1、Designation: A991/A991M 10 (Reapproved 2015)A991/A991M 17Standard 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 yearo
2、f original adoption or, in the 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 conduct a
3、 temperature uniformity survey on a furnace used to heat treat steelproducts. This method is used to determine the capability of the furnace to meet the permissible temperature variation specifiedin the applicable product specification, or as agreed to by the purchaser and supplier of heat treat ser
4、vices. Survey documentationrequirements, and the procedure used to subsequently establish the furnace working zone, are defined in this test method.1.2 This test method covers heat treat furnaces in any of the following categories:1.2.1 Continuous or semi-continuous conveyance furnaces,1.2.2 Batch f
5、urnaces, and1.2.3 Salt or liquid baths and fluidized beds.1.3 This test method only applies when specified in the product specification or the purchase order.1.4 Controlling a heat treatment of steel products using thermocouples attached to the extremities of each load is an alternativeto performing
6、 a furnace survey.1.5 By mutual agreement between the purchaser and the supplier of heat treat services, more stringent and/or additionalrequirements may be specified. The acceptance of any such additional requirements shall be dependent on negotiations with thesupplier and must be included in the o
7、rder as agreed upon by the purchaser and supplier.1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values fr
8、om thetwo systems may result in non-conformance with the standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the app
9、licability of regulatorylimitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the
10、World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E207 Test Method for Thermal EMF Test of Single Thermoelement Materials by Comparison with a Reference Thermoelementof Similar EMF-Temperature PropertiesE220 Test Method for Calibration of
11、 Thermocouples By Comparison TechniquesE230 Specification and Temperature-Electromotive Force (EMF) Tables for Standardized ThermocouplesE608/E608M Specification for Mineral-Insulated, Metal-Sheathed Base Metal Thermocouples2.2 SAE Standard:3AMS 2750 Pyrometry1 This test method is under the jurisdic
12、tion of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.13on Mechanical and Chemical Testing and Processing Methods of Steel Products and Processes.Current edition approved March 1, 2015April 15, 2017. Published March 2015April 201
13、7. Originally approved in 1998. Last previous edition approved in 20102015 asA991/A991M 10.A991/A991M 10 (2015). DOI: 10.1520/A0991_A0991M-10R15.10.1520/A0991_A0991M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual
14、 Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from Society of Automotive Engineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http:/www.sae.org.This document is not an ASTM standard and is intended only to provide
15、 the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the sta
16、ndard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions of Terms Specific to T
17、his Standard:3.1.1 batch furnace, nheating device in which material may be stationary or oscillating during the processing cycle.3.1.2 continuous conveyance furnace, nheating device through which material is moved intentionally at a constant rate duringthe processing cycle.3.1.3 extremities, nas ref
18、erring to furnace working zone; outer boundaries in all three dimensions (length, width, and height)of the material being processed.3.1.4 operating range, nexpected range of temperature over which a furnace will be controlled to heat treat steel products.3.1.5 primary survey, ninitial evaluation of
19、the furnace, or an evaluation triggered by the initiation of a major furnacemodification.3.1.6 secondary survey, nevaluation of the furnace triggered by the expiration of a time requirement.3.1.7 semi-continuous conveyance furnace, nheating device through which material is moved intentionally with a
20、predetermined start-stop-start pattern during the processing cycle.3.1.8 working zone, nmaximum volume and location in the furnace that meet the permissible temperature variation.4. Significance and Use4.1 Furnaces for heat treatment of steel products are used in many industries, in many ways. Regar
21、dless of heat treat furnacetype, or processing cycle, it may be necessary for users to know the temperature uniformity in the furnace and whether the materialis processed in a zone within the furnace that is capable of meeting the applicable permissible temperature variation requirements.4.2 The pro
22、cedures in this test method may be used by those using, manufacturing, and providing calibration service for, heattreat furnaces used to process steel products.5. Furnace Survey Equipment5.1 Thermocouples:5.1.1 Metal sheathed thermocouples shall be in accordance with Specification E608/E608M.5.1.2 T
23、he use of extension wires is permitted when compensated connectors, plugs, jacks, and terminal strips are used.5.1.3 Thermocouples made from spool wire shall meet the requirements of AMS 2750.5.1.4 The use of spliced extension wire is prohibited.5.1.5 Thermocouples may be reused if the requirements
24、of AMS 2750 (except Paragraphs 3.1.1.10 and 3.1.1.11 of Rev. D) aremet.5.2 Calibration:5.2.1 All reference, primary, secondary, test and working equipment, instrumentation and sensors used in conjunction with thistest method shall meet the requirements of calibration defined by Test Methods E207 and
25、 E220.5.2.2 Temperature measuring devices shall be calibrated within three months prior to use.5.2.3 Calibration shall be traceable to the National Institute of Standards Technology standards, or equivalent national standards.Calibration to such national standards shall be done at least once every t
26、wo years.5.2.4 Calibration shall be within the temperature range to be used in the survey and at intervals not greater than 200F 100Cfor primary and secondary standards.5.2.5 Correction factors, limits of error, and deviations shall be in accordance with Specification E230.6. Requirements6.1 Uniform
27、ity Survey Test Conditions:6.1.1 The furnace to be surveyed shall be capable of being tested at set point temperature(s) typical for the normal operatingrange.6.1.1.1 If the operating range does not exceed a spread of 300F 150C, the midpoint temperature shall be selected for thesurvey.6.1.1.2 If the
