ASTM F1940-07a(2019)

Standard Test Method for Process Control Verification to Prevent Hydrogen Embrittlement in Plated or Coated Fasteners

SIGNIFICANCE AND USE
5.1 This test method establishes a means to verify the prevention, to the extent possible, of IHE in steel fasteners during manufacture by maintaining strict controls during production operations such as surface preparation, pretreatments, and plating or coating. It is intended to be used as a qualification test for new or revised plating or coating processes and as a periodic inspection audit for the control of a plating or coating process.  
5.2 Passing this test allows fasteners to be stressed in tension to the minimum specified tensile load in air with almost no possibility of time delayed fracture in air as a result of IHE from processing. If the amount of residual hydrogen is not sufficient to induce cracking or fracture in the specimen under worst case conditions, then it can be concluded that all of the lots of fasteners processed during that period will not have sufficient residual hydrogen from processing to induce hydrogen embrittlement of the fasteners under stress in air if the process remains in control, unchanged and stable.  
5.3 If certified specimens with demonstrated sensitivity to IHE, processed with the fasteners, have a threshold ≥75 % of the incremental step load notched bend fracture stress, NFS(B)F1624, it is assumed that all fasteners processed the same way during the period will also pass any sustained load IHE test.
FIG. 1 Dimensional Requirements for a 0.4W-Notched Square Bar Bend Specimen
SCOPE
1.1 This test method covers a procedure to prevent, to the extent possible, internal hydrogen embrittlement (IHE) of fasteners by monitoring the plating or coating process, such as those described in Specifications F1137 and F1941. The process is quantitatively monitored on a periodic basis with a minimum number of specimens as compared to qualifying each lot of fasteners being plated or coated. Trend analysis is used to ensure quality as compared to statistical sampling analysis of each lot of fasteners. This test method consists of a mechanical test for the evaluation and control of the potential for IHE that may arise from various sources of hydrogen in a plating or coating process.  
1.2 This test method consists of a mechanical test, conducted on a standard specimen used as a witness, for the evaluation and control of the potential for IHE that may arise from various sources of hydrogen in a plating or coating process.  
1.3 This test method is limited to evaluating hydrogen induced embrittlement due only to processing (IHE) and not due to environmental exposure (EHE, see Test Method F1624).  
1.4 This test method is not intended to measure the relative susceptibility of steels to either IHE or EHE.  
1.5 This test method is limited to evaluating processes used for plating or coating ferrous fasteners.  
1.6 This test method uses a notched square bar specimen that conforms to Test Method F519, Type 1e, except that the radius is increased to accommodate the deposition of a larger range of platings and coatings. For the background on Test Method F519 testing, see publications ASTM STP 5432 and ASTM STP 962.3 The stress concentration factor is at a Kt = 3.1 ± 0.2. The sensitivity is demonstrated with a constant imposed cathodic potential to control the amount of hydrogen. Both the sensitivity and the baseline for residual hydrogen will be established with tests on bare metal specimens in air.  
1.7 The sensitivity of each lot of specimens to IHE shall be demonstrated. A specimen made of AISI E4340 steel heat treated to a hardness range of 50 to 52 HRC is used to produce a “worst case” condition and maximize sensitivity to IHE.  
1.8 The test is an accelerated (≤24 h) test method to measure the threshold for hydrogen stress cracking, and is used to quantify the amount of residual hydrogen in the specimen. The specimen undergoes sustained load and slow strain rate testing by using incremental loads and hold times under displacement control to measure a threshol...

