M7.C87800 Silicon Brass US standard material ASTM C87800*Materials for Permanent mold casting
T1 Test to check molten metal flow and trial production
Metal mold temperature approximately 95°C
Temperature during pouring about 1010°C
Molten metal flow is very good.
Molten metal is filled all the way up to up-hill part for degassing.
Good run of molten metal was observed even when the temperatures varied slightly due to repeated pouring experiment.
The run of the molten metal was about the same with fast and with slow flow of the molten metal supplied to the product part.
A defect was found in trial production caused by shrinkage in the part sandwiched by the core, which is the part that solidifies last.
We believe the defect can be resolved by using a different gate thickness and position.
T2 Teeter mold test
Result: good It can be used for permanent mold casting
Internal shrinkage showed a smooth surface.There are thin and deep shrinkages.。
In the deepest part of the shrinkage, a rough texture and cracks were observed through color check.
A plan that sufficiently considers metal mold castability including shrinkage is necessary.
Molten metal temperature may not be suitable.A temperature range must be used that is suitable for permanent mold casting.
Suitable melting technology may need to be confirmed.(The method used to make molten metal may have been unsuitable.)
T3 Confirmation of mechanical properties
Tensile strength: 513 N/mm2 Degree of elongation: 44%
Greatly exceeds the standards for common brass and bronze materials.
T4 Analysis and confirmation of molten metal components
|4.||At the time of test production||80.5||0.2||0.002||15.04||0.017||4.2||3ppm|
Molten metal management is relatively easy
T5 Confirming processability
Compared to common brass, it has higher viscosity and is very hard.
Chips are large and connected.
Processability is acceptable if the production efficiency conditions such as machine rotation speed are reduced.
T6 Evaluation of pressure resistance of trial production
This trial product was not perfect, but good results were obtained.Effects of metal mold plan are significant.
Preliminary trial production
Leakage was observed in part of the trial production.It was sandwiched by core sand and leaked at what seems to be the final solidification spot.There was no leakage at the part in direct contact with the metal mold.
True trial production
It can be improved through thickness settings and the way molten metal flows based on the metal mold plan.After changing the plan and thickness setting of the product, the results in true trial production were good.
Results and evaluation
Metal mold castability is good.
It can also be used as a material for permanent mold casting. For mass production through low-pressure permanent mold casting, continuous examination of permanent mold casting conditions, such as suitable pouring temperature and metal mold temperature, is necessary.Mass production is easily possible in the present state if the permanent mold casting product is small.
As the degree of shrinkage is large, sufficient examination of permanent mold casting plan is necessary.
However, the features of the plan must be changed from that for commonly used leaded brass material.
If we can find a suitable metal mold plan and suitable permanent mold casting conditions, higher values of mechanical properties can be obtained compared to commonly used brass, and therefore we can expect a reduced weight of permanent mold casting products through reduced thickness.