ASTM A991/A991M-98
(Test Method)Standard Test Method for Conducting Temperature Uniformity Surveys of Furnaces Used to Heat Treat Steel Products
Standard Test Method for Conducting Temperature Uniformity Surveys of Furnaces Used to Heat Treat Steel Products
SCOPE
1.1 This test method covers the procedures used to conduct a temperature uniformity survey on a furnace used to heat treat steel products. This method is used to determine the capability of the furnace to meet the permissible temperature variation specified in the applicable product specification, or as agreed to by the purchaser and supplier of heat treat services. Survey documentation requirements, and the procedure used to subsequently establish the furnace working zone, are defined in this test method.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation:A991/A991M–98
Standard Test Method for
Conducting Temperature Uniformity Surveys of Furnaces
Used to Heat Treat Steel Products
This standard is issued under the fixed designationA 991/A 991M; the number immediately following the designation indicates the year
of 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers the procedures used to conduct 2.1 ASTM Standards:
a temperature uniformity survey on a furnace used to heat treat E 207 Test Method for Thermal EMF Test of Single Ther-
steel products. This method is used to determine the capability moelement Materials by Comparison with a Reference
of the furnace to meet the permissible temperature variation Thermoelement of Similar EMF - Temperature Properties
specified in the applicable product specification, or as agreed to E 220 Test Method for Calibration of Thermocouples By
by the purchaser and supplier of heat treat services. Survey Comparison Techniques
documentation requirements, and the procedure used to subse- E 230 Specification and Temperature-Electromotive Force
quently establish the furnace working zone, are defined in this (EMF) Tables for Standardized Thermocouples
test method. E 608 Specification for Metal-Sheathed Base-Metal Ther-
1.2 This test method covers heat treat furnaces in any of the mocouples
following categories: 2.2 SAE Standard:
1.2.1 Continuous or semi-continuous conveyance furnaces, AMS 2750 - Pyrometry
1.2.2 Batch furnaces, and
3. Terminology
1.2.3 Salt or liquid baths and fluidized beds.
1.3 This test method only applies when specified in the 3.1 Definitions of Terms Specific to This Standard:
3.1.1 batch furnace, n—a heating device in which material
product specification or the purchase order.
1.4 Controlling a heat treatment of steel products using may be stationary or oscillating during the processing cycle.
3.1.2 continuous conveyance furnace, n—a heating device
thermocouples attached to the extremities of each load is an
alternative to performing a furnace survey. through which material is moved intentionally at a constant
rate during the processing cycle.
1.5 By mutual agreement between the purchaser and the
3.1.3 extremities, n—as referring to furnace working zone;
supplier of heat treat services, more stringent and/or additional
requirements may be specified. The acceptance of any such outer boundaries in all three dimensions (length, width, and
height) of the material being processed.
additional requirements shall be dependent on negotiations
with the supplier and must be included in the order as agreed 3.1.4 operating range, n—the expected range of tempera-
ture over which a furnace will be controlled to heat treat steel
upon by the purchaser and supplier.
1.6 The values stated in either inch-pound units or SI units products.
3.1.5 primary survey, n—the initial evaluation of the fur-
are to be regarded separately as standard. Within the text, the
SI units are shown in brackets. The values stated in each nace, or an evaluation triggered by the initiation of a major
furnace modification.
system are not exact equivalents; therefore, each system is to
be used independently of the other, without combining values 3.1.6 secondary survey, n—an evaluation of the furnace
triggered by the expiration of a time requirement.
in any way.
1.7 This standard does not purport to address all of the 3.1.7 semi-continuous conveyance furnace, n—a heating
device through which material is moved intentionally with a
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- predetermined start - stop - start pattern during the processing
cycle.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 3.1.8 working zone, n—the maximum volume and location
in the furnace that meet the permissible temperature variation.
This test method is under the jurisdiction of ASTM Committee A-1 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee Annual Book of ASTM Standards, Vol 14.03.
A01.13 on Mechanical and Chemical Testing and Processing Methods of Steel Discontinued; see 1994 Annual Book of ASTM Standards, Vol 14.03.
Products and Processes. Available from Society of Automotive Engineers, 400 Commonwealth Drive,
Current edition approved July 10, 1998. Published September 1998. Warrendale, PA 15096.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
A991/A991M
4. Significance and Use 6.2 Frequency of Uniformity Surveys:
6.2.1 Primary Surveys:
4.1 Furnaces for heat treatment of steel products are used in
6.2.1.1 A primary survey shall have been performed within
many industries, in many ways. Regardless of heat treat
twelve months prior to, or run concurrently with, the first
furnace type, or processing cycle, it may be necessary for users
production heat treatment to which this test method applies.
to know the temperature uniformity in the furnace and whether
6.2.1.2 Aprimary survey shall have been conducted when a
the material is processed in a zone within the furnace that is
capable of meeting the applicable permissible temperature major furnace modification is completed. A major furnace
modification includes, but is not limited to, the installation of
variation requirements.
4.2 The procedures in this test method may be used by those the following: a different burner type, a new heating element
design, a different type of insulation system, and, a different
using, manufacturing, and providing calibration service for,
heat treat furnaces used to process steel products. type of temperature controlling device.
6.2.1.3 Replacement of worn parts with similar parts or
5. Furnace Survey Equipment
patching of insulation that does not change the furnace
characteristics does not constitute a major furnace modifica-
5.1 Thermocouples:
tion.
5.1.1 Metal sheathed thermocouples shall be in accordance
6.2.1.4 The survey shall be conducted within twelve months
with Specification E 608.
prior to, or run concurrently with, the first production heat
5.1.2 The use of extension wires is permitted when com-
treatment performed after the modification.
pensated connectors, plugs, jacks, and terminal strips are used.
5.1.3 Thermocouples made from spool wire shall meet the 6.2.2 Secondary Surveys:
requirements of AMS 2750. 6.2.2.1 To maintain conformance with this test method, a
5.1.4 The use of spliced extension wire is prohibited.
secondary survey shall be conducted within twelve months
5.1.5 Thermocouples may be reused if the requirements of after the primary survey.
AMS 2750 (except Paragraph 3.1.1.7.2 of Rev. C) are met.
6.2.2.2 Secondary surveys shall be conducted at a typical
5.2 Calibration:
furnace set point temperature within the normal operating
5.2.1 All reference, primary, secondary, test and working
range. All other conditions described in 6.1 shall apply.
equipment, instrumentation and sensors used in conjunction
with this test method shall meet the requirements of calibration
7. Procedure
defined by Test Methods E 207, and E 220.
7.1 Survey measuring equipment shall meet the require-
5.2.2 Temperature measuring devices shall be calibrated
ments of Section 5.
within three months prior to use.
7.2 Test conditions and test frequency shall be as defined in
5.2.3 Calibration shall be traceable to the National Institute
6.1 and 6.2, respectively.
of Standards Technology standards, or equivalent national
7.3 Place thermocouples to monitor time and temperature
standards. Calibration to such national standards shall be done
profiles in the furnace to evaluate the uniformity of the
at least once every two years.
intended working zone. Place them at the outer extremities, the
5.2.4 Calibration shall be within the temperature range to be
center of the proposed working zone, and in areas of suspected
used in the survey and at intervals not greater than 200°F
variability in the proposed working zo
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