This document provides an overview and introduction to understanding the CQI9 standard for heat treatment processes. It discusses the goals of CQI9, the structure and contents of the standard, including sections on process tables, heat treatment assessment, thermocouples, instrument calibration, temperature uniformity surveys, and job audits. The document is intended to help users gain an intermediate understanding of specific areas of CQI9, with references to more detailed information in the original standard.

1. Understanding CQI9 Version3
Intermediate (Heat Treatment)
© Peter Sherwin | Eurotherm | V1 2014
Automotive Heat Treat Standard

2. Contents
1. CQI9 Overview
2. Process Tables
3. Heat Treatment Assessment
4. Thermocouples
5. Instrument Calibration
6. System Accuracy Test
7. Temperature Uniformity Survey
8. Job Audit
9. Process Tables A, B, C
Useful links
Further infromation
C
13
14
15
10
12
15
18
23
25
36
36
2
Introduction
The purpose of the guide is to provide an
understanding of the CQI9 standard*
This guide is part of as a series of six separate
publications which cover the following:
1. The Beginners Guide to Heat Treatment Control
2. Understanding CQI9 (intermediate)
3. Understanding AMS2750E (intermediate)
4. Practical PID for Heat Treaters (intermediate)
5. Advanced Control methods (expert)
6. Business Performance and algorithms (expert)
*this guide is not intended to replace the standard and concentrates on
specific areas - for the full detail please view the original standard.
In the CQI9 guide; we have not covered the induction heat treat process
and have concentrated on Process Tables A, B, and C. We do not cover
the property surveys in the TUS section.

3. CQI9 Overview
The goal of creating CQI9 (by AIAG ) is to have
a Heat Treat management system that provides
for continual improvement, prevent defects,
reduces variation and waste in the supply chain.
Driven by a number of very public recalls in the
automotive industry over the past few years,
there is definitely a heightened view on quality
in the supply of components in the Automotive
Industry.
The work group (made up of volunteers from
member companies in the automotive industry)
created CQI9 – Version 3 and issued the new
version in October 2011.
3
Audits and Auditor
ISO/TS16949 Quality standard dictates
manufacturing audits to take place on a
frequent basis to ensure the process is
operating as planned.
CQI9 is an annual Self Assessment to meet the
requirements of a manufacturing audit in the
Heat Treatment department.
Internal Auditor Qualifications
• Experience Quality Management System
internal Auditor (either to ISO9001 or
TS16949).
• Evidence of a minimum of 5 years Heat
Treating or combination of Practical Heat
Treatment and formal metallurgical
education totalling a minimum of 5 years.
• Understand the Automotive Quality Core
tools including Statistical Process Control,
Measurement Systems Analysis, Part
Approval, Failure mode and effects
analysis and advanced quality planning.

4. Process Tables
There are 8 generic process tables that are
referenced during the audit:
• Process Table A – Ferrous
– Caburizing, Carbonitriding, Carbon
Restoration or Correction, Neutral Hardening
(quench and temper), Austempering,
Martempering, Tempering, Precipitation
Hardening – Aging.
• Process Table B – Ferrous
– Nitriding (Gas), Ferritic Nitrocarburizing (Gas
or Salt)
• Process Table C – Aluminum
– Aluminum Heat Treating
• Process Table D – Ferrous
– Induction Heat Treating
• Process Table E - Annealing, Normalizing
and Stress Relieving
• Process Table F – Low Pressure
Carburizing
• Process Table G – Sinter Hardening
• Process Table H – Ion Nitriding
Any process that doesn’t affect the final
characteristics of the part are exempt from
conforming to CQI9.
4
Requirements
The Process Tables specify the tolerance and
frequency for checking process control
parameters and parts.
• Process and Test Equipment
• Pyrometry
• Process Monitor Frequencies
• In-Process/Final test frequencies
• Quenchant and Solution test frequencies
Reference Documents
TS16949 – Quality management system
ISO9001 – Quality management system
ISO17025 – calibration laboratory standard
IEC60584-1 – Thermocouple reference tables
ASTM E230 – Thermocouple Specifications

