Sign In · View Account▹ · Home; ASTM E() $; Add to Cart. Printed Edition + PDF; Immediate download; $; Add to Cart. ASTM E - Conducting Creep, Creep-Rupture, And Stress-Rupture Tests of Download as or read online from Scribd Eyela Rotary Evaporator PDF. Download as PDF or read online from Scribd. Flag for inappropriate content. Download ASTME Uploaded by. Akshay Varma. spicesinlaris.cf
|Language:||English, Portuguese, Arabic|
|Genre:||Fiction & Literature|
|ePub File Size:||30.39 MB|
|PDF File Size:||12.87 MB|
|Distribution:||Free* [*Registration Required]|
Creep test. The creep test is carried out by applying a constant load to a tensile specimen maintained at a constant temperature,. (according to ASTM E). ASTM E() in English | Standard Test Methods for Conducting Creep, Creep-Rupture, and Stress-Rupture Tests of Metallic Materials. ASTM E () Standard Method for Conducting Creep, Creep-Rupture, Materials, Annual Book of ASTM Standards, ASTM International, West Conshohocken. DOI: /wjm Downloads Views Citations.
When the thermocouples clean prior to exposure and during use at such equipment is used, the necessary corrections to obtain true elevated temperatures. For instance, compen- 5. When drift is a problem during outside of the capsule and for any force application variation tests, a method should be devised to check the readings of the due to sealing-ring friction, bellows or other features. Automatic temperature control is struments should be calibrated periodically against a secondary preferred.
Lead-wire error 5. This is particularly true when the creep characteristics with the precision required for the appli- properties are influenced by oxidation or corrosion during the test, cation of the data. The Practice E83 extensometer classification although other effects can also influence test results. Suitability of 5. Laboratories employing multiple surement instrumentation.
Peak to peak noise on the raw creep data ment methods. Noise levels exceeding these values must be Thermocouple calibration and instrument measuring errors initially intro- documented in the test report.
Secondly both thermo- 5. Therefore, the extensom- nation or deterioration with use, lead-wire error, error arising from method eter shall be attached to and indicate strain on opposite sides of of attachment to the specimen, direct radiation of heat to the bead, the specimen.
The reported strain shall be the average of the heat-conduction along thermocouple wires, etc. Representative thermocouples should be two separate readings.
Test Methods E8 are generally suitable for tests at elevated 5. According to shoulders.
The largest diameter or greatest width specimen tends to loosen as the cross-sectional area decreases specimen consistent with 6. In this case the extensometer may be attached dimensions need not be greater than A small number of grains in the 5. The tion conditions, can have a pronounced effect on the test results. When observed values of extension should be adjusted as described in corrosion oxidation occurs, the results may be a function of specimen size.
Likewise, surface preparation of specimens, if affecting results, becomes 8. Even with this adjustment the strain values are more important as the specimen size is reduced. But at temperatures where oxidation and creep are readily apparent, precisely fitted threads are difficult to maintain and to 5. Other gripping methods have been successfully used perature at the time of force application, unless a correction is 2, 6, 7. The extensometer correc- 6. The correction may be necessary to permit application of the force to the specimen in omitted if it has been established that the extensometer reading the furnace with the axiality specified in 5.
If the material is not changed by variations in room temperature. In evaluating available is sufficient, the use of elongated shoulder ends to the effect of such variations, the electronic instrumentation permit gripping outside the furnace is the easiest method. When the length of the specimen is necessarily restricted, 5. The good axiality of force application using 6.
Test Specimen and Sample a grip of this type has been demonstrated 6, 7. Any brazing or welding should be done in a jig or 6. Any thickness, diameter, or distance between flats, or machining should be done after brazing or welding. Extensometers shall be verified for freedom of movement prior to each test. Exceptions to this list shall be instruments in use when the test exceeds 6. It may be desirable calibration frequency, it is acceptable to perform the calibration immedi- to have the diameter or width of the reduced section of the ately following the conclusion of the test.
The 7. When specimens of this form are used nominal cost. Special care shall be exercised to minimize 7. Threads of the specimen shall be shows wear or damage.
