1、BRITISH STANDARD BS 7603:1992 ISO 4790:1992 Method for Determination of stresses in glass-to-glass sealingsBS7603:1992 This British Standard, having been prepared under the directionof the Laboratory Apparatus Standards Policy Committee, waspublished underthe authorityof the Standards Boardand comes
2、intoeffect on 15September1992 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference LBC/8 Draftfor comment 90/53963 DC ISBN 0 580 21158 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Laborat
3、ory Apparatus Standards Policy Committee (LBC/-) to Technical Committee LBC/8, upon which the following bodies were represented: British Glass Manufacturers Confederation Society of Glass Technology Amendments issued since publication Amd. No. Date CommentsBS7603:1992 BSI 09-1999 i Contents Page Com
4、mittees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Apparatus 2 5 Test specimen 2 6 Procedure 2 7 Expression of results 3 8 Test report 3 Annex A (informative) Bibliography 4 Figure 1 Principal stresses in the test specimen 1 Figure 2 Isocli
5、nic pictures between two crossed polarizers (light-field withlinear polarization, the sealed area at 45 to the axis ofpolarization) 3 List of references Inside back coverBS7603:1992 ii BSI 09-1999 National foreword This British Standard has been prepared under the direction of the Laboratory Apparat
6、us Standards Policy Committee. It is identical with ISO 4790:1992 Glass-to-glass sealings Determination of stresses, published by the International Organization for Standardization (ISO). It has been prepared by Subcommittee 5, Quality of glassware, of Technical Committee 48, Laboratory glassware an
7、d related apparatus, with the active participation and approval of the United Kingdom. Reference is made in this British Standard to FEPA Standard 43-GB:1984, published by the Federation of European Producers of Abrasive Products, 20 Avenue Reille, 75014 Paris, to which there is no corresponding ISO
8、 or British Standard. A copy of the FEPA Standard is obtainable from the Coated Abrasive Manufacturers Association, PO Box 58, Trafford Park Road, Manchester M171JD. This British Standard describes a method of test only and should not be used or quoted as a specification defining limits of performan
9、ce. Reference to this British Standard should indicate that the method of test used is in accordance with BS7603:1992. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with
10、a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard BS 7604 Method for determination of stress-optical coefficient of glass ISO 10345-1:1992 Part 1:1992 Tensile test (Identical) ISO 10345-2:1992 Part 2:1
11、992 Bending test (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the
12、amendment table on the inside front cover.BS7603:1992 BSI 09-1999 1 1 Scope This International Standard describes the test method for determining the stresses which may occur after the sealing of two glasses by means of stress birefringence. 2 Normative references The following standards contain pro
13、visions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the
14、possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 10345-1:1992, Glass Determination of stress-optical coefficient Part 1: Tensile test. ISO 10345-2:1992, Glass Determination of
15、stress-optical coefficient Part 2: Bending test. FEPA-Standard 43-GB:1984, Standard for coated abrasive grains of fused alumina and silicon carbide 1) . 3 Principle If two glasses are sealed together, stresses can persist in them after cooling. The value of these stresses depends on the differences
16、in the thermal, elastic and viscous properties of the glasses. In general, glasses become birefringent when they are subjected to stresses. For the relationship between the stress and the optical path difference resulting from the birefringence, the following equation applies: where For positive str
17、ess-optical coefficients K, in the case of a tensile stress in the glass, the value for %s shall have a positive sign (+), and in the case of a compressive stress in the glass a negative sign (). For negative stress-optical coefficients K, the signs of %s are the contrary. It is assumed that a plane
18、 state of stress is set up predominantly in the test specimen and that the stress zone in the direction of transmission of light in the vicinity of the sealed area is approximately homogenous. The three principal stresses are orientated in such a way that the first principal stress 1is perpendicular