General Information

• Status: Published
• Publication Date: 31-Jul-2019
• ICS: 21.060.01 - Fasteners in general
• Technical Committee: F16 - Fasteners
• Drafting Committee: F16.93 - Quality Assurance Provisions for Fasteners

Relations

• Replaces: ASTM F1940-07a(2014) - Standard Test Method for Process Control Verification to Prevent Hydrogen Embrittlement in Plated or Coated Fasteners
• Effective Date: 01-Aug-2019
• Refers: ASTM E1823-24a - Standard Terminology Relating to Fatigue and Fracture Testing
• Effective Date: 15-Feb-2024
• Refers: ASTM E1823-24 - Standard Terminology Relating to Fatigue and Fracture Testing
• Effective Date: 01-Feb-2024
• Refers: ASTM E8/E8M-24 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM F519-23 - Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments
• Effective Date: 01-Dec-2023
• Refers: ASTM E1823-20 - Standard Terminology Relating to Fatigue and Fracture Testing
• Effective Date: 01-Feb-2020
• Refers: ASTM F1624-12(2018) - Standard Test Method for Measurement of Hydrogen Embrittlement Threshold in Steel by the Incremental Step Loading Technique
• Effective Date: 01-Nov-2018
• Refers: ASTM F519-18 - Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments
• Effective Date: 01-Nov-2018
• Refers: ASTM E18-18 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Jul-2018
• Refers: ASTM F519-17a - Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments
• Effective Date: 01-Dec-2017
• Refers: ASTM E18-17 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Jul-2017
• Refers: ASTM F519-17 - Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments
• Effective Date: 01-Mar-2017
• Refers: ASTM E8/E8M-16 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 15-Jul-2016
• Refers: ASTM E8/E8M-15 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Feb-2015
• Refers: ASTM G5-14 - Standard Reference Test Method for Making Potentiodynamic Anodic Polarization Measurements
• Effective Date: 01-Nov-2014

Overview

ASTM F1940-07a(2019) - Standard Test Method for Process Control Verification to Prevent Hydrogen Embrittlement in Plated or Coated Fasteners sets out a reliable and repeatable procedure for verifying that steel fasteners manufactured with plating or coating are not susceptible to internal hydrogen embrittlement (IHE) resulting from processing. Developed by ASTM International, this standard is essential for quality control in fastener production, ensuring that manufacturing processes minimize the risks of delayed failures due to hydrogen ingress during plating or coating.

The method provides a way to qualify new or revised plating or coating processes and to audit existing processes periodically. Through controlled mechanical testing and trend analysis, this standard helps manufacturers maintain process stability and protect against hydrogen embrittlement that can compromise fastener integrity.

Key Topics

• Internal Hydrogen Embrittlement (IHE): The standard targets embrittlement caused by hydrogen introduced to the metal during manufacturing processes such as surface preparation, pretreatments, plating, or coating – not from environmental exposure.
• Process Control: Verifies production procedures are in control to prevent hydrogen embrittlement, using quantitative, periodic testing rather than testing every production lot.
• Test Specimen: Utilizes a notched square bar, processed in the same way as production fasteners, for mechanical testing to verify vulnerability to IHE.
• Sensitivity Testing: Test specimens made from high-hardness steel (AISI E4340, 50-52 HRC) are used to represent worst-case scenarios and demonstrate sensitivity to hydrogen embrittlement within the process.
• Mechanical Test Method: Includes four-point bending and incremental step loading under controlled rates to measure stress thresholds for hydrogen cracking.
• Statistical and Trend Analysis: Emphasizes the use of trend data over statistical sampling per batch, providing efficient yet robust verification of process quality.

Applications

ASTM F1940-07a(2019) is critically valuable for:

• Fastener Manufacturers: Used to qualify new or modified plating/coating lines, monitor ongoing production, and ensure customer requirements for hydrogen embrittlement resistance are met.
• Quality Assurance and Inspection: Enables periodic, representative audits of production processes without the need to test every fastener lot, thus saving time and resources.
• Plating and Coating Processors: Assists in selecting and controlling process parameters (e.g., acid pickling, plating current density) to minimize hydrogen ingress during surface treatments.
• Automotive, Aerospace, and Construction Industries: Where high-strength steel fasteners must avoid the risk of sudden, delayed failures due to hydrogen embrittlement.
• Supplier Certification: Provides evidence to purchasers that production processes are under control and produce fasteners with minimal residual hydrogen content.