Other 7. Procedure as closely as possible. Calibration and Standardization specimen as specified in Measurement of Dimensions of Test 7.
In addition, measure the largest extensometers, thermocouples 1 , potentometers, and microm- diameter or width in the reduced section and compare with eters shall be traceable to national standards, where systems of the minimum value to determine whether the requirements of traceability exist. Applicable ASTM standards and guidance 6. NOTE 7—Elongation values of specimens with rectangular cross sec- tions cannot be compared unless all dimensions including the thickness 7.
Therefore, an elongation specification should include the measured as described in 5. Using a Practice E Extensometers 1 yearA Thermocouples each lot run NOTE 8—Recognition must be given to the wide use of total elongation Precision Potentiometers dry cell type 1 month of fractured rupture specimens in judging materials.
Percentage elongation Micrometers and calipers 6 months is very dependent on the gage length over which it is measured. Recognition must be given, however, to the Weights every five years see 7. Therefore, 8. For most ductile metals a standard four-diameter gage length centered on a fracture occurring in a one near each end of the reduced section. For reduced sections longer than standard reduced section will give a higher elongation than the 50 mm or greater, add a third thermocouple near the center.
For this reason the use of several, congruent, standard gage 8. The majority test do not permit the difference between the indicated tem- of the stretching occurs near the fracture site. Then, place gage marks on the shoulders or measure using good quality pyrometric practice.
Also measure the adjusted length of the reduced section to the nearest 0. NOTE 9—It is recognized that true temperature may vary more than the indicated temperature. The permissible indicated temperature variations in as described in 8.
If a gage length, other than that specified 8. All laboratories length in the report. In the case of acceptance tests, any should keep both indicated and true temperature variations as small as deviation from 8. However, should temperatures vary outside the given limits, time and temperature of the variation shall be recorded and good 8.
This should be duced section between points on the two fillets where the clearly documented in the test report. It is well recognized, in view of the diameter or width is 1. This dimension is used as the divisor for temperature control is necessary.
The limits prescribed represent ranges that are common practice. The heating characteristics of the 8. It Specimens may be cleaned at the machining facility prior to may be desirable to stabilize the furnace at a temperature from receiving at the test lab. Report any temperature overshoot with specimen. Cast to size specimens typically do not need details of magnitude and duration.
E — 06 E Practice for Veri? Terminology 3. For the purpose of this practice only, some of the more general terms are used with the restricted meanings given below.
In general it varies from point to point around and along the reduced section of the specimen. In general, deformation is much larger than that developed during a creep test. Since the maximum deformation is only a few percent, a sensitive extensometer is required. The offset construction is shown in Test Methods E 8. The cross section is uniform within tolerances prescribed in 7. Creep tests measure the load-carrying ability for limited deformations. The two tests supplementcomplement each other in de?
In selecting material and designing parts for service at elevated temperatures, the type of test data used will depend on the criterion of load-carrying ability which bestthat better de? Apparatus 5.
Perfect axial alignment is difficult to obtain, especially when the pull rods and extensometer rods pass through packing at the ends of the furnace. NOTE 1—This requirement is intended to limit the maximum contribution of the testing apparatus to the bending which occurs during a test. It is recognized that even with quali? E — 06 specimen, lack of symmetry of that particular specimen, lateral force from furnace packing, and thermocouple wire, etc.
In these cases, measurements of bending strain on the specimen to be tested may be speci? When one is making an evaluation of equipment, the specimen form should be the same as that used during the elevated-temperature tests. The evaluation specimen concentricity shouldshall be as near perfect at least as good as reasonably possible.
Only elastic strains should occur throughout the reduced section. This requirement may necessitate use of a material different from that used during the elevated-temperature test. Gripping devices and pull rods may oxidize, warp, and creep with repeated use at elevated temperatures. Increased bending stresses may result.
