1、Designation: A320/A320M 15aStandard Specification forAlloy-Steel and Stainless Steel Bolting for Low-TemperatureService1This standard is issued under the fixed designation A320/A320M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This specification
3、2covers alloy steel bolting materialsand bolting components for pressure vessels, valves, flanges,and fittings for low-temperature service. See SpecificationA962/A962M for the definition of bolting. The bars shall behot-wrought and may be further processed by centerlessgrinding or by cold drawing. A
4、ustenitic stainless steel may besolution annealed or annealed and strain-hardened. Whenstrain hardened austenitic stainless steel is ordered, the pur-chaser should take special care to ensure that Appendix X1 isthoroughly understood.1.2 Several grades are covered, including both ferritic andaustenit
5、ic steels designated L7, B8, etc. Selection will dependon design, service conditions, mechanical properties, andlow-temperature characteristics. The mechanical requirementsof Table 1 indicate the diameters for which the minimummechanical properties apply to the various grades and classes,and Table 2
6、 stipulates the requirements for Charpy impactenergy absorption. The manufacturer should determine that thematerial can conform to these requirements before parts aremanufactured. For example, when Grade L43 is specified tomeet the Table 2 impact energy values at 150 F 101 C,additional restrictions
7、(such as procuring a steel with lower Pand S contents than might normally be supplied) in thechemical composition for AISI 4340 are likely to be required.NOTE 1The committee formulating this specification has includedseveral grades of material that have been rather extensively used for thepresent pu
8、rpose. Other compositions will be considered for inclusion bythe committee from time to time as the need becomes apparent. Usersshould note that hardenability of some of the grades mentioned mayrestrict the maximum size at which the required mechanical properties areobtainable.1.3 The following refe
9、renced general requirements are in-dispensable for application of this specification: SpecificationA962/A962M.1.4 Nuts for use with bolting are covered in Section 10 andthe nut material shall be impact tested.1.5 Supplementary Requirements are provided for use at theoption of the purchaser. The supp
10、lementary requirements shallapply only when specified in the purchase order or contract.1.6 This specification is expressed in both inch-pound unitsand SI units; however, unless the purchase order or contractspecifies the applicable M specification designation (SI) units,the inch-pound units shall a
11、pply.1.7 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformance
12、with the standard.2. Referenced Documents2.1 ASTM Standards:3A194/A194M Specification for Carbon Steel, Alloy Steel,and Stainless Steel Nuts for Bolts for High Pressure orHigh Temperature Service, or BothA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA962/A962M Specificatio
13、n for Common Requirements forBolting Intended for Use at Any Temperature from Cryo-genic to the Creep RangeE566 Practice for Electromagnetic (Eddy Current) Sorting ofFerrous MetalsF436 Specification for Hardened Steel WashersF606 Test Methods for Determining the Mechanical Proper-ties of Externally
14、and Internally Threaded Fasteners,Washers, and Rivets (Metric) F0606_F0606M1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloysand is the direct responsibility of SubcommitteeA01.22 on Steel Forgings and Wrought Fittings for PipingApplicatio
15、ns and BoltingMaterials for Piping and Special Purpose Applications.Current edition approved Nov. 1, 2015. Published November 2015. Originallyapproved in 1948. Last previous edition approved in 2015 as A320/A320M15.DOI: 10.1520/A0320_A0320M-15A.2For ASME Boiler and Pressure Vessel Code applications,
16、 see related Specifi-cation SA-320 in Section II of that Code.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website
17、.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.2 ASME Standards:4B1.1 Screw ThreadsB18.22.1 Plain Washers3. Ordering Information3.1 It is the purchasers responsibili
18、ty to specify in thepurchase order all information necessary to purchase theneeded materials. Examples of such information include, butare not limited to, the following:3.1.1 Quantity and size,3.1.2 Heat-treated condition, that is, for the austenitic stain-less steels, solution-treated (Class 1); so
19、lution-treated afterfinishing (Class 1A); and annealed and strain-hardened (Class2),3.1.3 Description of items required (bars, bolts, screws, orstuds),3.1.4 Nuts and washers, if required by the purchaser, inaccordance with Section 10, and3.1.5 Special requirements, in accordance with 5.1.1, 5.1.3,5.
