BS 7531:2006 pdf download

BS 7531:2006 pdf download.Rubber bonded fibre jointing for industrial and aerospace purposes – Specification.
C.6 Procedure
Centre the test piece on the anvil (C.2.1) in the loadiflg device (C.2.5) so (hat no edge is nearer than 5 mm to the outside diameter of the indenter and lIt the indenter (C.2.2) and gauges (C.2.3) and apply the preload (C.2.4) and maintain for a period of 15 s and record the preloaded thickness of the test piece.
Immediately apply the major load in a slow, uniform manner so that the total load is obtained within 10 s.
Maintain the total load for a penod of 60 s and record the thickness of the test piece. Cariy out this procedure on each test piece and cariy out a minimum of three tests.
C.7 Result
Calculate the difference between the indicating gauge(s) reading for each test an(l express this depth of impression as a percentage of the preloaded thickness of the material. Report the average of the three results.
Annex D (normative) Method of carrying out gas permeability test
D.1 Principle
This test assesses permeability properties of a gasket material at ambient temperature. The method indicates a measure of gas leakage through the body of the gasket.
D.2 Apparatus
The test. apparatus is as specified in DIN 3535-6 (see Figure D. 1 for a typical layout). All parts including the test piece are centred relative to each other. Suitable measures are taken to ensure that the test iiece uniformly loaded. The surfaces of the two sealing flanges shall be machined so that the mean roughness (R1) as defrned in B.S 1134.1 does not exceed 2 Om.
E.3 Test pieces
E.3.1 For Oil No. 3 and Water
For each test three pieces of material shall be cut, free from projecting fibres of dimensions 50mm x 25 mm with the longitudinal axis running in the direction of rolling of the sheet.
E.3.2 For Oil No. 1, Liquid 101 and Liquid B
For each test one J)ieee of material shall be cut, free from projecting fibres of dimensions 150 mm x 12.5 mm with the longitudinal axis running perpendicular to the direction of rolling of the sheet.
E.4 Conditioning
Condition the test pieces by heating for 1 h (± 5 mm) in the oven maintained at 100 ± 2cC. Remove the test pieces and place in the desiccator for a minimum of I h to cool to ambient temperature.
E.5 Procedure
E.5.1 Measure and record the thickness of the test pieces and where necessary (see Table 2) weigh to the nearest 0.001 g and record the mass.
E.5.2 Immerse the test pieces in sufficient volume of the test fluid to ensure complete immersion throughout the test and keep each test piece separate. For the water test use a covered vessel.
Place the immersed test pieces in the oven (except for Liquid B test) and maintain at the test temperature for the test period as shown in Table E.1.
E.5.3 At the end of the test period remove the test pieces afl(l allow to cool to below 25 °C for the period shown in Table E. 1.
E.5.4 Lightly blot the surfaces of the test pieces and measure and record the thickness and where required the mass. In the case of Liquid B this shall be (lone within 20 s of removal from the fluid.
E.6 Calculation
Calculate the increase in thickness and, where required, the mass and report the gain as the average (if the (leterminations expressed as a percentage of the original value.
F.3.2 Apply a series of Ioad.s with the top nut at room temperature to give dm1 gauge readings on the disc dynamometer corresponding to those obtained in F.2.3. Record load against centre bolt dial gauge readings.
F.3.3 Allow the apparatus to heat up to 300 C as recorded by the thermocouple and wait I ii for it to stabilize at this temperature. Repeat the calibration procedure in F.3.2.
F.3.4 Plot gasket stress/dial gauge reading to give the working calibration curve as shown in Figure A. 4 from the information obtained in F.3.2 and F.3.3.
AnnexG Method of test to determine
maximum stress value
G.1 Apparatus
G.1.1 S1e1 ring, an annular steel ring of the same size as the test
G.1.2 Rcsidu(d stress testing appa rut us, as detailed in Annex A.