1、Designation: B839 04 (Reapproved 2014)Standard Test Method forResidual Embrittlement in Metallic Coated, ExternallyThreaded Articles, Fasteners, and Rod-Inclined WedgeMethod1This standard is issued under the fixed designation B839; the number immediately following the designation indicates the year
2、oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONWhen atomic hydrogen enters steels and certain other allo
3、ys, it can cause loss of ductility or loadcarrying ability or cracking (usually as submicroscopic cracks), or catastrophic brittle failures atapplied stresses well below the yield strength or even the normal design strength for the alloys. Thisphenomenon often occurs in alloys that show no significa
4、nt loss in ductility, when measured byconventional tensile tests, and is frequently referred to as hydrogen-induced delayed brittle failure,hydrogen stress cracking, or hydrogen embrittlement. The hydrogen can be introduced duringcleaning, pickling, phosphating, electroplating, autocatalytic process
5、es, and in the service environmentas a result of cathodic protection reactions or corrosion reactions. Hydrogen can also be introducedduring fabrication, for example, during roll forming, machining, and drilling due to lubricantbreakdown as well as during welding or brazing operations.1. Scope1.1 Th
6、is test method covers the determination of, on astatistical basis, the probability of the existence of hydrogenembrittlement or degradation in:1.1.1 A batch of barrel electroplated, autocatalytic plated,phosphated, or chemically processed threaded articles or fas-teners and1.1.2 A batch of rack plat
7、ed threaded articles, fasteners, orrod.1.2 Industrial practice for threaded articles, fasteners, androd has evolved three graduated levels of test exposure toensure reduced risk of hydrogen embrittlement (see Section 3).These levels have evolved from commercial applicationshaving varying levels of c
8、riticality. In essence, they representthe confidence level that is required. They also represent thetime that finished goods are held before they can be shippedand used. This time equates to additional cost to the manufac-turer that may of necessity be added to the cost of the finishedgoods.1.3 This
9、 test method is applicable to threaded articles,fasteners, and rod made from steel with 1000 MPa (withcorresponding hardness values of 300 HV10 kgf, 303 HB, or 31HRc) or surface hardened threaded articles, fasteners, or rod.1.4 This test method shall be carried out after hydrogenembrittlement relief
10、 heat treatment in accordance with therequirements of Guide B850. It may also be used for assessingdifferences in processing solutions, conditions, and techniques.This test method has two main functions: first, when used witha statistical sampling plan it can be used for lot acceptance orrejection,
11、and second, it can be used as a control test todetermine the effectiveness of the various processing stepsincluding pre- and post-baking treatments to reduce the mobilehydrogen in the articles, fasteners, or rod. While this testmethod is capable of indicating those items that are embrittledto the ex
12、tent defined in Section 3, it does not guaranteecomplete freedom from embrittlement.1.5 This test method does not relieve the processor fromimposing and monitoring suitable process control.1.6 This test method has been coordinated with ISO/DIS10587 and is technically equivalent. (WarningGreat caresh
13、ould be taken when applying this test method. The heads ofembrittled articles, fasteners, or rod may suddenly break offand become flying projectiles capable of causing blindness orother serious injury. This hazard can occur as long as 200 hafter the test has started. Hence, shields or other apparatu
14、sshould be provided to avoid such injury.)NOTE 1Test Method F1940 can be used as a process control and1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 onTest Methods.Current edition approved May
15、 1, 2014. Published May 2014. Originallyapproved in 1994. Last previous edition approved in 2009 as B839 04(2009). DOI:10.1520/B0839-04R14.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1verification to prevent hydrogen embrittlement
16、in fasteners covered by thistest method.NOTE 2The use of inhibitors in acid pickling baths does notnecessarily guarantee avoidance of hydrogen embrittlement.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o
17、f this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B602 Test Method for Attribute Sampling of Metallic andInorganic CoatingsB697 Guide for Selection of Sampling Plans
18、 for Inspectionof Electrodeposited Metallic and Inorganic CoatingsF436 Specification for Hardened Steel WashersB850 Guide for Post-Coating Treatments of Steel for Reduc-ing the Risk of Hydrogen EmbrittlementF1940 Test Method for Process Control Verification toPrevent Hydrogen Embrittlement in Plated
19、 or CoatedFasteners2.2 ISO Standards:ISO/DIS 10587 Residual Embrittlement in Metallic Coated,Externally Threaded Articles, Fasteners and RodInclined Wedge Method3ISO 4519 Electrodeposited Metallic Coatings and RelatedFinishesSampling Procedures for Inspection by Attri-butes42.3 Military Standard:MIL
