Molding sand and sand core depending on shape, size composition and distribution of grains of sand, clay size, moisture and additives. The increase in demand for good surface finish and higher accuracy in castings requires certainty in the quality of the mold and core sand. Sand often test allows the use of cheaper local sand. It also ensures reliable mixing sand and allow use of the natural properties of molding sand. Will deliver sand test no change from the standard quality, and adjust the mixture to detect sand immediately to the particular needs so that it can minimize the.
In general the following tests are performed to judge the molding and casting foundry sands characteristics:
1. Moisture content Test
2. Clay content Test
3. Chemical composition of sand
4. Grain shape and surface texture of sand.
5. Grain size distribution of sand
6. Refractoriness of sand
7. Strength Test
8. Permeability Test
9. Flowability Test
10. Shatter index Test
11. Mould hardness Test.
1) Test Moisture Content: can the moisture content of the mixture, molding sand is determined by drying the size weighing 20 to 50 grams of sand molding with constant temperature up to 100 ° C in an oven for about an hour . It is then cooled to room temperature and then reweighing the molding sand. The moisture content in molding sand thus evaporated. The loss in weight of molding sand due to loss of moisture, gives the amount of moisture that can be expressed as a percentage of the original sand sample. Can the percentage of moisture content in molding sand also decide more quickly indeed an instrument called quick teller moisture. The instrument is based on the principle that when water and calcium carbide react, they form acetylene gas can be measured and this will in accordance with the moisture content. The instrument is available with a calibrated pressure gauge to read exactly the percentage of humidity present in the molding sand.