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AMERICAN SOCIETY for TESTING and MATERIALS COMMITTEE F-3 ON GASKETS Organized in 1962 CHAIRMAN: L. F. CRYSTAL. CATERPILLAR TRACTOR CO.. EAST PEORIA. ILL. 6 6tt Vice-Chairman: J. C. TOMAN, victor-oana coup. 9730 w. rooskvclt rlao. CHICAGO, ill. 90630 Vice-Chairman: G. G. PECK, general motors corp.. oetroit oicsel CNGine oiv.. . '3400 W. OUTER OR.. OETROIT. MICH. 46326 SECRETARY: J. A. LAA>SMA. AC SPARK PLUG OlV.. GENERAL MOTORS CORP.. 1601 N. AVCRILL AVE., FLINT. MICH. 46936 Membership Secretary: AGNES K. POTEPAN. grcene. tweeo Ano co.. ' ELM AVE.. NORTH WALES. PA. IS494 Address reply to -- October 23, 1969 ;fe& ! To: I. F. Ciystal R. F. Anderson G. E. Becker, Jr. J. A. Laansma G. D'Olier W. F. Hulse From: J. C. Toman SUBJECT: RECOMMENDED PRACTICE FOR EVALUATING NONMETALLIC GASKET COMPRESSIONS (Draft No. 1) , Ehclosed you will find a copy of subject test method which was letter bal loted in Subcommittee F-3.20 this summer. Please review the proposed method for editorial changes and bring your com ments to the meeting in Williamsburg for further discussion. Subcommittee F-3 20 hopes to have this method letter balloted in F-3 and advanced to ASTM for inclusion in the book of standards. Best regards - see you at the meeting. Tours truly, jjHcn -- '"aohn C. Toman, Chairman Subcommittee F-3.10 pt Enclosure VPD-153-0002333 DANA-290 ii Draft No. 1 Recommended Practice For Evaluating Hoaactallic Gasket Compressions In Flat Pace Casketed Joint Assemblies 1. SCOPE 1.1 This method of tect peonitB measurement of gasket compression ; resulting from the bolt preload on e flat face joint assembly . *-' \ ' at ambient temperature. f"V ' 2. SUMMARY OF CETHOD 2.1 The gasket compression is obtained from compressed thickness , measurements on soft cylindrically sloped solder plugs inserted in holes drilled or punched through the gasket in the thickness direction. Compression is accomplished in the flanged Joint assembly vhen the bolts are preloaded at ambient temperature. Solder, being inelastic, vlll remain at the compressed thickness of the gasket after the joint has been disassembled. 3. SIGNIFICANCE . . 3*1 Gasket compression^ produced by bolt preloads in a flanged joint are Tt important in the application engineering of a joint assembly. They Ii are related to the ability of a gasket to seal, to maintain tightness on assembly bolts, and to a variety of other gasket properties which, determine the service behavior of a joint assembly. Thus being able to determine the degree of expression in a gasket under the bolt preloading will penult one to make qualitative predictions on the behavior of a joint assembly vhen it comes in contact vith the. application or service environment. With the plug test, bending of a flange-facing between bolt centers can be measured, however, in c fev highly distortable flanges the raximian bending between bolt centers may not be detected. VPD-133-0002334 2- - 3.2 The variation in gas'.:et compressions at selected points in a flat face joint assembly reveals the decree of flange distortion / or the ability, of the flange to distribute the bolt preloads ' f uniformly over the gasket. I " .' 4. APPARATUS , ,, 4.1 Equipment for carrying out the test is shown in Figure, 1. The test >. Joint assembly can be almost any flat face flange design. Bolt preloading is accomplished by the band torque wrench, or high speed > . automatic vreockes#j-iay--be^enployecU Thickness measurements on the solder plugs and the uncornpressed gasket thickness are obtained using a dial gauge indicator graduated In .3001 in. The leather punch is for punching holes in the gasket a3 veil os for fabricatl.-v; the solder plugs. Tweezers make it possible to handle the solder . plugs in a convenient manner. :*ot shown is a vice for holding the Joint assenbly-and a round tapered file for enlarging the holes punched through the gasket. ' .. '* 4.2 The equipment for fabricating the solder plugs in shown in Figure 2. Solder is 50/50 tin load wire wrapped on a spool. The wire must be nade into a flat strip. This can be done by compressing the wire in a vise, a pair of flanges, pliers, or the wire nay be passed between two calender rolls used for processing elastomers. The solder plugs are punched from the strip with-the aid of the leather punch. ' Plug diameter is 1/32 in. and the height need only be such that the plug is compressed by the flanges men the gasket is also compressed. The initial thickness of the o'.