20、-STD-1312 Fastener Test Methods43. Terminology3.1 Definitions3.1.1 For the purposes of this test method the followingdefinitions apply:3.1.2 batcha distinct portion of items processed collec-tively as a single group through the same identical treatmentsteps at the same time on the same rack or in th
21、e same barrel.3.1.3 embrittledwhere parts fail immediately or up to 48 hin test.3.1.3.1 DiscussionThe degree to which parts within asingle plated batch or a given lot can be embrittled can varyover a wide range. The degree of embrittlement is a function ofthe concentration of atomic hydrogen in the
22、individual parts inthe batch or lot, measured in parts per million, and in particularthat portion of the hydrogen that is mobile or free to migrate toareas of high stress concentration.3.1.4 Grade 48 proofwhere there are no failures after 48 hof test.3.1.5 Grade 96 proofwhere there are no failures a
23、fter 96 hof test.3.1.6 Grade 200 proofwhere there are no failures after200 h of test.3.1.7 lota group of items processed through the same orsimilar steps at the same time or over a contiguous time periodand from the same heat of material. The lot may be brokendown into a number of batches for proces
24、sing purposes andthen reassembled into the same lot.4. Summary of Test Method4.1 The threaded articles, fasteners, or rod are subjected tostress by tensioning with a mating nut after insertion through aclearance hole in a hardened rectangular wedge of steel; seeFig. 1. Additional hardened rectangula
25、r pieces of steel withparallel faces are provided as filler plates and are inserted sothat the required length of the threaded article is placed undertest. Other loading systems and fixtures are permissible as longas the same load, angle, and exposure are created for the test.The upper surface of th
26、e wedge is ground at an angle to thelower surface. The mating nut is tensioned by any meanscapable of measuring tensile load. The torque method de-scribed in 6.4 is one such method. If the torque method of2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer S
27、ervice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from Standardizati
28、on Documents Order Desk, Bldg. 4, Section D,700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.FIG. 1 Example of 6 Wedge and Parallel Filler PlateB839 04 (2014)2tightening is used, the fasteners are torqued to the desiredvalue, held for the minimum specified hours, and then checkedto determi
29、ne if the initial torque has been maintained. Follow-ing this they are examined for embrittlement failures. SeeSection 9.NOTE 3Increasing the applied torque by a small percentage as a safetyfactor is not recommended.5. Significance and Use5.1 The use of this test method can significantly reduce ther
30、isk of sudden catastrophic failure of threaded articles andfasteners, below their design strength, due to hydrogen em-brittlement.6. Apparatus6.1 Test Fixture comprising a hardened wedge (see Fig. 1),one or more filler plates, and a hardened washer. The hole ineach shall be as close to the major dia
31、meter of the threadedarticle, fastener, or rod being tested as practical. Excessclearance space may cause the fastener to tilt in the hole andcan result in a failure at a lower torque value.6.2 Fixture With Multiple Holes has been found useful formultiple or repetitive testing. The fixture can be re
32、adily madefrom a rectangular piece of an air hardening grade of steel withone face ground to the appropriate wedge angle and hardenedto HRc60.6.3 WedgeShall have an angle as specified in Table 1.6.4 Filler Plate(s)Shall be of the same steel grade andhardness as the wedge fixture and have a thickness
33、 such that,after installation and tightening, a minimum of three fullthreads of the test fastener will be engaged and no more thanfive full threads will extend beyond the nut.6.5 WasherShall be HRc38 to 45 and shall conform to therequirements of Specification F436.6.6 Torque Application DeviceIf the
34、 torque method oftightening is used, the tightening torque shall be determinedusing a load measuring device capable of measuring the actualtension induced in the article, fastener, or rod as the item istightened.6.7 Torque DeterminationFive items from the test lot shallbe selected at random. Each sh
35、all be assembled into the loadmeasuring device, mated with a nut, and the nut tightened untila load equal to 75 % of the ultimate tensile strength of the itemis induced. The torque required to induce this load shall bemeasured and the arithmetic average of the five measuredtorques shall be the tight
36、ening torque. Calculated torque versustension methods of testing such as the T = KDL formula usedin MIL-STD-1313 are not sufficiently accurate for use in thistest and shall not be used.7. Sampling7.1 The document specifying this test method shall specifyan AQI level and sampling plan to be used. Gui
37、dance in theselection of sampling plans is provided in Guide B697. Widelyused sampling plans are provided in Test Method B602 and itsequivalent ISO 4519.7.2 A minimum sample size of 30 pieces is necessary fromeach embrittlement relief treated batch that exceeds 500 piecesplated as a single group.8.
