1、BRITISH STANDARD BS 4966:1991 Incorporating Amendment No. 1 Specification for Silica refractories for use in coke ovensBS4966:1991 This British Standard, having been prepared under the directionof the Refractory Products Standards Policy Committee, was published underthe authority of the BoardofBSI
2、and comes into effect on 28 February 1991 BSI 03-2000 First published as BS 4966-1 July1973 Second edition May 1982 Third edition as BS 4966 February1991 The following BSI references relate to the work on this standard: Committee reference RPM/10 Draft for comment 89/38159 DC ISBN 0 580 18753 5 Comm
3、ittees responsible for this British Standard The preparation of this British Standard was entrusted by the Refractory Products Standards Policy Committee (RPM/-) to Technical Committee RPM/10, upon which the following bodies were represented: British Ceramic Research Ltd. British Coal Corporation Br
4、itish Metallurgical Plant Constructors Association British Steel Industry Coke Oven Managers Association Institute of Refractories Engineers Refractories Association of Great Britain Amendments issued since publication Amd. No. Date Comments 9698 September 1997 Indicated by a sideline in the marginB
5、S4966:1991 BSI 03-2000 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Classification 1 4 Sampling 1 5 Inspection 2 6 Chemical composition and physical properties 2 7 Dimensional tolerances 3 8 Appearance 3 Appendix A Testing 6 Appendix B Powder dens
6、ity 6 Appendix C Distribution of brick sizes within the tolerance band 6 Appendix D Selected tables from BS 6065:1981 7 Figure 1 Permitted edge damage on class A faces 5 Figure 2 Permitted corner damage on class A faces 5 Figure 3 Permitted edge damage on class B faces 5 Figure 4 Permitted corner da
7、mage on class B faces 5 Figure 5 Permitted edge damage on class C faces 5 Figure 6 Permitted corner damage on class C faces 5 Table 1 Schedule of composition and physical properties when selection is based on procedures using a guaranteed value for the mean 1 Table 2 Schedule of composition and phys
8、ical properties when selection is based on procedures employing a guaranteed value limit 2 Table 3 Schedule for cold crushing strength using test limit values 2 Table 4 Number of samples for cold crushing strength test for different batch sizes 2 Table 5 Tolerances on dimensions 3 Table 6 Single sam
9、pling plans in the case of a guaranteed value for the mean 7 Table 7 Single sampling plans with a fixed unilateral limit for the individual values and a known standard deviation 7 Publication(s) referred to Inside back coverBS4966:1991 ii BSI 03-2000 Foreword This British Standard has been prepared
10、under the direction of the Refractory Products Standards Policy Committee. It supersedes BS4966-1:1982 which is withdrawn. Attention is drawn to BS6886:1987 “Specification for alumina-silicate refractories for use in coke ovens”. The two specifications have been written in the same style. NOTEFor th
11、e convenience of readers, selected tables from BS6065:1981 are given inAppendix D. 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 a British Standard does not of itsel
12、f confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 8, 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 indi
13、cated in the amendment table on the inside front cover.BS4966:1991 BSI 03-2000 1 1 Scope This British Standard specifies classification, the chemical and physical requirements, and tolerances on dimensions and defects, for silica refractories that contain not less than93% silica and are for use in c
14、oke oven construction. It specifies the methods of sampling, testing and analysis to be used for bricks and shapes of silica material. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard, the def
15、initions given in BS3446 apply, together with the following. surface crazing a rectilinear network of fine hairline microcracks, generally intergranular and entirely confined to within5mm of the brick face NOTEIt is not usually visible to the naked eye on clean as-fired brick faces, but is revealed
16、by a surface cover of dark powder or dust. 3 Classification 3.1 Two types of silica refractories are specified: type1 and type2 (dense). These shall be defined by the properties given inTable 1, Table 2 and Table 3. 3.2 Two categories of brick shall be defined by differences in manufacturing process
17、es: category Pbricks are pressed and category M bricks are rammed or hand moulded. 3.3 For the purposes of this British Standard the faces of the bricks shall be classified as follows: class A: faces in contact with the coal; class B: faces in contact with the gases; class C: other faces. NOTEClassi
18、fication of the faces is designated by the customer and bricks may have a combination of classified faces. 4 Sampling 4.1 General When a sampling plan from BS6065 is used (see 4.2 and 4.3), it shall be stated whether the acceptance is to be based on either a mean value with a standard deviation (see
