1、Designation: A320/A320M 11Standard 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 Department of Defense.1. Scope*1.1 This specification2cover
3、s alloy steel bolting for pres-sure vessels, valves, flanges, and fittings for low-temperatureservice. See Specification A962/A962M for the definition ofbolting. The bars shall be hot-wrought and may be furtherprocessed by centerless grinding or by cold drawing.Austeniticstainless steel may be solut
4、ion annealed or annealed andstrain-hardened. When strain hardened austenitic stainless steelis ordered, the purchaser should take special care to ensure thatAppendix X1 is thoroughly understood.1.2 Several grades are covered, including both ferritic andaustenitic steels designated L7, B8, etc. Selec
5、tion 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 stipulates the requirements for Charpy
6、 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 (such as procuring a steel with lower P
7、and 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 purpose. Other compositions will be consi
8、dered 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 referenced general requirements are in-disp
9、ensable 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 supplementary requirements shallapply only
10、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 apply.1.7 The values stated in either SI
11、 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-conformancewith the standard.2. Referenced Documen
12、ts2.1 ASTM Standards:3A194/A194M Specification for Carbon and Alloy SteelNuts for Bolts for High Pressure or High TemperatureService, or BothA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA962/A962M Common Requirements for Bolting Intendedfor Use at Any Temperature from Cry
13、ogenic to the CreepRangeE566 Practice for Electromagnetic (Eddy-Current) Sortingof Ferrous MetalsF436 Specification for Hardened Steel WashersF606 Test Methods for Determining the Mechanical Prop-erties of Externally and Internally Threaded Fasteners,1This specification is under the jurisdiction of
14、ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.22 on Steel Forgings and Wrought Fittings for PipingApplications and BoltingMaterials for Piping and Special Purpose Applications.Current edition approved May 1, 2011. Published June 20
15、11. Originallyapproved in 1948. Last previous edition approved in 2010 as A320/A320M10a.DOI: 10.1520/A0320_A0320M-11.2For ASME Boiler and Pressure Vessel Code applications, see related Specifi-cation SA-320 in Section II of that Code.3For referenced ASTM standards, visit the ASTM website, www.astm.o
16、rg, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box
17、C700, West Conshohocken, PA 19428-2959, United States.Washers, Direct Tension Indicators, and Rivets2.2 ASME Standards:4B1.1 Screw ThreadsB18.22.1 Plain Washers3. Ordering Information3.1 It is the purchasers responsibility to specify in thepurchase order all information necessary to purchase theneed
18、ed 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); solution-treated afterfinishing (Class 1A); and annealed and strain-hardened (Clas
19、s2),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, 5.1.2,5.1.3, and 12.1.4. Common Requirements4.1 Bolting supplied to this specification s
20、hall conform tothe requirements of SpecificationA962/A962M. These require-ments include test methods, finish, thread dimensions, mac-roetch (carbon and alloy steels only) marking, certification,optional supplementary requirements, and others. Failure tocomply with the requirements of Specification A
21、962/A962Mconstitutes nonconformance with this specification. In case ofconflict between the requirements in this specification andSpecification A962/A962M, this specification shall prevail.4.2 For L7M bolting, the final heat treatment, which may bethe tempering operation if conducted at 1150 F 620 C
22、minimum, shall be done after machining and forming opera-tions, including thread rolling and any type of cutting.5. Materials and Manufacture5.1 Heat Treatment:5.1.1 Bolting shall be allowed to cool to room temperatureafter rolling or forging. Grades L7, L7A, L7B, L7C, L7M, L43,L1, L70, L71, L72, an
23、d L73 shall be reheated to above theupper critical temperature and liquid quenched and tempered.Grades B8, B8C, B8M, B8T, B8F, B8P, B8LN, and B8MLNshall receive a carbide solution treatment. Products made fromsuch material are described as Class 1. This shall consist ofholding the material for a suf
24、ficient time at a temperature atwhich the chromium carbide will go into solution and thencooling in air or in a liquid medium at a rate sufficient toprevent reprecipitation of the carbide. Material thus treated isdescribed as Class 1. If specified in the purchase order, materialshall be solution tre
25、ated in the finished condition; material sotreated is described as Class 1A.5.1.2 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 isidentified as Class 2.5.1.3 If scale-free br
26、ight finish is required, this shall bespecified in the purchase order.5.1.4 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 threads and any type of cutting.6. Mechanica
