BS ISO 3384-1 pdf free download

BS ISO 3384-1-2019 pdf free download.Rubber, vulcanized or thermoplastic — Determination of stress relaxation in compression Part 2: Testing with temperature cycling.
5.2 Counterforce-measuring device, capable of measuring compression forces in the desired range with an accuracy of 1 % of the measured value. The continuous‑measurement system monitors the test piece during the whole duration of the test, thus making continuous measurement of the change in counterforce with time possible. The deformation of the test piece shall be kept within ±0,01 mm for the duration of the test. If it is not possible to keep the deformation constant within this tolerance due to the spring effect in load cells, a correction may be done mechanically or mathematically.
5.3 Test environment
5.3.1 For tests in gaseous media, an air oven in accordance with the requirements of ISO 188 shall be used. An oven meeting the requirements specified for one of the ovens used in ISO 188:2011, method A, is recommended. For cycling the temperature, the oven shall have a cooling and heating capability and be able to change the temperature at a rate of 1,0 °C/min ± 0,5 °C/min. If the testing is done in nitrogen, oxidative ageing will be eliminated and the result will be due to thermal ageing only. This can be used to simulate conditions where the product is not exposed to air, such as seals used in oil or steam.
5.3.2 For tests in liquids, the compression device shall be totally immersed in a liquid in a bath, or a closed vessel for volatile or toxic fluids, such that free circulation of the liquid can take place through the holes in the compression plates. The liquid shall be maintained at the specified temperature by proper control of a heater and circulation of the liquid in the bath or, alternatively, by placing the liquid bath and compression device within an air oven as specified above.
5.3.3 It is recommended that the air used for air exchange be passed through an air dryer to give it a dew point not higher than –40 °C in order to avoid ice formation which can introduce friction in the measuring system.
5.4 Temperature-measuring equipment, with a sensing element of appropriate precision. The temperature‑sensing element shall be installed in such a way that it accurately measures the temperature of the test piece.
NOTE A Pt100 sensor has been found to be suitable for temperature measurement.
6 Calibration
The requirements for calibration of the test apparatus are given in Annex A.
7 Test piece
7.1 Type and preparation of test pieces
7.1.1 General
Test pieces shall be prepared either by moulding or by cutting from moulded sheets or products, in accordance with ISO 23529.
NOTE The results obtained from test pieces of different sizes are not comparable.
7.1.2 Cylindrical test pieces
The test piece shall be a cylindrical disc of diameter 13,0 mm ± 0,5 mm and thickness 6,3 mm ± 0,3 mm.
7.1.3 Ring test pieces
The preferred ring test piece is a ring of square cross-section cut from a flat sheet of the test material
by means of rotary cutters. For a suitable machine for the preparation of small ring test pieces, see
Annex A of ISO 37:2017.
The dimensions of test pieces shall be:
— thickness: 2,0 mm ± 0,2 mm;
— inner diameter: 15,0 mm ± 0,2 mm;
— radial width: 2,0 mm ± 0,2 mm.
The sheets may be prepared by moulding or from finished articles by cutting and buffing.BS ISO 3384-1 pdf download.