20、1.4, and 13.1.4. Common Requirements4.1 Bolting materials and bolting components supplied tothis specification shall conform to the requirements of Speci-fication A962/A962M. These requirements include testmethods, finish, thread dimensions, macroetch (carbon andalloy steels only) marking, certifica
21、tion, optional supplemen-tary requirements, and others. Failure to comply with therequirements of Specification A962/A962M constitutes non-conformance with this specification. In case of conflict be-tween the requirements in this specification and SpecificationA962/A962M, this specification shall pr
22、evail.5. Materials and Manufacture5.1 Heat Treatment:5.1.1 Bolting materials shall be allowed to cool to roomtemperature after rolling or forging. Grades L7, L7A, L7B,L7C, L7M, L43, L1, L70, L71, L72, and L73 shall be reheatedto above the upper critical temperature and liquid quenchedand tempered. G
23、rades B8, B8C, B8M, B8T, B8F, B8P, B8LN,and B8MLN shall receive a carbide solution treatment. Prod-ucts made from such material are described as Class 1. Thisshall consist of holding the bolting material for a sufficient timeat a temperature at which the chromium carbide will go intosolution and the
24、n cooling in air or in a liquid medium at a ratesufficient to prevent reprecipitation of the carbide. Boltingmaterial thus treated is described as Class 1. If specified in thepurchase order, bolting material shall be solution treated in thefinished condition and shall be described as Class 1A.5.1.2
25、Use of water quenching is prohibited for any ferriticgrade when heat treatment is performed after heading orthreading.5.1.3 When increased mechanical properties are desired,austenitic bolting shall be solution annealed and strain hard-ened if specified in the purchase order; material so treated isid
26、entified as Class 2.5.1.4 If scale-free bright finish is required, this shall bespecified in the purchase order.5.1.5 For L7M bolting, the final heat treatment, which maybe the tempering or stress-relieving operation conducted at1150 F 620 C minimum, shall be done after machining orrolling of the th
27、reads and any type of cutting.6. Mechanical Requirements6.1 Tensile Properties:6.1.1 Bolting material as represented by the tension speci-mens shall conform to the requirements as to tensile propertiesprescribed in Table 1 at room temperature after heat treatment(see 5.1.1). Alternatively, Class 2 S
28、train Hardened HeadedBolting Components shall be tested full size after strainhardening to determine tensile strength and yield strength andshall conform to the requirements prescribed in Table 1.Should the results of full size tests conflict with results oftension specimen tests, full size test res
29、ults shall prevail.6.1.2 Number of Tests:6.1.2.1 For heat-treated bars, one tension test and oneimpact test consisting of three specimens shall be made foreach diameter of each heat represented in each temperingcharge. When heat treated without interruption in continuousfurnaces, the material in a l
30、ot shall be the same heat, same priorcondition, same size, and subjected to the same heat treatment.Not fewer than two tensile tests and two impact tests arerequired for each lot containing 20 000 lbs 9000 kg or less.Every additional 10 000 lbs 4500 kg or fraction thereofrequires an additional tensi
31、le test and impact test.6.1.2.2 For studs, bolts, screws, etc., one tension test andone set of three impact specimens shall be made for eachdiameter of each heat involved in the lot. Each lot shall consistof the following:Diameter, in. mm Lot Size, lb kg118 30 and under 1500 680 or fraction thereofO
32、ver 118 30 to 134 45,incl4500 2040 or fractionthereofOver 134 45 to 212 65,incl6000 2700 or fractionthereofOver 212 65 100 pieces or fraction thereof6.1.2.3 Full Size Specimens, Headed Bolting ComponentsHeaded bolts, studs, or screws 112 in. in body diameter andsmaller, with body length three times
33、the diameter or longer,and which are produced by upsetting or forging (hot or cold)shall be subjected to full size testing in accordance with 6.1.3.This testing shall be in addition to tensile testing as specified in6.1.1. The lot size shall be shown in 6.1.2.2. Failure shall occurin the body or thr
34、eaded sections with no failure, or indicationsof failure, such as cracks, at the junction of the head and shank.6.1.3 Full Size Bolting Components, Wedge TensileTestingWhen applicable, see 6.1.2.3. Headed bolts, studs, orscrews shall be wedge tested full size in accordance withAnnex A3 of Test Metho
