1. Application

This applies to test method of water sensitivity measurement.

2. Definition

Water sensitivity is defined as change of compactability caused by change of moisture content of green sand.

3. Muller

A small-size sand mill such as that for laboratory use can be conveniently used, though any type that gives sufficient mulling may be used. An agitator-type mixer giving excessive temperature rise is not suitable.

4. Testing procedure

4.1 Mulling and measurement of sand with different moisture content

Sand is sampled in a volume twice that of the muller capacity and is halved into two parts.

One part is mulled in the muller for 10 minutes and compactability and moisture content are measured according to;
TJFS-107: Green sand compactability test method
TJFS-201: Green sand moisture content test method , respectively.

Then water in the volume of 1% of the sand is added to the other half and measurement is made similarly.

4.2 Calculation of water sensitivity

Water sensitivity is the amount of water necessary to change the compactability by 10%, and is calculated by the following equation.

\[WS = {10(M1-M2) \over CB1-CB2} \]

where

\[ \left\{ \begin{array}{l} WS &= water \ sensitivity \\ M1 &= moisture \ content \ after \ water \ addition \\ M2 &= moisture \ content \ of \ the \ original \ sand \\ CB1 &= compactability \ after \ water \ addition \\ CB2 &= compactability \ of \ the \ original \ sand \end{array} \right. \]

5. Expression

Water sensitivity is expressed in a dimensionless number.

6. Record

The result is calculated to the first decimal place.