ÖNORM EN ISO 2039-2

1 .I This part of IS0 2039 specifies a method for determining the indentation hardness of plastics by means of the Rockwell hardness tester using the Rockwell M, L and R hardness scales. 1.2 A Rockwell hardness number is directly related to the indentation hardness of a plastic material; the higher the Rockwell hardness number, the harder the material. Due to a short overlap of Rockwell hardness scales by this procedure, two different Rockwell hardness numbers of different scales may be obtained on the same material, both of which may be technically correct. 1.3 For materials having high creep and recovery, the timefactors involved in application of the major and minor loads have a considerable effect on the results of the measurements. 1.4 An alternative method of using the apparatus to give hardness on the Rockwell-cc hardness scale is specified in the annex which shows how this scale may be related to the hardness measurement of IS0 2039-l.