5. 1
Heat Treat Assessment

6. Heat Treat System Assessment
The following sections are identified in the HTSA:
1. Management Responsibility & Quality Planning,
2. Floor and Material Handling Responsibility
3. Equipment.
The auditor needs to provide objective evidence to each question (or state N/A) to assess whether the
current status is satisfactory or not satisfactory, if not satisfactory there should be an immediate action
statement completed on the paperwork.
How can your Instrument Supplier assist with meeting the specification requirements?
1. Supply or assist selection of Calibrated Thermocouples
2. Provide Process Instrument (Control, Record etc.) to meet the accuracy requirement of the
standard.
3. Provide Field test (TUS/SAT) systems to meet the accuracy and reporting requirements of the
standard.
4. Help with a Critical spares list and preventive maintenance for instruments.
5. Calibration of Instruments
6. Operator training on instrumentation
7. Provide input into Continuous Improvement (particularly for TUS and SAT requirements)
8. Alarm/Check system to help with management review (required every 24 hours) and test
frequencies.
9. Data records to provide Quench delay and Temper delay information and report on trends over time.
10. Instruments to support Thermocouple, SAT and TUS management. 6

7. Management Responsibility & Quality Planning (Sec1)
There are 20 questions in this section and these cover the management oversight of the process as
well as ensuring the Process Planning documents have been completed (and are reviewed) for each
process .
• Resources
– Responsibility matrix for key functions to ensure they are performed by qualified personnel
– Dedicated and qualified heat treat person.
– Documented evidence of training for all employees. Qualification for each role. Assessment of effectiveness of the training.
• Planning
– Advanced Quality Planning (feasibility study)
– FMEA (what can go wrong from the experience of a cross functional team, controls in place to minimize the risks).
– Control Plan (address all process steps and process parameters – is this current)
– All referenced specifications available (and timely review of new issues)
– Process Specification for all active processes (usually a job-card stating Temperature, Time, Gas Flows, Loading rates etc.)
– Process Capability (initial and after any major rebuild – appropriate for parts, eg. Tensile strength, hardness, case-depth etc.)
– Internal assessments including CQI9 undertaken on an annual basis
– Procedures and Work Instructions available for Heat Treat Personnel (emergencies, start-up, shutdown, quality, operation)
– Preventive maintenance program – data used to form a predictive maintenance program
– Critical spares list to minimize production disruptions
– Different steel mill heats requiring different heat treat parameters must be process separately
• Reaction
– Analysis of data over time for trends (trend analysis, reaction reports)
– Documented Management review of Process characteristics every 24 hours (includes chart data, out-of-control and alarm
conditions)
– OEM Customer notified when parts are reprocessed
– Customer and Internal Concerns, reviewed, addressed and documented
– Quarantine area authorization by Quality Manager (or designee)
• Improvements
– Continual improvement plan for each process including quality, productivity and production delivery dates
7

8. Floor and Material Handling Responsibility (Sec2)
There are 16 questions in this section which cover receipt of goods, creating paperwork and tracking
product throughout the entire process and finishes with Inspection requirements.
• Documentation / Contract review
– Customer requirements adequately transferred to internal heat treat documents. Process to resolve discrepancies.
– Outgoing lot(s) shall be traceable to incoming lot(s)
– Loading rate specified, documented and controlled
• Production System
– Clearly identified and staged throughout the process. No possibility of mixing treated/untreated batches.
– Prevent movement of non-conforming product into the production system
– Identify trap points to reduce risk of mixed or damaged parts. Monitor every changeover
– Are containers free from inappropriate material (properly emptied).
– Operators trained in unplanned events and how to use the quality system to properly segregate product
– Handling, storage and packaging suitable to maintain product quality
– Housekeeping policy ensures the plant is conducive to providing quality product
– Parts free from contaminants which could affect processing results
– Quench system monitored, documented and controlled; includes quench delay and temper delay times
– Soluble oil or rust preventive solutions monitored for suitability (documented tolerances)
– Process Control frequencies in line with requirements of Process Tables
• Inspection
– In-Process and Final Test Frequencies in line with Process Tables
– Is product test equipment verified and calibrated as required and internally reviewed, approved and documented
8

