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1、BRITISH STANDARD BS 1344-17: 1998 ISO 2745:1998 Methods of testing vitreous enamel finishes Part 17: Resistance to hot sodium hydroxide solution ICS 25.220.50 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1344-17:1998 This British Stand
2、ard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 July 1998 BSI 04-1999 ISBN 0 580 30029 3 Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffie
3、ldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1344-17:1998 BSI 04-1999i Contents Page National forewordii Foreword2 1Scope1 2Normative references1 3Principle1 4Reagents1 5Apparatus1 6Test specimens1 7Procedure2 8Expression of results2 9Test report2 Annex A (
4、informative) BibliographyInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1344-17:1998 ii BSI 04-1999 National foreword This part of BS 1344, Methods of testing vitreous enamel finishes, reproduces ISO 2745:1998 and imple
5、ments it as the UK national standard. It supersedes BS 1344-17:1975 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee STI/36, Vitreous enamel coatings, which has the responsibility to: aid enquirers to understand the text; present to the responsible int
6、ernational/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to i
7、ts secretary. The standard is now published in 22 parts: Part 1: Determination of resistance to thermal shock of coatings on articles other than cooking utensils and fabricated sheet steel components; Part 2: Resistance to citric acid at room temperature; Part 3: Determination of resistance to sulph
8、uric acid at room temperature; Part 4: Resistance to abrasion (obsolescent); Part 5: Determination of resistance to hot detergent solutions used for washing textiles; Part 6: Resistance to alkali; Part 7: Determination of resistance to heat; Part 8: Determination of resistance to boiling citric acid
9、; Part 9: Determination of resistance to boiling water and water vapour; Part 10: Determination of resistance to condensing hydrochloric acid vapour; Part 11: High voltage test for enamelled articles for service under highly corrosive conditions; Part 12: Production of specimens for testing coatings
10、 on sheet steel; Part 13: Production of specimens for testing coatings on cast iron; Part 14: Apparatus for testing with acid and neutral liquids and their vapours; Part 15: Apparatus for testing with alkaline liquids; Part 16: Resistance to thermal shock of coatings on cooking utensils; Part 17: Re
11、sistance to hot sodium hydroxide solution; Part 18: Determination of fluidity behaviour Fusion flow test; Part 19: Apparatus for determination of resistance to hot detergent solutions used for washing textiles; Part 20: Low voltage test for detecting and locating defects; Part 21: Determination of t
12、he resistance of vitreous enamelled articles to impact Pistol test; Part 22: Determination of resistance to thermal shock of coatings for fabricated sheet steel components such as burners and pan supports for cookers. Various steels suitable for vitreous enamelling are described in BS EN 10209 and i
13、n BS 1449-2. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1344-17:1998 BSI 04-1999 iii Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI S
14、tandards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsib
15、le for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, the ISO title page, page ii, pages 1 and 2, an inside back cover and a back co
16、ver. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Cop
17、y: sheffieldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1344-17:1998 ii BSI 04-1999 Foreword ISO (the International Organization for Standardization) i
18、s a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represe
19、nted on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards
20、 adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 2745 was prepared by Technical Committee ISO/TC 107, Metallic and other ino
21、rganic coatings, Subcommittee SC 6, Vitreous and porcelain enamels. This second edition cancels and replaces the first edition (ISO 2745:1973), which has been technically revised. Annex A of this International Standard is for information only. Descriptors: Non-metallic coatings, protective coatings,
22、 enamels, vitreous enamels, porcelain enamels, tests, chemical tests, sodium hydroxide, alkali resistance tests, high temperature tests. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1344-17:1998 BSI 04-19991 1 Scope This International
23、Standard specifies a method of test for determining the resistance of flat surfaces of vitreous and porcelain enamels to a hot solution of sodium hydroxide. NOTE This method of test may also be used for determining the chemical resistance of enamels to other alkaline agents and can also be carried o
24、ut at temperatures below 80 C, but this should be stated in the test report. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. A
25、ll standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standar
26、ds. ISO 1042:, Laboratory glassware One-mark volumetric flasks1). ISO 2723:1995, Vitreous and porcelain enamels for sheet steel Production of specimens for testing. ISO 2724:1973, Vitreous and porcelain enamels for cast iron Production of specimens for testing. ISO 2734:1997, Vitreous and porcelain
27、enamels Apparatus for testing with alkaline liquids. ISO 3696:1987, Water for analytical laboratory use Specification and test methods. 3 Principle Enamelled test specimens are exposed to attack by a sodium hydroxide solution, c(NaOH) = 0,1 mol/l, at 80 C for 24 h (1 d). The loss in mass is determin
28、ed and used to calculate the rate of loss in mass per unit area. NOTEThe lower rate of loss in mass per unit area, the higher the resistance of the vitreous and porcelain enamel to hot sodium hydroxide. 4 Reagents Use only reagents of recognized analytical grade and only distilled water, or water of
29、 equivalent purity (grade 3 water complying with ISO 3696). 4.1 Sodium hydroxide solution, c(NaOH) = 0,1 mol/l Dissolve 4 g of NaOH in distilled water and make up to 1 l. To prevent this test solution from absorbing carbon dioxide, ensure that it is kept in a sealed container. Use a fresh aliquot of