Therefore, grips and pull rods should be periodically retested for axiality and reworked when necessary. The extension of the specimen shall not allow the force application system to introduce eccentricity of force application in excess of the limits speci? The extension of the specimen should not allow the loading system to introduce eccentricity of loading in excess of the limits speci? The take-up mechanism should avoid introducing shock loads, overloading due to friction or inertia in the loading system, or apply torque to the specimen.
Precautions should be made to minimize the transmission of shock to neighboring test machines and specimens when a specimen fractures. When such equipment is used, the necessary corrections to obtain true specimen loads must be made. For instance, compensation must be made for differences in pressures inside and outside of the capsule and for any load variation due to sealing-ring friction, bellows or other features.
The take-up mechanism shall avoid introducing shock forces, overloading due to friction or inertia in the force application system, or apply torque to the specimen. Precautions shall be made to minimize the transmission of shock to neighboring test machines and specimens when a specimen fractures. Vibration and shock effects may be seen as noise in the curve when plotting the creep versus time.
When such effects are visible in the plotted data, vibration and shock should not introduce apparent noise to the creep data in excess of 7. When such equipment is used, the necessary corrections to obtain true specimen applied forces shall be made. For instance, compensation shall be made for differences in pressures inside and outside of the capsule and for any force application variation due to sealing-ring friction, bellows or other features.
Automatic temperature control is preferred. NOTE 2—The media in which the specimens are tested may have a considerable effect on the results of tests. This is particularly true when the properties are in?
The boldface numbers in parentheses refer to the list of references at the end of this standard. Other calibrated methods of temperature measurement may be used if they are well characterized with respect to standard thermocouple measurement methods. NOTE 3—Such measurements are subject to two types of error. Thermocouple calibration and instrument measuring errors initially introduce uncertainty as to the exact temperature. Secondly both thermocouples and measuring instruments may be subject to variation with time.
Common errors encountered in the use of thermocouples to measure temperatures include:include, calibration error, drift in calibration due to contamination or deterioration with use, lead-wire error, error arising from method of attachment to the specimen, direct radiation of heat to the bead, heat-conduction along thermocouple wires, etc.
Representative thermocouples should be calibrated from each lot of wires used for making base-metal thermocouples. Except for relatively low temperatures of exposure, base-metal thermocouples are subject to error upon reuse unless the depth of immersion and temperature gradients of the initial exposure are reproduced. Consequently base-metal thermocouples should be calibrated by the use of representative thermocouples and actual thermocouples used to measure specimen temperatures shouldshall not be calibrated.
Base-metal thermocouples also should not be re-used without clipping back to remove wire exposed to the hot zone and rewelding.. Any reuse of base-metal thermocouples after relatively low-temperature use without this precaution should be accompanied by recalibration data demonstrating that calibration was not unduly affected by the conditions of exposure. Care should be exercised to keep the thermocouples clean prior to exposure and during use at elevated temperatures.
When drift is a problem during tests, a method should be devised to check the readings of the thermocouples on the specimens during the test. For reliable calibration of thermocouples after use, the temperature gradient of the testing furnace must be reproduced during the recalibration. Lead-wire error should be checked with the lead wires in place as they normally are used.
The sensitivity and accuracy of the extensometer should be made part of the report of test results. The Practice E 83 extensometer classi?
Suitability of the sensor type and characteristics for creep measurement should be determined before implementation of the system.
Suitability of individual sensors should be periodically evaluated or evaluated upon occurrence of signi? Peak to peak noise on the raw creep data should not exceed 7.
Noise levels exceeding these values must be documented in the test report. Therefore, the extensometer shouldshall be attached to and indicate strain on opposite sides of the specimen. The reported strain shouldshall be the average of the strains on the two sides, either a mechanical or electrical average internal to the instrument or a numerical average of two separate readings. For example, when materials with low ductility are tested, failure tends to occur at the extensometer attachments unless these are located on the specimen shoulders.
In this case the extensometer may be attached to the specimen shoulders or to small ribs or grooves machined at the ends of the reduced section of the specimen for that purpose 5.
E — 06 observed values of extension should be adjusted as described in 9. The extensometer correction equation or chart should have specimen temperature as well as room temperature as a variable.
