BS 1902-4 6-1985 Methods of testing refractory materials - Properties measured under an applied stress - Determination of resistance to abrasion at ambient temperature (abradabilit.pdf

1、BRITISH STANDARD BS1902-4.6: 1985 Methods of testing Refractory materials Part 4: Properties measured under an applied stress Section 4.6 Determination of resistance to abrasion at ambient temperature (abradability index at ambient temperature) (method1902-406) UDC666.76.017:620.178.162BS1902-4.6:19

2、85 This British Standard, having been prepared under the directionof the Refractory Products Standards Committee, was published under the authorityof the Board of BSI andcomes into effect on 28February1985 BSI03-1999 The following BSI references relate to the work on this standard: Committee referen

3、ce RPM/1 Draft for comment83/77597DC ISBN 0 580 14305 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Refractory Products Standards Committee (RPM/-) to Technical Committee RPM/1, upon which the following bodies were represented: Briti

4、sh Ceramic Research Association British Steel Industry Electricity Supply Industry in England and Wales Engineering Equipment and Materials Users Association Institute of Refractories Engineers Refractories Association of Great Britain Refractory Contractors Association Society of Glass Technology A

5、mendments issued since publication Amd. No. Date of issue CommentsBS 1902-4.6:1985 BSI 03-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Designation 1 3 Definition 1 4 Principle 1 5 Apparatus 1 6 Assembly of abrasion apparatus 1 7 Correction factor C and calib

6、ration of abrasion apparatus 2 8 Preparation of test pieces 2 9 Test procedure (abradability index) 2 10 Sieving and replacement of abrasive 3 11 Calculation of abradability index 3 12 Test report 3 Figure 1 Assembly of abradability apparatus 4 Figure 2 Details of abradability apparatus 5 Publicatio

7、ns referred to Inside back coverBS1902-4.6:1985 ii BSI 03-1999 Foreword This Section of BS1902-4 has been prepared under the direction of the Refractory Products Standards Committee. It supersedes Appendix C of BS1902-1A:1966 which is to be deleted by amendment. The method of test described in this

8、Section measures the same property of the material under test as that described in BS1902-4.7 but at ambient or room temperature instead of at an elevated temperature of up to1400C. The method is based on the Morgan-Marshall tests 1) . A British Standard does not purport to include all the necessary

9、 provisions of a contract. Users of British Standards are responsible 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 and ii, pages1 to6

10、, 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 amendment table on theinside front cover. 1) F. H. Aldred, A. Elliott and K. W. Cowling. Brit. Ceram. Soc., 1955, 54, 239.BS 1902-4.6:1

11、985 BSI 03-1999 1 NOTEThis Section is to be read in conjunction with BS1902-4.0 2)“Introduction” and BS1902-3.1 “Guidance on sampling”. Section4.0 sets out the general arrangement of BS1902 and lists the Sections of Part4. 1 Scope This Section of BS1902-4 describes a method for determining the resis

12、tance to abrasion (abradability index) of bricks or blocks of refractory materials at ambient temperature. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Designation The method of determination of resistance to abrasion described in this Sectio

13、n is referred to by the following designation: Method1902-406. 3 Definition For the purposes of this Section of BS1902 the following definition applies. abradability index an index which represents100times the volume in centimetres cubed of material abraded from a test piece which has been subjected

14、 to bombardment by brown fused alumina grain for a specified time under specified conditions 4 Principle The loss in mass of a dried test piece is measured when it is subjected to the abrasive action of a specific quantity of calibrated brown fused alumina grain. The abradability index of the test p

15、iece in terms of volume loss is obtained by calculation using the measured loss in mass, a calibration correction derived from the standardization of the abrasion apparatus and alumina grain, the bulk density of the test piece and a multiplication factor of100. 5 Apparatus 5.1 Abrasion apparatus, as

16、 in Figure 1 and Figure 2 and consisting of an electric blower with variable transformer control, a calibrated venturi in which the abrasive grain is entrained in an air stream, a manometer, an abrasion chamber incorporating a test piece holder and an exhaust system to recover the abrasive grain. Th

17、e electric blower shall be capable of maintaining a pressure differential of at least250mm water pressure between the venturi and abrasion chamber when abrasive is running through the apparatus. The manometer, calibrated to measure a pressure differential of250mm water pressure, shall be connected t

18、o a tapping point at the air inlet to the venturi and another point located at the top of the abrasion chamber. The test piece holder and a suitable exhaust system shall be anchored to the chamber cover and shall incorporate means of adjusting the position of the test piece as described in clause6.