9. Equipment (Sec3)
There are 14 questions in this section all about Equipment checks (not including Induction Heat Treat)
• Quality Checks
– Temperature, Carbon and Quench monitoring systems on Furnaces, Generators and Quench systems. Process Tables Section 1.0
– Process equipment calibrations posted, certified and current
– Temperature Uniformity Surveys done as per Process Tables.
• Maintenance Checks
– Thermocouple & protection tubes replaced as per Process Tables, Section 2.0
– Alarm checks quarterly or after rebuild or repair (alarms that could cause non-conforming product). Safety related checked as per
heat treaters requirements. Alarm checks should be documented.
– Do all atmosphere furnaces and generators have flow scope or flow meters for all gases and is the periodic service documented
– Is salt chemistry in the austenitizing salt bath monitored – see section 3.0 for frequency of checks
– The quench system shall be analyzed periodically for cooling curve response, water content, salt concentration as specified in the
applicable Process Tables, Section 5.0. The quench characteristics shall be specified by the quench supplier or heat treater and
documented review of conformance
• Production Checks
– Variation from Setpoint within tolerance from Process Tables Section 2.0
– Are generators and furnace atmospheres continuously monitored, automatically controlled and documented within +/-0.05% of
setpoint. Oxy probes or IR gas analysis should have a backup method of checking (dewpoint, electrical wire resistance, gas
analysis, shim stock, carbon bar etc.). Frequencies to Table Sec 3.0.
– If back up verification does not correlate within pre-established limits how is the discrepancy resolved (should be noted in control
plan)
– Are all ammonia lines equipped with a fail-safe method to prevent ammonia leak into the furnace for non-ammonia bearing
atmosphere processes. Three-valve ammonia system is permitted..
– Is there a 3 hour minimum purge of the furnace atmosphere when switching from an ammonia bearing atmosphere to a non-
ammonia bearing – this should be logged. If less than 3 hours this should be done with conclusive test data to show no significant
amount of residual ammonia.
– Is there a rigorous fail safe to prevent non uniform loading of parts – if not, there should be an infrared temperature pyrometer to
monitor under temperature alarm within 50°F (28°C) of the furnace set point. Sight glasses should be cleaned at regular intervals.
9

10. 2
Thermocouples

11. 2. Thermocouples
General
Guidelines for recommend temperature ranges or
upper limits should be taken from ASTM E230, IEC
60584-1 or other national standards.
Thermocouples should be traceable to national
institutes (e.g.. NIST, PTB etc.)
Calibration
Calibration before first use in the working
temperature range and at intervals no greater than
250°F
Certificates should state actual temperature,
nominal temperature, correction factor for each
point, provider of calibration data and calibration
method. Interpolation between test points is allowed,
extrapolation outside test points is not.
External sources need to be accredited to
ISO/IEC17025 or other national equivalent. Internal
sources need to calibrate with the intent of
ISO/IEC17025 or other national equivalent. Records
of training and qualifications need to kept of internal
personnel performing calibrations.
Thermocouples may be individually calibrated or
made from calibrated rolls as long as the ends of the
rolls meet the accuracy requirements.
11
Introduction
Document the date the thermocouple is placed in
service. Damaged thermocouples may not be
reused and Type K and E reuse the depth of
insertion shall be equal to or greater than the depth
of insertion of any previous use.
Control, Monitoring and Recording Thermocouples –
Accuracy required is +/-1.1°C (+/-2.0°F) or +/-0.4%.
Calibrated against a primary or secondary standard
thermocouple.
Replace every two years if Noble metal (B,R,S) is
used over 760°C (1400°F) or Base Metal (K,N,J,E)
used below 760°C (1400°F).
Replace every year for Base Metal (K,N,J,E) used
above 760°C (1400°F).
TUS and SAT thermocouple
Accuracy +/-1.1°C (+/-2.0°F) or +/-0.4%.
Replace every 2 years for B,R,S (SAT Probe
method, TUS).
Replace SAT comparative thermocouples as per
Control thermocouple. Base metal replace after 180
uses less than 980°C (1800°F) or 90 uses above
980°C (1800°F).