Typical steps under the standard include preparing notched bar specimens, processing them alongside fasteners, subjecting them to controlled loading, and interpreting results to determine if the processing line remains safe and stable against IHE.

Related Standards

Manufacturers and quality professionals may find these additional ASTM standards relevant:

• ASTM F519 – Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments
• ASTM F1624 – Measurement of Hydrogen Embrittlement Threshold in Steel by the Incremental Step Loading Technique
• ASTM F1137 – Phosphate/Oil Corrosion Protective Coatings for Fasteners
• ASTM F1941 / F1941M – Electrodeposited Coatings on Threaded Fasteners
• ASTM E18 – Rockwell Hardness of Metallic Materials
• ASTM E4 – Force Verification of Testing Machines

Adherence to ASTM F1940-07a(2019) supports robust process control regimes, contributing to the reliability and safety of fasteners used in demanding engineering applications.

Keywords: ASTM F1940, hydrogen embrittlement, process control, plated fasteners, coated fasteners, IHE prevention, quality assurance, mechanical testing, steel fasteners, plating process verification.

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:F1940 −07a (Reapproved 2019)
Standard Test Method for
Process Control Verification to Prevent Hydrogen
Embrittlement in Plated or Coated Fasteners
This standard is issued under the fixed designation F1940; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Method F519 testing, see publications ASTM STP 543 and
ASTM STP 962. The stress concentration factor is at a K =
t
1.1 This test method covers a procedure to prevent, to the
3.1 6 0.2. The sensitivity is demonstrated with a constant
extent possible, internal hydrogen embrittlement (IHE) of
imposed cathodic potential to control the amount of hydrogen.
fasteners by monitoring the plating or coating process, such as
Boththesensitivityandthebaselineforresidualhydrogenwill
those described in Specifications F1137 and F1941. The
be established with tests on bare metal specimens in air.
process is quantitatively monitored on a periodic basis with a
minimumnumberofspecimensascomparedtoqualifyingeach 1.7 The sensitivity of each lot of specimens to IHE shall be
lotoffastenersbeingplatedorcoated.Trendanalysisisusedto demonstrated. A specimen made of AISI E4340 steel heat
ensure quality as compared to statistical sampling analysis of treatedtoahardnessrangeof50to52HRCisusedtoproduce
eachlotoffasteners.Thistestmethodconsistsofamechanical a “worst case” condition and maximize sensitivity to IHE.
test for the evaluation and control of the potential for IHE that
1.8 The test is an accelerated (≤24 h) test method to
may arise from various sources of hydrogen in a plating or
measurethethresholdforhydrogenstresscracking,andisused
coating process.
to quantify the amount of residual hydrogen in the specimen.
1.2 This test method consists of a mechanical test, con- The specimen undergoes sustained load and slow strain rate
ducted on a standard specimen used as a witness, for the testing by using incremental loads and hold times under
evaluation and control of the potential for IHE that may arise displacement control to measure a threshold stress in an
from various sources of hydrogen in a plating or coating accelerated manner in accordance with Test Method F1624.
process.
1.9 In this test method, bending is used instead of tension
1.3 This test method is limited to evaluating hydrogen becauseitproducesthemaximumlocallimitloadtensilestress
induced embrittlement due only to processing (IHE) and not in a notched bar of up to 2.3 times the yield strength as
duetoenvironmentalexposure(EHE,seeTestMethodF1624). measured in accordance withTest Method E8/E8M.Afastener
that is unintentionally exposed to bending on installation may
1.4 This test method is not intended to measure the relative
attain this maximum local tensile stress.
susceptibility of steels to either IHE or EHE.
