30CR104.pdf

mg rover group engineering standards issue no:mgr es: title: page 1 of 4 date: - printed copy is uncontrolled - check issue is current - 2 materials tests fluid resistance to elastomeric materials may 1987 30.cr.104 contents 1 scope and purpose4procedure / test 2 apparatus5calculation 3 specimen preparation6appendix 1 scope and purpose 1.1these methods are applicable to elastomeric materials in sheet or tube form. note:when conducting ageing tests in flammable fluids, appropriate safety precautions must be taken both in the handling and storage of the fluids, and in the design, construction and location of the test apparatus. 2 apparatus 2.1 method a - volume change 2.1.1 a source of heat capable of maintaining the specified temperature + 2c e.g., electrothermal mantle, fluid bath, etc. 2.1.2 chemical balance, accurate to 0,5 mg. 2.1.3suitable balance pan bridge. 2.1.4a suitable glass immersion vessel. where evaporative losses are likely to be significant, a condenser system must be fitted (see fig 1). 2.1.5length of inert wire (not copper) or nylon thread. 2.1.6a suitable glass beaker. 2.1.7thermometer of suitable temperature range. 2.2method b changes in mechanical properties 2.2.1apparatus required as detailed in bls.30.tp.903 and clauses 2.1.1, 2.1.4, 2.1.5 and 2.1.7 above. 3 specimen preparation mg rover group engineering standards issue no:mgr es: title: page 2 of 4 date: - printed copy is uncontrolled - check issue is current - 2 materials tests fluid resistance to elastomeric materials may 1987 30.cr.104 3.1method a 3.1.1hose samples: prepare three test pieces of 25mm nominal length by mechanically stripping any reinforcement. 3.1.2flat samples: cut out three test pieces with nominal dimensions 25mm x 25mm x 2,5mm 3.2method b - prepare three tensile test specimens by cutting as specified in bls.30.tp.903. 4 procedure / test 4.1suspend specimen by means of the inert wire from balance hook above the pan and weigh to the nearest 1mg. 4.1.2mount a suitable glass beaker on the bridge above the pan and completely immerse the suspended specimen in distilled or de-ionised water at 20 + 2c. 4.1.3completely remove all adherent air bubbles from the specimen. note:addition of 0.1 per cent wetting agent to the water is permissible. 4.1.4weigh the suspended specimen to the nearest 1mg and then remove surface moisture. 4.1.5completely immerse the specimen in the test fluid, under the conditions specified, taking care to avoid contact between samples or with the glass immersion vessel. the ratio of the volume of test fluid to the total volume of the test specimens shall be at least 100:1. loss of test fluid shall be kept to a minimum during the test period (see clause 2.1.4). 4.1.6on completion of the specified test period, cool the specimens to room temperature. cooling shall be completed within 30 minutes and carried out with the specimens immersed in test fluid. 4.1.7remove cooled specimens and wipe off surplus test fluid using a suitable absorbent paper. 4.1.8repeat the weighing procedure detailed in clauses 4.1.1 to 4.1.4 inclusive within 15 minutes of removing specimens from the test fluid. 4.1.9calculate the percentage volume change for each specimen in accordance with clause 5 and report the mean value. 4.2method b - change in mechanical properties 4.2.1calculate the cross sectional area of the test specimens in accordance with bls.30.tp.903. 4.2.2completely immerse the specimen in the test fluid under the conditions specified, taking care to avoid contact between samples or with the glass immersed vessel. the ratio of the volume of test mg rover group engineering standards issue no:mgr es: title: page 3 of 4 date: - printed copy is uncontrolled - check issue is current - 2 materials tests fluid resistance to elastomeric materials may 1987 30.cr.104 fluid to the total volume of the test specimens shall be at least 100:1. loss of test fluid shall be kept to a minimum during the test period (see clause 2.1.4). 4.2.3on completion of the specified test period, cool the specimens to room temperature. cooling shall be completed within 30 minutes and carried out with the specimens immersed in test fluid. 4.2.4remove cooled specimens and wipe off surplus test fluid using a suitable absorbent paper. 4.2.5determine mechanical properties in accordance with bls.30.tp.903 within 15 minutes of removing specimens from the test fluid. 4.2.6 report the mean percentage change in both elongation and tensile strength. 5 calculation 5.1% volume change=(c - d) - (a - b) x 100 a - b where: a = initial weight in air b = initial weight in water c final weight in ai