12. 3
Instrument Calibration

13. Instrumentation
Instruments shall be calibrated to NIST or similar national standard. Calibration performed to
manufacturers instructions or if in operation and running at typical operating temperature, a single
point calibration is acceptable. For each channel that can be altered a calibration is required.
Calibration frequency for control, monitoring and recording is either Option 1. Quarterly (single-point or
multi-point) or Option 2. Semi-annual if the SAT is performed quarterly by Probe Method A and multi-
point calibration is used.
Calibration Label minimum data: Date of Calibration. Due date of next calibration. Technician initials.
Serial number of the instrument.
Calibration Results:
Furnace ID.
Make, model and serial number of instrument calibrated (not applicable to PLC controlling devices). Standard of test instrument used.
Method of Calibration.
Ambient Temperature and humidity
Required accuracy
Initial and final values at each calibration point
Initial and corrected offset/bias values
Statement of acceptance
Any limitations or restrictions of the calibration
Date the calibration was performed
Due data of next calibration
Technician who performed the calibration with Signature
Calibration company if no performed in-house
Sign-off by responsible person in the heat treat organization
Temperature for each control zone shall be recorded by a recording instrument. 5 minute intervals max (analog recorders) 2 minutes for digital recorders.
Test instruments shall have a minimum readability of 1.0°C or 1.0°F.
Controlling, Monitoring, Recording instruments shall have a minimum readability of 1.0°C or 1.0°F for digital instruments or 2.0°C or 4.0°F for analog recorders.
Temperature resolution 55°C max per cm or 250°F max per inch 5°C max per chart line or 10°F max per chart line.
Offsets are generally discouraged, if used then this needs to be fully documented and not exceed 2°C or 4°F.
13

14. Instrumentation
Temperature for each control zone shall be recorded by a recording instrument. 5 minute intervals max
(analog recorders) 2 minutes for digital recorders.
Test instruments shall have a minimum readability of 1.0°C or 1.0°F.
Controlling, Monitoring, Recording instruments shall have a minimum readability of 1.0°C or 1.0°F for
digital instruments or 2.0°C or 4.0°F for analog recorders.
Temperature resolution 55°C max per cm or 250°F max per inch 5°C max per chart line or 10°F max
per chart line.
Offsets are generally discouraged, if used then this needs to be fully documented and not exceed 2°C
or 4°F.
Electronic records: the system shall create write-once, read-only electronic records that cannot be
altered without detection.
Calibration Accuracy
Control, Monitor or Recording
3 months against Field Test Instrument (single of multipoint) +/-2.0°C (+/-4.0°F)
6 months against Primary Standard +/-2.0°C (+/-4.0°F)
Field Test Instrument
SAT/TUS 12 months against Primary or Secondary Standard +/-0.6°C (+/-1.0°F) or +/-0.1%
14

15. 4
System Accuracy Test
(TUS)

16. SAT
Probe Method A
Quarterly Check between uncorrected reading of the control
temperature system and the corrected reading of a test
temperature system. Tip distance 50mm or 2.0” max.
Temperature indication of control instrument to be accurate
within +/-5°C (+/-10°F) or the test thermocouple. Any electronic
offset in the control instrument (for TUS purpose) shall be
included in the SAT calculation.
Probe Method B
Quarterly Check between uncorrected reading of the control
temperature thermocouple indicated on a test instrument and
the corrected reading of a test temperature system. Recorded at
the highest point in the temperature cycle.
Comparative Method
Monthly Check between uncorrected reading of the control
temperature system and the uncorrected reading of any other
permanently installed monitoring system.
Temperature delta shall not differ more than +/-1°C (+/-2°F). If
thermocouples are in the same protection tube they should be a
different type (eg. Type K with Type N, Type R with Type S).
16
SAT Thermocouple <2.0” distance
from tip of Control Thermocouple
` `
<2.0”
Comparative
Probe
A/B
Probe B
Probe A /
Comparative

17. SAT Records
Offset/bias assigned to the correction of a SAT error shall not
exceed 2°C or 4°F. This is separate from the offset/bias
assignable to a calibration error or TUS.
Test Records
ID of the Thermocouple being tested
ID of the Test Thermocouple and Instrument
Date and time of day of the test
Observed control instrument reading
Observed test instrument reading
Test Thermocouple and Test Instrument correction factors
Corrected Test Thermocouple reading
SAT difference
Indication of Test acceptance or failure
ID of Technician performing the test
External calibration company if applicable
Sign-off by responsible person in the heat treat organization
17
SAT Thermocouple <2.0” distance
from tip of Control Thermocouple
` `
<2.0”
Comparative
Probe
A/B
Probe B
Probe A /
Comparative

