1) Refractory sand
a) Silica sand
b) Magnesite
c) Zircon
d) Dolomite
e) Olivine
f) Sillimanite
g) Graphite / carbon
2) Molding sand
a) Natural sand
1) Contains binding materials. (5-20% clay)
2) Needs only water (5-8%) to mix before making the mold.
3) Permits easy patching and finishing of mold.
4) Contains considerable organic matter.
5) Less refractory as compared to synthetic sand.
6) Employed for casting cast iron and non-ferrous metals.
7) Less cost.
b) Synthetic sand
1) Consists of; natural sand (base) with or without clay, binder (bentonite), moisture.
2) Sand formulation is done in order to acquire certain desired properties not possessed by natural sand.
3) Used for casting steel and other ferrous and non-ferrous alloys.
c) Loam sand:
1) The clay content is of order of 50% or so.
2) The ingredients of loam sand may be fine sands, finely ground refractory, clay, graphite and fibrous reinforcement.
3) Molds for casting large bells etc. are made up of brick frame-work and lined with loam sand and dried.
4) Sweep or skeleton pattern may be used for loam molding.
Types of sands used in molds:
1) Green sand
2) Dry sand
3) Loam sand
4) Synthetic sand
5) Core sand
6) Parting sand
7) Facing sand
8) Backing sand
9) Sharp sand
10) System sand
11) Heap sand
12) Oil or molasses sand
No comments:
Post a Comment