1、Designation: A320/A320M 11aA320/A320M 14Standard 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
2、 of revision, 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
3、specification2 covers alloy steel bolting for pressure vessels, valves, flanges, and fittings for low-temperature service.See Specification A962/A962M for the definition of bolting. The bars shall be hot-wrought and may be further processed bycenterless grinding or by cold drawing.Austenitic stainle
4、ss steel may be solution annealed or annealed and strain-hardened. Whenstrain hardened austenitic stainless steel is ordered, the purchaser should take special care to ensure that Appendix X1 is thoroughlyunderstood.1.2 Several grades are covered, including both ferritic and austenitic steels design
5、ated L7, B8, etc. Selection will depend ondesign, service conditions, mechanical properties, and low-temperature characteristics. The mechanical requirements of Table 1indicate the diameters for which the minimum mechanical properties apply to the various grades and classes, and Table 2 stipulatesth
6、e requirements for Charpy impact energy absorption. The manufacturer should determine that the material can conform to theserequirements before parts are manufactured. For example, when Grade L43 is specified to meet the Table 2 impact energy valuesat 150 F 101 C, additional restrictions (such as pr
7、ocuring a steel with lower P and S contents than might normally besupplied) in the chemical composition for AISI 4340 are likely to be required.NOTE 1The committee formulating this specification has included several grades of material that have been rather extensively used for the presentpurpose. Ot
8、her compositions will be considered for inclusion by the committee from time to time as the need becomes apparent. Users should note thathardenability of some of the grades mentioned may restrict the maximum size at which the required mechanical properties are obtainable.1.3 The following referenced
9、 general requirements are indispensable for application of this specification: SpecificationA962/A962M.1.4 Nuts for use with bolting are covered in Section 10 and the nut material shall be impact tested.1.5 Supplementary Requirements are provided for use at the option of the purchaser. The supplemen
10、tary requirements shallapply only when specified in the purchase order or contract.1.6 This specification is expressed in both inch-pound units and SI units; however, unless the purchase order or contractspecifies the applicable M specification designation (SI) units, the inch-pound units shall appl
11、y.1.7 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance
12、with the standard.2. Referenced Documents2.1 ASTM Standards:3A194/A194M Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or BothA370 Test Methods and Definitions for Mechanical Testing of Steel ProductsA962/A962M Specification for Common Requirem
13、ents for Bolting Intended for Use atAny Temperature from Cryogenic to theCreep Range1 This specification is under the jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloysand is the direct responsibility of Subcommittee A01.22on Steel Forgings and Wrought Fittings for Piping
14、Applications and Bolting Materials for Piping and Special Purpose Applications.Current edition approved Nov. 1, 2011May 1, 2014. Published December 2011May 2014. Originally approved in 1948. Last previous edition approved in 2011 asA320/A320M11.11a. DOI: 10.1520/A0320_A0320M-11a.10.1520/A0320_A0320M
15、-14.2 For ASME Boiler and Pressure Vessel Code applications, see related Specification SA-320 in Section II of that Code.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer
16、 to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all chan
17、ges accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Bar
18、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E566 Practice for Electromagnetic (Eddy-Current) Sorting of Ferrous MetalsF436 Specification for Hardened Steel WashersF606 Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasten
19、ers, Washers, DirectTension 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 the purchase order all information necessary to purchase the neededmaterials. Examples of such information includ
20、e, but are not limited to, the following:3.1.1 Quantity and size,3.1.2 Heat-treated condition, that is, for the austenitic stainless steels, solution-treated (Class 1); solution-treated after finishing(Class 1A); and annealed and strain-hardened (Class 2),3.1.3 Description of items required (bars, b
21、olts, screws, or studs),3.1.4 Nuts and washers, if required by the purchaser, in accordance with Section 10, and3.1.5 Special requirements, in accordance with 5.1.1, 5.1.2, 5.1.3, and 13.1.4. Common Requirements4.1 Bolting supplied to this specification shall conform to the requirements of Specifica
