1.1 This part of GB/T 3398 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 time-factors 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-o hardness scale is specified in the annex which shows how this scale may be related to the hardness measurement of GB/T 3398.1.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of GB/T 3398. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 2411-2008 Plastics and Ebonite — Determination of Indentation Hardness by Means of a Durometer (Shore Hardness) (ISO 868:2003, IDT)
GB/T 2918-1998 Plastics — Standard Atmospheres for Conditioning and Testing (idt ISO 291:1997)
GB/T 3398.1-2008 Plastics — Determination of Hardness — Part 1: Ball Indentation Method (ISO 2039-1:2001, IDT)