- 1 islet before compression r.ced not be equal. VPD-153-0002335 f - ` '' % Pvr 4: El. hhiiv * - :. r^.: ;':y-.ki v?Sh,v* - 3- 5. commons 5.1 When the test ia performed on m assembly line or In a service environment sufficient tine nhou.ld elapse for the flenges, bolts. I and gasket to reach equilibrium with the anbient temperature ar.a I humidity conditions. - . ' 5.2 VJhen the test is performed under controlled conditions in the , { laboratory, the gasket specimen is conditioned in accordance with the procedure described in the classifications (Type 1, 2, or 3) '> in AST!! F10U, Classification System for Nonnetallic Casket Materials. Flange fasteners end washers are held at the test temperature (70 to o07) at least U hours prior to assembly. 6. TEST SPECIMENS 6.1 Three gasket specimens ere tested. They arc die cut from the gasket material In sheet form. Size and slape of the specinensmu-.t be such as to fit the particular flange design. 6.2 Flanges, fasteners, and washers are the same as those specified for application. They should be cleaned with reagent grade tricolors!;.ylcr.e or other suitable solvent. Cleansing tissues raay be used to remove dirt, oil or greese. After cleaning the mating screw threads should be given a light coating of SAE 20 engine oil. 7. PROCEDURE 7.1 The initial or uncompressed thickness of the gasket Is measured, .poles are punched through the gasket ?t the points where compressions are to be evaluated, the holes beir- "T-cd using e round tapered file s: VPD-153-0002336 A , ' ;.................................. i '' . : :'r - U- ; . that they are slightly Larger than the diameter of a solder p4ua. Plugs are inserted in the holes with the gasket resting on a flange facing. The test Joint assembly is assembled, preloaded to eome prescribed tightening torque, then disassembled immediately. Compressed thickness measurements are made on the solder plugs. These measurements are equal to the compressed thickness exhibited by the gasket vhen it was loaded in the Joint assembly. . 8. . CALCUIATTOII AIJP E.'TEF.PrETATICii 8.1 Equation for calculating the compression as a percentage of the original gasket .thickness is: c x 100 vhere: . c = percentage .compression in the gasket, tQ*> initial uncompressed thickness of the gasket, in, tc compressed gasket thickness as measured on a soldei; plug, in. 3.2 Figure 3 illustrates a graph for plotting compressed thickness values for the gasket. The particular points of compression were selected to reveal the bending distortion In the flange facing between bolt centers. Eendir.g is revealed by drawing a cur/e through the gasket compressed thickness data which ere represented by vcrtical dark bars. Percentage compression is indicated below each bar. VPD-153-0002337 * 8.3 These percentage compressions vere produced in the test flange by an initial flange pressure which con be obtained from a load compression or stress strain curve for the gasket material. This approach to determining initial flange pressure is most adaptable to gasket materials whose load compression characteristics are not dependent on shape factor. r' v 8.U The plug test will indicate not only the distribution of gasket compressions but also the distribution of initial flenge pressures ' in joint assemblies exhibiting flange distortion. 9. EFFORT . 9.1 The report should indicate the following: 9.1.1 Uncompressed gasket thickness, 9*1.2 Compressed gasket thickness, . 9*1*3 Percentage compression in the gasket, 9.1.U Conditions of test, temperature, relative humidity, 9*1*5 Photograph of a disassembled view of the joint assembly, 9.1.6 Gasket identification, 9.1.7 Method of bolt lording 9.1.8 Bolt torque, . 9.1.9 Bolt size, material and thread condition, 9*1.10 Top view of gasket showing solder plug locations, 9.1.11 Data plot 6Laiilar to Figure 3, 9.1.12 Flange: material, thickness, v'dth, and bolt spacing, 9.1.13 Conditioning of gasket before *-*t, . 9.I.1U Tightening sequence on bolt3. . . . ~ VPD-153-0002338