ASTM A1100-16(2022)

Standard Guide for Qualification and Control of Induction Heat Treating

SIGNIFICANCE AND USE
4.1 This guide helps purchasers assess induction processes including the critical parameters that can affect product quality. It guides the evaluation of heat-treating vendor performance and capabilities to ensure higher and more consistent product quality.  
4.2 Refer to Appendix X1 for a flow chart for the use of this guide.
SCOPE
1.1 This guide covers the process control and product properties verification of continuous heat treating of material using a quench and temper induction process (surface hardening, surface heat treating, and batch heat-treated products using induction are not considered in this guide). Examples of products covered by this guide may include products covered by API Specifications 20E, 5L, and 5CT.  
1.2 This guide indicates some features of induction heat treating compared to furnace heat treating. Induction heat treating processes typically operate at higher temperatures compared to furnace processes.  
1.3 This guide addresses the features and requirements necessary for induction heating and ancillary equipment. However, induction equipment may be used in combination with convection heating equipment (for example, gas or electric furnaces).  
1.4 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2022
• ICS: 25.180.10 - Electric furnaces
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.13 - Mechanical and Chemical Testing and Processing Methods of Steel Products and Processes

Relations

• Refers: ASTM A941-24 - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-Mar-2024
• Refers: ASTM A255-10(2018) - Standard Test Methods for Determining Hardenability of Steel
• Effective Date: 01-Sep-2018
• Refers: ASTM E18-18 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Jul-2018
• Refers: ASTM A941-17 - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-Sep-2017
• Refers: ASTM E18-17 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Jul-2017
• Refers: ASTM A941-15 - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-Nov-2015
• Refers: ASTM E7-15 - Standard Terminology Relating to Metallography
• Effective Date: 01-Jun-2015
• Refers: ASTM E7-14 - Standard Terminology Relating to Metallography
• Effective Date: 01-Nov-2014
• Refers: ASTM A255-10(2014) - Standard Test Methods for Determining Hardenability of Steel
• Effective Date: 01-Oct-2014
• Refers: ASTM E10-14 - Standard Test Method for Brinell Hardness of Metallic Materials
• Effective Date: 01-May-2014
• Refers: ASTM A751-14 - Standard Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
• Effective Date: 01-Mar-2014
• Refers: ASTM A941-13b - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-Jun-2013
• Refers: ASTM A941-13a - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-May-2013
• Refers: ASTM A941-13 - Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• Effective Date: 01-Apr-2013
• Refers: ASTM E18-12 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Dec-2012

Overview

ASTM A1100-16(2022) is a standardized guide published by ASTM International that provides comprehensive guidelines for the qualification and control of induction heat treating, specifically for continuous quench and temper induction processes. This standard is designed to help purchasers, manufacturers, and heat treaters evaluate, control, and document critical process parameters during induction heat treatment to achieve high and consistent product quality.

Covering products such as bars, rods, tubes, and pipes-particularly those under API Specifications 20E, 5L, and 5CT-this guide sets out best practices for process control, equipment verification, maintenance, and validation of finished products. It compares key aspects of induction heat treating with furnace heat treating, highlighting the benefits and considerations unique to induction processes.

Key Topics

• Process Control and Monitoring
  The standard emphasizes meticulous control of all process variables, including power supply, induction coils, line speed, quench system, and pyrometers. Documented procedures are required for verifying equipment capabilities, calibration, and system maintenance.

• Manufacturing Procedures
  Detailed written procedures must include product composition, dimensions, prior microstructure, precise process steps, and equipment configurations. These procedures serve as the foundation for consistent, repeatable manufacturing outcomes.

• Equipment Qualification and Maintenance
  Induction heat treating equipment must be regularly verified and calibrated following both manufacturer recommendations and the included guide schedules. Regular preventive maintenance is essential for maintaining process integrity and minimizing equipment-related variability.