19、5.2 A balance, with an accuracy of 0.01g. 5.3 Scales, suitable for weighing6.35kg of alumina grain to an accuracy of 0.01kg. 5.4 Drying oven, with control for drying at110C. 5.5 Stop watch. 5.6 Brown fused alumina grain, angular grain of between1.7mm and7104m size grading. 5.7 Calibrated carbon bloc

20、ks, of specified loss in mass when subjected to abrasion under specified test conditions. NOTESuitable carbon blocks (5.7), a calibrated venturi (5.1) and engineering drawings for the abrasion apparatus are available from the British Ceramic Research Association Ltd, Penkhull, Stoke-on-Trent. 5.8 Te

21、st sieves, of nominal aperture size1.7mm and7104m in accordance with BS410. 6 Assembly of abrasion apparatus The abrasion apparatus shall be assembled as shown in Figure 1 and Figure 2 and as follows. a) The test piece holder shall be adjusted so that when the lid of the abrasion chamber is bolted i

22、n position the75mm 50mm face of a test piece is inclined at45 to the centre line of the venturi and the distance between the centre of this face and the outlet of the venturi is38mm 2mm. NOTEThis distance may be adjusted by inserting a metal plate between either the flange of the venturi and the abr

23、asion chamber or the test piece holder and the lid of the chamber. b) Adjustments shall be made to the alignment of the test piece holder and venturi so that in repeated trial runs the abrasive impacts centrally on the target area. c) Seals between the lid and abrasion chamber, the venturi flange an

24、d abrasion chamber shall be airtight (see Figure 2). d) Connections between the manometer, venturi and manometer-abrasion chamber shall be airtight and clipped. e) Trial runs shall be carried out to find the voltage or transformer setting necessary to give a pressure difference of2505mm of water pre

25、ssure across the manometer while the abrasive is passing through the apparatus. 2) In preparation.BS1902-4.6:1985 2 BSI 03-1999 NOTEMethods of adjustment should be such that when once set up, further adjustment is not necessary after changing the test piece. 7 Correction factor C and calibration of

26、abrasion apparatus 7.1 General A new or serviced abrasion apparatus shall be checked for correct operation using standardized carbon blocks (see5.7) and fresh alumina grain. If, after assembly of abrasion apparatus in accordance with clause6, the value of loss in mass for calibrated carbon blocks is

27、 not obtainable, then a correction factor shall be applied in subsequent tests. NOTEWith continued use of the apparatus, there will be a loss of abrasive power of the alumina grain and gradual wear of the venturi so that the apparatus will require recalibration at suitable intervals to obtain a new

28、correction factor which incorporates these changes. 7.2 Procedure for determining correction factor C Weigh6.35 0.01kg of dry, freshly sieved brown fused alumina grain and place in the hopper of the abrasion apparatus. Weigh a dried calibrated carbon test piece to the nearest0.01g, place in the test

29、 piece holder and secure the lid to the abrasion chamber. Adjust the voltage or transformer reading to the previously determined setting and start the blower. Release the abrasive, at the same time starting the stop watch, and check that the manometer reading settles to the required250 5mm water pre

30、ssure difference. If necessary adjust the voltage or transformer setting from time to time to maintain the required pressure difference during the test run. Immediately the abrasive has cleared the funnel of the venturi stop the stop watch and note the time. When the alumina grain has finished disch

31、arging from the cyclone switch off the blower. Allow sufficient time for the blower to run to stop before releasing the lid of the abrasion chamber and removing the test piece. Reweigh the test piece to the nearest0.1g and calculate the loss in mass. Repeat the procedure using the opposite face of t

32、he same test piece or another test piece from the same batch of calibrated carbon test pieces. 7.3 Time of test The time taken in each test for the abrasive to pass through the venturi shall be between7min and9min. If the recorded time is significantly longer than9min the requirements of clause5 sha

33、ll be verified. NOTEThe recorded time for the abrasive to pass through the venturi is used to monitor consistent operation of the abrasion apparatus. This time depends on several factors. Whatever the time within the acceptable range, the variation between successive test runs for a particular machi