18. 5
Temperature Uniformity Survey
(TUS)

19. TUS
If the operating temperature range is equal to or less than 170°C (305°F) then only one
temperature within the range is required, if it is greater than 170°C then the minimum and maximum
temperature of the operating range shall be tested. For aluminum heat treating this range is reduced
to 85°C (155°F)
Survey shall replicate the furnace system parameters during normal products. If safety risks then an
atmosphere or air or inert gas may be used. The TUS can be performed with an empty furnace but
the thermocouples must be attached to a fixture so they are securely located. If performed with a
loaded furnace, the load should replicate typical operations.
If using Heat sinks they should represent the typical size of the heat treated product.
If Vacuum levels used - should be set at the lowest level but don’t need to be less than 1 micron Hg
(1x10-3 Torr or 1.3x10-3 millibar)
Continuous Furnaces can be surveyed by Volumetric Method (pusher furnaces) or Plan Method (belt
furnaces).
Test T/C’s should be traversed through the furnace at a typical speed and representing all locations,
data collection starts as soon as they enter the furnace and recorded at least every 30 seconds.
Manual data collection not allowed. Compare with the Process record and the soak time should be
clearly be shown.
19

20. TUS
Number should be ?
Typical rectangular and cylindrical shaped furnaces
Data collection when the TUS thermocouples are loaded into the furnace. Recorded automatically at
least one set of readings every two minutes. No manual data collection.
Compare to the Process record.
When the furnace control normally cycles around setpoint and the TUS thermocouples have
stabilized continue data collection for a minimum of 30 minutes.
Property surveys not outlined in this guide.
Thermocouple failures – 10 – 16 Thermocouples, 1 failure. >16 thermocouples, less than or equal to
10% failures – no corner failures of a TUS allowed.
TUS pass if, all readings are within the temperature tolerance during the defined soak period and the
upper tolerance was not exceeded at any time. The time to recover, stabilized did not exceed the
time limit specified in any applicable process specifications and the TUS is run for the minimum time.
The organizations internal process specification for soak time was met – this should be defined.
The TUS shall be performed using independent test instrumentation and compensation for known
deviations in the instrumentation shall be made by electronic or mathematical corrections.
20

21. TUS Report Requirements
Furnace ID.
Method of TUS
Survey Test Temperature
TUS Thermocouple quantity and location (detailed photo or diagram)
TUS thermocouple calibration report including correction factors
Survey test instrument calibration report including calibration and correction factors for each
adjustable channel.
Corrected readings of all TUS thermocouples at each survey temperature. Readings identified as
corrected or uncorrected.
Any limitations or restrictions of the TUS
Testing company identification (if not performed in-house)
Name & Signature of the technician performing the TUS
Survey start/stop time and start/stop date
Data collection period or soak period
Survey test instrument ID
Control instrument tuning parameters (PID Values)
Furnace survey thermocouple catastrophic failures
Time and temperature profile data for all TUS and Control Thermocouples for all zones. Control
Thermocouple data shall be generated by the associated process recorder or data acquisition
system
Indications of test past or test fail status
Summary of final plus and minus readings at each test temperature
Sign-off by responsible person in the heat treat organization
21

22. TUS Report Requirements
<0.1m3 (3ft3) 5 Thermocouples
0.1 to 8.5m3 (3ft3 to 300ft3) 9 Thermocouples
Greater than 8.5m3, add a minimum one thermocouple for each 3m3.
Total offset/bias shall not exceed 2.0°C (4.0°F)
[Picture of positions]
Plane Method
Work Zone Width <=300mm (1ft) >300mm (1ft)
<0.75m (2.5ft) 3 5
0.75m to 1.5m 3 7
1.5m to 2.4m 3 8
>2.4m for each 0.6m add 1 8
For <=300mm - Two TUS thermocouple locations shall be within 50mm (2”) of the work zone corners
and one TUS thermocouple at the center – the rest uniformly distributed throughout a plane
perpendicular to the conveyance direction.
For >300mm Four TUS thermocouples shall be within 50mm (2”) of the work zone corners and the
remainder shall be at the center and symmetrically distributed about the center of a plane
perpendicular to the conveyance direction.
22

