1. Application

This applies to the test method for determining green sand volatile component.

2. Definition

Green sand volatile component is defined as the weight loss expressed in % of the sample weight, when a green sand sample in a covered crucible is heated at 900 degree C for 7 minutes, while avoiding contact with air. The volatile component includes gas generated by thermal decomposition under reducing atmosphere of organic materials such as coal powder, or starch. It also includes water that remains after the drying condition of TJFS-201 (Green sand moisture content test method).

3. Instrument and apparatus

3.1 Balance

A balance of the precision of 0.001g is used.

3.2 Thermometer by thermocouple

A thermometer capable of measuring temperature of 895 to 905 degree C.

3.3 Heater

An electric furnace satisfying the following conditions is used.

1. Before inserting the sample for heating at 900 degree C, the furnace has a zone of a uniform temperature of 900±5 degree C with a volume sufficiently larger than the sample itself.
2. The furnace is capable of returning to the original temperature in three minutes after the sample is inserted.

3.4 Porcelain crucible

A porcelain crucible of an approximate capacity of 10ml with a fitting drop lid for covering is used. An example is shown in Fig.1. Before using a new crucible, it is empty heated at 900 degree C until reaching a constant weight. If carbon is adhered to the crucible after measuring volatile component, the crucible is again empty heated.

4. Testing procedure

4.1 Sample

A sample of 10g is taken from sand dried according to the process in TJFS-201(Green sand moisture content test method). It is crushed in an agate mortar to the fineness below 250μm. If moisture is absorbed during crushing, the sample after crushing is dried until reaching a constant weight.

4.2 Operation

1. The furnace temperature is raised and the space for the crucible is kept at 900 degree C.
2. A sample of 2g is weighed and put in a crucible of known weight.
3. The crucible is covered with a lid, and is given tapping for a few times on a clean, hard, and flat base to make the sample thickness in the crucible uniform.
4. The sample crucible is inserted in the furnace. Temperature is confirmed to have recovered to 900±20 degree C within three minutes. Then the temperature is kept constant.
5. The crucible is heated for 420 seconds or 7 minutes.
6. At the end of the heating time, the crucible is immediately taken out and cooled for three minutes in an open air, and then cooled in a desiccator for 20 minutes. At the end of the cooling time, the crucible is weighed immediately.

4.3 Calculation of the volatile component

The volatile component is calculated by the following equation.

\[V = { ( W_1 - W_2 ) \over W_1 } \times 100 \]

where

\[ \left\{ \begin{array}{l} V &= volatile \ component \ (％) \\ W_1 &= sample \ weight \ (g) \\ W_2 &= weight \ after \ heating \ (g) \end{array} \right. \]

5. Expression

Green sand volatile component is expressed in %.

6. Record

The result is calculated to the second decimal place. Test is repeated two times or more and averaged using values within 5% deviation. Note: This method is a modification of the volatile component determination method in JIS M 8812 (Coals and cokes—Industrial analysis).