ASTM_F_1459_-_06_2012.pdf

Designation:F145906(Reapproved 2012)Standard Test Method forDetermination of the Susceptibility of Metallic Materials toHydrogen Gas Embrittlement(HGE)1This standard is issued under the fixed designation F1459;the number immediately following the designation indicates the year 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.1.Scope1.1 This test method covers the quantitative determinationof the susceptibility of metallic materials to hydrogenembrittlement,when exposed to high pressure gaseous hydro-gen.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility 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 Documents2.1 ASTM Standards:E384 Test Method for Knoop and Vickers Hardness ofMaterials3.Summary of Test Method3.1 Athin disk metallic specimen is subjected to an increas-ing gas pressure at constant rate until failure(bursting orcracking of the disk).The embrittlement of the material can beevaluated by comparing the rupture pressures of identical diskspecimens in hydrogen(PH2)and in a reference inert gas suchas helium(PHe)(1,2).23.2 The ratio PHe/PH2can be used to evaluate the suscepti-bility of the metallic material to gaseous hydrogen embrittle-ment.The ratio is dependent on the pressurization rate.A ratioof 1 or less indicates the material is not susceptible to hydrogenembrittlement.A ratio greater than 1 indicates that the materialis susceptible to hydrogen embrittlement and the susceptibilityincreases as the ratio increases.4.Significance and Use4.1 This test method will provide a guide for the choice ofmetallic materials for applications in high pressure hydrogengas.4.2 The value of the PHe/PH2ratio will be a relativeindication of the severity of degradation of the mechanicalproperties to be expected in hydrogen.5.Apparatus5.1 A basic test system shall consist of the following items:5.1.1 Test Cell,consists of two flanges as shown schemati-cally in Fig.1.5.1.1.1 The test cell shall befabricated from materials suchas 316 stainless steel in the annealed condition that are notsusceptible to HGE(3,4).5.1.1.2 The seals shall be elastomer O-rings for heliumtesting and hydrogen testing at rates of 10 bar/min(145psig/min)or higher.For hydrogen tests at a lower rate,indiumO-rings shall be used.5.1.1.3 An evaluation port(Item 1 in Fig.1)on the lowerflange is used to check gas purity and adjust pressurization rate.5.1.2 The test cell is pressurized with hydrogen or heliumthrough a pneumatic system.Fig.2 schematically illustrates thepneumatic system.5.1.2.1 The pressurization rate shall be adjustable in thesystem.Athrottle valve is used to adjust the pressurization ratein Fig.2.6.Gases6.1 Helium,purity 99.995 minimum,6000-psig(41 400-kPa)or higher pressure source.6.2 Hydrogen,purity 99.995 minimum,6000-psig(41 400-kPa)or higher pressure source.7.Specimen Preparation7.1 Fifteen(15)specimens with identical dimensions andtemper conditions shall be prepared for each test program.Six(6)specimens are to be tested in helium and nine(9)specimensare to be tested in hydrogen.One specimen is to be tested at thepredetermined pressurization rate in helium or hydrogen asprescribed in 8.2.3.1This test method is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommittee F07.04 onHydrogen Embrittlement.Current edition approved June 1,2012.Published August 2012.Originallyapproved in 1993.Last previous edition approved in 2006 as F1459 06.DOI:10.1520/F1459-06R12.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.2 The specimens for the test cell,illustrated in Fig.1,havea diameter of 58 mm(2.28 in.)and a thickness of 0.75 mm(0.030 in).If not available,other thickness between 0.25 and 1mm(0.010 and 0.040 in.)are also acceptable.7.3 The disk specimen shall have a flatness of less than110mm(1254in.)deflection.7.4 The surface of the disk specimen shall be free of oxides.The surface roughness Ra shall be 0.001 mm(40 in.)or less.7.5 The disk specimen shall be prepared by a method thatdoes not alter mechanical properties of the material at the edgeof the specimen.Microhardness testing should be conductedper Test Method E384 at the outer edge of the specimen(outside the tested area)to ensure it is as a means of confirmingthat the mechanical properties were not altered.7.6 The specimens shall be cleaned,free of grease and driedbefore test.8.Pro