The correction may be omitted if it has been established that the extensometer reading is not changed by variations in room temperature. In evaluating the effect of such variations, the electronic instrumentation should also be calibrated at various ambient temperatures.
Sampling 6. One test shall be made on each lot. Test Specimen and Sample 7. According to 7. Otherwise, the specimen should have a reduced section of circular cross section.
The largest diameter or greatest width specimen consistent with 7. NOTE 4—Specimen size in itself has little effect on creep and rupture properties provided the material is sound and is not subject to appreciable surface corrosion or orientation effects. A small number of grains in the specimen cross section, or preferred orientation of grains due to fabrication conditions, can have a pronounced effect on the test results.
When corrosion oxidation occurs, the results may be a function of specimen size. Likewise, surface preparation of specimens, if affecting results, becomes more important as the specimen size is reduced.
NOTE 5—Satisfactory axial alignment may be obtained with precisely machined threaded ends. But at temperatures where oxidation and creep are readily apparent, precisely? Practical considerations require the use of relatively loose-? Other gripping methods have been successfully used 2, 6. If the material available is sufficient, the use of elongated shoulder ends to permit gripping outside the furnace is the easiest method. The pin holes should be accurately centered on extensions of the centerline of the gage section.
The good axiality of loading offorce application using a grip of this type has been demonstrated 6. When these are used, care must be exercised to maintain coaxiality of the centerlines of the extensions and the gage length. Any brazing or welding should be done in a jig or?
Any machining should be done after brazing or welding.
Customers Who Bought This Also Bought
It may be desirable to have the diameter or width of the reduced section of the specimen slightly smaller at the center than at the ends. The diameter or width at the ends of the reduced section shall not be greater than When specimens of this form are used to test brittle low ductility materials, failure may regularly occur at the? In these cases, the center of the reduced section may be made smaller by a gradual taper from the ends and the exception to the requirements above noted in the report.
Specimen surfaces shall be smooth and free from undercuts and scratches. Special care shouldshall be exercised to minimize disturbance of surface layers by cold work, which produces high residual stresses plastic deformation, or other undesired effects. The axis of the reduced section shouldshall be straight within Threads of the specimen shouldshall be concentric with this axis within the same tolerance. Other means of gripping shouldshall have comparable tolerances.
If the specimen does not meet the requirements speci? The magnitude of the deviations should be reported. Calibration and Standardization 8. Applicable ASTM standards are listed beside the device. The maximum period between calibrations and veri? Exceptions to this list shall be instruments in use when the test exceeds calibration period. Procedure 9. Difference in readings before and after the exercise should be recorded.
Procedure 8. In addition, measure the largest diameter or width in the reduced section and compare with the minimum value to determine whether the requirements of 7.
NOTE 67—Elongation values of specimens with rectangular cross sections cannot be compared unless all dimensions including the thickness are equal. Therefore, an elongation speci?
Using a gage length equal to 4. NOTE 78—Recognition must be given to the wide use of total elongation of fractured rupture specimens in judging materials. Percentage elongation is very dependent on the gage length over which it is measured.
Adherence to the customary gage length of four times the specimen diameter is, therefore, very desirable.
ASTM E 139:2011
Recognition must be given, however, to the approved use of longer or shorter gage length to specimen diameter ratios in rupture testing and the possible objectionprohibition to using gage marks to de? Therefore, reporting of elongation for longer gage lengths should be acceptable, provided the gage length is clearly indicated.
For most ductile metals a standard four-diameter gage length centered on a fracture occurring in a longer than standard reduced section will give a higher elongation than the standard test. For this reason the use of several, congruent, standard gage lengths to cover a long reduced section is not recommended.
The majority of the stretching occurs near the fracture site. Since stretching is not uniform over the length of the reduced section, the percent elongation depends on the gage length.
Then, place gage marks on the shoulders or measure the over-alloverall length of the specimen. Also measure the adjusted length of the reduced section to the nearest 0. If a gage length, other than that speci? In the case of acceptance tests, any deviation from 9. This dimension is used as the divisor for converting the observed extension to strain in the reduced section see Specimens may be cleaned at the machining facility prior to receiving at the test lab.