• Process Validation Testing
  Upon implementation of a new manufacturing procedure, thorough testing-including chemical analysis, hardness testing, mechanical property evaluation, and metallurgical inspection-is required to validate the process and establish tolerance ranges for process variables.

• Record Keeping
  The standard mandates comprehensive documentation and retention of critical records such as equipment verifications, calibration data, manufacturing procedures, and validation testing outcomes, ensuring full traceability and compliance.

Applications

The ASTM A1100 standard has practical value in a variety of industrial settings where induction heat treating is employed for steel products. Key applications include:

• Oil and Gas Industry
  Supporting the qualification of heat-treated steel bars, rods, tubes, and pipes compliant with API 20E, 5L, and 5CT, used in drilling, pipelines, and casing applications.

• Metal Processing and Manufacturing
  Applicable in plants and facilities specializing in high-throughput, automated production of steel components demanding consistently high mechanical properties and surface integrity.

• Quality Assurance and Vendor Evaluation
  Purchasers and manufacturers can use the guide to audit and qualify heat-treating vendors, ensuring adherence to critical process parameters and document control requirements to safeguard product performance.

• Continuous Improvement and Compliance
  The framework supports companies in refining their induction heat treating processes, achieving energy efficiency, minimizing material waste, and maintaining compliance with international standards and customer requirements.

Related Standards

ASTM A1100-16(2022) references and aligns with several key standards that support the implementation of induction heat treating:

• ASTM Standards:

  • ASTM A255: Tested methods for determining the hardenability of steel.
  • ASTM A1058: Mechanical testing of steel products.
  • ASTM A751: Chemical analysis of steel products.
  • ASTM A941 & ASTM E7: Terminology relevant to steel and metallography.
  • ASTM E10, E18, E112, E384: Standards for hardness and grain size testing.

• API Specifications:

  • API 20E, 5L, 5CT: Specifications for alloy and carbon steel bolting, line pipe, and casing/tubing.

• ASM Handbook Volume 4C: Induction Heating and Heat Treatment.

• ANSI/NCSL Z540.3: Calibration requirements for measuring and test equipment.

These related documents provide further technical details and testing protocols supporting the effective implementation of induction heat treating process control as described in ASTM A1100.