30、 solution for each test. NOTEFor preparing the test solution it is advisable to use a standard phial (USA: vial) with 4 g of NaOH. Place the standard phial on a one-mark volumetric flask (see 5.7) and tap the upper and lower membranes of the standard phial with a blunt glass rod to allow the standar
31、d solution to fall into the flask. Rinse the glass rod and the standard phial into the flask with carbon dioxide-free distilled water and make the solution up to 1 l. 4.2 Acetic acid solution, concentration 5 % (V/V), for cleaning the test specimens. 4.3 Cleaning medium, for example ethanol, (C2H5OH
32、), or water containing a few drops of liquid detergent, for cleaning and degreasing the test specimens. 5 Apparatus 5.1 Test apparatus, complying with ISO 2734. 5.2 Thermostatically controlled liquid bath (containing demineralized or distilled water), incorporating a stirrer or other rotating device
33、 for use with one or more pieces of test apparatus. It shall be capable of being sealed against loss by evaporation and of allowing temperatures up to 100 C to be kept constant to 0,1 C. 5.3 Thermometer, calibrated and graduated in 0,1 C steps, for use with the thermostatically controlled liquid bat
34、h. 5.4 Drying oven, capable of maintaining temperatures of at least 130 C. 5.5 Desiccator, internal diameter of at least 200 mm. 5.6 Polypropylene bottle, of 1 000 ml capacity and capable of being closed. 5.7 One-mark volumetric flask, 1 000 ml capacity and complying with class A of ISO 1042. 5.8 Fu
35、nnel, of maximum diameter 70 mm. 5.9 Balance, accurate to 0,2 mg. 5.10 Sponge, soft. 6 Test specimens 6.1 Prepare at least two test specimens in accordance with the International Standards for the appropriate base metal, i.e. use circular test specimens in accordance with ISO 2723 and ISO 2724, for
36、sheet steel and cast iron, respectively. 6.2 Rinse the test specimens with water. If necessary, use a cleaning and degreasing medium (4.3). Then dry the test specimens for 2 h in the drying oven (5.4) at 110 C 5 C. Allow the test specimens to stand for at least 2 h in the desiccator (5.5) and finall
37、y, weigh the test specimens to the nearest 0,2 mg (starting mass). 1) To be published. (Revision of ISO 1042:1983). Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 06:21:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1344-17:1998 2 BSI 04-1999 7 Procedure 7.1 Carry out one determination for
38、 each test specimen. 7.2 Place the test specimen in the protective envelope of the test apparatus (5.1) such that the side with the cover coat enamel faces the opening. Fix the test specimen in the test apparatus (5.1) such that the side with unprotected cover coat faces the interior of the apparatu
39、s. Screw down the six wing-nuts evenly to ensure that the test apparatus is watertight. NOTEDamage to the enamel on weak or distorted test specimens in the apparatus can be avoided by placing a rubber ring between the protective envelope and the flange plate of the apparatus. 2 mm to 3 mm thick rubb
40、er rings made of heat-resistant rubber are suitable for this purpose (inside diameter 80 mm, outside diameter 100 mm, Shore hardness A/70/1 according to ISO 868). 7.3 Place the sealed test apparatus in the thermostatically controlled liquid bath (5.2), heated to 80 C 1 C, such that the filling nozzl
41、e juts out over the water bath by approximately 10 mm. Leave the test apparatus in this position for at least 10 min until it is filled with the test solution (see 7.4). NOTEThe test apparatus may also be placed in the cold thermostatically controlled liquid bath and heated to 80 C 1 C. 7.4 Heat abo
42、ut 1 000 ml of the test solution (4.1) to 80 C 1 C in the polypropylene bottle (5.6) and then pour it through the funnel (5.8) into the test apparatus which is still in the thermostatically controlled liquid bath. Seal the cylinder of the test apparatus (5.1) with the stopper and cover the opening o
43、f the liquid bath. With its bulb close to the test apparatus in the liquid bath at half the height of the test apparatus, use the thermometer (5.3) to check that the test temperature is maintained at 80 C 1 C throughout the test. If two or more pieces of test apparatus are used, place the thermomete
44、r between them. 7.5 24 h (1 d) after pouring the test solution into the test apparatus, remove the test apparatus from the bath using hooks; pour away the test solution and rinse the interior of the test apparatus with distilled or demineralized water. Take the test specimen out of the protective en
45、velope and wipe it three times with the sponge (5.10) previously soaked in cold acetic acid solution (4.2), then rinse it with cold water. Carefully remove any residues of the protective envelopes from the test specimen, then dry the latter for 2 h in the drying oven (5.4) at 110 C 5 C. After a furt
46、her 2 h in the desiccator (5.5) weigh the test specimen to the nearest 0,2 mg (final mass). 7.6 Disregard test specimens which show defects such as pinholes down to the metal, chipped edges or edge corrosion and test a corresponding number of new specimens. 8 Expression of results 8.1 Calculate the
47、rate of loss in mass per unit area for a test time of 24 h (1 d), v24, expressed in grams per square metre per hour, using the following equation: where 8.2 Calculate the arithmetic mean of the two individual values. If the difference between the individual values of the rate of loss in mass per uni
48、t area, v24, exceeds 30 % of the arithmetic mean, conduct a further test. Calculate a new arithmetic mean. 9 Test report The test report shall include the following information: a) reference to this International Standard, i.e. “determined in accordance with ISO 2745:1998”; b) identification of the
49、enamel tested; c) the rate of loss in mass per unit area, v24, expressed in grams per square metre per hour, rounded to the nearest 1 103g m2 h1, the arithmetic mean and the number of single values; d) any deviation from the test procedure specified (see note in clause 1). .(1) m is the loss in mass of the test specimen (starting mass minus final mass), in grams; 50is the exposed area of the test specimen, in square centimetres; 24is the exposure time of the test specimen to