23. 6
Job Audit

24. Job Audit
Minimum of one heat treat part job audit during each assessment. Preferable critical parts.
Specific part taken from shipping area and audits all related paperwork.
20 Questions, Customer or internal requirement, Refer documentation, Actual Condition, Pass/Fail
• Quality
– Are contract review, APQP, FMEA, Control Plan performed by qualified individuals
– Are customer specifications available
– Is there a shop traveller created to meet customer requirements
– Is material identification maintained throughout heat treat process
– Is there documented evidence of receiving inspection
– Are the loading/racking requirements defined
– Is the proper recipe or process specification used (list
– What are the product inspection requirements
– Requirements: Test Method, Test Frequency or quantity, Selection of Samples, Specification
• Operator or Inspector Responsibilities
– Were appropriate process steps signed off
– Were all inspection steps, as documented in the control plan performed
– Were steps/operations performed that were not documented in control plan
– If additional steps performed, were they authorized
– Does the specification allow for reprocessing or rework
– Was the certification signed by an authorized individual
– Are the parts and containers free of inappropriate objects or contamination
• Packaging
– Are packaging requirements identified
– Are parts packaged to minimize mixed parts
• Shipping
– Were the Parts properly identified
– Were the containers properly labelled 24

25. 7
Process Table A, B, C

26. Process Table – A (Carburizing etc.)
• Process and Test Equipment Requirements
– All furnaces, generators and quench systems shall have temperature indicating instruments
– Continuous strip charts and/or data loggers required for temperature and carbon monitoring
– A program for furnace and generator burnout is required (carbon bearing atmosphere)
– Furnace weigh scales shall be verified quarterly and calibrated annually
– Dew Pointers, 3 Gas IR, Spectrometers etc. to verify carbon potential shall be calibrated annually
– Verification of calibration of spectrometers, Carbon IR shall be checked daily prior to use
– Verification of calibration of 3 Gas IR, with zero gas and span shall be performed weekly
– Oxygen probe controllers shall be calibrated quarterly (singe/multipoint) or 6 months (multipoint)
– All hardness test equipment shall be calibrated annually, verified daily per ASTM standard or equivalent
– Files for testing hardness requirement shall be verified per the customer requirement
– Refractometers shall be verified prior to use and calibrated annually (quenchants, water solutions)
• Pyrometry
– Thermocouples and calibration shall conform to stated accuracy requirements
– Instrumentation shall conform to stated accuracy requirements
– System Accuracy Test (SAT) check of the control thermocouple
– Annual TUS (or after major rebuild) +/-15°C (25.0°F) Hardening, +/-10°C (20.0°F) Tempering
– Recorded temperatures for austenitizing controlled within +/-10°C (15.0°F) . Furnace temperature shall be controlled with soak
times starting at the lower tolerance limit.
– Recorded temperatures for tempering controlled within +/-5°C (10.0°F) . Furnace temperature shall be controlled with soak times
starting at the lower tolerance limit.
– Infrared pyrometers shall be calibrated annually using approved methods.
26

27. Process Table – A (Carburizing etc.)
Process Monitor Frequencies
• Primary Temperature Control instrument
– Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms systems can satisfy the sign off
– Sign-off required for each shift for generators
• Monitor Atmosphere Generation
– Continuously monitored and alarmed. Or for other systems (Nitrogen Methanol) can be either continuously monitored and
alarmed or sign off every 2 hours.
• Monitor primary atmosphere controls
– Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms systems can satisfy the sign off
• Daily verify primary furnace atmosphere control method by back up method.
• Daily check salt chemistry or part decaburization from austenitizing salt baths.
Quench Media Process Parameters
• Temperature
– Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms systems can satisfy the sign off
• Quench Level
– Continuous monitor with alarm or daily verification
• Agitation
– Daily visual check or monitor the agitation during quenching with alarm systems set with limits.
27

