, a comparative study of microstructure evolution in Sr
modified Al-7Si-0.3Mg alloy isothermally held at semi-solid state under
conditions of (i) cooling from liquid state and (ii) partial melting from solid
state to the semi-solid temperature was carried out. The effect of cooling
rate (0.01 to100 K/s ) on the microstructure during solidification of semisolid
alloy is studied. Partial melting of alloy results in the fi...
Sep
26
2007
Light alloys
Surface tension and Viscosity of Mg alloys
Soo-han Park and Bo-young Hur
Gyeongsang National University, S. Korea
67 th World Foundry Congress
The rheological characteristics are the most important factors in casting
process and metallic foam manufacturing especially. The surface tension
(by the ring method) and the viscosity (by the rotation method) of molten
Mg alloys (AZ91 and AM60) have been measured under pure Ar or SF6
+CO2 atmosphere. The surface tension and the viscosity of Mg alloys were
investigated in the temperature range of 600-850oC, and the effects of the
additio...
Sep
26
2007
Light alloys
A study on semi solid squeeze forging of high strength brass
K.H. Choe*, G.S.Cho*, K.W. Lee*, Y.J. Choi**, K.Y. Kim*** and M.H. Kim****
*KITECH, Korea, **Hanbat N. U, Korea.*** Hankuk Aviation U, Korea. ****Inha U, Korea
67th World Foundry Congress
The microstructures and mechanical properties of high strength brass
made by semi solid squeeze forging were investigated and compared with
those of conventionally hot forged product and gravity die castings. No
shrinkage or gas hole was found in squeeze forgings. Fine equiaxed
crystals developed at the center of squeeze forgings, while grains in the
corner of squeeze forgings were elongated perpendicular to the pressure
direction. The g...
Sep
18
2007
Cast iron
The filtration of large grey and ductile iron castings
E. Wiese
Foseco PLC, UK.
67th World Foundry Congress
Filtration of mass produced automobile castings is widely and successful applied,
less common and more difficult is the filtration of large castings heavier than
1.000 kg. The paper deals with the special problems of applying filtration to such
castings including; filter selection, description of three special filtration gating
system concepts, along with ten case studies are given.
Sep
18
2007
Mould and coremaking
A new generation of advanced polyurethane coldbox binders for aluminium castings
A. Schrey,
Foseco GmbH, Borken (Germany)
67th World Foundry Congress
When casting Aluminium there are specific problems of core breakdown
and removal, that are not found with ferrous castings. The lower pouring
temperatures of aluminium result in lower core sand temperatures and
reduced resin binder breakdown from thermal decomposition [1]. With less
breakdown, the cores retain higher strength after casting and can be
difficult to remove with mechanical vibration at shake-out (Figure 1).
Additional time a...
