Document E4eEJqk48L9LGGRvQKGNQN4g

FELLOWSHIP REPORT ATI-73 MYRIL C, SHAW RESEARCH FELLOW ASBESTOS TEXTILE INSTITUTE PHILADELPHIA TEXTILE INSTITUTE PHILADELPHIA, PA, REPORT #39 December 6, 1956 MS 003297 MT-002701 PRODUCED Heat Aging Test on Asbestos Cloths Styles 36PIO and 26P1U ATI-73 Introduction The subject of heat aging tests for asbestos textiles, the procedures and techniques to be followed and the extent and character of degradation resulting therefrom have been discussed in detail in several previous reports by this writer* It is generally understood that heat aging tests when conducted for control purposes over short periods of time or under unique heating conditions should not be regarded as simulative service tests nor should the results be interpreted in terms of specific ultimate service characteristics* Heat aging tests do effectively serve to distinguish quality or grade dif ferences between cloths and also may indicate differences in the fiber quality or grades which may have been used in manufacturing cloths of the same grade* Indeed, this latter determination may be one of the most important revelations resulting from such tests. In an effort to obtain significant data and information that might serve as the basis upon which may be established industry-wide heat aging character istics for certain asbestos textiles, the Technical and Sales Promotion Com mittees directed the Fellow to conduct a series cf heat aging tests on an indus try-wide selection of cloths of styles 36PIO and 26P11;, in all available grades. This work has been completed and the results of the tests are here reported. Test Procedure Samples, For this work, five member companies submitted materials for test as follows: 26P1U - Underwriters -h samples 26P1U - Grade AA -3 " 36PIO - Commercial - 2 " 36PIO - Underwriters - f? " 36PIO - Grade AA -3 " 36P10 - Grade AAA - U Sample Preparation* Tests were run only in the warp direction using eight warp-grab samples of each cloth for each test* The results, as reported, are the average of eight determinations for each sample. Cloth Characteristics, The characteristics of each of the samples as related to weight, thickness"and construction are set forth in Table I, Certain of these characteristics are noted with an asterick and + or - which serves to indicate that the property so noted is either in excess of or less than the tolerable limits as presently accepted by the industry. Heat Aging Test Pror.edn.re* The test procedure followed in this work was in conformance with the practice as recommended on previous occasions by the writer. That is, an air circulating oven was used, the test samples were laid in a single layer on a wire mesh screen within the oven, and the samples were permitted to condition under room conditions for 30 minutes following the test before the tensile strength determinations were made. The duration of each test was 2 hours. The temperatures at which these tests were conducted were 300F, U00F, 500F, 600F, 700F and 800F, PRODUCED MT-002702 JM-83 MS 003298 ATI-73 2- . Investigational Data The results of the tests here conducted are set forth in Table II, wherein the breaking strength, in pounds, is givenj in Table III, wherein the percentage strength retentions are presented} and in Plates I, II, III and IV which graphically presents the data contained in Tables II and III, Plates I and III set forth the data in terms of pounds breaking strength and Plates II and IV present the same data in terms of percent strength retention* It will be observed that the cloths are grouped according to style and grade in both the tables and the graphs, 26P1U, The selection of four Underwriters Grade and three Grade AA cloths in style 26P1U show ranges in tensile strength, as received, of from 8U to 110 pounds for Underwriters Grade and from 91 to 113 for Grade AA, Plates III and IV graphically present this information and, in addition, show the increased differences between maximum and minimum values as a result of heat aging. For example, the Underwriters Grade cloth at 1|00F shows a range of from 57 to 87 pounds and at 600F from 22 to 52 pounds. The same style cloth in Grade AA exhibits even more marked differences, ranging from 91 to 113 pounds as re ceived, 86 to 122 pounds at 300F and 5h to 98 pounds at 500F, Plotted on each of the graphs are lines connecting the bar plots, the dotted line representing the range average or medium value and the solid line the average or arithmetic mean value. For the most part, the two values are not greatly different, being not more than two pounds apart for Grade AA and five pounds apart in two instances for Underwriters Grade, However, it will be seen that the difference between the maximum and minimum values and the average values is considerably greater than tolerance provisions would permit. For example, in Underwriters Grade, the "as received" tensile strength will be found to range from 8U to 110 pounds with an average of 96 pounds. This would require a specification of 96 + 12# or 12*!