28. Process Table – A (Carburizing etc.)
Process Monitor Frequencies
– Monitor time in furnace, cycle time or belt speed (each batch or twice/shift or speed change for continuous furnace)
– Monitor load size of fixturing or loading rate (each batch or twice/shift or speed change for continuous furnace)
– Quench Delay Time (door starts to open to the time the load is at the bottom of quench tank) – (each batch or basket for pusher
furnace not applicable to shaker or pusher furnace where parts free fall into the quench)
– Temper Delay Time – maximum time documented on control plan (each batch, each load)
• In-Process/Final Test Frequencies
– Microstructure at 100x and 400x, visual references available (each batch, daily per furnace for continuous)
– Surface Hardness (each batch, every 2 hours for continuous)
– Core Hardness – where specified (each batch, every 4 hours for continuous)
– Case depth – where specified (each batch, every 4 hours for continuous)
• Quenchant and Solution Test Frequencies
– Polymer Quench Media Concentration (daily) Cooling Curve (Semi annual)
– Water Quench Suspended solids (Semi annual)
– Salt Quench concentration and/or specific gravity (daily) Suspended solids (Semi annual)
– Brine or Caustic Quench Media concentration and/or specific gravity (daily) suspended solids (semi annual)
– Oil Quench Media water content, suspended solids, viscosity, cooling curve, total acid, flash point (semi annual)
– Rust Preventive – Soluble oil concentration (2x/week)
– Washers concentration of cleaner (daily) temperature of solution if above ambient (each shift)
28

29. Process Table – B (Nitriding etc.)
• Process and Test Equipment Requirements
– All furnaces, generators and quench systems shall have temperature indicating instruments
– Continuous strip charts and/or data loggers required for temperature and carbon monitoring
– A program for furnace and generator burnout is required (carbon bearing atmosphere)
– Furnace weigh scales shall be verified quarterly and calibrated annually
– Dew Pointers, 3 Gas IR, Spectrometers etc. to verify carbon potential shall be calibrated annually
– All hardness test equipment shall be calibrated annually, verified daily per ASTM standard or equivalent
– Files for testing hardness requirement shall be verified per the customer requirement
– Refractometers shall be verified prior to use and calibrated annually (quenchants, water solutions)
• Pyrometry
– Thermocouples and calibration shall conform to stated accuracy requirements
– Instrumentation shall conform to stated accuracy requirements
– System Accuracy Test (SAT) check of the control thermocouple
– Annual TUS (or after major rebuild) +/-15°C (25.0°F) Hardening, +/-10°C (15.0°F) Tempering
– Recorded temperatures controlled within +/-10°C (15.0°F) . Furnace temperature shall be controlled with soak times starting at
the lower tolerance limit.
– Infrared pyrometers shall be calibrated annually using approved methods.
29

30. Process Table – B (Nitriding etc.)
Process Monitor Frequencies
• Primary Temperature Control instrument
– Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms systems can satisfy the sign off
– Sign-off required for each shift for generators
• Monitor Atmosphere Generation
– Continuously monitored and alarmed. Or for other systems (Nitrogen Methanol) can be either continuously monitored and
alarmed or sign off every 2 hours.
• Monitor primary atmosphere controls
– Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms systems can satisfy the sign off. Daily
for Salt bath.
• Dissociation of ammonia shall be checked in gas nitriding
– Each batch (rotary furnace only) or Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms
systems can satisfy the sign off. Continuous furnace every 4 hours. Generators daily,.
• Gas ratios for ferritic nitrocarburizing shall be checked
– Each batch or every 2 hours minimum for Continuous furnaces
• Daily check salt chemistry used for austenitization, or decaburization on the parts
Quench Media Process Parameters
• Temperature
– Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms systems can satisfy the sign off
• Quench Level
– Continuous monitor with alarm or daily verification. Check salt baths daily
• Agitation
– Daily visual check or monitor the agitation during quenching with alarm systems set with limits. Salt baths daily.
30

