ISO 48-3:2018 pdf free
ISO 48-3:2018 pdf free.Rubber, vulcanized or thermoplastic – Determination of hardness
The essential parts of the apparatus are as follows, the appropriate dimensions and forces being shown in Table 1. Detailed information can be found in References [3] and[4].
Vertically guided plunger, having a ball or spherical surface on the lower end, and means for supporting the plunger so that the spherical tip is kept slightly above the surface of the annular foot prior to applying the contact force.
Means for applying a contact force and an additional indenting force to the plunger, making allowance for the mass of the plunger, including any fittings attached to it, and for the force of any spring acting on it, so that the forces actually transmitted through the spherical end of the plunger are as specified.
Means for measuring the increase in depth of indentation of the plunger caused by the indenting force, either in millimetres with a maximum uncertainty of 0,001 mm, or reading directly in VLRH with a resolution such that a reading to at least 0,5 VLRH is possible.
Flat annular foot, normal to the axis of the plunger and having a central hole for the passage of the plunger. The foot rests on the test piece and shall be rigidly connected to the indentation measurement device so that a measurement is made of the movement of the plunger relative to the foot (i.e. the top surface of the test piece), not relative to the surface supporting the test piece.
If it is required that measurements be made on test pieces with a curved surface, a calibration has to be carried out. Tests need to be made on test pieces of the material with both flat and curved surfaces. The hardness difference (H curved – H flat) which is found for the flat and the curved test pieces is used with opposite sign as correction of the hardness values obtained on test pieces of a similar material with a curved surface.ISO 48-3 pdf download.