$, As the temperatures increase the tolerance requirements also increase, for example, Underwriters Grade at 600F has a range of from from 23 pounds to 53 pounds and would require a specification of 35 i 18 pounds or 5l$, The same relative relationships exist for the Grade AA cloths, 36P10, The cloths in style 36P10 fall within much closer tensile strength ranges with only the Grade AAA materials exhibiting excessive ranges of values. Plates I and II graphically present this data. The Commercial grade cloths in this style are represented by only two cloths and it is perhaps unwise to consider this data as representative of the industry's production of this material. However, the "as received" tensile strength values of the cloths submitted exceed the presently accepted values of 95 pounds by from 20 to U5 pounds. As the temperatures of test increase the range of strengths decreases to + U pounds from the average of approximately 21 pounds at temperatures above 500F. It will also be observed that the strength characteristics of the Commercial grade and Underwriters grade cloths are quite similar over the entire range and not greatly different with the average values being approximately 21.5 and 33,0 pounds respectively. MS 003299 MT-002703 PRODUCED ATI-73 Sample # 301 308 313 319 302 318 322 303 309 304 307 310 314 317 305 311 320 306 312 316 321 Style 26P14 ii ii ii 26P1U ii it 36P10 ii 36P10 n n it t! 36P10 ii n 36P10 it n ii Table I Cloth Construction Data Grade Weight Thickness Unde ii ii it 1,-70 1,56 1,47*(-) 173 0,059 0,054 0,055 0o057 AA 1,82*(+) 0C057 it 1*73 0*056 ii 1*67 0o050 Connie ii Und* it ti it ti AA ii u 2C23 2*29 2*35 2.45*(+) 230 2 *21 2*24 2e29 2,30 2.30 0*075 0,076 0.071 0c-084*(+) 0,076 0e080 0,077 0,072 0,072 0e088-*(+) AAA 2*33 it 2,19 it 2.21 0,073 0.068 0,076 ii 2.44*(+) 0,078 Construction 15 x 13,7 14.6 x 13.3 14 x 14 15 x 14 14,6 x 13.3 15 x 14.3 15 x 14 18,7 x 9 18 x 9 18.3 x 9,3 18,6 x 8.8 18,3 x 8.7 18.3 x 9 18,6 x 9 18,7 x 9 18.3 x 9 18.3 x 9.3 18,3 x 9.3 18 x 9 18 x 9 18.3 x 9.7 MS 003300 IWT-002704 produced -itTable II ATI-73 Tensile Strength Pounds 26P1U Und. 26P11* AA 36P10 Comm, 36P10 Und, 36P10 AA 36P10 AAA # 301 308 313 319 Avr. 302 318 322 Avr, 303 309 Avr, 30l* 307 310 31U 317 Avr, 305 311 320 Avr, 306 312 316 321 Avr, As Received 85.8 106,2 81*. 2 110.0 96.55 91.2 95. 1* 113.8 100.1 ill*. 8 139.1* 127.1 127.0 mu.8 1U3.2 139.0 136.1* 138.1 128.2 12l*.i* 136.2 129.6 131*.2 168.0 162,6 163.6 157,1 300F 79,5 98.75 80,8 102 0 9 90.5 86 ,,9 96 121.9 102,0 103.5 138,5 121.0 117.63 1UU.0 11*2,0 125.5 121* .75 130,77 121.25 12i*.30 136.1 127.22 126.5 169.8 161.0 170.1 156,85 1*00F 57.0/ 87.75 61**25 70.5 69,87 73.1 80,9 98oO 81*,0 63.56 107.7 85.63 68.75 102.5 107.7 82c62 89.3 90.2 99.12 108.1 109.0 105.U1 121.25 156.1 160.1 11*0.7 ll*l*.51* 5oof 25,62 52.80 38,9 1*2.1 39.85 5U.0 73.25 98.10 75.12 20j0 39.62 29.81 28.6 1*1* ,1* 1*9.5 39.8 55.0 i*3.l*6 80.5 80.25 89.87 83.51* 10i*.l 152.3 157.5 136.0 137.5 600F 22.6 52,5 30,5 32,2 3i*.l*5 53.1* 70.0 9U.1 72.5 17.5 26.75 22.12 28.6 36.25 37.12 26,5 1*5,0 3l*.69 80.3 66.5 86,62 77.81 103.3 11*7.1* U*5.0 132.9 132.2 700F 23,62 50.6 28,0 29.25 32.87 51*.62 71.60 85,1*0 70.51* 17.12 26.0 21.56 29.75 3U .1* 35.0 2U.9 1*3.25 33.1*6 82.0 70.8 87.6 80.1 107.0 159.1* 152,39 138.90 139.1*2 800F 26,0 51.7 29.12 30.1* 31**3 53.0 72.0 81.6 68.9 17.6 2l*,9 21.2 28.8 33.6 33.6 25 .U 1*1.6 32.6 79.0 67.37 86.9 77.2 100,6 150.5 152.1* 130.0 133.1* MT-002705 PRODUCED JM`83 MS 003301 ATI-73 -5-* Table III 26P11* Undi 26PU* AA 36P10 Comm 36P10 Und 36P10 AA 36P10 AAA # 301 308 313 319 Ayr* 302 318 322 Avr, 303 309 Avr, 301* 307 310 311* 317 Avr, 30^ 311 320 Avr* 306 312 316 321 Avr, Percent Tensile Strength Retention 300F 1*00F 5oof 600F 93,5 92,6 96.0 93.5 93,9 66.5 82.3 76,2 6!