In all cases, specimens should be handled carefully to avoid imparting oil from skin to the specimen. Cast to size specimens typically do not need cleaning. In attaching thermocouples to a specimen, the junction mustshall be kept in intimate contact with the specimen and shielded from radiation. E — 06 particular furnace and test temperature, the difference in indicated temperature from an unshielded bead and a bead inserted in a hole in the specimen has been shown to be less than one half the variation listed in 9.
The bead should be as small as possible and there shouldshall be no shorting of the circuit such as could occur from twisting the thermocouple wires behind the bead or from a bare attachment wire touching both bare thermocouple wires.
Ceramic insulators should be used on the thermocouples in the hot zone for test temperatures high enough to damage standard thermal insulation on the thermocouple wires. The remaining portions of the wires shall be thermally shielded and electrically insulated by a suitable covering.
If some other electrical insulation material is used in the hot zone, it should be carefully checked to determine whether the electrical insulating properties are maintained with higher temperatures.
More From Akshay Varma
For reduced sections 2 in. The permissible indicated temperature variations in 9. All laboratories should keep both indicated and true temperature variations as small as practicable. However, should temperatures vary outside the given limits, time and temperature of the variation shall be recorded and good engineering judgementjudgment taken to assure the variations did not affect testing of the material and that the results of the test are valid. This should be clearly documented in the test report.
It is well recognized, in view of the extreme dependency of strength of materials on temperature, that close temperature control is necessary. The limits prescribed represent ranges that are common practice. The heating characteristics of the furnace and the temperature control system should be studied to determine the power input, temperature set point, proportioning control adjustment, and control-thermocouple placement necessary to limit transient temperature overshoots.
Report any temperature overshoot with details of magnitude and duration. Unless otherwise speci? Record the time to attain test temperature and the time at temperature before loading. Disturbances causing require an investigation that may necessitate using good engineering judgment regarding the temperature ofimpact on the specimen to fall below the limits speci?
Temperature deviations may be cause for rejection of the test and require retesting. Allowing the temperature to fall below the nominal temperature reduces creep rate and prolongs rupture time, both characteristics being very sensitive to test temperature.
Low temperatures usually do not damage the material as can over temperature, which may considerably accelerate creep. Consequently under temperature should be cause for retesting only when the time at under temperature signi?
NOTE —Cooling and reheating of the specimen under stress can have a signi? Creep properties may be similarly effected. If the stress force is removed before the above time or temperature decrease is exceeded, the rupture test can be restarted after the cause for disturbance has been corrected.
It has not been determined if a creep test can be restarted.
The report shall indicate that the test was interrupted by cooling, length of interruption or decrease, or both in temperature prior to removal of stress, and from what temperature the test was restarted. For example, threaded connections should not be turned to the end of the threads or bottomed.
If threads are loosely? If packing is used to seal the furnace, it must not be so tight that the extensometer arms or pull rods are displaced or their movement restricted. The strain change from zero force to the instant of full force application shall also be recorded see 9.
E — 06 the stress-strain curve during loading force application may be used to evaluate the operation of the apparatus before the specimen is? On the other hand, obtaining the loading force application curve usually requires slower loading force application than would be used if creep only was measured.
This slower loading force application sometimes results in greater strain at the instant of full-load full force application than if the loadforce had been applied without the delays caused by incremental loading.The take-up mechanism should avoid introducing shock loads, overloading due to friction or inertia in the loading system, or apply torque to the specimen.
The take-up mechanism shall avoid time. If packing is used to seal the furnace, it must not be extrapolating the linear portion of the force-extension curve. Using a Practice E This is the easiest and least expensive way to grip specimens in the furnace, with threaded high temperature pull rods. If it is a product test you may want the Universal Test Machine with a furnace for higher force and larger specimens. Precautions should be made to minimize the transmission of shock to neighboring test machines and specimens when a specimen fractures.