Designation:E1928−13StandardPracticeforEstimatingtheApproximateResidualCircumferentialStressinStraightThin-walledTubing1ThisstandardisissuedunderthefixeddesignationE1928;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Aqualitativeestimateoftheresidualcircumferentialstressinthin-walledtubingmaybecalculatedfromthechangeinoutsidediameterthatoccursuponsplittingalengthofthin-walledtubing.Thispracticeassumesalinearstressdistributionthroughthetubewallthicknessandwillnotprovideanestimateoflocalstressdistributionssuchassurfacestresses.(Veryhighlocalresidualstressgradientsarecommonatthesurfaceofmetaltubingduetocolddrawing,peening,grinding,etc.)TheHatfieldandThirkellformula,aslatermodifiedbySachsandEspey,2providesasimplemethodforcalculatingtheapproximatecircumferentialstressfromthechangeindiameterofstraight,thin-walled,metaltubing.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:3E6TerminologyRelatingtoMethodsofMechanicalTesting3.Terminology3.1ThedefinitionsinthispracticeareinaccordancewithTerminologyE6.4.SignificanceandUse4.1Residualstressesintubingmaybedetrimentaltothefutureperformanceofthetubing.Suchstressesmay,forexample,influencethesusceptibilityofatubetostresscorro-sioncrackingwhenthetubeisexposedtocertainenviron-ments.4.2Residualstressesinnewthin-walledtubingareverysensitivetotheparametersofthefabricationprocess,andsmallvariationsintheseparameterscanproducesignificantchangesintheresidualstresses.See,forexample,Table1,whichshowstheresidualstressesmeasuredbythispracticeinsamplesfromsuccessiveheatsofaferriticCr-Mo-Nistainlesss...