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Keywords: induction heat treating, ASTM A1100, process control, equipment calibration, steel bar, oil and gas, quench and temper, product verification, manufacturing procedure, heat treat vendor qualification.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: A1100 − 16 (Reapproved 2022)
Standard Guide for
Qualification and Control of Induction Heat Treating
This standard is issued under the fixed designation A1100; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This guide covers the process control and product 2.1 ASTM Standards:
properties verification of continuous heat treating of material A255 Test Methods for Determining Hardenability of Steel
using a quench and temper induction process (surface A751 Test Methods and Practices for Chemical Analysis of
hardening, surface heat treating, and batch heat-treated prod- Steel Products
ucts using induction are not considered in this guide). Ex- A941 Terminology Relating to Steel, Stainless Steel, Related
amples of products covered by this guide may include products Alloys, and Ferroalloys
covered by API Specifications 20E, 5L, and 5CT. A1058 Test Methods for Mechanical Testing of Steel
Products—Metric
1.2 This guide indicates some features of induction heat
E7 Terminology Relating to Metallography
treating compared to furnace heat treating. Induction heat
E10 Test Method for Brinell Hardness of Metallic Materials
treating processes typically operate at higher temperatures
E18 Test Methods for Rockwell Hardness of Metallic Ma-
compared to furnace processes.
terials
1.3 This guide addresses the features and requirements
E112 Test Methods for Determining Average Grain Size
necessary for induction heating and ancillary equipment.
E384 Test Method for Microindentation Hardness of Mate-
However, induction equipment may be used in combination
rials
with convection heating equipment (for example, gas or
2.2 ASM Standards:
electric furnaces).
ASM Handbook Volume 4C Induction Heating and Heat
1.4 Units—The values stated in SI units are to be regarded Treatment
2.3 API Specifications
as the standard. No other units of measurement are included in
20E Alloy and Carbon Steel Bolting for Use in the Petro-
this standard.
leum and Natural Gas Industries
1.5 This standard does not purport to address all of the
5CT Specification for Casing and Tubing
safety concerns, if any, associated with its use. It is the
5L Specification for Line Pipe
responsibility of the user of this standard to establish appro-
2.4 ANSI Standard:
priate safety, health, and environmental practices and deter-
ANSI/NCSL Z540.3 Requirements for the Calibration of
mine the applicability of regulatory limitations prior to use.
Measuring and Test Equipment
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3. Terminology
ization established in the Decision on Principles for the
3.1 For definitions of terms used in this guide, refer to
Development of International Standards, Guides and Recom-
Terminologies A941 and E7.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
This guide is under the jurisdiction of ASTM Committee A01 on Steel, the ASTM website.
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee Available from American Society for Metals (ASM International), 9639
A01.13 on Mechanical and Chemical Testing and Processing Methods of Steel Kinsman Rd., Materials Park, OH 44073-0002, http://www.asminternational.org.
Products and Processes. Available from American Petroleum Institute (API), 1220 L. St., NW,
Current edition approved Sept. 1, 2022. Published October 2022. Originally Washington, DC 20005-4070, http://www.api.org.
approved in 2016. Last previous edition approved in 2016 as A1100 – 16. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/A1100-16R22. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A1100 − 16 (2022)
3.2 Definitions of Terms Specific to This Standard: 5.2 The documented procedures shall address verification,
3.2.1 induction heat treating, v—process by which an elec- calibration, and maintenance of the equipment as described in
tromagnetic field is used to induce a voltage in an electrically
the following.
conductive material thereby causing current flow and heat is
5.3 Verification and Calibration of Equipment—Equipment
generated in the electrically conductive material through the
for the heat-treating line shall be verified and calibrated at a
Joule heating effect. (See ASM Handbook 4C, p. 18.)
level necessary to achieve the tolerances determined in Section
3.2.2 major rebuild, n—any rebuild or repair that could alter
6. It is recommended that calibration of test equipment follow
the temperature uniformity characteristics of an induction heat
the guidelines in ANSI/NCSL Z540.3. Equipment capabilities
treat line.
are related to the product chemistry, product dimensions, and
3.2.3 product, n—set of similar materials to be heated by
production rate. It is possible that different products may
passing through induction coils under the same conditions as
require different tolerance ranges for parameter settings. These
