1、BRITISH STANDARD BS 6200-3.8.5: 1991 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.8 Determination of carbon Subsection 3.8.5 Cast iron and pig iron: gravimetric method for the determination of non-combined carbonBS6200-3.8.5:1991 This British St
2、andard, having been prepared under the directionof the Iron and Steel Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 29 November1991 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Dr
3、aft for comment 91/35213 DC ISBN 0 580 19946 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Iron and Steel Standards Policy Committee (ISM/-) to Technical Committee ISM/18, upon which the following bodies were represented: BCIRA Briti
4、sh Steel Industry Department of Trade and Industry (Laboratory of the Government Chemist) Ferro Alloys and Metals Producers Association Ministry of Defence Amendments issued since publication Amd. No. Date CommentsBS6200-3.8.5:1991 BSI 09-1999 i Contents Page Committees responsible Inside front cove
5、r Foreword ii 1 Scope 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Sampling 1 6 Procedure 1 7 Calculation and expression of results 1 8 Test report 2 Publication(s) referred to Inside back coverBS6200-3.8.5:1991 ii BSI 09-1999 Foreword This Subsection of BS6200 has been prepared under the direction
6、of the Iron and Steel Standards Policy Committee and supersedes method2 for the determination of graphitic and combined carbon in BSI Handbook No. 19, to which it is technically equivalent. It should be used in conjunction with BSEN10036. BS 6200 is a multipart British Standard covering all aspects
7、of the sampling and analysis of iron, steel and other ferrous metals. A list of contents, together with general information, is given in Part1. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct appl
8、ication. 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 and ii, pages 1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright da
9、te) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6200-3.8.5:1991 BSI 09-1999 1 1 Scope This Subsection of BS 6200 describes a gravimetric method for the determination of non-combined carbon in cast iron and pig iron. The method i
10、s applicable to non-combined carbon contents equal to or greater than0.1% (m/m). It is to be used in conjunction with BSEN10036. NOTEThe titles of the publications referred to in this Subsection of BS6200 are listed on the inside back cover. 2 Principle The test portion is dissolved in dilute nitric
11、 acid in which non-combined carbon is insoluble. The residue is collected on a refractory filter, washed, dried, and oxidized by combustion in oxygen at high temperature. The carbon dioxide evolved is absorbed in a weighed absorption bulb, and the non-combined carbon calculated from the increase in
12、mass. 3 Reagents During the analysis, use only reagents of recognized analytical grade and only grade3 water as specified in BS3978. 3.1 Hydrochloric acid, diluted1+19. To500mL of water, add 50 mL of hydrochloric acid, density =1.16g/mL to1.18g/mL, mix, dilute to1L and mix. 3.2 Hydrofluoric acid, 40
13、% (m/m). 3.3 Nitric acid, diluted2+3. To600mL of water, add400mL of nitric acid, =1.42g/mL, and mix. 3.4 Sodium hydroxide solution. To1L of water, with stirring, add10g of sodium hydroxide. Store in a stoppered polyethylene bottle. 3.5 Other reagents, as specified in clause4 of BSEN10036. 4 Apparatu
14、s 4.1 Ordinary laboratory apparatus 4.2 Crucible. A silica grid crucible with a synthetic ceramic fibre pad, or a porous refractory thimble, carbon-free, and in either case of a diameter suitable for the combustion apparatus of BSEN10036, and for use at a high temperature. 4.3 Apparatus, as specifie
15、d in clause5 of BSEN10036. 5 Sampling Carry out sampling in accordance with BS1837. NOTEBS 6200-2, which will supersede BS1837, is currently in preparation. On its publication this Subsection will be amended to include sampling in accordance with BS6200-2. 6 Procedure 6.1 Test portion Weigh, to the
16、nearest0.001g, a test portion of1g to2g in the form of solid samples cut from plates approximately2mm thick and broken up with pliers, to avoid the possibility of errors arising from segregation. 6.2 Blank test In parallel with the determination, and following the same procedure, carry out a blank t
17、est using the same quantities of all reagents and the same apparatus. 6.3 Determination Place the test portion in a400mL tall-form beaker. Add60mL of nitric acid (3.3), and warm gently until dissolution of the sample appears complete except for particles of graphite and silica. Add1mL of hydrofluori
18、c acid (3.2), heat to boiling and boil for5min. Cover the beaker and continue to heat at just below boiling point for a further45min. When chromium is present increase the heating time to at least1h. Do not allow the volume of the solution to fall below40mL and, if necessary, make further additions
19、of nitric acid (3.3). Boil for5min and filter by suction through the silica crucible (4.2). Wash the beaker and filter three times with hot water, three times with sodium hydroxide (3.4), three times with hydrochloric acid(3.1), and finally six times with hot water. Remove surplus moisture by suctio
20、n, and dry the crucible and contents for1h at105 C to110 C. Transfer to the combustion tube and, without the addition of flux, determine the non-combined carbon by combustion at900 C to1000 C in accordance with the procedure described in BSEN10036. 7 Calculation and expression of results Calculate t
21、he non-combined carbon content, expressed as a percentage by mass, from the equation: non-combined carbon = where m 1is the mass of carbon dioxide from the test portion (in g); m 0is the mass of carbon dioxide from the blank test (in g); m is the mass of the test portion (in g). 27.29m 1 m 0 () m -B
22、S6200-3.8.5:1991 2 BSI 09-1999 NOTEThe combined carbon content of the test sample may be calculated by subtracting the non-combined carbon content, determined in accordance with this Subsection of BS6200, from the total carbon content, determined in accordance with BSEN10036, on test portions taken
23、from adjacent positions on the same sawn piece or milled pin. 8 Test report The test report shall include the following information: a) all information necessary for the identification of the sample, the laboratory and the date of analysis; b) the method used by reference to this Subsection of BS620
24、0; c) the results, and the form in which they are expressed; d) any unusual features noted during the determination; e) any operation not specified in this British Standard, or any optional operation which may have influenced the results.BS6200-3.8.5:1991 BSI 09-1999 Publication(s) referred to BS 18
25、37, Methods for the sampling of iron, steel, permanent magnet alloys and ferro-alloys. BS 3978, Specification for water for laboratory use. BS 6200, Sampling and analysis of iron, steel and other ferrous metals. BS 6200-1, Introduction and contents 1) . BS 6200-2, Method of sampling and sample prepa
26、ration 2) . BS EM 10036, Chemical analysis of ferrous materials. Determination of total carbon in steels and irons. Gravimetric method after combustion in a stream of oxygen. BSI Handbook No. 19 Methods for the sampling and analysis of iron, steel and other ferrous metals 1) . 1) Referred to in the
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