35、ds and Definitions A370 and shall4Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Two Park Ave., New York, NY 10016-5990, http:/www.asme.org.A320/A320M 15a2TABLE1MechanicalRequirementsClassandGrade,Diameter,inmmHeatTreatmentMinimumTemperingTemperatureF
36、CTensileStrength,min,ksiMPaYieldStrength,min,ksiMPa(0.2%offset)Elongationin2in.or50mmmin,%ReductionofArea,min,%HardnessmaxFerriticSteelsL7,L7A,L7B,L7C,L70,L71,L72,L731251051650321HBWor35HRC21265andunderAquenchedandtempered1100593860725L431251051650321HBWor35HRC4100andunderAquenchedandtempered1100593
37、860725L7M100801850235HBWBor99HRB21265andunderAquenchedandtempered1150620690550L11251051650.125andunderAquenchedandtempered860725AusteniticSteelsCClass1:B8,B8C,B8M,B8P,B8F,B8T,B8LN,B8MLN,alldiameterscarbidesolutiontreated75515302053050223HBWDor96HRBClass1A:B8A,B8CA,B8MA,B8PA,B8FA,B8TA,B8LNA,B8MLNA,al
38、ldiameterscarbidesolutiontreatedinthefinishedcondition75515302053050192HBWor90HRBClass2:B8,B8C,B8P,B8F,B8T:carbidesolutiontreatedandstrainhardened3420andunder1258601006901235321HBWor35HRCover34to120to25,incl115795805501530321HBWor35HRCover1to11425to32,incl105725654502035321HBWor35HRCover114to11232to
39、40,inclA100690503452845321HBWor35HRCClass2:B8M:carbidesolutiontreatedandstrainhardened3420andunder110760956551545321HBWor35HRCover34to120to25,incl100690805502045321HBWor35HRCover1to11425to32,incl95655654502545321HBWor35HRCover114to11232to40,inclA90620503453045321HBWor35HRCATheseupperdiameterlimitswe
40、reestablishedonthebasisthatthesewerethelargestsizescommonlyavailablethatconsistentlymetspecificationpropertylimits.Theyarenotintendedasabsolutelimitsbeyondwhichboltingmaterialscouldnolongerbecertifiedtothespecification.BTomeetthetensilerequirements,theBrinellhardnessshallnotbelessthan200HBWor93HRB.C
41、Class1productsaremadefromsolution-treatedmaterial.Class1Aproductsaresolutiontreatedinthefinishedconditionforcorrosionresistance;heattreatmentiscriticalforenhancingthisphysicalpropertyandmeetingthemechanicalpropertyrequirements.Class2productsaremadefromsolution-treatedmaterialthathasbeenstrainhardene
42、d.Austeniticsteelsinthestrain-hardenedconditionmaynotshowuniformpropertiesthroughoutthecrosssection,particularlyinsizesover34in.20mmindiameter.DForsizes34in.20mmindiameterandsmaller,amaximumhardnessof241HBW(100HRB)ispermitted.A320/A320M 15a3conform to the tensile strength shown in Table 1.The minimu
43、mfull size breaking strength (lbf) for individual sizes shall be asfollows:Ts 5 UTS 3As (1)where:Ts = Wedge tensile strengthUTS = Tensile strength specified in Table 1, andAs = Stress area, square inches, as shown in ASME B1.1or calculated as follows:As 5 0.785 D 2 0.974/n!2(2)where:D = Nominal thre
44、ad size, andn = The number of threads per inch.6.2 Impact Properties:6.2.1 Requirements:6.2.1.1 Impact tests are required for the grades shown inTable 3. Class 1, 1A, and 2 austenitic steels for temperaturesabove -325 F -200 C; Class 1 and 1Aaustenitic Grades B8,B8A, B8P, B8PA, B8C, B8CA, B8LN, and
45、B8LNAabove -425F -255 C; and ferritic or austenitic bolting12 in. (12.5 mm)and smaller, are exempt from impact testing, unless Supple-mentary Requirement S1 is specified in the purchase order (see1.4). All other material furnished under this specification shallbe tested. Material of Grades L7, L7A,
46、L7B, L7C, L7M, L43,L70, L71, L72, and L73 shall show a minimum impact energyabsorption of 20 ft lbf 27 J and of Grade L1 a minimumimpact energy absorption of 40 ft lbf 54 J at the testtemperature when tested by the procedure specified in theapplicable portions of Sections 19 to 28 of Test Methods an
47、dDefinitions A370. The temperature of the coolant used forchilling the test specimens shall be controlled within 63F1.5 C. Test temperatures for ferritic grades are listed in Table4. Exceptions to this requirement are permissible, and theimpact tests may be made at specified temperatures differentth
48、an those shown in Table 4, provided the test temperature is atleast as low as the intended service temperature and the boltingis suitably marked to identify the reported test temperature.When impact testing is required for austenitic grades, testcriteria shall be agreed upon between the supplier and
49、 pur-chaser.6.2.1.2 The impact test requirements for standard and sub-size Charpy test specimens are prescribed in Table 2.6.2.2 Number of Tests:6.2.2.1 The test requirements for heat-treated bars are givenin 6.1.2.1.6.2.2.2 For test requirements on studs, bolts, screws, etc.,see 6.1.2.2.6.2.2.3 Impact tests are not required to be made on heat-treated bars, bolts, screws, studs, and stud bolts12