1.10 The values stated in inch-pound units are to be re-
1.5 This test method is limited to evaluating processes used
garded as standard. The values given in parentheses are
for plating or coating ferrous fasteners.
mathematical conversions to SI units that are provided for
1.6 This test method uses a notched square bar specimen
information only and are not considered standard.
that conforms to Test Method F519, Type 1e, except that the
1.11 This standard does not purport to address all of the
radius is increased to accommodate the deposition of a larger
safety concerns, if any, associated with its use. It is the
range of platings and coatings. For the background on Test
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
This test method is under the jurisdiction of ASTM Committee F16 on mine the applicability of regulatory limitations prior to use.
Fasteners and is the direct responsibility of Subcommittee F16.93 on Quality
Assurance Provisions for Fasteners.
Current edition approved Aug. 1, 2019. Published September 2019. Originally L. Raymond, ed., Hydrogen Embrittlement Testing.ASTM International, 1974.
published as approved in 1998. Last previous edition approved in 2014 as L. Raymond, ed., Hydrogen Embrittlement: Prevention and Control. ASTM
F1940–07a(2014). DOI: 10.1520/F1940-07AR19. International, 1988.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1940−07a (2019)
1.12 This international standard was developed in accor- 3.1.3 ISL —thresholdfromanincrementalsteploadteston
th
dance with internationally recognized principles on standard- a plated or processed specimen.
ization established in the Decision on Principles for the
3.1.4 NFS(B)—notched fracture strength in air of a bare
Development of International Standards, Guides and Recom-
specimeninbendingatloadingratesof50to250ksi/min(350
mendations issued by the World Trade Organization Technical
to 1700 MPa/min).
Barriers to Trade (TBT) Committee.
3.1.5 NFS(B) —notched fracture strength in air of a
F1624
bare specimen in bending at Test Method F1624 step loading
2. Referenced Documents
rates.
2.1 ASTM Standards:
3.1.6 process—a defined event or sequence of events that
D1193Specification for Reagent Water
may include pretreatments, plating, or coating and posttreat-
E4Practices for Force Verification of Testing Machines
ments that are being evaluated or qualified.
E8/E8MTest Methods for Tension Testing of Metallic Ma-
3.1.7 threshold—themaximumloadattheonsetofcracking
terials
that is identified by a 5% drop in load of NSF(B) under
E18Test Methods for Rockwell Hardness of Metallic Ma- F1624
displacement control.
terials
E29Practice for Using Significant Digits in Test Data to
4. Summary of Test Method
Determine Conformance with Specifications
E177Practice for Use of the Terms Precision and Bias in 4.1 Specimensoffixedgeometry,certifiedtohavebeenheat
ASTM Test Methods treated to a hardness range of 50 to 52 HRC, and which have
E399Test Method for Linear-Elastic Plane-Strain Fracture beencertifiedtoexhibitsensitivitytoembrittlementfromtrace
Toughness K of Metallic Materials amounts of residual hydrogen in steel, are processed with
Ic
E691Practice for Conducting an Interlaboratory Study to actual parts.
Determine the Precision of a Test Method
4.2 An unstressed test specimen is processed in accordance
E1823TerminologyRelatingtoFatigueandFractureTesting
with the plating or coating process being qualified. The
F519Test Method for Mechanical Hydrogen Embrittlement
specimenisthentestedunderincrementalsteploadtomeasure
Evaluation of Plating/Coating Processes and Service En-
the threshold stress. The loading rate must be slow enough to
vironments
ensure that the threshold stress will be detected if deleterious
F1137Specification for Phosphate/Oil Corrosion Protective
amounts of hydrogen are present in “worst case” sensitized
Coatings for Fasteners
specimens. Loading rate protocols are defined in 9.2 and Test
