ISO INTERNATIONAL STANDARD 7884-7 First edition 1987-12-15 INTERNATIONALORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXKAYHAPOAHAAOPrAHW3ALWANOCTAHAAPTW3AUMW AN Interna Doc Sect Glass - Viscosity and viscometric fixed points - Part 7 : Determination of annealing point and strain point by beam bending Referencenumber ISO7884-7:1987(E) No reproduction or networking permited without license from IHS Not for Resale Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standardsbodies(iSOmemberbodies).Thework of preparingInternational Standardsis normally carried out throughISO technical committees.Eachmember bodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhas the right to be represented onthat committee.International organizations,govern- mental and non-governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the Iso Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 7884-7 was prepared by Technical Committee ISO/TC 48, Laboratory glassware and related apparatus. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. International Organization for Standardization, 1987 Printed in Switzerland Copyright International Organization for Standardization No reproduction or networking permitted without license from IHS Not for Resale ISO 7884-7 : 1987 (E) INTERNATIONAL STANDARD Glass - Viscosity and viscometric fixed points Part 7 : Determination of annealing point and strain point by beam bending Introduction temperature and viscosity-time relationships besides the fixed points. In this part of IS0 7884, however, the device and procedure are lnternational Standard ISo 7884, Glass Viscosity and restricted to the fixed-point determination. iviscometric fixed points, consists of the following separate parts : 2 Field of application Part 1: Principles for determining viscosity and viscometric This method is applicable to all glasses of normal bulk-produc fixed points. tion compositions, unless the preparation of suitable test Part 2 : Determination of viscosity by rotation viscometers. specimens is hindered by special reasons. The method is par- ticularly suited for glasses that for one reason or another are Part 3: Determination of viscosity by fibre elongation not adaptable for flame-working. viscometer. Part 4 : Determination of viscosity by beam bending. Generally, the annealing point and strain point fallinto a range of temperature between 300 and 800 oC, depending on the Part 5: Determination of working point by sinking bar viscometer. type of glass. Part 6 : Determination of softening point. Reference Part 7 : Determination of annealing point and strain point by beam bending. IEC Publication 584-1, Thermocouples - Part 1: Reference Part8: Determination of (dilatometric) transformation tables. temperature. 4 Definitions Scope For the purposes of this part of ISO 7884, the following defini- tions apply. ThispartofiSO7884specifiesamethodof determiningthean- nealing point and the strain point of a glass by beam bending. These values have been found useful for specifying the cooling 4.1 annealing range:The range of temperature in which stresses in glass articles can be relieved at a commercially programme in the production of glassware.The annealing desirable rate. point and strain point include a well-defined temperature decrease during the measurement. For purposes of comparingglasses,the annealingrangeis assumedto correspondtothetemperaturesbetweenthean- At temperatures corresponding to the annealing and strain