27、l Requirements6.1 Tensile Properties:6.1.1 The material as represented by the tension specimensshall conform to the requirements as to tensile propertiesprescribed in Table 1 at room temperature after heat treatment(see 5.1.1). Alternatively, Class 2 Strain Hardened HeadedFasteners shall be tested f
28、ull size after strain hardening todetermine tensile strength and yield strength and shall conformto the requirements prescribed in Table 1. Should the results offull size tests conflict with results of tension specimen tests,full size test results shall prevail.6.1.2 Number of Tests:6.1.2.1 For heat
29、-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 lot shall be the same heat, same priorcondition, same size
30、, 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 tensile test and impact test.6.1.2.2 For studs, bolts, screws,
31、 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 thereofOver 118 30 to 134 45,incl4500 2040 or fractionthereofOver
32、 134 45 to 212 65,incl6000 2700 or fractionthereofOver 212 65 100 pieces or fraction thereof6.1.2.3 Full Size Specimens, Headed FastenersHeadedfasteners 112 in. in body diameter and smaller, with bodylength three times the diameter or longer, and which areproduced by upsetting or forging (hot or col
33、d) shall besubjected to full size testing in accordance with 6.1.3. Thistesting 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 threaded sections with no failure, or indicationsof failure, such as cracks, at the
34、junction of the head and shank.6.1.3 Full Size Fasteners, Wedge Tensile TestingWhenapplicable, see 6.1.2.3. Headed fasteners shall be wedge testedfull size in accordance with Annex A3 of Test Methods andDefinitions A370 and shall conform to the tensile strength4Available from American Society of Mec
35、hanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.A320/A320M 112TABLE 1 Mechanical RequirementsClass and Grade, Diameter, in mm Heat TreatmentMinimumTemperingTemperatureF CTensileStrength,min, ksiMPaYield Strength,min, ksiMPa (0.2
36、%offset)Elongationin2in.or 50mm min, %Reductionof Area,min, %HardnessmaxFerritic SteelsL7, L7A, L7B, L7C, L70, L71, L72, L73 125 105 16 50 321 HBW or 35HRC212 65 and underAquenched and tempered 1100593860 725L43 125 105 16 50 321 HBW or 35HRC4 100 and underAquenched and tempered 1100593860 725L7M 10
37、0 80 18 50 235 HBWBor99 HRB212 65 and underAquenched and tempered 1150620690 550L1 125 105 16 50 . . .1 25 and underAquenched and tempered 860 725Austenitic SteelsCClass 1: B8, B8C, B8M, B8P,B8F, B8T, B8LN, B8MLN, all diameterscarbide solution treated 755153020530 50 223 HBWDor96 HRBClass 1A: B8A, B
38、8CA, B8MA, B8PA,B8FA, B8TA, B8LNA,B8MLNA, all diameterscarbide solution treated in thefinished condition755153020530 50 192 HBW or 90HRBClass 2: B8, B8C, B8P, B8F, B8T: carbide solution treated and strainhardened34 20 and under 12586010069012 35 321 HBW or 35HRCover34 to 1 20 to 25, incl 11579580550
39、15 30 321 HBW or 35HRCover 1 to 114 25 to 32, incl 1057256545020 35 321 HBW or 35HRCover 114 to 112 32 to 40, inclA1006905034528 45 321 HBW or 35HRCClass 2: B8M: carbide solution treated and strainhardened34 20 and under 1107609565515 45 321 HBW or 35HRCover34 to 1 20 to 25, incl 1006908055020 45 32
40、1 HBW or 35HRCover 1 to 114 25 to 32, incl 956556545025 45 321 HBW or 35HRCover 114 to 112 32 to 40, inclA906205034530 45 321 HBW or 35HRCAThese upper diameter limits were established on the basis that these were the largest sizes commonly available that consistently met specification property limit
41、s. They are not intended as absolute limits beyondwhich bolting materials could no longer be certified to the specification.BTo meet the tensile requirements, the Brinell hardness shall not be less than 200 HBW or 93 HRB.CClass 1 products are made from solution-treated material. Class 1A products ar
42、e solution treated in the finished condition for corrosion resistance; heat treatment is critical for enhancing this physical property andmeeting the mechanical property requirements. Class 2 products are made from solution-treated material that has been strain hardened.Austenitic steels in the stra
43、in-hardened condition may not show uniform propertiesthroughout the cross section, particularly in sizes over34 in. 20 mm in diameter.DFor sizes34 in. 20 mm in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted.A320/A320M113shown in Table 1. The minimum full size breaking str
44、ength(lbf) for individual sizes shall be as follows:Ts 5 UTS 3 As (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 D20.974/n!2(2)where:D = Nominal thread size, andn = The numb
45、er 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 B8LNAabove -425F -255 C;
46、 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, L7B, L7C, L7M, L43,L70,
47、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 andDefinitions A370. The t
48、emperature 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 differentthan those shown in Table
49、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 pur-chaser.6.2.1.2 The impact test requirements for standard and sub-size Charpy test specimens are prescribed in Table 2.
