Testing Instruments By Standards
The standard test method includes a test procedure to measure the hardness of thermoplastic rubber and vulcanized rubber. The hardness of a material is attained by the distinction in the penetration depth of a ball having specified dimensions under two conditions of contact namely, with a small and initial force and with a large and final force. The difference between the penetration is taken at a specified time and converted to a hardness scale value. This method is technically same as ISO 48.