19、 to the surface of the test specimen; the second principal stress 2is parallel to the sealed area and to the surface of the test specimen; the third principal stress 3is perpendicular to the sealed area (see Figure 1). In equation (1), represents the difference between the principal stresses 2and 3
20、. In the vicinity of the sealed area, the principal stress 3is small in comparison with the principal stress 2 , so that in equation (1), may be treated as equivalent to principal stress 2 . The optical path difference, which occurs when light passes between the two light waves oscillating in the di
21、rection of principal stresses 2and 3 , is caused by the differing speeds of propagation in birefringent test specimens. 1) FEPA: Federation of European Producers of Abrasive Products. . . . (1) is the tensile or compressive stress; %s is the optical path difference; K is the stress optical coefficie
22、nt; a is the light path in the test specimen (which is identical with the height h of the test specimen). %s aK - = Key e = 0,5 mm (see 6.6) b Breadth of the glass pieces h Height of the test specimen and the glass pieces l Length of the test specimen and the glass pieces 1 , 2 , 3Principal stresses
23、 in the test specimen Figure 1 Principal stresses in the test specimen BS7603:1992 2 BSI 09-1999 4 Apparatus 4.1 Furnace, for sealing and cooling the test specimen as described in 5.3.1 and 5.3.2. 4.2 Stress-testing equipment, for a survey method for testing the test specimen as described in 6.1 and
24、6.2. 4.3 Measuring device, capable of measuring the height h of the test specimen to 0,1 mm. 4.4 Polarization measuring equipment, with a compensator capable of measuring the optical path difference in the vicinity of zero setting to 5 nm. Depending on the table of functions of the compensator used,
25、 either white light or a light source of spectral wave range between 540 nm and590 nm is recommended (spectral lamps or incandescent lamps with an interference filter). NOTE 1The deviations between any optical path differences measured in the wave range between 540 nm and 590 nm are smaller than the
26、 uncertainty of the polarization measuring equipment. 5 Test specimen 5.1 Dimensions of glass pieces (see Figure 1) The two glass pieces to be sealed together shall be of equal size and shall comply with the following requirements: height h: 4 mm to 10 mm, preferably 5 mm; length l: 20 mm (approx.);
27、 breadth b: 10 mm (approx.); the corners and edges of the test pieces may be rounded. 5.2 Condition of glass pieces The glass pieces shall be free of striae, gaseous and solid inclusions in the vicinity of the surfaces to be sealed. The surfaces of the glass pieces to be sealed shall be flat, with a
28、 roughness less than that achieved by polishing with an abrasive of particle size P 240 according to FEPA-Standard 43-GB. 5.3 Preparation of the test specimen 5.3.1 Seal two glass pieces completely together, on the surfaces prepared for sealing, to form one test specimen (see Figure 1). During this
29、procedure, any deformation of the flat sealed surface shall be avoided. 5.3.2 Since the result of the measurement can be affected by the cooling rate applied to the test specimen in the visco-elastic range of the glasses, the test specimen shall be cooled at a rate of(2 0,2) C per min, within the fo
30、llowing temperature range: the upper limit of temperature range is determined by the temperature at which the glass of the test specimen which has the higher viscosity has reached a dynamic viscosity of10 13 dPas; the lower limit lies 150 C below the temperature at which the glass with the lower vis
31、cosity has a dynamic viscosity of 10 13 dPas. Outside this temperature range the only requirement is that temporary stresses occuring during cooling shall not cause splits in the test specimen. 5.3.3 After sealing, the surfaces of the test specimen through which the light passes (see Figure 1) shall
32、 be treated so that they are parallel to each other and perpendicular to the sealed area. 6 Procedure 6.1 In order to verify that the sealing of the test specimen is without any defects (see 5.3.1), the symmetry of the stress picture should be checked in each half of the test specimen by means of st
33、ress-testing equipment (see Figure 2). 6.2 In addition, both halves of the test specimen shall be tested for splits. Splits in one or both halves of the test specimens disturb the stress symmetry and this may affect the results of the measurements taken as described in 6.6. For such test specimens,
