1、Designation: E139 11Standard Test Methods forConducting Creep, Creep-Rupture, and Stress-RuptureTests of Metallic Materials1This standard is issued under the fixed designation E139; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These test methods cover
3、the determination of theamount of deformation as a function of time (creep test) andthe measurement of the time for fracture to occur whensufficient force is present (rupture test) for materials whenunder constant tensile forces at constant temperature. It alsoincludes the essential requirements for
4、 testing equipment. Forinformation of assistance in determining the desirable numberand duration of tests, reference should be made to the productspecification.1.2 These test methods list the information which should beincluded in reports of tests. The intention is to ensure that alluseful and readi
5、ly available information is transmitted tointerested parties. Reports receive special attention for thefollowing reasons: (1) results from different, recognized pro-cedures vary significantly; therefore, identification of methodsused is important; (2) later studies to establish importantvariables ar
6、e often hampered by the lack of detailed informa-tion in published reports; (3) the nature of prolonged tests oftenmakes retest impractical, and at the same time makes it difficultto remain within the recommended variations of some con-trolled variables. A detailed report permits transmittal of test
7、results without implying a degree of control which was notachieved.1.3 Tests on notched specimens are not included.These testsare addressed in Practice E292.1.4 Tests under conditions of short times are not included.These test methods are addressed in Test Methods E21.1.5 The values stated in inch-p
8、ound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther
9、esponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Method
10、s of Mechanical TestingE8 Test Methods for Tension Testing of Metallic MaterialsE21 Test Methods for Elevated Temperature Tension Testsof Metallic MaterialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE74 Practice of Calibration of Force-Measuring
11、 Instru-ments for Verifying the Force Indication of Testing Ma-chinesE83 Practice for Verification and Classification of Exten-someter SystemsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE220 Test Method for Calibration of Thermocouples ByComparison TechniquesE292 Test Me
12、thods for Conducting Time-for-RuptureNotch Tension Tests of MaterialsE633 Guide for Use of Thermocouples in Creep and Stress-Rupture Testing to 1800F (1000C) in AirE1012 Practice for Verification of Test Frame and SpecimenAlignment Under Tensile and Compressive Axial ForceApplication3. Terminology3.
13、1 DefinitionsThe definitions of terms relating to creeptesting, which appear in Section E of Terminology E6 shallapply to the terms used in this practice. For the purpose of thispractice only, some of the more general terms are used with therestricted meanings given below.3.2 Definitions of Terms Sp
14、ecific to This Standard:1These test methods are under the jurisdiction of the ASTM Committee E28 onMechanical TestingCurrent edition approved June 1, 2011. Published August 2011. Originallyapproved in 1958. Last previous edition approved in 2006 as E139 06. DOI:10.1520/E0139-11.2For referenced ASTM
15、standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM
16、International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.1 axial strainthe average of the strain measured onopposite sides and equally distant from the specimen axis.3.2.2 bending strain the difference between the strain atthe surface of the specimen and
17、 the axial strain. In general itvaries from point to point around and along the reduced sectionof the specimen.3.2.2.1 maximum bending strainmeasured at a positionalong the length of the reduced section of a straight unnotchedspecimen.3.2.3 creepthe time-dependent strain that occurs after theapplica
18、tion of a force which is thereafter maintained constant.3.2.4 creep-rupture testa test in which progressive speci-men deformation and the time for rupture are measured. Ingeneral, deformation is much larger than that developed duringa creep test.3.2.5 creep testa test that has the objective of measu
19、ringcreep and creep rates occurring at stresses usually well belowthose which would result in fracture during the time of testing.Since the maximum deformation is only a few percent, asensitive extensometer is required.3.2.6 gage lengththe original distance between gagemarks made on the specimen for
20、 determining elongation afterfracture.3.2.7 length of the reduced sectionthe distance betweentangent points of the fillets which bound the reduced section.3.2.7.1 The adjusted length of the reduced section is greaterthan the length of the reduced section by an amount calculatedto compensate for stra
21、in in the fillet region (see 8.2.3).3.2.8 plastic strain during force applicationthe portion ofthe strain during force application determined as the offsetfrom the linear portion to the end of a stress-strain curve madeduring force application. The offset construction is shown inTest Methods E8.3.2.