19、Table 1) or on a limiting quality value accompanied by an acceptance quality level (AQL) (seeTable 2). NOTE 1Since the use of this specification will involve the determination of the suitability of material supplied for a specific purpose, the importance of sampling cannot be overemphasized. NOTE 2G
20、uidance on the use of BS6065 is given in BS6434. 4.2 Sampling for testing control properties Sampling for testing control properties (seeclause6) shall be carried out in accordance with one of the methods given in BS6065. 4.3 Sampling for measurement of attributes Sampling for measurement of attribu
21、tes (seeclauses7 and 8) shall be carried out in accordance with a fixed sampling plan. NOTESuch a plan should be agreed between the manufacturer and the purchaser and may be one of the methods given inBS6065. Table 1 Schedule of composition and physical properties when selection is based on procedur
22、es using a guaranteed value for the mean a Properties Type of brick Silica type 1 Silica type 2 (dense) Mean (4 G ) Standard deviation (B) Mean (4 G ) Standard deviation (B) Apparent porosity (%) Category P 23.25 1.5 20.25 1.5 Category M 25.75 1.5 22.25 1.5 Powder density (g/cm 3 ) (seeAppendix B) 2
23、.33 0.01 2.33 0.01 Permanent linear change at 1500 C (%) 0.3 0.1 0.3 0.1 Refractoriness-under-load ( C) (Load of0.35 MPa 0.006 MPa) 1640 15 1640 15 Silica content (%) 94.5 1.0 94.5 1.0 a The mean (4 G ) and the standard deviation (B) as used in the tables represent the mean and the standard deviatio
24、n of the population as a whole. The sample mean (x) and the sample standard deviation (s) may be related to the values inTable 6.BS4966:1991 2 BSI 03-2000 Table 2 Schedule of composition and physical properties when selection is based on procedures employing a guaranteed value limit a Table 3 Schedu
25、le for cold crushing strength using testing limit values (see6.3) 5 Inspection An area illuminated to a minimum of500lux shall be provided for inspection purposes. 6 Chemical composition and physical properties 6.1 General The composition and physical properties of silica refractories shall be as gi
26、ven in eitherTable 1 orTable 2, andTable 3 when tested in accordance with the test methods given inAppendix A. 6.2 Control properties The control properties shall be selected from those shown inTable 1, Table 2 and Table 3. Those shown inTable 1 and Table 2 shall be used for acceptance testing in ac
27、cordance with BS6065. NOTEWherever possible, a maximum of three control tests should be agreed. 6.3 Cold crushing strength test The number of samples for any batch size in the cold crushing strength test (seeTable 3) shall be selected in accordance withTable 4. No individual value shall lie outside
28、the limits given. The batch mean shall be greater than or equal to the guaranteed mean. The manufacturer shall be in a position to provide individual values when requested by the purchaser. Table 4 Number of samples for cold crushing strength test for different batch sizes Properties Type of brick S
29、ilica type 1 Silica type 2 (dense) Limit (T) Standard deviation (B) Limit (T) Standard deviation (B) Apparent porosity (%) Category P k 25.75 1.5 k 22.75 1.5 Category M k 28.5 1.5 k 24.75 1.5 Powder density (g/cm 3 ) (seeAppendix B) k 2.35 0.01 k 2.35 0.01 Permanent linear change (%) k 0.5 0.1 k 0.5
30、 0.1 Refractoriness-under-load ( C) (Load of0.35 MPa 0.006 MPa) U 1620 15 U 1620 15 Silica content (%) U 93 1.0 U 93 1.0 a These values are to be used in conjunction withTable 7 and are based on an AQL of 4%. Property Type of brick Silica type 1 Silica type 2 Upper limit Guaranteed mean Lower limit
31、Upper limit Guaranteed mean Lower limit Cold crushing strength (MN/m 2 ) Category P 100 32 22 100 35 24 Category M 100 31 20 100 33 22 Total mass of batch, t Number of samples 1 to 9 6 10 to 99 8 100 to 199 12 200 to 299 16 300 to 399 20 400 to 499 24 U 500 28BS4966:1991 BSI 03-2000 3 7 Dimensional
32、tolerances Linear dimensional tolerances shall be as given inTable 5 when tested in accordance with the test methods given inAppendix A. The calculated values of tolerance shall be rounded up to the next millimetre. The distribution of bricks within the upper and lower limits of the tolerance shall
33、be such that a satisfactory construction is possible (seeAppendix C), whilst taking into account that an acceptable joint thickness is possible. Where requested by the purchaser at the time of ordering, the manufacturer shall provide a production control chart, or histogram, of inspected and measure
34、d controlled dimensions for each batch presented for inspection. NOTE 1When a plan for sampling by attributes is used (4.3), an AQL should be agreed, as described in BS6065. NOTE 2The control dimensions, used for acceptance testing in accordance with BS 6065 (or other agreed plan), should be selecte
