Rockwell hardness values are expressed as a combination of a hardness number and a scale symbol representing the indenter and the minor and major loads. The hardness number is expressed by the symbol HR and the scale designation. UNITEDTEST hardness testers are based on the same construction principle of the COMP series which are already well known for their economic, reliability and easy using.

Principle:

1. The indenter moves down into position on the part surface
2. A minor load is applied and a zero reference position is established
3. The major load is applied for a specified time period (dwell time) beyond zero
4. The major load is released leaving the minor load applied

The resulting Rockwell number represents the difference in depth from the zero reference position as a result of the application of the major load.

Model:
XHR-150 Plastic Rockwell Hardness Tester

1), High measuring accuracy, reliable performance and wide applicable fields;
2), This tester adopts motorized testing method, the testing force can be loaded, kept and unloaded automatically.
3), Application: Hard plastics, hard rubbers, aluminum, tin, copper, soft steel, synthetic resins, fricative materials, etc.

∮3.175mm, 6.35mm, 12.7mm ball indenter
large testing table, medium testing table, V-shaped table,
4pcs hardness blocks,
Power cord

ASTM E18 “Standard Test Methods for Rockwell Hardness of Metallic Materials”

ISO 6508 “Metallic materials — Rockwell hardness test”

ASTM D785 “Standard Test Method for Rockwell Hardness of Plastics and Electrical Insulating Materials”