34、ne will not normally be more than5s. It is, however, normal for the time to decrease with gradual contamination and wear of the abrasive so that over several test runs the variation in time will depend largely on the hardness of the test material. 7.4 Calculation of correction factor C The correctio

35、n factor C shall be calculated from the average loss in mass from the two tests in7.2, as given by the equation 7.5 Frequency of calibration 7.5.1 During testing the loss in mass of two faces of the carbon test pieces (see7.2) shall be measured at the beginning and again at the end of each set of10t

36、ests (or part thereof). The average of the four results shall be used to determine a value for calibration factor C to be applied to the set of tests. 7.5.2 If during a set of test runs any of the following changes are necessary, the correction factor C shall be determined before and after the event

37、 and the latter value for C applied to the tests: a) servicing of the abrasion apparatus; b) screening of the abrasive; c) using of fresh abrasive. 8 Preparation of test pieces Test pieces shall be rectangular prisms75mm 50mm 25mm taken from a brick or block. The abradability index shall be determin

38、ed on a75mm 50mm face which may be a newly cut surface (abradability index of interior) or an original manufactured surface (abradability index of skin). Whichever type of surface is measured at least four faces shall be abraded to obtain a mean value. The position(s) in the brick or block from wher

39、e test pieces are taken shall be such that the faces to be abraded are normal to the direction of pressing. The positions shall be recorded. NOTEIf positions other than those specified are to be used this should be the subject of an agreement between the interested parties, but is outside the scope

40、of this standard. 9 Test procedure (abradability index) Determine the bulk density of each test piece in accordance with the method in BS1902-3.8. C specified loss in mass for carbon block average measured loss in mass - =BS 1902-4.6:1985 BSI 03-1999 3 Dry the test pieces at110C to constant mass, th

41、en cool and weigh to the nearest0.01g before abrasion tests are carried out. Place the test piece in the holder, secure the lid to the abrasion chamber and abrade with6.35 0.01kg of dry freshly sieved brown fused alumina grain as described in7.2. Reweigh the test piece to the nearest0.01g. 10 Sievin

42、g and replacement of abrasive Sieve used abrasive at least every10test runs using1.7mm and7104m aperture sieves (see5.8). Discard material greater than1.7mm and less than7104m and weigh the remaining abrasive. If necessary the mass shall be adjusted to6.35 0.01kg by discarding abrasive or by adding

43、fresh abrasive. Used abrasive having a correction factor C which has increased by $ 20% of its original value shall be discarded and replaced with new abrasive. NOTEThe abrasive gradually becomes contaminated with particles of test material but this is normally corrected by the calibration procedure

44、 at the start and finish of each set of test runs. However with some materials, e.g.unfired castable refractories, abrasion of relatively soft matrix material may lead to contamination by large aggregate which in subsequent tests obstructs the passage of the abrasive through the venturi. At such tim

45、es it may be necessary to sieve the abrasive more frequently. 11 Calculation of abradability index Calculate the abradability index of each test piece using the equation where m 1is the initial mass of the dried test piece (ing); m 2is the mass of the abraded test piece (in g); P bis the bulk densit

46、y of the test piece (in g/cm 3 ); C is the correction factor. 12 Test report The test report shall include the following information: a) the testing establishment; b) the date of the test; c) a reference to this method of test, i.e.determined in accordance with method1902-406; d) the designation of

47、bricks or blocks tested (manufacturer, type, shape, batch number etc.); e) the number of test pieces per type of material and their location in the brick(s) or block(s); f) the correction factor used; g) the individual integer values of the abradability index; h) reference to the type of face tested

48、, i.e.either “skin” or “interior” face (see clause8). abradability index m 1 m 2 P b -C 100 =BS1902-4.6:1985 4 BSI 03-1999 Figure 1 Assembly of abradability apparatusBS 1902-4.6:1985 BSI 03-1999 5 Figure 2 Details of abradability apparatus6 blankBS1902-4.6:1985 BSI 03-1999 Publications referred to B

49、S410, Specification for test sieves. BS1902, Methods of testing refractory materials. BS1902-3.1, Guidance on sampling. BS1902-3.8, Determination of bulk density, true porosity and apparent porosity of dense shaped products (methods1902-308). BS1902-4.0, Introduction 3) . BS1902-4.7, Determination of resistance to abrasion at elevated temperatures up to1400 C (abradability index at elevated temperatures) (method1902-