22、tion A962/A962M. These requirementsinclude test methods, finish, thread dimensions, macroetch (carbon and alloy steels only) marking, certification, optionalsupplementary requirements, and others. Failure to comply with the requirements of Specification A962/A962M constitutesnonconformance with this
23、 specification. In case of conflict between the requirements in this specification and SpecificationA962/A962M, this specification shall prevail.4.2 For L7M bolting, the final heat treatment, which may be the tempering operation if conducted at 1150 F 620 C minimum,shall be done after machining and
24、forming operations, 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 temperature after rolling or forging. Grades L7, L7A, L7B, L7C, L7M, L43, L1,L70, L71, L72, and L73 shall be reheated to above the upper
25、critical temperature and liquid quenched and tempered. Grades B8,B8C, B8M, B8T, B8F, B8P, B8LN, and B8MLN shall receive a carbide solution treatment. Products made from such material aredescribed as Class 1. This shall consist of holding the material for a sufficient time at a temperature at which t
26、he chromium carbidewill go into solution and then cooling in air or in a liquid medium at a rate sufficient to prevent reprecipitation of the carbide.Material thus treated is described as Class 1. If specified in the purchase order, material shall be solution treated in the finishedcondition; materi
27、al so treated is described as Class 1A.5.1.2 When increased mechanical properties are desired, austenitic bolting shall be solution annealed and strain hardened ifspecified in the purchase order; material so treated is identified as Class 2.5.1.3 If scale-free bright finish is required, this shall b
28、e specified in the purchase order.5.1.4 For L7M bolting, the final heat treatment, which may be the tempering or stress-relieving operation conducted at 1150 F620 C minimum, shall be done after machining or rolling of the threads and any type of cutting.6. Mechanical Requirements6.1 Tensile Properti
29、es:6.1.1 The material as represented by the tension specimens shall conform to the requirements as to tensile properties prescribedin Table 1 at room temperature after heat treatment (see 5.1.1). Alternatively, Class 2 Strain Hardened Headed Fasteners shall betested full size after strain hardening
30、to determine tensile strength and yield strength and shall conform to the requirementsprescribed in Table 1. Should the results of full size tests conflict with results of tension specimen tests, full size test results shallprevail.6.1.2 Number of Tests:6.1.2.1 For heat-treated bars, one tension tes
31、t and one impact test consisting of three specimens shall be made for each diameterof each heat represented in each tempering charge. When heat treated without interruption in continuous furnaces, the material ina lot shall be the same heat, same prior condition, same size, and subjected to the same
32、 heat treatment. Not fewer than two tensiletests and two impact tests are required for each lot containing 20 000 lbs 9000 kg or less. Every additional 10 000 lbs 4500kg or fraction thereof requires an additional tensile test and impact test.4 Available from American Society of Mechanical Engineers
33、(ASME), ASME International Headquarters, ThreeTwo Park Ave., New York, NY 10016-5990,http:/www.asme.org.A320/A320M 1426.1.2.2 For studs, bolts, screws, etc., one tension test and one set of three impact specimens shall be made for each diameterof each heat involved in the lot. Each lot shall consist
34、 of 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 134 45 to 212 65,incl6000 2700 or fractionthereofOver 212 65 100 pieces or fraction thereof6.1.2.3 Full Size Specimens, Headed FastenersHeaded fas
35、teners 1 12 in. in body diameter and smaller, with body length threetimes the diameter or longer, and which are produced by upsetting or forging (hot or cold) shall be subjected to full size testingin accordance with 6.1.3. This testing shall be in addition to tensile testing as specified in 6.1.1.
36、The lot size shall be shown in6.1.2.2. Failure shall occur in the body or threaded sections with no failure, or indications of failure, such as cracks, at the junctionof the head and shank.6.1.3 Full Size Fasteners, Wedge Tensile TestingWhen applicable, see 6.1.2.3. Headed fasteners shall be wedge t
37、ested full sizein accordance with Annex A3 of Test Methods and Definitions A370 and shall conform to the tensile strength shown in Table 1.The minimum full size breaking strength (lbf) for individual sizes shall be as follows:Ts5UTS3As (1)where:Ts = Wedge tensile strengthUTS = Tensile strength speci
38、fied in Table 1, andAs = Stress area, square inches, as shown in ASME B1.1 or calculated as follows:As50.785 D20.974/n!2 (2)where:D = Nominal thread 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 in Table 3.
