ISO 00048:2010 pdf free download – Rubber, vulcanized or thermoplastic – Determination of hardness (hardness between 10 IRHD and 100 IRHD).
6.2 Methods N, H, L and M
6.2.1 General
The test pieces shall have their upper and lower surfaces flat, smooth and parallel to one another.
Tests intended to be comparable shall be made on test pieces of the same thickness.
6.2.2 Thickness
6.2.2.1 Methods N and H
The standard test piece shall be 8 mm to 10 mm thick and shall be made up of one or more layers of rubber, the thinnest of which shall not be less than 2 mm thick. All surfaces shall be flat and parallel.
Non-standard test pieces may be either thicker or thinner, but not less than 4 mm thick.
6.2.2.2 Method L
The standard test piece shall be 10 mm to 15 mm thick and shall be made up of one or more layers of rubber, the thinnest of which shall not be less than 2 mm thick. All surfaces shall be flat and parallel. Non-standard test pieces may be either thicker or thinner, but not less than 6 mm thick.
6.2.2.3 Method M
The standard test piece shall have a thickness of 2 mm ± 0,5 mm. Thicker or thinner test pieces may be used, but in no case less than 1 mm thick. Readings made on such test pieces do not in general agree with those obtained on the standard test piece.
6.2.3 Lateral dimensions
6.2.3.1 Methods N, H and L
The lateral dimensions of both standard and non-standard test pieces shall be such that no test is made at a distance from the edge of the test piece less than the appropriate distance shown in Table 2.
When test pieces thicker than 4 mm are tested on the microtest instrument because the lateral dimensions or the available flat area do not permit testing on a normal instrument, the test shall be made at a distance from the edge as great as possible.
6.3 Methods CN, CH, CL and CM
The test piece shall be either a complete article or a piece cut therefrom. The underside of a cut piece shall be such that it can be properly supported during the hardness test. If the surface on which the test is to be made is cloth-marked, it shall be buffed prior to testing. Test pieces shall be allowed to recover at a standard laboratory temperature (see ISO 23529) for at least 16 h after buffing and shall be conditioned in accordance with Clause 8. The conditioning period may form part of the recovery period.
7 Time interval between vulcanization and testing
Unless otherwise specified for technical reasons, the following requirements shall be observed (see
ISO 23529):
— For all normal test purposes, the minimum time between vulcanization and testing shall be 16 h. In cases of arbitration, the minimum time shall be 72 h.
— For non-product tests, the maximum time between vulcanization and testing shall be 4 weeks and, for evaluations intended to be comparable, the tests, as far as possible, shall be carried out after the same time interval.
For product tests, whenever possible, the time between vulcanization and testing shall not exceed 3 months. In other cases, tests shall be made within 2 months of the date of receipt by the purchaser of the product.
8 Conditioning of test pieces
8.1 When a test is made at a standard laboratory temperature (see ISO 23529), the test pieces shall be maintained at the conditions of test for at least 3 h immediately before testing.
8.2 When tests are made at higher or lower temperatures, the test pieces shall be maintained at the conditions of test for a period of time sufficient to reach temperature equilibrium with the testing environment, or for the period of time required by the specification covering the material or product being tested, and then immediately tested.
9 Temperature of test
The test shall normally be carried out at standard laboratory temperature (see ISO 23529). When other temperatures are used, these shall be selected from the list of preferred temperatures specified in ISO 23529.