ASTM B839-04(2009)
(Test Method)Standard Test Method for Residual Embrittlement in Metallic Coated, Externally Threaded Articles, Fasteners, and Rod—Inclined Wedge Method
Standard Test Method for Residual Embrittlement in Metallic Coated, Externally Threaded Articles, Fasteners, and Rod—Inclined Wedge Method
SIGNIFICANCE AND USE
The use of this test method can significantly reduce the risk of sudden catastrophic failure of threaded articles and fasteners, below their design strength, due to hydrogen embrittlement.
SCOPE
1.1 This test method covers the determination of, on a statistical basis, the probability of the existence of hydrogen embrittlement or degradation in:
1.1.1 A batch of barrel electroplated, autocatalytic plated, phosphated, or chemically processed threaded articles or fasteners and
1.1.2 A batch of rack plated threaded articles, fasteners, or rod.
1.2 Industrial practice for threaded articles, fasteners, and rod has evolved three graduated levels of test exposure to ensure reduced risk of hydrogen embrittlement (see Section 3). These levels have evolved from commercial applications having varying levels of criticality. In essence, they represent the confidence level that is required. They also represent the time that finished goods are held before they can be shipped and used. This time equates to additional cost to the manufacturer that may of necessity be added to the cost of the finished goods.
1.3 This test method is applicable to threaded articles, fasteners, and rod made from steel with ≥1000 MPa (with corresponding hardness values of 300 HV10 kgf, 303 HB, or 31 HRc) or surface hardened threaded articles, fasteners, or rod.
1.4 This test method shall be carried out after hydrogen embrittlement relief heat treatment in accordance with the requirements of Guide B850. It may also be used for assessing differences in processing solutions, conditions, and techniques. This test method has two main functions: first, when used with a statistical sampling plan it can be used for lot acceptance or rejection, and second, it can be used as a control test to determine the effectiveness of the various processing steps including pre- and post-baking treatments to reduce the mobile hydrogen in the articles, fasteners, or rod. While this test method is capable of indicating those items that are embrittled to the extent defined in Section 3, it does not guarantee complete freedom from embrittlement.
1.5 This test method does not relieve the processor from imposing and monitoring suitable process control.
1.6 This test method has been coordinated with ISO/DIS 10587 and is technically equivalent. (Warning—Great care should be taken when applying this test method. The heads of embrittled articles, fasteners, or rod may suddenly break off and become flying projectiles capable of causing blindness or other serious injury. This hazard can occur as long as 200 h after the test has started. Hence, shields or other apparatus should be provided to avoid such injury.)
Note 1—Test Method F1940 can be used as a process control and verification to prevent hydrogen embrittlement in fasteners covered by this test method.
Note 2—The use of inhibitors in acid pickling baths does not necessarily guarantee avoidance of hydrogen embrittlement.
1.7 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
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Standards Content (Sample)
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Designation: B839 − 04(Reapproved 2009)
Standard Test Method for
Residual Embrittlement in Metallic Coated, Externally
Threaded Articles, Fasteners, and Rod—Inclined Wedge
Method
This standard is issued under the fixed designation B839; 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.
INTRODUCTION
When atomic hydrogen enters steels and certain other alloys, it can cause loss of ductility or load
carrying ability or cracking (usually as submicroscopic cracks), or catastrophic brittle failures at
applied stresses well below the yield strength or even the normal design strength for the alloys. This
phenomenon often occurs in alloys that show no significant loss in ductility, when measured by
conventional tensile tests, and is frequently referred to as hydrogen-induced delayed brittle failure,
hydrogen stress cracking, or hydrogen embrittlement. The hydrogen can be introduced during
cleaning,pickling,phosphating,electroplating,autocatalyticprocesses,andintheserviceenvironment
as a result of cathodic protection reactions or corrosion reactions. Hydrogen can also be introduced
during fabrication, for example, during roll forming, machining, and drilling due to lubricant
breakdown as well as during welding or brazing operations.
1. Scope corresponding hardness values of 300 HV , 303 HB, or 31
10kgf
HR ) or surface hardened threaded articles, fasteners, or rod.
c
1.1 This test method covers the determination of, on a
statistical basis, the probability of the existence of hydrogen
1.4 This test method shall be carried out after hydrogen
embrittlement or degradation in:
embrittlement relief heat treatment in accordance with the
1.1.1 A batch of barrel electroplated, autocatalytic plated,
requirements of Guide B850. It may also be used for assessing
phosphated, or chemically processed threaded articles or fas-
differencesinprocessingsolutions,conditions,andtechniques.
teners and
Thistestmethodhastwomainfunctions:first,whenusedwith
1.1.2 A batch of rack plated threaded articles, fasteners, or
a statistical sampling plan it can be used for lot acceptance or
rod.
rejection, and second, it can be used as a control test to
determine the effectiveness of the various processing steps
1.2 Industrial practice for threaded articles, fasteners, and
rod has evolved three graduated levels of test exposure to includingpre-andpost-bakingtreatmentstoreducethemobile
ensurereducedriskofhydrogenembrittlement(seeSection3). hydrogen in the articles, fasteners, or rod. While this test
These levels have evolved from commercial applications method is capable of indicating those items that are embrittled
having varying levels of criticality. In essence, they represent to the extent defined in Section 3, it does not guarantee
the confidence level that is required. They also represent the
complete freedom from embrittlement.
time that finished goods are held before they can be shipped
1.5 This test method does not relieve the processor from
and used. This time equates to additional cost to the manufac-
imposing and monitoring suitable process control.
turer that may of necessity be added to the cost of the finished
goods.