F1624Test Method for Measurement of Hydrogen Em-
Method F1624.
brittlement Threshold in Steel by the Incremental Step
4.3 If the threshold in air of the specimen is ≥75%
Loading Technique
NFS(B) , then the process is considered as to not produce
F1624
F1941 Specification for Electrodeposited Coatings on
sufficient hydrogen to induce time delayed IHE failures in the
Threaded Fasteners (Metric) F1941_F1941M
plated or coated fasteners. See 9.3 for optional limits.
G5Reference Test Method for Making Potentiodynamic
Anodic Polarization Measurements 4.4 If the threshold in air of the specimen is <75%
NFS(B) ,thentheprocessisconsideredpotentiallyembrit-
2.2 SAE Standards: F1624
tling.Actualfastenersmadewithsteelhavingahardnesslower
AMS 2759Hot Drawn, Normalized and Tempered Steel
than that of the square bar specimen have more tolerance for
Bars. UNS G43406 (AISI E4340)
residual hydrogen because of the process.Therefore, threshold
AMS 3078 Corrosion Preventive Compound, Solvent
requirements must be adjusted based upon the correlation
Cutback, Cold-Application
between the specimen fracture strength NBS(B) and
AMS 6415 F1624
actual fastener hardness. An example of this adjustment is
presented in Appendix X1.
3. Terminology
3.1 Terms and Symbols Specific to This Standard:
5. Significance and Use
3.1.1 environmental hydrogen embrittlement (EHE)—test
5.1 This test method establishes a means to verify the
conducted in a specified environment—embrittlement caused
prevention, to the extent possible, of IHE in steel fasteners
by hydrogen introduced into steel from external sources.
during manufacture by maintaining strict controls during
3.1.2 internal hydrogen embrittlement (IHE)—test con-
production operations such as surface preparation,
ducted in air—embrittlement caused by residual hydrogen
pretreatments, and plating or coating. It is intended to be used
from processing
as a qualification test for new or revised plating or coating
processes and as a periodic inspection audit for the control of
a plating or coating process.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.2 Passing this test allows fasteners to be stressed in
Standards volume information, refer to the standard’s Document Summary page on
tensiontotheminimumspecifiedtensileloadinairwithalmost
the ASTM website.
no possibility of time delayed fracture in air as a result of IHE
Available from Society of Automotive Engineers (SAE), 400 Commonwealth
Dr., Warrendale, PA 15096-0001, http://www.sae.org. from processing. If the amount of residual hydrogen is not
F1940−07a (2019)
sufficient to induce cracking or fracture in the specimen under charging potential of the specimen can be controlled with a
worst case conditions, then it can be concluded that all of the reference saturated calomel electrode (SCE) or equivalent
lots of fasteners processed during that period will not have reference electrode such as with A/AgCl in accordance with
sufficient residual hydrogen from processing to induce hydro- Practice G5.
gen embrittlement of the fasteners under stress in air if the
NOTE1—Aloadingdevicethatmeetsthedisplacementcontrolstepload
process remains in control, unchanged and stable.
test requirements and the potentiostatic control requirements of Test
Method F1624 and Test Method F519 is available.
5.3 If certified specimens with demonstrated sensitivity to
IHE, processed with the fasteners, have a threshold ≥75% of
7. Materials and Reagents
the incremental step load notched bend fracture stress,
7.1 Materials—UNS G43406 (AISI E4340) in accordance
NFS(B) , it is assumed that all fasteners processed the
F1624
with AMS 6415.
same way during the period will also pass any sustained load
IHE test.
7.2 Reagents:
7.2.1 Corrosion preventive compound, meeting require-
6. Apparatus
ments of AMS 3078.
6.1 Testing Machine—A computerized, four-point bend, 7.2.2 Solution of reagent water in accordance with Specifi-
