1. Application

This applies to test method of green sand hardness.

2. Definition

Green sand hardness is defined as hardness measured at the center of the specimen bottom with a green sand hardness tester.

3. Testing apparatus and instrument

3.1 Green sand hardness tester

The principle of the test is the same as that of Brinnel hardness. The tester is equipped with a ball of 5.08 mm in diameter. When pressed against a molded sand surface, the ball starts moving at the load of 1.03N, and sinks 2.54mm at the load of 2.32N. The movement is converted into a movement of an indicator on a dial. The range of movement of the indicator corresponding to the above range of ball movement is divided in 100 measures on the dial to express hardness.

3.2 Examination

The instrument used in the test are checked at an appropriate interval to maintain the necessary precision.

4. Testing procedure

4.1 Specimen preparation

Test specimens are prepared by the method of TJFS-101 (Preparation of standard green sand specimen). Then the specimen in the cylinder is pushed by a rod from the ramming side until the specimen bottom comes to flush with the cylinder end. The sand forming a specimen should not be reused in another test.

4.2 Hardness measurement

The tester is pressed slowly against the center of the specimen bottom until the tester bottom touches the specimen surface and the dial is read off.

5. Expression

Hardness is read off from the dial and expressed in a dimensionless number.

6. Record

The result is read in a two-digit number. Tests are repeated three times or more from the same batch of sand and average value is calculated from results within ±5% of the standard deviation.

Standard compliant product