1.6 This test method has been coordinated with ISO/DIS
10587 and is technically equivalent. (Warning—Great care
1.3 This test method is applicable to threaded articles,
should be taken when applying this test method. The heads of
fasteners, and rod made from steel with ≥1000 MPa (with
embrittled articles, fasteners, or rod may suddenly break off
and become flying projectiles capable of causing blindness or
ThistestmethodisunderthejurisdictionofASTMCommitteeB08onMetallic
other serious injury. This hazard can occur as long as 200 h
and Inorganic Coatingsand is the direct responsibility of Subcommittee B08.10 on
after the test has started. Hence, shields or other apparatus
Test Methods.
should be provided to avoid such injury.)
Current edition approved Sept. 1, 2009. Published December 2009. Originally
approved in 1994. Last previous edition approved in 2004 as B839 – 04. DOI:
10.1520/B0839-04R09. NOTE 1—Test Method F1940 can be used as a process control and
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B839 − 04 (2009)
verificationtopreventhydrogenembrittlementinfastenerscoveredbythis
test method.
NOTE 2—The use of inhibitors in acid pickling baths does not
necessarily guarantee avoidance of hydrogen embrittlement.
1.7 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 appro-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
B602Test Method for Attribute Sampling of Metallic and
Inorganic Coatings
B697Guide for Selection of Sampling Plans for Inspection
of Electrodeposited Metallic and Inorganic Coatings
F436Specification for Hardened Steel Washers
B850GuideforPost-CoatingTreatmentsofSteelforReduc-
ing the Risk of Hydrogen Embrittlement
F1940Test Method for Process Control Verification to
Prevent Hydrogen Embrittlement in Plated or Coated
Fasteners
2.2 ISO Standards:
ISO/DIS 10587Residual Embrittlement in Metallic Coated,
Externally Threaded Articles, Fasteners and Rod—
Inclined Wedge Method
ISO 4519Electrodeposited Metallic Coatings and Related
Finishes—Sampling Procedures for Inspection by Attri-
butes
2.3 Military Standard:
MIL-STD-1312Fastener Test Methods
3. Terminology
FIG. 1 Example of 6° Wedge and Parallel Filler Plate
3.1 Definitions—
3.1.1 For the purposes of this test method the following
definitions apply:
3.1.5 Grade 96 proof—wheretherearenofailuresafter96h
3.1.2 batch—a distinct portion of items processed collec-
of test.
tively as a single group through the same identical treatment
3.1.6 Grade 200 proof—where there are no failures after
steps at the same time on the same rack or in the same barrel.
200 h of test.
3.1.3 embrittled—wherepartsfailimmediatelyorupto48h
3.1.7 lot—a group of items processed through the same or
in test.
similarstepsatthesametimeoroveracontiguoustimeperiod
3.1.3.1 Discussion—The degree to which parts within a
and from the same heat of material. The lot may be broken
single plated batch or a given lot can be embrittled can vary
down into a number of batches for processing purposes and
overawiderange.Thedegreeofembrittlementisafunctionof
then reassembled into the same lot.
the concentration of atomic hydrogen in the individual parts in
thebatchorlot,measuredinpartspermillion,andinparticular
4. Summary of Test Method
thatportionofthehydrogenthatismobileorfreetomigrateto
4.1 The threaded articles, fasteners, or rod are subjected to
areas of high stress concentration.
stressbytensioningwithamatingnutafterinsertionthrougha
3.1.4 Grade 48 proof—wheretherearenofailuresafter48h
clearance hole in a hardened rectangular wedge of steel; see
of test.
Fig. 1. Additional hardened rectangular pieces of steel with
parallel faces are provided as filler plates and are inserted so
that the required length of the threaded article is placed under
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
test.Otherloadingsystemsandfixturesarepermissibleaslong
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
as the same load, angle, and exposure are created for the test.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
The upper surface of the wedge is ground at an angle to the
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
lower surface. The mating nut is tensioned by any means
4th Floor, New York, NY 10036, http://www.ansi.org.
capable of measuring tensile load. The torque method de-
Available from Standardization Documents Order Desk, Bldg. 4, Section D,
700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. scribed in 6.4 is one such method. If the torque method of
B839 − 04 (2009)
TABLE 1 Wedge Angle Selection (in degrees)
torquesshallbethetighteningtorque.Calculatedtorqueversus
Articles with tension methods of testing such as the T = KDL formula used
Articles with Unthreaded
Nominal Size of Unthreaded Lengths 2
in MIL-STD-1313 are not sufficiently accurate for use in this
Lengths Less than
Threaded Article Diameters
2 Diameters
test and shall not be used.
and Longer
2to6mm 6 6
7. Sampling
1 1
⁄16 to ⁄4 in. 6 6
6to18mm 4 6
7.1 The document specifying this test method shall specify
1 3
⁄4 to ⁄4 in. 4 6
a
...
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