38、Procedure8.1 Test Item PlacementPlace the test items in the clear-ance holes with the heads positioned against the angle of thewedge. In the case of items with square, hexagonal, or similarstraight side heads, a straight side shall be placed against theangle of the wedge. In the case of elliptical o
39、r other shapedheads, the side with the minor radius of the ellipse shall beplaced against the angle of the wedge. In the case of itemswithout heads, studs, or threaded rod, one end shall be nuttedand tested as the head. When the items are threaded withdifferent pitch threads, the finer thread shall
40、be treated as thehead. Nut the free end of the items and run them up finger-tight. No significance has been found between the start of thethread on an article in relation to the angle of the wedge.8.2 Torque ApplicationClamp the wedge device with thenutted ends facing in a convenient position in a s
41、ecurelyattached vice. Using a calibrated torque tool tighten the nuts tothe desired torque and record the values. The wedge should beremoved from the vice and left undisturbed for the test period.See Section 3.9. Evaluation9.1 Cracks, Separated Heads, and BreakageAfter thespecified holding period is
42、 complete, examine each item forfailures such as cracks, separated heads, and breakage. Usefinger pressure to check each head for breakage. Cracks can beidentified by examination at 10 magnification, magneticparticle inspection, or the use of a liquid dye penetrant.9.2 Relaxed TorqueFollowing the ex
43、amination of thespecimens in 9.1, place the wedge in a vice and carefully turneach mating nut, with the torque tool, in the on direction untila forward angular motion, after break loose, is noticeable.Record the torque value at break loose and compare it with theinitially recorded torque. Torque rel
44、axation greater than 10 %shall be recorded as failure. Remove the nuts and examine theitems for transverse cracks, which shall also be recorded asfailure.10. Report10.1 Report the following information:10.1.1 ASTM designation number of this test method,10.1.2 Batch identification number and total nu
45、mber ofparts in the batch,TABLE 1 Wedge Angle Selection (in degrees)Nominal Size ofThreaded ArticleArticles with UnthreadedLengths Less than2 DiametersArticles withUnthreaded Lengths 2Diametersand Longer2to6mm 6 6116 to14 in. 6 66to18mm 4 614 to34 in. 4 6over 18 to 38 mm 0 4over34 to 112 in. 0 4B839
46、 04 (2014)310.1.3 Number of parts tested,10.1.4 Number of broken parts, parts with visible cracks orother observed failures, and parts that exhibited relaxed torque,and10.1.5 Duration of the test method.11. Precision and Bias11.1 PrecisionThe precision of this test method has notbeen determined.11.2
47、 BiasThe bias has not been determined.12. Keywords12.1 hydrogen embrittlement test; metallic coated; residualembrittlement test; testing threaded articles; threaded fasteners;threaded rodAPPENDIX(Nonmandatory Information)X1. SOURCES OF INTRODUCTION OF HYDROGEN INTO THREADED ARTICLESX1.1 The preparat
48、ion and metallic coating of threadedarticles, fasteners, and rod are usually accomplished by thebarrel-plating process. In this process, quantities of an item areplaced within a containment vessel, called a barrel. The barrelis designed to move the group of items, together, through eachof the proces
49、s steps, allowing ready ingress and egress ofprocessing solutions and rinses.As the barrel is moved throughthe process steps, it is also rotated such that the individualitems are constantly cascading over one another. In some of theprocess steps, notably the electrocleaning and electroplatingsteps, an electric current is applied to the group of items. Thecascading action randomly exposes the surfaces of eachindividual piece to the process electrodes while also maintain-ing electrical continuity among all the parts.X1.2 During both the electrolyti
