1、Designation: A991/A991M 10Standard Test Method forConducting Temperature Uniformity Surveys of FurnacesUsed to Heat Treat Steel Products1This standard is issued under the fixed designation A991/A991M; the number immediately following the designation indicates the yearof original adoption or, in the
2、case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the procedures used to conducta temperature uniformity survey o
3、n a furnace used to heat treatsteel products. This method is used to determine the capabilityof the furnace to meet the permissible temperature variationspecified in the applicable product specification, or as agreed toby the purchaser and supplier of heat treat services. Surveydocumentation require
4、ments, and the procedure used to subse-quently establish the furnace working zone, are defined in thistest method.1.2 This test method covers heat treat furnaces in any of thefollowing categories:1.2.1 Continuous or semi-continuous conveyance furnaces,1.2.2 Batch furnaces, and1.2.3 Salt or liquid ba
5、ths and fluidized beds.1.3 This test method only applies when specified in theproduct specification or the purchase order.1.4 Controlling a heat treatment of steel products usingthermocouples attached to the extremities of each load is analternative to performing a furnace survey.1.5 By mutual agree
6、ment between the purchaser and thesupplier of heat treat services, more stringent and/or additionalrequirements may be specified. The acceptance of any suchadditional requirements shall be dependent on negotiationswith the supplier and must be included in the order as agreedupon by the purchaser and
7、 supplier.1.6 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-confor
8、mancewith the standard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior
9、 to use.2. Referenced Documents2.1 ASTM Standards:2E207 Test Method for Thermal EMF Test of Single Ther-moelement Materials by Comparison with a ReferenceThermoelement of Similar EMF-Temperature PropertiesE220 Test Method for Calibration of Thermocouples ByComparison TechniquesE230 Specification and
10、 Temperature-Electromotive Force(EMF) Tables for Standardized ThermocouplesE608/E608M Specification for Mineral-Insulated, Metal-Sheathed Base Metal Thermocouples2.2 SAE Standard:3AMS 2750 Pyrometry3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 batch furnace, nheating device
11、in which materialmay be stationary or oscillating during the processing cycle.3.1.2 continuous conveyance furnace, nheating devicethrough which material is moved intentionally at a constantrate during the processing cycle.3.1.3 extremities, nas referring to furnace working zone;outer boundaries in a
12、ll three dimensions (length, width, andheight) of the material being processed.3.1.4 operating range, nexpected range of temperatureover which a furnace will be controlled to heat treat steelproducts.1This test method is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Relat
13、ed Alloys and is the direct responsibility of SubcommitteeA01.13 on Mechanical and Chemical Testing and Processing Methods of SteelProducts and Processes.Current edition approved April 1, 2010. Published April 2010. Originallyapproved in 1998. Last previous edition approved in 2008 as A991/A991M 08.
14、DOI: 10.1520/A0991_A0991M-10.2For referenced ASTM 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.3Available from Society of Autom
15、otive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001, http:/www.sae.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.5 primary survey, ninitial
16、 evaluation of the furnace,or an evaluation triggered by the initiation of a major furnacemodification.3.1.6 secondary survey, nevaluation of the furnace trig-gered by the expiration of a time requirement.3.1.7 semi-continuous conveyance furnace, nheating de-vice through which material is moved inte
17、ntionally with apredetermined start-stop-start pattern during the processingcycle.3.1.8 working zone, nmaximum volume and location inthe furnace that meet the permissible temperature variation.4. Significance and Use4.1 Furnaces for heat treatment of steel products are used inmany industries, in man
18、y ways. Regardless of heat treatfurnace type, or processing cycle, it may be necessary for usersto know the temperature uniformity in the furnace and whetherthe material is processed in a zone within the furnace that iscapable of meeting the applicable permissible temperaturevariation requirements.4
19、.2 The procedures in this test method may be used by thoseusing, manufacturing, and providing calibration service for,heat treat furnaces used to process steel products.5. Furnace Survey Equipment5.1 Thermocouples:5.1.1 Metal sheathed thermocouples shall be in accordancewith Specification E608/E608M
