１. Application

This applies to test method of green sand grain size ratio measurement.

2. Definition:

Grain size ratio of green sand is defined as the size ratio of dried sand after removing all the clay content by the method ruled in TJFS-204 (Green sand total clay test method).

3. Instrument apparatus

3.1 Balance

A balance of the precision of 0.01g is used.

3.2 Sieve

Sieve frame diameter is 200mm and the sieves of the following nominal mesh sizes (μm) are selected from those ruled by JIS Z 8801 (standard sieves): 3350, 2360, 1700, 1180, 850, 600, 425, 300, 212, 150, 106, 75, 53, and pan.

Note: Pan is a dish that collects fine particles passed through the sieve of the nominal mesh size of 53μm.

3.3 Sieve machine

A Rotap sieve machine is used as a rule. However, a machine with an equivalent sieving performance may also be used.

4. Testing procedure

4.1 Sample

The total volume of the dried substance after removing the total clay content from green sand by the method ruled in TJFS-204 (Green sand total clay test method) is used as the sample.

4.2 Operation

Sieves are stacked in the order of mesh size and the sample is put in the top sieve. The stacked sieves, after covered with a lid, is vibrated for 15 minutes by the machine, where vibration is given by tapping the top of the stacked sieve in a specified manner. Then the sieves are removed from the machine and the sand on each sieve is weighed.

4.3 Calculation of the grain size ratio

Mass % of each grain size is calculated by the following equation.

\[R = { E \over B } \times 100 \]

where

\[ \left\{ \begin{array}{l} R &= weight \ ratio \ of \ each \ grain \ size \ (％) \\ E &= weight \ of \ the \ sand \ on \ each \ sieve \ (g) \\ B &= weight \ of \ the \ sample, \ including \ the \ total \ clay \ content \ (g) \end{array} \right. \]

5. Expression

Each grain size ratio is expressed in %.

6. Record

6.1 The result is calculated to the first decimal place. Test is repeated two times or more from the same batch of sand. In calculating the average size ratio, the size of the largest size ratio is taken and the one above and below are also taken. If their deviation of the size ratio is confirmed to be within 5%, the data is used for averaging.

6.2 The green sand grain size ratio is expressed in % of the total weight including the total clay.

6.3 If the grain fineness number of the sand excluding the total clay is needed, it is calculated by the following equation, using the sand weight on each sieve and the size factor Sn in the Table 1.

\[FN = \frac{\sum ( Wn \times Sn )}{ \sum Wn} \]

where
\[ \left\{ \begin{array}{l} FN &= fineness \ number \\ Wn &= sand \ grain \ weight \ on \ each \ sieve, \ including \ pan \ (g) \\ Sn &= the \ grain \ size \ factor \ in \ Table1 \end{array} \right. \]