ASTM F1940-01

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

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 applies to externally threaded tensile fasteners that can also be loaded in bending during installation.
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 ferrous fasteners that are susceptible to time-delayed fracture caused by the diffusion of hydrogen under stress.
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 STP543 and ASTM STP962. 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 A notched four-point bend specimen undergoes sustained load and slow strain rate testing by using incremental loads and hold times under displacement control to measure a threshold stress in an accelerated manner in accordance with Test Method F1624. The test is an accelerated (24 h) incrementally increasing step load test method that measures the threshold for hydrogen stress cracking that is used to quantify the amount of residual hydrogen in the specimen.
1.9 In this test method, bending is used instead of tension because it produces the maximum local limit load tensile stress in a notched bar of up to 2.3 times the yield strength as measured in accordance with Test Method E 8. A fastener that is unintentionally exposed to bending on installation may attain this maximum local tensile stress.
1.10 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.11 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Apr-2001
• ICS: 21.060.01 - Fasteners in general
• Technical Committee: F16 - Fasteners
• Drafting Committee: F16.93 - Quality Assurance Provisions for Fasteners

Relations

• Replaces: ASTM F1940-99 - Standard Test Method for Process Control Verification to Prevent Hydrogen Embrittlement in Plated or Coated Fasteners
• Effective Date: 10-Apr-2001
• Replaced By: ASTM F1940-07 - Standard Test Method for Process Control Verification to Prevent Hydrogen Embrittlement in Plated or Coated Fasteners
• Effective Date: 01-May-2007
• Referred By: ASTM B633-23 - Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel
• Effective Date: 10-Apr-2001
• Referred By: ASTM A193/A193M-23 - Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
• Effective Date: 10-Apr-2001
• Referred By: ASTM A574-21 - Standard Specification for Alloy Steel Socket-Head Cap Screws
• Effective Date: 10-Apr-2001
• Referred By: ASTM F2833-11(2017) - Standard Specification for Corrosion Protective Fastener Coatings with Zinc Rich Base Coat and Aluminum Organic/Inorganic Type
• Effective Date: 10-Apr-2001
• Referred By: ASTM F2882/F2882M-17 - Standard Specification for Screws, Alloy Steel, Heat Treated, 170 ksi and 1170 MPa Minimum Tensile Strength (Inch and Metric)
• Effective Date: 10-Apr-2001
• Referred By: ASTM F3019/F3019M-19 - Standard Specification for Chromium Free Zinc-Flake Composite, with or without Integral Lubricant, Corrosion Protective Coatings for Fasteners
• Effective Date: 10-Apr-2001
• Referred By: ASTM F1941/F1941M-16 - Standard Specification for Electrodeposited Coatings on Mechanical Fasteners, Inch and Metric
• Effective Date: 10-Apr-2001
• Referred By: ASTM A194/A194M-23 - Standard Specification for Carbon Steel, Alloy Steel, and Stainless Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both
• Effective Date: 10-Apr-2001
• Referred By: ASTM F3125/F3125M-22 - Standard Specification for High Strength Structural Bolts and Assemblies, Steel and Alloy Steel, Heat Treated, Inch Dimensions 120 ksi and 150 ksi Minimum Tensile Strength, and Metric Dimensions 830 MPa and 1040 MPa Minimum Tensile Strength
• Effective Date: 10-Apr-2001
• Referred By: ASTM F1136/F1136M-11(2019) - Standard Specification for Zinc/Aluminum Corrosion Protective Coatings for Fasteners
• Effective Date: 10-Apr-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F 1940 – 01
Standard Test Method for
Process Control Verification to Prevent Hydrogen
1
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 The sensitivity of each lot of specimens to IHE shall be
demonstrated. A specimen made of AISI E4340 steel heat
1.1 This test method covers a procedure to prevent, to the
treatedtoahardnessrangeof50to52HRCisusedtoproduce
extent possible, internal hydrogen embrittlement (IHE) of
a “worst case” condition and maximize sensitivity to IHE.
fasteners by monitoring the plating or coating process, such as
1.8 A notched four-point bend specimen undergoes sus-
those described in Specifications F1137 and F1941. The
tained load and slow strain rate testing by using incremental
process is quantitatively monitored on a periodic basis with a
loads and hold times under displacement control to measure a
minimumnumberofspecimensascomparedtoqualifyingeach
threshold stress in an accelerated manner in accordance with
lotoffastenersbeingplatedorcoated.Trendanalysisisusedto
Test Method F1624. The test is an accelerated (#24 h)
ensure quality as compared to statistical sampling analysis of
incrementally increasing step load test method that measures
eachlotoffasteners.Thistestmethodconsistsofamechanical
the threshold for hydrogen stress cracking that is used to
test for the evaluation and control of the potential for IHE that
quantify the amount of residual hydrogen in the specimen.
may arise from various sources of hydrogen in a plating or
1.9 In this test method, bending is used instead of tension
coating process.
becauseitproducesthemaximumlocallimitloadtensilestress
1.2 This test method applies to externally threaded tensile
in a notched bar of up to 2.3 times the yield strength as
fastenersthatcanalsobeloadedinbendingduringinstallation.
measured in accordance with Test Method E8.Afastener that
1.3 This test method is limited to evaluating hydrogen
isunintentionallyexposedtobendingoninstallationmayattain
induced embrittlement due only to processing (IHE) and not
this maximum local tensile stress.
due to environmental exposure (EHE, see Test Method
1.10 The values stated in inch-pound units are to be re-
F1624).
garded as standard. The values given in parentheses are
1.4 This test method is not intended to measure the relative
mathematical conversions to SI units that are provided for
susceptibility of steels to either IHE or EHE.
information only and are not considered standard.
1.5 This test method is limited to ferrous fasteners that are
1.11 This standard does not purport to address all of the
susceptible to time-delayed fracture caused by the diffusion of
safety concerns, if any, associated with its use. It is the
hydrogen under stress.
responsibility of the user of this standard to establish appro-
1.6 This test method uses a notched square bar specimen
priate safety and health practices and determine the applica-
that conforms to Test Method F519, Type 1e, except that the
bility of regulatory limitations prior to use.
radius is increased to accommodate the deposition of a larger
range of platings and coatings. For the background on Test
2. Referenced Documents
2
Method F519 testing, see publications ASTM STP 543 and
3
2.1 ASTM Standards:
ASTM STP 962. The stress concentration factor is at a K =
t
4
D1193 Specification for Reagent Water
3.1 6 0.2. The sensitivity is demonstrated with a constant
5
E4 Practices for Force Verifications of Testing Machines
imposed cathodic potential to control the amount of hydrogen.
5
E8 TestMethodsforTensionTestingofMetallicMaterials
Boththesensitivityandthebaselineforresidualhydrogenwill
E18 Test Methods of Rockwell Hardness and Rockwell
be established with tests on bare metal specimens in air.
5
Superficial Hardness of Metallic Materials
E29 Practice for Using Significant Digits in Test Data to
6
Determine Conformance with Specifications
1
This test method is under the jurisdiction of ASTM Committee F16 on
E177 Practice for Use of the Terms Precision and Bias in
Fasteners and is the direct responsibility of Subcommittee F16.93 on Quality
6
Assurance Provisions for Fasteners. ASTM Test Methods
Current edition approved April 10, 2001. Published July 2001. Originally
published as F1940–98. Last previous edition F1940–99.
2
Hydrogen Embrittlement Testing, ASTM STP 543, American Society for
4
Testing and Materials, 1974.
Annual Book of ASTM Standards, Vol 11.01.
3
5
Hydrogen Embrittlement; Prevention and Control, ASTM STP 962, America
...