This part of GB/T 3398 specifies a method for determining the hardness of plastics and ebonite by means of a loaded ball indenter.
The ball indentation hardness determined by this method may provide data for research and development, quality control and acceptance or rejection under specifications.
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 2918-1998 Plastics--standard atmospheres for conditioning and testing (idt ISO 291:1997)
3 Term and definition
For the purposes of this part of GB/T 3398, the following term and definition apply.
3.1
ball indentation hardness
HB
the quotient of the load on the ball indenter by the surface area of the impression caused by the ball indenter after a specified time of load application, expressed in newtons per square millimetre (N/mm2).
4 Principle
The method consists of forcing a ball under a specified load into the surface of the test specimen. The depth of impression is measured under load. The surface area of the