defined in 6.3 process variables. (Including as examples bar,
tolerance ranges shall be documented as part of the manufac-
rod, tube, pipe.)
turing procedures (Section 6). Classification and characteriza-
3.2.4 quench media, n—coolant used to quench out the work
tion of a heat-treat line based on equipment accuracy ranges
piece.
and equipment capabilities may be conducted using the method
3.2.4.1 Discussion—Typically, it contains water or water
described in Appendix X4. It is recommended that verification
and a polymer-based quench media.
of equipment performance be conducted with heated product.
Cold tests (for example, testing material handling, sensors, and
3.2.5 refractometer, n—device used to measure the concen-
controls) are useful, but equipment on an induction heat
tration of quench media that is mixed with water.
3.2.5.1 Discussion—Typical units are in degrees Brix and treating line may behave differently with heated product.
are approximately equivalent to half the volume concentration.
5.3.1 Power Supply Units:
3.2.6 sensors, n—need to identify the type of sensors as they
5.3.1.1 The power supply units shall be capable of achiev-
are already in some standards.
ing the rated power and nominal frequency designated for the
equipment by the manufacturer. Heating capabilities to achieve
3.2.7 skin depth, n—also called depth of current penetration;
target temperatures should be verified at the point of installa-
the depth to which an alternating current will flow in a
conductor. (See Appendix X3.) tion of new power equipment, including ancillary equipment
and devices such as connecting power cables and induction
4. Significance and Use
coils, and records of these capabilities should be kept (see 9.1).
4.1 This guide helps purchasers assess induction processes
NOTE 1—The output power is a function of the voltage and current of
including the critical parameters that can affect product quality.
the electrical system. If voltage or current is limited (because of high
It guides the evaluation of heat-treating vendor performance
inductance, for example), the maximum power will be limited. For this
and capabilities to ensure higher and more consistent product
reason, it is important to ensure that the power supply is evaluated with the
quality.
induction coil and desired product so that accurate power capabilities are
determined.
4.2 Refer to Appendix X1 for a flow chart for the use of this
guide. 5.3.1.2 The power level for any given manufactured product
may be selected at the heat treater’s discretion to achieve the
5. Equipment
necessary target manufacturing procedure parameters. The
5.1 Equipment Capabilities—Equipment used to produce
output power stability should be monitored at regular intervals
the desired heat-treated product shall be capable of achieving
to ensure sufficient power stability to achieve the tolerance
target heat-treat parameters. Parameters shall be documented
levels documented in Section 6. Incoming power to the plant
as per Section 6, and Section 7 shall be used to verify that the
can affect output power stability; therefore, incoming power
manufacturing procedure has been well developed, proper
may be monitored to ensure consistent output power capabili-
parameter tolerances have been selected, and equipment is
ties. Various power quality measuring devices are available for
capable of achieving all parameter settings. Documented pro-
monitoring incoming plant power and output power during
cedures for the verification of equipment capabilities,
operation.
calibration, and maintenance shall be maintained. These docu-
5.3.1.3 The frequency at each induction coil should be
mented procedures shall address all critical equipment for the
verified and documented within each manufacturing procedure
induction heat treatment line including, at minimum, the
to ensure heating consistency. Periodic checks of the frequency
following:
at the induction coils should be conducted.
5.1.1 All power supply units including relevant
components,
NOTE 2—The frequency is affected by the power level and the
inductance of the system. Changes to the coil design, size of product,
5.1.2 All induction coils,
cooling media through the coil, current/voltage ratio, coil cable
5.1.3 Quench system and components,
connections, and other factors can affect the frequency at the output coil.
5.1.4 Pyrometers and other temperature-sensing devices,
Changes in the output frequency can affect the depth of the induced
5.1.5 Material handling as it pertains to line speed control,
current in the work piece (skin depth) and, therefore, the thermal gradient
and
within the work piece (see Appendix X3). Frequency can be measured
5.1.6 Controls. using most standard multi-meters.
A1100 − 16 (2022)
5.3.1.4 It is not expected that power supply units will as it becomes contaminated with minerals, oil, scale, rust, and
require calibration unless otherwise stipulated by the manufac- other undesirable materials. The frequency of this refreshing of
turer of the equipment. Calibration and verification shall follow the quenchant depends on results from periodic monitoring of