34、only the sign of stress can be determined, as described in 6.7. 6.3 Take all measurements at room temperature between 15 C and 35 C. Any test temperatures differing from this range shall be stated in the test report. 6.4 Measure the thickness of the test specimen in the measuring area (see 6.6). 6.5
35、 When the surfaces of the test specimens through which the light passes are not sufficiently smooth for the stress picture to be clear, it is advisable to place the test specimen in an immersion fluid, for example water in the case of fine polished surfaces. The bottom of the immersion vessel itself
36、 shall not have any interfering birefringence and optical path difference.BS7603:1992 BSI 09-1999 3 6.6 When the light is passed through a split-free test specimen in a perpendicular direction, measure the principal stresses lying parallel to both sides of the sealed surface as the optical path diff
37、erences, one after another at a distance of e = 0,5 mm from the sealed surface and at the centre of the test specimen (see also Figure 1). In the case of a test specimen with one non-transparent glass piece, the optical path difference can only be measured in the transparent half of the test specime
38、n. In the case of a test specimen of which one-half consists of an agreed reference glass, possibly of the same type of glass, it is sufficient to measure the optical path difference of the birefringence in the reference glass half. 6.7 When the type of stress is not clearly revealed by measurement
39、of the optical path difference, and in the case of a test specimen having splits, determine by means of the stress testing equipment and by comparison with a tension or compression test piece, whether the optical path difference is the result of tensile or compressive stress. 7 Expression of results
40、 For each half of the test specimen for which the optical path difference has been measured according to 6.6, calculate the stress birefringence %n from the numerical equation (2) and the principal stress 2from the numerical equation (3): where 8 Test report The test report shall include the followi
41、ng information: a) reference to this International Standard; b) types and designations of the glasses sealed; c) cooling rate, if other than (2 0,2) C per min; d) testing temperature, if outside the range 15 C to 35 C; e) for each half of a split-free test specimen: the stress birefringence %n, in n
42、anometres per centimetre, to the nearest 5 nm/cm; principal stress 2 , in newtons per square millimetre, to the nearest 0,1 N/mm 2 , with the corresponding sign according to clause 3; the stress-optical coefficient K, expressed in10 6mm 2 /N, used for the calculation of the principal stress 2 ; f) f
43、or test specimens with splits, the type of stress (tensile or compressive). NOTEThe areas which appear dark have an optical path difference of zero (stress free) or a whole multiple of the medium wave-length used. Dark parts also occur at the points at which the direction of principal stress in the
44、test specimen coincides with the axis of polarization. Figure 2 Isoclinic pictures between two crossed polarizers (light-field with linear polarization, the sealed area at 45 to the axis of polarization) . . . (2) . . . (3) %n %s h - = 2 0,1 %s hK - = %n is the stress birefringence, in nanometres pe
45、r centimetre; %n is the optical path difference, in nanometres (see clause 3 for information concerning the sign) K is the stress-optical coefficient, expressed in10 6mm 2 /N, according to ISO 10345-1 or ISO 10345-2; h is the height, in centimetres, of the test specimen; 2 is the principal stress, i
46、n newtons per square millimetre.BS7603:1992 4 BSI 09-1999 Annex A (informative) Bibliography 1 FPPL, L. and MNCH, E. Praktische Span-nungsoptik (3 rded.) Berlin, Gttingen, Heidelberg: Springer-Verlag (1972). 2 MESMER, G. Spannungsoptik (1 sted.) Berlin:Springer-Verlag (1939). 3 MLLER-POUILLET Lehrbu
47、ch der PhysikII,1.(11 thed.) Braunschweig: Verlag Vieweg(1929). 4 WOLF, H. Spannungsoptik (2 nded.) Berlin, Gttingen, Heidelberg: Springer-Verlag (1976). 5 COKER, E.G. and FILON, L. N. G. A Treatise on Photo-Elasticity, Cambridge (1957). 6 FROCHT, M. M. Photoelasticity, New York (1957). 7 KUSKE, A.
48、Einfhrung in die Spannungsoptik, Stuttgart (1959). 8 RINNE, F. and BEREK, M. Anleitung zur allgemeinen und Polarisations-Mikroskopie der Festkrper im Durchlicht (3 rded.) Stuttgart:E.Schweizerbartsche Verlagsbuchhandlung (1973).BS7603:1992 BSI 09-1999 List of references See national foreword.BS 7603
49、:1992 ISO4790:1992 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest ame