39、 Class 1, 1A, and 2 austenitic steels for temperatures above-325 F -200 C; Class 1 and 1A austenitic Grades B8, B8A, B8P, B8PA, B8C, B8CA, B8LN, and B8LNA above -425 F -255C; and ferritic or austenitic bolting 12 in. (12.5 mm) and smaller, are exempt from impact testing, unless SupplementaryRequirem
40、ent S1 is specified in the purchase order (see 1.4). All other material furnished under this specification shall be tested.Material of Grades L7, L7A, L7B, L7C, L7M, L43, L70, L71, L72, and L73 shall show a minimum impact energy absorption of20 ft lbf 27 J and of Grade L1 a minimum impact energy abs
41、orption of 40 ft lbf 54 J at the test temperature when testedby the procedure specified in the applicable portions of Sections 19 to 28 of Test Methods and Definitions A370. The temperatureof the coolant used for chilling the test specimens shall be controlled within 63 F 1.5 C. Test temperatures fo
42、r ferritic gradesare listed in Table 4. Exceptions to this requirement are permissible, and the impact tests may be made at specified temperaturesdifferent than those shown in Table 4, provided the test temperature is at least as low as the intended service temperature and thebolting is suitably mar
43、ked to identify the reported test temperature. When impact testing is required for austenitic grades, testcriteria shall be agreed upon between the supplier and purchaser.6.2.1.2 The impact test requirements for standard and subsize Charpy test specimens are prescribed in Table 2.6.2.2 Number of Tes
44、ts:6.2.2.1 The test requirements for heat-treated bars are given in 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 bolts 12 in. 12.5 mm andunder in diameter.6.2.3 T
45、est SpecimensFor sections 1 in. 25 mm or less in diameter, test specimens shall be taken at the axis; for sections over1 in. 25 mm in diameter, midway between the axis and the surface.6.3 Hardness Requirements:6.3.1 The hardness shall conform to the requirements prescribed in Table 1. Hardness testi
46、ng shall be performed in accordancewith either Specification A962/A962M or with Test Methods F606.6.3.2 The maximum hardness of Grade L7M shall be 235 HBW or 99 HRB (conversion in accordance with Table Number 2Bof Test Methods and Definitions A370). Minimum hardness shall not be less than 200 HBW or
47、 93 HRB. Conformance to thishardness shall be ensured by testing each bolt or stud by Brinell or Rockwell B methods in accordance with 6.3.1.6.3.2.1 The use of 100 % electromagnetic testing for hardness as an alternative to 100 % indentation hardness testing ispermissible when qualified by sampling
48、using indentation hardness testing. Each lot tested for hardness electromagnetically shallA320/A320M 143TABLE 3 Chemical Requirements (Composition, %)AType . . . . . . FerriticSteelsGradeSymbol . . . . . L7, L7M, L70 L7A, L71 L7B, L72 L7C, L73 L43 L1Description . . . Chromium-MolybdenumBCarbon-Molyb
49、denum(AISI 4037)Chromium-Molybdenum(AISI 4137)Nickel-Chromium-Molybdenum(AISI 8740)Nickel-Chromium-Molybdenum(AISI 4340) Low-Carbon BoronRange,%ProductVariation,% Range,%ProductVariation,% Range,%ProductVariation,% Range,%ProductVariation,% Range,%ProductVariation,% Range,%ProductVariation,%Over orUnderOver orUnderOver orUnderOver orUnderOver orUnderOver orUnderCarbon 0.380.48C0.02 0.350.400.02 0.350.400.02 0.380.430.02 0.380.430.02 0.170.240.01Manganese 0.751.000.04 0.700.900.03 0.700.9