the manufacturer’s recommended schedule or the schedule quenchant chemistry.
outlined in Table 1, whichever is more frequent. 5.3.3.2 Quench flow rate shall be verified periodically
5.3.2 Induction Coils—Induction coils are an important part according to the schedule in Table 1 using a method suggested
of the power supply units. The verified power output and by the equipment manufacturer or selected by the producer and
voltage/current match depend on the interconnection of coils described in a documented procedure maintained by the heat
and power supply units. For example, connecting coils in series treater.
or parallel to a power supply may significantly affect efficiency, 5.3.4 Pyrometers:
inductance, and overall ability to heat the product. Verification 5.3.4.1 Pyrometers shall be placed at positions along the
of equipment should include consideration of coil connections heat treat line to establish heating rates and soak times
and interconnect wiring functionality. Reverification of output accurately, as appropriate for the application. Pyrometer posi-
power capabilities should occur after any changes to the coil tion shall be consistent and recorded (see 9.1).
designs or the interconnections. In the instance of multiple 5.3.4.2 Pyrometer calibration by the pyrometer manufac-
induction coil designs on the same line, all coils will be turer typically entails calibration using a blackbody furnace
properly identified, and design/model number will be specified under highly controlled conditions. The tolerance and accuracy
in the manufacturing procedure. of a pyrometer on a heat-treat mill can be significantly reduced
5.3.3 Quench System: compared to measurement of a blackbody furnace in laboratory
5.3.3.1 Quench media composition shall be documented for conditions. The tolerance and accuracy for each pyrometer
every manufacturing procedure. Composition may include shall be provided by the pyrometer manufacturer based on the
documentation of polymer chemistry, supplier, age, brine target material composition and temperature for the pyrometer
concentration, water chemistry, and so forth as applicable. application. In addition, it is recommended that pyrometer
Verification of quench media composition, if applicable, shall accuracy be verified during production with the use of a
be conducted at the interval specified in Table 1. Use of a “master” pyrometer. The master pyrometer may be a hand-held
refractometer is recommended, when applicable, to determine or other unit in which the accuracy of the device has been
the concentration at the start and during the operation. Note verified off-line using a target material with similar surface
that quench media compositions are also affected by waste finish, composition, temperature, and ambient conditions com-
material in the quench (that is, scale, rust, and so forth). It may pared to the heated product. Temperature accuracy of the
be necessary to periodically discard and replace quench media master pyrometer is typically verified through the use of
TABLE 1 Verification and Calibration Frequency
A
Parameters/Features to Verify Event Reverification Frequency
After installation/commissioning of Once per year
• Power Stability new power supply unit
Power Supply
B
• Nominal frequency range Creation of a new MP At time of new MP verification
C
After major rebuild of equipment Once per year
After installation/commissioning of Once per year
• Visual inspection of interconnect
Induction Coils new coils
wiring and coil connections
After major rebuild of equipment Once per year
Installation/commissioning of new Monthly
quench system or component;
after flushing quench system
• Composition
Mill startup After system remains dormant for
Quench more than 14 days
Creation of new MP At time of new MP verification
Installation/commissioning of new Once every 3 months for first year,
• Flow quench system or component annually thereafter
Creation of new MP At time of new MP verification
Installation of new pyrometer Once every 3 months for first year,
D
annually thereafter
Pyrometer is sent out for repair Once every 3 months for first year,
D
Pyrometers • Temperature accuracy annually thereafter
Pyrometer is exposed to conditions After each event
not recommended by the
manufacturer
Installation of new drive equipment or Once every 6 months for first year,
E
measurement device annually thereafter
Line Speed • Speed
Major rebuild or repair of drive Once every 6 months for first year,
equipment or measurement device annually thereafter
A
Verify parameter at time of “event” and after initial verification follow this frequency.
B
MP = Manufacturing procedure.
C
See Note 5.
D
The use of a master pyrometer for verification is recommended.
E
Line speed measurement device may include tachometer, laser velocimeter, or other suitable means to determine line speed of product.
A1100 − 16 (2022)
thermocouples attached to the off-line target material. Com- 6. Procedure
parison to the master pyrometer should not be considered a