35、d by agreement (see also6.2). A maximum of three control dimensions are normally agreed, but for shapes with included gas ports or recesses more may be necessary. NOTE 3The grouping of bricks into size intervals (size banding) may be found helpful for certain shapes. If batches of bricks are found o
36、n inspection to have dimensions that are consistently close to the tolerance limits noted inTable 5, then these batches shall be clearly marked by the manufacturer to permit subsequent identification and the manufacturer shall be in a position to notify the customer before despatch. Table 5 Toleranc
37、es on dimensions 8 Appearance 8.1 General The requirements given in8.2 shall not be taken as representing the average quality of the batch, but only as a means of defining acceptance limits. NOTE 1An agreed sampling plan (see clause4) should be adopted for checking the appearance of each batch of br
38、icks. When a plan for sampling by attributes is used (4.3), an AQL should be agreed, as described in BS 6065. NOTE 2The bricks should be compact and of evenly burnt homogeneous structure; they should have full firm corners and all arrises and tongues should be firm and strong. When broken, bricks sh
39、ould show an even texture and be free from deleterious cracks, voids and laminations. NOTE 3Certain laminations may be revealed by tapping the as-formed surface with a50g or100g steel hammer. 8.2 Limits on defects of external appearance 8.2.1 General Limits on defects of external appearance shall co
40、mply with8.2.2 to8.2.5 when tested in accordance with the test methods givenAppendix A. 8.2.2 Damage to corners and edges The maximum dimensions of damage to the corners and edges of class A, B and C faces shall be as shown inFigure 1 toFigure 6. Where faces of different classes adjoin on a brick, t
41、he maximum dimensions of damage to the corners and edges where they join shall be as shown for the highest class face. In this connection, A shall be taken to be the highest class face and C the lowest class face. 8.2.3 Maximum number of defects per brick The maximum number of defects per brick shal
42、l be as follows: class A face: 1 edge and 1 corner defect; class B face: 1 edge and 1 corner defect; class C face: 2 edge and 2 corner defects. Where a class C face adjoins a class A or B face, the maximum number of defects shall be in accordance with the requirements of the higher class face. Defec
43、ts to corners and edges shall be separated by a minimum distance of25mm. Identification marks shall be clearly legible and shall not be on class A faces. 8.2.4 Cracks 8.2.4.1 Width The maximum crack width shall be not greater than0.2mm. NOTEThe width of surface cracks may be measured using a hand ma
44、gnifier incorporating a measuring device. Dimension Limits of tolerance Linear dimensions: k 200 mm 2 mm 201 mm to 300 mm 3 mm 301 mm to 400 mm 4 mm 400 mm 5 mm Shape distortion, arch on forming depth: Dimensions k 200 mm 2 mm Dimensions 200 mm 1% Shape warpage 2 mm or 0.5% whichever is the greatest
45、 Shape twist 2 mmBS4966:1991 4 BSI 03-2000 8.2.4.2 Length The maximum crack length shall be as follows: class A face: 25mm for any one crack with the total sum of crack lengths on the face not exceeding 50mm; class B face: 50 mm for any one crack with the total sum of crack lengths on the face not e
46、xceeding 100mm; class C face: 75 mm for any one crack with the total sum of crack lengths on the face not exceeding 150mm. For a continuous crack extending over two or more faces, the length on any classified face shall not exceed the limits stated above and the total length shall not exceed 50mm. N
47、OTESurface crazing (see clause2) is not considered as a crack defect. 8.2.5 Craters The maximum dimensions for craters shall be as follows: class A face: diameter of 3 mm and a depth of3mm; class B face: diameter of 6 mm and a depth of3mm; class C face: diameter of 8 mm and a depth of5mm, providing
48、they are more than 15mm from an adjacent class A or class B face. Craters that are within15mm from one of these faces are to be assessed under the criteria for the respective face craters. NOTE 1Surface conditioning. Class B and C faces may be ground or cut providing that the brick complies with the
49、 tolerances and limits specified. NOTE 2Hidden craters may be revealed in discoloured areas by lightly tapping such areas with the flat face of a50g or 100g steel hammer.BS4966:1991 BSI 03-2000 5 Figure 1 Permitted edge damage on class A faces Figure 2 Permitted corner damage on class A faces Figure 3 Permitted edge damage on classBfaces Figure 4 Permitted corner damage on classBfaces Figure 5 Permitted edge damage on class C faces Figure 6 Permitted corner damage on class C facesBS4966:1991 6 BSI 03-2000 Appen
