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Casting Process & Alloy Comparisons


Casting
Process Comparison
Process Precision Sand Castings Rubber Plaster Molding Investment (Lost Wax) Castings Permanent Mold "Graphite" Permanent Mold Die Casting V-Process Castings
Typical Size Range oz. - 100 lbs. oz. - 30 lbs. oz. - 20 lbs. oz. - 100 lbs. oz. - 10 lbs. oz. - 30 lbs. Up to 150 lbs.
Tolerances ±.020" to 10", then add ±.001"/", thereafter.
Add minimum of .010 " across the parting line and for cored features.
±.010" to 8", then add ±.001"/", thereafter.
Add minimum of .005" across the parting line and for cored features.
±.003" to 1/4" ±.004" to 1/2" ±.005" to 3", then add ±.003"/". ±.015"/" to 1", then add ±.002"/".
Add ±.010" to .030" across the parting line.
±.005" Add ±.002" across the parting line. ±.002"/" Add ±.015" across the parting line. ±.02" to 6", then add ±.002"/" Add ±.02" across the parting line.
Flatness Within .015"
(geometry dependent)
Within .010"
(geometry dependent)
Within .015"
(geometry dependent)
       
Surface Finish 120-175 RMS, except on cored areas. 63-125 RMS 63-125 RMS 150-300 RMS 25 RMS or better 32-63 RMS 125-150 RMS
Minimum Draft Required 1/2° to 3° 1/2° to 2° None 2° to 4° 1° to 2° 1° to 3° None
Minimum Wall Section Typical:
.140"-.187"
Minimum: .080"
(geometry dependent)
Typical:
.100" -.187"
Minimum: .040"
(geometry dependent)

.060"

.187"

.100"

.030" to .060"

.125"
Typical Quantities All <2,000 <1,000 >500 500-1500 >2,500 All
Typical Tooling Price (N.R.E.)
$800 - 4K

$3K - 15K

$3K - 10K

$5K - 15K

$1.5K - 5.5K

$5K - 250K

$3K - 6K
Nominal Lead Times Samples:
1 - 4 wks.
Production:
1 - 5 wks. after approval.
Samples:
2 - 4 wks.
Production:
1 - 5 wks. after approval.
Samples:
2 - 4 wks.
Production:
5 - 12 wks.
after approval.
Samples:
8 - 20 wks.
Production:
10 - 12 wks.
after approval.
Samples:
3 - 6 wks.
Production:
2 - 4 wks.
after approval.
Lifetime use.
Samples:
12 - 26 wks.
Production:
8 - 14 wks.
after approval.
Samples:
2 - 6 wks.
Production:
2 - 6 wks.
after approval.



The following table illustrates properties of cast and wrought alloys.
Alloy Comparison
Alloy Heat Treatment* Tensile Strength (ksi) Ultimate Tensile Strength (ksi)Yield Elongation in 2 inches (%) Typical Brinell Hardness (500 kgf load, (10-mm ball))
A356.2 F 19 - 3.0 40-70
A356.2 T51 23 16 - 45-75
A356.2 T6 30 20 3.0 55-90
A356.2 T7 31 29 3.0 60-90
A319 T6 31 20 1.5 65-95
535 (Almag) F 35 18 8.0 60-90
Zinc-ZA8 F 38 28 1.5 85-90
Zinc-ZA12 F 42 30 2 105-125
6061 (Wrought) T6 45 40 12.0 95
A380 (Die Cast) F 47 23 3.5 80


*Heat Treatment of Aluminum Castings
F As Cast - Castings are cooled naturally from the mold in room temperature air with no further heat-treatment.
T-51 Aging Treatment - Castings that are artificially aged by heating metal to 400F for 7-9 hours.
T-6 Solution Heat-treated and Artificially Aged - Castings are Solution Heat-treated by heating metal to 1000F for 4-12 hours and quenched in water at 150-212F.
T-7 Solution Heat-treated and Stabilized - Castings are stabilized to carry them beyond the point of maximum hardness, providing control of growth or residual stress, or both.

This technical information has been contributed by
General Foundry Service

Click on Company Name for a Detailed Profile

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