20、.5.1.2 The use of extension wires is permitted when com-pensated connectors, plugs, jacks, and terminal strips are used.5.1.3 Thermocouples made from spool wire shall meet therequirements of AMS 2750.5.1.4 The use of spliced extension wire is prohibited.5.1.5 Thermocouples may be reused if the requi
21、rements ofAMS 2750 (except Paragraphs 3.1.1.10 and 3.1.1.11 of Rev. D)are met.5.2 Calibration:5.2.1 All reference, primary, secondary, test and workingequipment, instrumentation and sensors used in conjunctionwith this test method shall meet the requirements of calibrationdefined by Test Methods E20
22、7 and E220.5.2.2 Temperature measuring devices shall be calibratedwithin three months prior to use.5.2.3 Calibration shall be traceable to the National Instituteof Standards Technology standards, or equivalent nationalstandards. Calibration to such national standards shall be doneat least once every
23、 two years.5.2.4 Calibration shall be within the temperature range to beused in the survey and at intervals not greater than 200F100C for primary and secondary standards.5.2.5 Correction factors, limits of error, and deviations shallbe in accordance with Specification E230.6. Requirements6.1 Uniform
24、ity Survey Test Conditions:6.1.1 The furnace to be surveyed shall be capable of beingtested at set point temperature(s) typical for the normaloperating range.6.1.1.1 If the operating range does not exceed a spread of300F 150C, the midpoint temperature shall be selected forthe survey.6.1.1.2 If the o
25、perating range exceeds a spread of 300F150C, survey at the minimum and maximum set pointtemperature for the normal operating range, except that themaximum temperature need not be higher than 2000F1100C.6.1.2 Either typical or maximum production size and weightfurnace loads shall be utilized during t
26、he survey. Use ofrepresentative material to simulate product during survey ispermitted.6.1.3 The furnace atmosphere and operating conditionsshall be representative of those used in production.6.2 Frequency of Uniformity Surveys:6.2.1 Primary Surveys:6.2.1.1 A primary survey shall have been performed
27、 withintwelve months prior to, or run concurrently with, the firstproduction heat treatment to which this test method applies.6.2.1.2 A primary survey shall have been conducted when amajor furnace modification is completed. A major furnacemodification includes, but is not limited to, the installatio
28、n ofthe following: a different burner type, a new heating elementdesign, a different type of insulation system, and, a differenttype of temperature controlling device.6.2.1.3 Replacement of worn parts with similar parts orpatching of insulation that does not change the furnacecharacteristics does no
29、t constitute a major furnace modifica-tion.6.2.1.4 The survey shall be conducted within twelve monthsprior to, or run concurrently with, the first production heattreatment performed after the modification.6.2.2 Secondary Surveys:6.2.2.1 To maintain conformance with this test method, asecondary surve
30、y shall be conducted within twelve monthsafter the primary survey.6.2.2.2 Secondary surveys shall be conducted at a typicalfurnace set point temperature within the normal operatingrange. All other conditions described in 6.1 shall apply.7. Procedure7.1 Survey measuring equipment shall meet the requi
31、re-ments of Section 5.7.2 Test conditions and test frequency shall be as defined in6.1 and 6.2, respectively.7.3 Place thermocouples to monitor time and temperatureprofiles in the furnace to evaluate the uniformity of theintended working zone. Place them at the outer extremities, thecenter of the pr
32、oposed working zone, and in areas of suspectedvariability in the proposed working zone. Attach survey testsensors to, or set them in the load.7.4 For proposed working zones less than 12 in. 300 mmin height, it is acceptable to monitor the center height location,it is not necessary to monitor both th
33、e top and bottom of theheating chamber. For proposed working zones greater than, orequal to, 12 in. 300 mm in height, both top and bottomextremities must be monitored.7.5 Continuous Conveyance and Semi-Continuous Convey-ance Furnaces:A991/A991M 1027.5.1 Convey test sensors through the furnace. The r
34、ate ofconveyance shall be representative of normal operating condi-tions.7.5.2 The frequency of temperature recordings shall becapable of detecting variations from the test temperature rangeduring the entire conveyance through the furnace.7.5.3 Several conveyances with the test sensors attached toth