28、 operating range exceeds a spread of 300F 150C, survey at the minimum and maximum set point temperaturefor the normal operating range, except that the maximum temperature need not be higher than 2000F 1100C.6.1.2 Either typical or maximum production size and weight furnace loads shall be utilized du
29、ring the survey. Use ofrepresentative material to simulate product during survey is permitted.6.1.3 The furnace atmosphere and operating conditions shall be representative of those used in production.6.2 Frequency of Uniformity Surveys:6.2.1 Primary Surveys:6.2.1.1 Aprimary survey shall have been pe
30、rformed within twelve months prior to, or run concurrently with, the first productionheat treatment to which this test method applies.A991/A991M 1726.2.1.2 A primary survey shall have been conducted when a major furnace modification is completed. A major furnacemodification includes, but is not limi
31、ted to, the installation of the following: a different burner type, a new heating element design,a different type of insulation system, and, a different type of temperature controlling device.6.2.1.3 Replacement of worn parts with similar parts or patching of insulation that does not change the furn
32、ace characteristicsdoes not constitute a major furnace modification.6.2.1.4 The survey shall be conducted within twelve months prior 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 tes
33、t method, a secondary survey shall be conducted within twelve months after theprimary survey.survey and additional surveys within every twelve month period thereafter.6.2.2.2 Secondary surveys shall be conducted at a typical furnace set point temperature within the normal operating range. Allother c
34、onditions described in 6.1 shall apply.7. Procedure7.1 Survey measuring equipment shall meet the requirements of Section 5.7.2 Test conditions and test frequency shall be as defined in 6.1 and 6.2, respectively.7.3 Place thermocouples to monitor time and temperature profiles in the furnace to evalua
35、te the uniformity of the intendedworking zone. Place them at the outer extremities, the center of the proposed working zone, and in areas of suspected variabilityin the proposed working zone. Attach survey test sensors to, or set them in the load.7.4 For proposed working zones less than 12 in. 300 m
36、m in height, it is acceptable to monitor the center height location, itis not necessary to monitor both the top and bottom of the heating chamber. For proposed working zones greater than, or equalto, 12 in. 300 mm in height, both top and bottom extremities must be monitored.7.5 Continuous Conveyance
37、 and Semi-Continuous Conveyance Furnaces:7.5.1 Convey test sensors through the furnace. The rate of conveyance shall be representative of normal operating conditions.7.5.2 The frequency of temperature recordings shall be capable of detecting variations from the test temperature range duringthe entir
38、e conveyance through the furnace.7.5.3 Several conveyances with the test sensors attached to the steel product, under the same conditions, may be made to ensurethat any recurrent temperature profiles are determined at all test locations throughout the furnace.7.5.4 Alternative surveying techniques a
39、re described in 7.7.7.6 Batch and Batch Liquid Media Furnaces:7.6.1 Take readings starting when the control instrument rises to within 200F 100C of the set point temperature and continuethroughout the hold cycle at the set point temperature.7.6.2 Take readings at a minimum frequency of 1/10 the norm
40、al hold time.7.6.3 Take the readings frequently enough to detect variations from the test temperature range and to determine the extremesof the recurrent temperature profile, if any.7.6.4 Alternative surveying techniques are described in 7.7.7.7 Alternative Surveying TechniquesWhen agreed to by the
41、purchaser and the supplier of heat treat services, alternativesurveying techniques may be used to characterize the temperature uniformity of the furnace and subsequently define the size andlocation of the working zone. Examples of these surveying techniques are listed below.7.7.1 Statistical Samplin
42、g:7.7.1.1 When it is impossible or impractical to perform the tests outlined in 7.57.5 and 7.6 and 7.6, it is permissible to substitutean analysis of the resultant mechanical properties of the steel products heat treated in the subject furnace to validate temperatureuniformity. Details of this proce
43、dure shall be as agreed to between purchaser and supplier.7.7.2 Sequential Load Sensors:7.7.2.1 This procedure may be used as an alternative to those described in 7.57.5 and 7.6 and 7.6. It provides validation oftemperature uniformity by a series of tests rather than a single test. In each test, det
44、ermine the temperature variation pattern at oneor more of the test locations.7.7.2.2 The frequency of test shall be six months.7.7.2.3 The temperature shall be within the normal operating range, with the narrowest permissible variation for the materialapplied to the survey.7.7.2.4 Run the furnace wi
45、th a load similar to that used in a normal production cycle.7.7.2.5 Load or test sensors shall be arranged in, or in contact with, the test load.7.7.2.6 Control setting(s) shall be identical to those used in normal production.7.7.2.7 Take readings starting when the control instruments rises to withi
46、n 200F 100C of the set point temperature andcontinued throughout the hold cycle at the set point temperature.A991/A991M 1737.7.2.8 Record the temperature of all load test and working sensors frequently enough to detect when the specified operatingrange is exceeded, and at least five cycles of any re
47、current pattern have been observed.7.7.2.9 If no recurrent temperature profile is detected, take readings at intervals of five minutes or less, for at least 30 min afterthermal equilibrium is reached.8. Documentation of Survey Results8.1 Organizations performing surveys in accordance with this test
48、method shall keep pertinent documentation of the conditionsand procedures used in the completion of the survey on file for a minimum of five years.8.2 Pertinent documentation shall include, but not be limited to, the following:8.2.1 Specific identification of furnace surveyed,8.2.2 Date of the unifo
49、rmity 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 speed (when applicable),8.2.4 Size and weight of steel product loaded in furnace at time of survey,8.2.5 Item identification numbers (lot, heat serial, etc.),and so forth),8.2.6 Time and temperature data, including original temperature charts or original manually recorded data,8.2.7 Dimensions and location of the working zone(s),8.2.8 Number and location of the survey thermocouples,8.2.9 Largest observe