6.1 Manufacturing Procedure—A manufacturing procedure
replacement for regular calibration of the on-line pyrometers,
shall be established and maintained as a record (see 9.1) by the
which should be performed according to the manufacturer’s
heat treater for each product. The manufacturing procedure
specification. Records of pyrometer calibration and verification
shall include details of the process variables outlined in 6.3.
shall be maintained (see 9.1). Calibration and verification
NOTE 4—Although API 20E also outlines a “manufacturing procedure”
should follow the manufacturer’s recommended schedule or
with similar elements, the procedure described here is separate and
the schedule outline in Table 1.
distinct with no intention to exactly match the format of API Specification
20E.
NOTE 3—Proper selection of an appropriate pyrometer technology is
essential to ensuring the accuracy. Single-wavelength pyrometers are most
6.2 Manufacturing Procedure Qualification—The manufac-
common, but also least accurate. Higher accuracy can typically be
turing procedure shall be qualified through product testing as
achieved with shorter wavelength pyrometers, but pyrometer accuracy is
described in Section 7. Product testing as described in Section
also highly influenced by the emissivity setting. Additional information on
7 may also be used to establish the tolerance ranges for the
pyrometer technologies is provided in X4.1.
process variables in the manufacturing procedure. Requalifica-
5.3.5 Verifying Line Speed—Line speed and product rotation
tion of the manufacturing procedure is required for any major
are critical parameters that affect the heating and cooling rates
rebuild of the equipment.
as well as the soak time. Line speed shall be documented in the
NOTE 5—Examples of items that constitute a major rebuild that could
manufacturing procedure as described in 6.3.4. Verification and
change the temperature uniformity characteristics include, but are not
calibration of material-handling capabilities should include a
limited to: (1) Changes in induction coil design or placement; transformer
means for verifying line-speed measuring devices as well as
design changes; inverter component changes; or changes to connecting
synchronization of rolls and drives (that is, gap control).
power cables to, between, and from power supply units and coils; (2)
Changes in the location, type, or manufacturer of temperature-measuring
Synchronization of driven rolls becomes critical for control of
devices; (3) New designs for components used to convey parts through the
uniform rotation of product and control of gaps between
process; and (4) Changes to the quench media, design, or position or
products to minimize end effects during heating (see Appendix
changes to the quench plumbing that may impact the exit flow and
X3 for additional information on end effects). Methods for
pressure of quenchant.
verification and calibration of material-handling equipment
6.3 Product and Process Variables—The manufacturing
shall follow the equipment manufacturer’s instructions and
procedure may be structured in a format determined by the heat
may include the use of a calibrated off-line measurement
treater provided that it contains details on the process variables
device such as a laser velocimeter or other suitable device.
as stipulated in 6.3.1 – 6.3.9. Tolerances for each process
Verification of line speed should be conducted at multiple
variable are determined by the heat treater based on each
locations along the heat treat line (for example, entry, austen-
individual product physical property requirements.
itizing section, tempering section, and so forth) taking into
6.3.1 Product Composition—Nominal composition, steel
account thermal expansion of the product, as applicable.
grade, or range of chemistries for any given product shall be
Calibration and verification records shall be maintained (see
included in the manufacturing procedure.
9.1) and shall follow the manufacturer’s recommended sched-
6.3.2 Product Dimensions—Nominal dimensions or range
ule or the schedule outline in Table 1, whichever is more
of dimensions shall be listed for the manufacturing procedure.
frequent.
Dimensions shall include length, outside diameter and, in the
5.3.6 Controls:
case of tube and pipe, wall thickness and inside diameter.
5.3.6.1 Functionality and calibration of controls should be
NOTE 6—Wall thickness variations may require power and line speed
verified during installation and after any major rebuild (see
adjustment to maintain target temperature.
Note 5) to the heat-treat line and performed according to the
equipment manufacturer’s recommendation.
6.3.3 Product Prior Microstructure—Prior microstructure
or thermal processing method may be included in manufactur-
5.3.6.2 The heat-treat producer shall have a documented
ing procedure at the heat treater’s choice.
procedure that addresses the verification and maintenance of
the controls for each qualified line according to the guidelines 6.3.4 Line Speed—Line speed for each stage of the heat-