35、e steel product, under the same conditions, may be made toensure that any recurrent temperature profiles are determined atall test locations throughout the furnace.7.5.4 Alternative surveying techniques are described in 7.7.7.6 Batch and Batch Liquid Media Furnaces:7.6.1 Take readings starting when
36、the control instrumentrises to within 200F 100C of the set point temperature andcontinue throughout the hold cycle at the set point temperature.7.6.2 Take readings at a minimum frequency of 1/10 thenormal hold time.7.6.3 Take the readings frequently enough to detect varia-tions from the test tempera
37、ture range and to determine theextremes of the recurrent temperature profile, if any.7.6.4 Alternative surveying techniques are described in 7.7.7.7 Alternative Surveying TechniquesWhen agreed to bythe purchaser and the supplier of heat treat services, alternativesurveying techniques may be used to
38、characterize the tempera-ture uniformity of the furnace and subsequently define the sizeand location of the working zone. Examples of these surveyingtechniques are listed below.7.7.1 Statistical Sampling:7.7.1.1 When it is impossible or impractical to perform thetests outlined in 7.5 and 7.6, it is
39、permissible to substitute ananalysis of the resultant mechanical properties of the steelproducts heat treated in the subject furnace to validate tem-perature uniformity. Details of this procedure shall be as agreedto between purchaser and supplier.7.7.2 Sequential Load Sensors:7.7.2.1 This procedure
40、 may be used as an alternative tothose described in 7.5 and 7.6. It provides validation oftemperature uniformity by a series of tests rather than a singletest. In each test, determine the temperature variation pattern atone or more of the test locations.7.7.2.2 The frequency of test shall be six mon
41、ths.7.7.2.3 The temperature shall be within the normal operat-ing range, with the narrowest permissible variation for thematerial applied to the survey.7.7.2.4 Run the furnace with a load similar to that used in anormal production cycle.7.7.2.5 Load or test sensors shall be arranged in, or incontact
42、 with, the test load.7.7.2.6 Control setting(s) shall be identical to those used innormal production.7.7.2.7 Take readings starting when the control instrumentsrises to within 200F 100C of the set point temperature andcontinued throughout the hold cycle at the set point tempera-ture.7.7.2.8 Record t
43、he temperature of all load test and workingsensors frequently enough to detect when the specified oper-ating range is exceeded, and at least five cycles of any recurrentpattern have been observed.7.7.2.9 If no recurrent temperature profile is detected, takereadings at intervals of five minutes or le
44、ss, for at least 30 minafter thermal equilibrium is reached.8. Documentation of Survey Results8.1 Organizations performing surveys in accordance withthis test method shall keep pertinent documentation of theconditions and procedures used in the completion of the surveyon file for a minimum of five y
45、ears.8.2 Pertinent documentation shall include, but not be lim-ited to, the following:8.2.1 Specific identification of furnace surveyed,8.2.2 Date of the uniformity survey,8.2.3 Identification of the heat treat procedure,8.2.3.1 Set point temperatures,8.2.3.2 Type of atmosphere,8.2.3.3 Conveyance sp
46、eed (when applicable),8.2.4 Size and weight of steel product loaded in furnace attime of survey,8.2.5 Item identification numbers (lot, heat serial, etc.),8.2.6 Time and temperature data, including original tem-perature charts or original manually recorded data,8.2.7 Dimensions and location of the w
47、orking zone(s),8.2.8 Number and location of the survey thermocouples,8.2.9 Largest observed temperature variation from the setpoints during the hold cycle,8.2.10 The time interval of the test, including the totalelapsed time. Starting time and chart speed shall be marked onthe original temperature c
48、harts,8.2.11 All pertinent equipment calibration information,8.2.12 Deviations from the test method including, but notlimited to, thermocouple failure, malfunction, or disconnec-tion.8.2.13 Name of personnel conducting the survey, and8.3 All data may be electronically recorded.9. Interpretation of R
49、esults and Establishment of theWorking Zone9.1 The results of the primary survey describe the tempera-ture uniformity of a furnace under a specific set of operatingconditions. Results of the application of this test method shallbe expressed as a variation from a temperature set point.9.2 Establishment of the furnace working zone is made bycomparing the temperature variation required by the productspecification, or agreed to by purchaser and supplier of heattreat services, with the variation from the temperature set pointas determined by this uni
