ASTM D785, ISO 2039 Rockwell Hardness

Scope:

Rockness hardness ASTM D785 test method includes two different procedures for testing the indentation hardness of plastics and plastic-related electrical insulating materials using the Rockwell hardness tester. The Rockwell Hardness Test is a hardness calculation that is dependent on the net increase in depth of impact when a load is applied. Hardness numbers have no units and are generally given in the R, L, M, E, and K scales. Higher numbers mean tougher materials.

Test Procedure:

A typical sample is positioned on the Rockwell Hardness Tester’s surface. The gauge is reset to zero after a small load is applied. The primary force is exerted by tripping a lever. The main load is withdrawn after 15 seconds. After allowing the sample to recover for 15 seconds, the hardness value is read off the tester dial while a slight load is still applied.

Sample size: 

A standard sample for the Rockwell Hardness test is 6.4 mm (0.25 inches) thickness that is either molded or cut from a sheet.

Data: 

The different hardness value is visually recorded directly from the dial with suitable R, L, M, E or K scales. The tougher the object, the higher the number on each scale. Plastics are often measured using R and M scales.

Conclusion:

ASTM D785 test method aids in determining the hardness of plastics and the information obtained is applied in specifying their applications. The quality and durability check is performed to ensure better performance of plastics commercially.