digitaldisplacementcontrolledloadingframethatiscapableof cation D1193 Type IV, and 3.5% reagent grade NaCl.
holding 0.5% of the NFS(B) and is programmed to increase
8. Test Specimen
incrementally in steps of load and time to vary the effective
−5 −8 −1
strainrateattherootofthenotchbetween10 and10 s is
8.1 The test specimen shall be a 0.4W-notched square bar
required to conduct these tests. Testing machines shall be
bend specimen: 0.4W-SqB(B), as shown in Fig. 1.
within the guidelines of calibration, force range, resolution,
8.2 The notch shall be in the LS orientation in accordance
and verification of Practice E4.
with Terminology E1823.
6.2 Gripping Devices—Pin-loading devices consistent with
8.3 The stress concentration factor for the specimen is K =
t
Test Method E399 four-point bend fixtures shall be used to
3.1 6 0.2.
transmit the measured load applied by the testing machine to
the test specimen. NOTE 2—For the relationship between geometry and K see Stress
t,
Concentration Factors.
6.3 Potentiostatic Control—For verification testing of the
sensitivity of the specimens to residual hydrogen from
processing, an inert container and potentiostat shall be used to 6
Peterson,R.E., Stress Concentration Factors,JohnWileyandSons,NewYork,
impose a cathodic potential on the specimen. The cathodic 1974.
FIG. 1Dimensional Requirements for a 0.4W-Notched Square Bar Bend Specimen
F1940−07a (2019)
8.4 Manufacture: 8.6.4 The notched bend fracture strength, NFS(B), of bare
8.4.1 The test specimen blanks shall be heat treated in specimens is measured in air in four-point bending under
accordance withAMS 2759 to meet the hardness requirement displacementcontrolatloadingratesof50to250ksi/min(350
of 50 to 52 HRC in accordance with Test Methods E18. to 1700 MPa/min). The rupture load is used as a measure of
RoundinginaccordancewithPracticeE29permitsanabsolute strength.
hardness range of 49.6 to 52.5 HRC. The hardness shall be
8.7 Sensitivity Test:
determined by the average of three measurements made
8.7.1 The sensitivity to IHE must be demonstrated for each
approximately midway between the notch and the end of the
lot of specimens by exposing three trial specimens in air and
specimen.
three trial specimens in an embrittling environmental after
8.4.2 The surface finish of all notches shall be finished with
manufacture and inspection in accordance with 8.4 through
a tool capable of attaining a surface roughness of 16 RMS or
8.6. The specimens tested shall be representative of the lot.
better. The other surfaces shall have a finish of 32 RMS or
8.7.2 Sensitivity Specimen Preparation:
better.
8.7.2.1 Ultrasonically clean in acetone for 5 to 10 min to
8.4.3 Alldimensionsexceptforthelengthshallbeproduced
remove the corrosion preventive compound and oils/dirt.
after quenching and tempering to final hardness. The 0.40-in.
8.7.2.2 Do not acid clean.
(10-mm) dimension shall be produced by low stress grinding.
8.7.3 Based on the loading profile schedule in Table 2, the
The notch shall be rough machined by wire EDM to within
requirementsforsensitivityoftheheat-treatedlotofspecimens
0.020 in. (0.5 mm) of the final notch depth and low stress
shall be demonstrated if bare specimens fracture in less than 5
ground to the final depth. No chemical or mechanical cleaning
h at an imposed potential of −1.2 V versus SCE in a 3.5%
shall be allowed after final machining.
NaCl solution and no delayed fracture occurs in less than 14 h
8.4.4 Straighteningafterfinalheattreatmentbeforemachin-
or≥85%NFS(B)onbarespecimenstestedinair(seeTable3).
ing is prohibited.
8.7.4 The average of the results of the three bare specimens
8.5 Storage—Before plating or coating, all specimens shall tested in air shall be used as the baseline notched fracture
be protected during storage to prevent corrosion. A suitable strength, NFS(B) .
F1624
means of protection is to coat the specimen with a corrosion
8.8 Certification:
preventive compound meeting the requirements ofASM 3078.