*.l 72,3 29,8 19.6 1*6,1 38,2 Ii0c9 26.3 1*9.3 36.2 29.3 35.3 95 *2 100.5 107,0 100,9 80,0 81*8 86,2 83.7 59.2 76,8 86.5 7U,2 58.6 73.5 83.0 71.7 90,2 99,5 9U.9 55.5 77.1 66.3 17.1* 28.1* 22.9 15.2 19.3 17.2 92,5 99,5 99,0 97.6 91.5 96.0 5U.1 71.0 75.0 59.5 65.5 65.0 22.1*0 30,60 3U.50 28,60 t*0.1*0 31.3 22,1*0 25.00 25.80 19.20 33.00 25,1 9U.5 99.9 99,9 98.1 77.2 87,0 80,0 81.1* 62.7 61*.5 65.8 6U,3 62.5 53.1* 63.0 59.7 9U.0 101,0 99.0 10U.0 99,5 90,3 92,8 98,5 86,0 91.9 77.5 90.5 96,5 83.0 86.9 76.5 87.8 89.2 81,0 83.6 700F 27.6 1*7.5 33.2 26.6 33.7 60.0 75.2 75.0 70.0 1U.9 18.3 16.6 23.1* 23.8 2l*.l* 17.9 31.6 2U.2 63.8 57.0 61*.2 61.7 79.7 9U.8 93.8 85.0 88.1* 800F 30.3 1*8.5 3l*.5 27.6 35.2 58.1 75.5 71.7 68.1* 15.3 ' 17.8 16.5 22.7 23.2 23.1* 18.2 30.5 23.6 61.5 5i*,o 63.0 59.5 7U.9 89.5 93.5 79.5 ei*.i* MS 003302 PRODUCE I*-*3 MT-002706 ATI-73 ATI-73 ATI-73 100 Grade I I ! !,-nT-!*t q`-; trr-f- urhrrr 30 20 A, A R " : : i. 300 4 (>0 Tejni p ei MT-002709 500 uu.'i,j.:U4A- ii- jl; i t ii>i PR0DUCBlj-- * 1*. I**. JM - 83 JM-83 ATI-73 --10-- Cloths in both Grades AA and AAA exhibit relatively good strength retention characteristics over the temperature range here used, reaching minimum strengths at 600F and exhibiting properties as good or better than minimum at tempera tures of 700F and 800F, The Grade AA cloth reaches a minimum value of ap proximately 77 pounds or of the original strength and Grade AAA shows a minimum value of 132 pounds or 83# of the original strength* Analysis of Results An analysis of the results of the tests conducted during this investigation reveals several significant facts. First, the range of tensile strength values for the style 26P1U in grades Underwriters and AA are in excess of tolerable limitations both "as received" and "after heat aging" at temperatures up to 800F, The tensile strength of the cloths "as received" ranges from 8U to 110 pounds for Underwriters grade and from 91 to llU pounds for Grade AA, which is the equivalent of approximately + 13# variation for Underwriters and + lU# for Grade AA* These variations become even more pronounced as the heat aging tempera tures are increased. It would seem that an effort should be made to reduce or resolve this wide range in tensile strength values before an attempt is made to write specifications in this instance* Secondly, the tensile strength characteristic of the cloths in style 36P10 appear to be within tolerable limits for consideration of the problem at hand. All of the tensile strength values obtained for 36P10 in all grades "as received" exceeded the presently accepted industry-wide standards and the average values for each group were considerably in excess of the standard* Thirdly, the minimum tensile strength values resulting from heat aging were obtained, in most cases, at 600F and heat treatment at higher tempera tures did not appear to materially reduce this figure, in fact, in two cases, an increase was obtained at 700F over that obtained at 600F, This latter phenomenon occurred in 36P10 style cloths in Grades AA and AAA and is undoubt edly attributable to the loss of moisture by the asbestos fibers with the re sultant contraction within the fiber bundles with increased frictional resistance between the individual fibers resulting* Conclusions The writer has made an effort to point out in reporting the results of earlier extensive investigations covering heat aging tests ranging in time periods of from five minutes up to seven days and over temperatures of from 200F to over 2500F, that the results to be obtained are dependent upon fac tors of cloth construction and composition as well as the time and temperature of test, To endeavor to define a time-temperature relationship for a grade of material irrespective of the weight, weave and construction can be quite mis leading, To ideally meet the requirements, each cloth construction should be considered as a group within itself and the full range of grade-temperaturetensile strength relationships within this group should be used to provide information of significance. Such tabulations for the two styles of cloth here investigated have been set up based upon the results of this work and are presented in Tables IV and V, It will be noted that in Table IV, wherein the data is presented in terms of pounds, tensile strength, the strengths MS 003307 PRODUCED JM -83 MT-002711