T1 Test to check molten metal flow and trial production
Metalmold temperature approximately 95°C
Temperatureduring pouring about 1010°C
Molten metal flow is good
Moltenmetal sufficiently fills the mold up to up-hill part for degassing.
Therun of the molten metal was about the same with fast and with slow flow of themolten metal supplied to the product part.
Adefect was found in trial production caused by shrinkage in the part sandwichedby the core, which is the part that solidifies last.。
We believe the defect can be resolved by using adifferent gate thickness and position
T2 Teeter mold test
Result: Good It can be used for Permanent mold casting
Theinner surface of internal shrinkage was bumpy with deep shrinkage. Crackswere observed in the shrinkage.
Colorcheck of the internal shrinkage part indicated a large red stained area on thesurface, and the texture tended to be rougher.
A planthat sufficiently considers metal mold castability including shrinkage isnecessary.
Moltenmetal temperature may not be suitable. Atemperature range must be used that is suitable for Permanent mold casting.
Suitablemelting technology may need to be confirmed. (The method used to make molten metal may have been unsuitable. )
T3 Confirmation of mechanical properties
Tensilestrength: 451 N/mm2 Degreeof elongation: 37%
Greatly exceeds the standards for common brass and bronze materials.
T4 Analysis and confirmation of molten metal components
| Cu | Sn | Pb | Zn | Bi | Fe | Niｉ | Si | Cd | ||
|---|---|---|---|---|---|---|---|---|---|---|
| 1. | Standard value | 73.0-77.0 | 0.3Max | 0.2Max | 18.0-23.0 | 0.5-1.0 | 0.1Max | 0.2Max | 2.8-3.2 | |
| 2. | Purchased materials | 74.76 | 0.07 | 0.05 | 21.31 | 0.71 | 0.03 | 0.01 | 3.03 | 8ppm |
| 3. | Before melting | 75.2 | 0.03 | 0.007 | 20.86 | 0.81 | 0.02 | 0.005 | 3.03 | 8ppm |
| 4. | At the time of test production | 75.6 | 0.03 | 0.008 | 20.41 | 0.789 | 0.02 | 0.005 | 3.13 | 7ppm |
Moltenmetal management is relatively easy
Attentionto Zn depletion is required but no significant depletion was observed.
T5 Confirming processability
It ishard and tough compared to common brass.
Chipsare small but larger than those of common brass.
Processabilityis in the range where there is no problem if the condition is changed.
T6 Evaluation of pressure resistance of trial production
Result
Thistrial product was not perfect, but good results were obtained.Metalmold plan and casting condition have large effects on pressure resistance.
Preliminary trial production
Leakagewas observed in all products in preliminary trial production.Leakagewas observed at the part sandwiched by core sand that solidifies last.There was no leakage at the part in direct contactwith the metal mold.
True trial production
It canbe improved through thickness settings and the way molten metal flows based onthe metal mold plan.Afterchanging the plan and thickness setting of the product, the results in truetrial production were good.
Results and evaluation
Metal mold castability is good.
It can also be used as a material for Permanent mold casting.
Massproduction through low-pressure Permanent mold casting is possible but continuedinvestigations of Permanent mold casting conditions, such as suitable pouringtemperature as well as metal mold temperature, are necessary. Massproduction is easily possible in the present state if the Permanent mold castingproduct is small. However,the features of the plan must be changed from that for commonly used leadedbrass material.
If wecan find a suitable metal mold plan and suitable Permanent mold casting conditions,higher values of mechanical properties can be obtained compared to commonlyused brass, and therefore we can expect a reduced weight of Permanent mold castingproducts through reduced thickness.