22、9 reduced section, of the specimenthe central portionof the length having a cross section smaller than the ends whichare gripped. The cross section is uniform within tolerancesprescribed in 6.6.3.2.10 strain during force applicationthe change in strainduring the time interval from the start of force
23、 to the instant offull-force application.3.2.11 stress-rupture testa test in which time for rupture ismeasured, no deformation measurements being made duringthe test.3.2.12 total plastic strain, at a specified time equal to thesum of plastic strain during force application plus creep.3.2.13 total st
24、rain, at a specified timeequal to the sum ofthe strain during force application plus creep.4. Significance and Use4.1 Rupture tests, properly interpreted, provide a measure ofthe ultimate load-carrying ability of a material as a function oftime. Creep tests measure the load-carrying ability for limi
25、teddeformations. The two tests complement each other in definingthe load-carrying ability of a material. In selecting material anddesigning parts for service at elevated temperatures, the type oftest data used will depend on the criterion of load-carryingability that better defines the service usefu
26、lness of the material.5. Apparatus5.1 Testing Machine:The accuracy of the testing machine shall be within thepermissible variation specified in Practices E4.5.1.1 Exercise precaution to ensure that the force on thespecimens is applied as axially as possible. Perfect axialalignment is difficult to ob
27、tain, especially when the pull rodsand extensometer rods pass through packing at the ends of thefurnace. However, the machine and grips should be capable ofapplying force to a precisely made specimen so that themaximum bending strain does not exceed 10 % of the axialstrain, when the calculations are
28、 based on strain readings takenat the lowest force for which the machine is being qualified.NOTE 1This requirement is intended to limit the maximum contribu-tion of the testing apparatus to the bending which occurs during a test. Itis recognized that even with qualified apparatus, different tests ma
29、y havequite different percent bending strains due to chance orientation of aloosely fitted specimen, lack of symmetry of that particular specimen,lateral force from furnace packing, and thermocouple wire, etc.5.1.1.1 In testing of low ductility material, even a bendingstrain of 10 % may result in lo
30、wer strength than would beobtained with improved axiality. In these cases, measurementsof bending strain on the specimen to be tested may bespecifically requested and the permissible magnitude limited toa smaller value.5.1.1.2 The testing apparatus may be qualified by measure-ments of axiality made
31、at room temperature. When one ismaking an evaluation of equipment, the specimen form shouldbe the same as that used during the elevated-temperature tests.The evaluation specimen concentricity shall be at least as goodas called out in the specimen drawing. Only elastic strainsshould occur throughout
32、the reduced section. This requirementmay necessitate use of a material different from that usedduring the elevated-temperature test.5.1.1.3 Test Method E1012, or an equivalent test method(3),3shall be used for the measurement and calculation ofbending strain for round, rectangular, and thin strip sp
33、ecimens.5.1.1.4 Axiality measurements should be made at roomtemperature during the initial setup of the assembled testmachine, (including the pull rods, and grips) before use fortesting. Gripping devices and pull rods may oxidize, warp, andcreep with repeated use at elevated temperatures. Increasedb
34、ending stresses may result. Therefore, grips and pull rodsshould be periodically retested for axiality and reworked whennecessary.5.1.2 The testing machine shall incorporate means of takingup the extension of the specimen so that the applied force willbe maintained within the limits specified in 5.1
35、. The extensionof the specimen shall not allow the force application system tointroduce eccentricity of force application in excess of thelimits specified in 5.1.1. The take-up mechanism shall avoidintroducing shock forces, overloading due to friction or inertiain the force application system, or ap
36、ply torque to the speci-men.3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.E139 1125.1.3 The testing machine shall be erected to secure reason-able freedom from vibration and shock due to external causes.Precautions shall be made to minimize the trans
37、mission ofshock to neighboring test machines and specimens when aspecimen fractures. Vibration and shock effects may be seen asnoise in the curve when plotting the creep versus time. Whensuch effects are visible in the plotted data, vibration and shockshould not introduce apparent noise to the creep
38、 data in excessof 7.5 % total creep or total plastic strain. Such externalvibrations shall not result in applied force errors in excess of+1 % of the specified test force.5.1.4 For high-temperature testing of materials which arereadily attacked by their environment (such as oxidation ofmetal in air)
39、, the specimen may be enclosed in a capsule so thatit can be tested in a vacuum or inert-gas atmosphere. Whensuch equipment is used, the necessary corrections to obtain truespecimen applied forces shall be made. For instance, compen-sation shall be made for differences in pressures inside andoutside
40、 of the capsule and for any force application variationdue to sealing-ring friction, bellows or other features.5.2 Heating Apparatus:The apparatus for and method of heating the specimens shallprovide the temperature control necessary to satisfy the re-quirements specified in 8.4.4 without manual adj
41、ustments morefrequent than once in each 24-h period after force application.Automatic temperature control is preferred.5.2.1 Heating shall be by an electric resistance or radiationfurnace with the specimen in air at atmospheric pressure unlessother media are specifically agreed upon in advance.NOTE
42、2The media in which the specimens are tested may have aconsiderable effect on the results of tests. This is particularly true when theproperties are influenced by oxidation or corrosion during the test,although other effects can also influence test results.5.3 Temperature-Measuring Apparatus (1):5.3
43、.1 The method of temperature measurement must besufficiently sensitive and reliable to ensure that the temperatureof the specimen is within the limits specified in 8.4.4.5.3.2 Temperature shall be measured with calibrated ther-mocouples in conjunction with calibrated thermocouple mea-surement instru
44、mentation. Other calibrated methods of tem-perature measurement may be used if they are wellcharacterized with respect to standard thermocouple measure-ment methods.NOTE 3Such measurements are subject to two types of error. Ther-mocouple calibration and instrument measuring errors initially introduc
45、euncertainty as to the exact temperature. Secondly both thermocouples andmeasuring instruments may be subject to variation with time. Commonerrors encountered in the use of thermocouples to measure temperaturesinclude, calibration error, drift in calibration due to contamination ordeterioration with
46、 use, lead-wire error, error arising from method ofattachment to the specimen, direct radiation of heat to the bead, heat-conduction along thermocouple wires, etc.5.3.3 Temperature measurements shall be made with cali-brated thermocouples. Representative thermocouples should becalibrated from each l
47、ot of wires used for making base-metalthermocouples. Except for relatively low temperatures ofexposure, base-metal thermocouples are subject to error uponreuse unless the depth of immersion and temperature gradientsof the initial exposure are reproduced. Consequently base-metal thermocouples should
48、be calibrated by the use ofrepresentative thermocouples and actual thermocouples used tomeasure specimen temperatures shall not be calibrated. Base-metal thermocouples also should not be re-used withoutclipping back to remove wire exposed to the hot zone . Anyreuse of base-metal thermocouples after
49、relatively low-temperature use without this precaution should be accompa-nied by recalibration data demonstrating that calibration wasnot unduly affected by the conditions of exposure.5.3.3.1 Noble-metal thermocouples are also subject to errorsdue to contamination, etc., and should be annealed periodicallyand checked for calibration. Care should be exercised to keepthe thermocouples clean prior to exposure and during use atelevated temperatures.5.3.3.2 Measurement of the drift in calibration of thermo-couples during use is difficult. When drift is a problem durin
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