8.8.1 Each lot of specimens manufactured shall be certified
8.6 Inspection: to indicate that it meets the conditions found in this section,
8.6.1 A lot shall consist of only those specimens cut from including the following information:
the same heat of steel in the same orientation, heat treated 8.8.1.1 Manufacturer of specimen lot.
together in the same furnace, quenched and tempered together, 8.8.1.2 Traceability to raw material, heat treatment,
and subjected to the same manufacturing processes. manufacturing, and inspection.
8.6.2 One transverse section shall be microstructurally ex- 8.8.1.3 Test results for requirements in Table 1 and Table 3.
amined to ensure that if any orientation effects exist, the notch
9. Process Control Testing
will be in the LS orientation in accordance with Terminology
E1823.
9.1 Testing Protocol:
8.6.3 All notched square bar bend specimens shall be
9.1.1 Specimen Preparation—The specimens, as received,
considered suitable for test purposes if the sampling and
shall be processed and qualified with the fasteners. It is
inspection results conform to the requirements of Table 1.
importantthatthespecimensbeexposedtothesameprocessas
the fasteners for the test to be a valid. Even if the fasteners do
notrequireadegreasingandcleaningprocessbeforeplatingor
coating, the specimens shall be degreased to remove the
TABLE 1 Lot Acceptance Criteria for 0.4W-Notched Square Bar
corrosion preventive compound and cleaned in acetone and
Bend Specimens
then placed in the process with the fasteners. An application
Sampling
Item of Each Requirement/Method guideline, to be used as a template for the use of this test
Lot
method, is provided in Appendix X2.
A
Hardness 5 % 50 to 52 HRC in accordance with Test
9.1.2 Number—One or more specimens per process per
Method E18. Round the average of
inspection period shall be used.
three readings per specimen in
accordance with Practice E29.
Dimensions 100 % Meet tolerances of corresponding
TABLE 2 Minimum Step-Loading Profile Requirements for
drawings. Notch dimension verified
Accelerated (< 24h) Incremental Step Load Sensitivity Tests
with shadow graphic projection at 50 to
100 %. %NFS(B) # h ^h %NFS(B) # h ^h %NFS(B) # h ^h
10 1 1 65 1 8 88 1 15
Notched Fracture 10 ea NFS(B) of each specimen must be within
20 1 2 70 1 9 90 1 16
strength in ±5 % of the average.
30 1 3 75 1 10 92 1 17
bending, NFS(B)
40 1 4 80 1 11 94 1 18
A
50 1 5 82 1 12 96 1 19
If the hardness requirements of any of the sampled specimens are not satisfied,
only those specimens of the lot that are individually inspected for conformance to 55 1 6 84 1 13 98 1 20
60 1 7 86 1 14 100 1 21
these requirements shall be used for testing.
F1940−07a (2019)
TABLE 3 Sensitivity Test Requirements of Specimens TABLE 5 Within Laboratory Notch Fracture Strength,
NFS Summary of Results
(Baseline)
Bare in air Each specimen tested shall have threshold
$85 % of the average notched bend fracture
95 %
strength, NFS(B) (Table 1)
SQBs Repeat-
Avg. Std. Dev
Tested Min. Max. ability
x s
Bare at potential of –1.2 V Each specimen tested shall have threshold
N Limit
versus SCE in 3.5 % #50 % of the average notched bend
r
NaCl solution in Spec- fracture strength NFS(B) (Table 1)
Study 1 37 219.5 6.52 204.4 232.1 18.26
ification D1193 Type IV
Study 2 30 218.5 4.22 210.8 225.9 11.82
•
reagent water
Average of study averages, x = 219.0
•
Average of study standard deviations, s = 5.37
9.1.3 Testspecimensshallbeprocessedonce.Strippingand
TABLE 6 Precision Statistics
reuse of specimens is prohibited.
Repea- Reprod- 95 % 95 %
Fracture
9.1.4 The nominal print dimensions from Fig. 1 of the bare
tability ucibility Repeat- Reprod-
Imposed Strength
metal specimens shall be used in all calculations. Standard Standard ability ucibility
Potential Average
Deviation Deviation Limit Limit
•
9.1.5 The specimens shall be in the LS orientation with the
x
S S r R
r R
notch loaded in tension.
-1.2 V 71.22 9.88 9.88 27.66 27.66
-1.0 V 85.1
...