of Table 1 or the equipment manufacturers’ recommendation, treat process and methods for its verification shall be included
whichever is more stringent. in manufacturing procedure. The method for measuring and
verifying the line speed shall be described in the manufacturing
5.3.7 Maintenance—The heat-treat producer shall have a
procedure. The device(s) used to measure the line speed shall
documented and fully implemented preventive maintenance
be calibrated and maintained as described in 5.3.5.
procedure that addresses the following equipment and follows
6.3.5 Austenitizing—Target temperature and respective tol-
the manufacturer’s recommendations:
erances for austenitizing shall be included in the manufacturing
5.3.7.1 Material handling,
procedure. It is the temperature at which the product is held
5.3.7.2 Induction coils,
before quenching. The method for verifying the target tempera-
5.3.7.3 Power supply units,
ture shall be described in the manufacturing procedure. The
5.3.7.4 Quench systems including regular inspection and
time that product is held at the target austenitizing temperature
cleaning of spray nozzles and maintenance of pumps, and
shall be included in the manufacturing procedure. This may be
5.3.7.5 Pyrometers. recorded as a combination of distance (length of coils, number
A1100 − 16 (2022)
NOTE 7—Ideal diameter (DI) values (measured or calculated based on
of coils, and space between coils) and line speed or total time
chemical analysis per Test Method A255 methods) are very useful for
at target temperature. Verification of adequate austenitizing
each heat-lot material hardenability evaluation. Capability of each lot of
soak time may involve the use of in-line or handheld tempera-
material to achieve the required final properties for each size/grade/class
ture measurement devices (for example, a master pyrometer),
of final product should be carefully considered based on reported
modeling and simulation, metallurgical evaluation, or other
chemistry, DI, and prior conditions. Test Method A255-calculated DI
values are based on average grain size—7 typical for as many as-rolled,
means at the heat treater’s choice.
fully killed steels with grain refiners such as Al, Nb/Cb, and others. Larger
6.3.6 Quench Media—The quench media type (for example,
grains tend to increase DI, while smaller result in somewhat lower
water, oil, emulsions, mill coolant compositions) and the
hardenability.
quench media temperature shall be included in the manufac-
7.3 Mechanical Properties:
turing procedure. The quench media temperature may be
7.3.1 Hardness, tensile, and Charpy impact testing of fin-
measured at a location convenient to the manufacturer;
ished product should be used as applicable to validate each
however, this location shall be consistent to ensure reliable
product manufacturing procedure and establish acceptable
process monitoring.
tolerance ranges for process variables. Test Methods A1058 or
6.3.7 Quench Flow and Pressure—The flow rate and pres-
other suitable standard should provide guidance on these test
sure of the quenchant shall be included in the manufacturing
methods.
procedure, or as an alternative, the as-quenched hardness of the
7.3.2 Cross-sectional hardness checks on larger diameter
product shall be measured to demonstrate that the flow and
bars and thick-walled tube with DI values indicating material
pressure are adequate to achieve the desired martensitic trans-
limitations for through-hardening can provide valuable data on
formation.
depth of martensitic transformation and through thickness
6.3.8 As-Quenched Product Temperature—The target tem-
uniformity of mechanical properties. Test Method A255 may
perature or temperature range at the exit of the quench section
be used for checking hardenability during the creation of a new
shall be included in the manufacturing procedure. The method
manufacturing procedure or as a verification step during
for verifying the target temperature or temperature range shall
production.
be described in the manufacturing procedure. As an alternative,
7.3.3 When performed, bulk hardness measurements may
the as-quenched hardness of the product may be measured.
be conducted in accordance with internationally recognized
6.3.9 Tempering—Target temperature and respective toler-
Test Methods such as E10 or E18, as appropriate. Microhard-
ances for tempering shall be included in manufacturing proce-
ness measurements may be conducted in accordance with Test
dure. It is the temperature at which the product is held before
Method E384. Hardness measurements should be taken in
exit from the tempering section. The method for verifying the
opposite quadrants of a sample cross section and along a
target temperature shall be described in the manufacturing
sample length as indicated in Fig. 1 to verify process consis-
procedure. Time that product is held at the target-tempering
tency and proper selection of process variables for the estab-
temperature shall be included in the manufacturing procedure.
lished manufacturing p
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