31. Process Table – B (Nitriding etc.)
Process Monitor Frequencies
– Monitor time in furnace, cycle time or belt speed (each batch or twice/shift or speed change for continuous furnace)
– Monitor load size of fixturing or loading rate (each batch or twice/shift or speed change for continuous furnace)
– Quench Delay Time if applicable (door starts to open to the time the load is at the bottom of quench tank) – (each batch or
basket for pusher furnace not applicable to shaker or pusher furnace where parts free fall into the quench)
• In-Process/Final Test Frequencies
– Microstructure at 100x and 400x, visual references available (each batch, daily per furnace for continuous/salt bath)
– Surface Hardness (each batch, every 2 hours for continuous, each batch salt bath)
– Core Hardness – where specified (each batch, every 4 hours for continuous, each batch salt bath)
– Case depth – where specified (each batch, every 4 hours for continuous, each batch salt bath)
• Quenchant and Solution Test Frequencies
– Polymer Quench Media Concentration (daily) Cooling Curve, viscosity or titration (Semi annual)
– Water Quench Suspended solids (Semi annual)
– Salt Quench analysis and contaminants (Semi annual)
– Brine or Caustic Quench Media concentration and/or specific gravity (daily) suspended solids (semi annual)
– Oil Quench Media water content, suspended solids, viscosity, cooling curve, total acid, flash point (semi annual)
– Rust Preventive – Soluble oil concentration (2x/week)
– Washers concentration of cleaner (daily) temperature of solution if above ambient (each shift)
31

32. Process Table – C (Aluminum etc.)
• Process and Test Equipment Requirements
– All furnaces, generators and quench systems shall have temperature indicating instruments
– Continuous strip charts and/or data loggers required for temperature and carbon monitoring
– Furnace weigh scales shall be verified quarterly and calibrated annually
– All hardness test equipment shall be calibrated annually, verified daily per ASTM standard or equivalent
– Files for testing hardness requirement shall be verified per the customer requirement
– Refractometers shall be verified prior to use and calibrated annually (quenchants, water solutions)
• Pyrometry
– Thermocouples and calibration shall conform to stated accuracy requirements
– Instrumentation shall conform to stated accuracy requirements
– System Accuracy Test (SAT) check of the control thermocouple
– Annual TUS (or after major rebuild) +/-5°C (10.0°F) Solution/Aging, +/-15°C (25.0°F) Annealing. At min and max temperature of
the operating range
– If operating range is less than +/-85°C (155°F) then only one temperature to be tested.
– Solution Treating and Aging, Recorded temperatures controlled within +/-5°C (10°F) . Furnace temperature shall be controlled
with soak times starting at the lower tolerance limit.
– Annealing ,Recorded temperatures controlled within +/-10°C (15°F) . Furnace temperature shall be controlled with soak times
starting at the lower tolerance limit.
– Infrared pyrometers shall be calibrated annually using approved methods.
32

33. Process Table – C (Aluminum etc.)
Process Monitor Frequencies
• Primary Temperature Control instrument
– Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms systems can satisfy the sign off
– Sign-off required for each shift for generators
Quench Media Process Parameters
• Temperature
– Continuous recording with sign off every 2 hours or each batch (if under 2 hours). Alarms systems can satisfy the sign off
• Quench Level
– Daily verification.
• Agitation
– Daily visual check or monitor the agitation during quenching with alarm systems set with limits.
33

34. Process Table – C (Aluminum etc.)
Process Monitor Frequencies
– Monitor time in furnace, cycle time or belt speed (each batch or twice/shift or speed change for continuous furnace)
– Monitor load size of fixturing or loading rate (each batch or twice/shift or speed change for continuous furnace)
– Quench Delay Time if applicable (door starts to open to the time the load is at the bottom of quench tank) – (each batch or
basket for pusher furnace or roller hearth continuous furnaces)
• In-Process/Final Test Frequencies
– Hardness or tensile testing (each batch, every 4 hours for continuous)
• Quenchant and Solution Test Frequencies
– Polymer Quench Media Concentration (daily) Cooling Curve(Semi annual)
– Water Quench Suspended solids (Semi annual)
– Washers concentration of cleaner (daily) temperature of solution if above ambient (each shift)
34

35. Useful Links
Carbon Probe Sensors
2-Loop Controllers (3500 series)
Paperless chart (6000 series chart recorders)
PID Controller / Recorder (nanodac)
Regulatory Compliance (AMS2750E)
Aerodaq (thermocouple management)
eos (data storage solutions)
AMS2750E TUS report software
Electronic Timer
Programmer (3504 Programmer)
Further information
standards.sae.org/ams2750e
www.pri-network.org
www.aiag.org
© Peter Sherwin | Eurotherm | 2014