1、Designation: A320/A320M 15aA320/A320M 17Standard 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 materials and bolting components for pressure vessels, valves, flanges, andfittings for low-temperature service. See Specification A962/A962M for the definition of bolting. The bars shall be hot-wroughtand may be further processed by centerless grinding or b
4、y cold drawing. Austenitic stainless steel may be solution annealed orannealed and strain-hardened. When strain hardened austenitic stainless steel is ordered, the purchaser should take special care toensure that Appendix X1 is thoroughly understood.1.2 Several grades are covered, including both fer
5、ritic and austenitic steels designated 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
6、 classes, and Table 2 stipulatesthe 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, a
7、dditional restrictions (such as procuring 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 extensive
8、ly used for the presentpurpose. Other 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 obtai
9、nable.1.3 The following referenced 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 opti
10、on of the purchaser. The supplementary 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) unit
11、s, the inch-pound units shall apply.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 syst
12、ems may result in non-conformance with the standard.1.8 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby t
13、he World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:31 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 a
14、nd Wrought Fittings for Piping Applications and Bolting Materials for Piping and Special Purpose Applications.Current edition approved Nov. 1, 2015March 15, 2017. Published November 2015April 2017. Originally approved in 1948. Last previous edition approved in 2015 asA320/A320M15.15a. DOI: 10.1520/A
15、0320_A0320M-15A.10.1520/A0320_A0320M-17.2 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 AST
16、M Standardsvolume information, refer 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 po
17、ssible to adequately depict all changes 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 standardC
18、opyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1A194/A194M Specification for Carbon Steel, Alloy Steel, and Stainless Steel Nuts for Bolts for High Pressure or HighTemperature Service, or BothA370 Test Methods and Definitions for Mecha
19、nical Testing of Steel ProductsA962/A962M Specification for Common Requirements for Bolting Intended for Use atAny Temperature from Cryogenic to theCreep RangeE566 Practice for Electromagnetic (Eddy Current) Sorting of Ferrous MetalsF436F436/F436M Specification for Hardened Steel Washers (Metric) F0
20、436_F0436M Inch and Metric DimensionsF606F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners,Washers, and Rivets (Metric) F0606_F0606M Direct Tension Indicators, and Rivets2.2 ASME Standards:4B1.1 Screw ThreadsB18.22.1 Plain Washers3. Ord
21、ering Information3.1 It is the purchasers responsibility to specify in the purchase order all information necessary to purchase the neededmaterials. Examples of such information include, but are not limited to, the following:3.1.1 Quantity and size,3.1.2 Heat-treated condition, that is, for the aust
22、enitic 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, bolts, screws, or studs),3.1.4 Nuts and washers, if required by the purchaser, in accordance with Section 10, and3.1.
23、5 Special requirements, in accordance with 5.1.1, 5.1.3, 5.1.4, and 13.1.4. Common Requirements4.1 Bolting materials and bolting components supplied to this specification shall conform to the requirements of SpecificationA962/A962M. These requirements include test methods, finish, thread dimensions,
24、 macroetch (carbon and alloy steels only)marking, certification, optional supplementary requirements, and others. Failure to comply with the requirements of SpecificationA962/A962M constitutes nonconformance with this specification. In case of conflict between the requirements in this specificationa
25、nd Specification A962/A962M, this specification shall prevail.5. Materials and Manufacture5.1 Heat Treatment:5.1.1 Bolting materials 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 upp
26、er 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 suchmaterial are described as Class 1. This shall consist of holding the bolting material for a sufficient time at a temperature
27、 at whichthe chromium carbide will go into solution and then cooling in air or in a liquid medium at a rate sufficient to preventreprecipitation of the carbide. Bolting material thus treated is described as Class 1. If specified in the purchase order, boltingmaterial shall be solution treated in the
28、 finished condition and shall be described as Class 1A.5.1.2 Use of water quenching is prohibited for any ferritic grade when heat treatment is performed after heading or threading.5.1.3 When increased mechanical properties are desired, austenitic bolting shall be solution annealed and strain harden
29、ed ifspecified in the purchase order; material so treated is identified as Class 2.5.1.4 If scale-free bright finish is required, this shall be specified in the purchase order.5.1.5 For L7M bolting, the final heat treatment, which may be the tempering or stress-relieving operation conducted at 1150
30、F620 C minimum, shall be done after machining or rolling of the threads and any type of cutting.6. Mechanical Requirements6.1 Tensile Properties:6.1.1 Bolting material as represented by the tension specimens shall conform to the requirements as to tensile propertiesprescribed in Table 1 at room temp
31、erature after heat treatment (see 5.1.1). Alternatively, Class 2 Strain Hardened Headed BoltingComponents shall be tested full size after strain hardening to determine tensile strength and yield strength and shall conform tothe requirements prescribed in Table 1. Should the results of full size test
32、s conflict with results of tension specimen tests, full sizetest results shall prevail.6.1.2 Number of Tests:4 Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http:/www.asme.org.A320/A320M 1726.1.2.1 For heat-tr
33、eated bars, one tension test 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
34、, and subjected to the same 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.6.1.2.2 For studs, bolts, screw
35、s, 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 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 fractionthereof
36、Over 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 1 12 in. in body diameter and smaller,with body length three times the diameter or longer, and which are produced by up
37、setting or forging (hot or cold) shall be subjectedto full size testing in accordance with 6.1.3. This testing shall be in addition to tensile testing as specified in 6.1.1. The lot sizeshall be shown in 6.1.2.2. Failure shall occur in the body or threaded sections with no failure, or indications of
38、 failure, such ascracks, at the junction of the head and shank.6.1.3 Full Size Bolting Components, Wedge Tensile TestingWhen applicable, see 6.1.2.3. Headed bolts, studs, or screws shallbe wedge tested full size in accordance with Annex A3 of Test Methods and Definitions A370 and shall conform to th
39、e tensilestrength 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 specified in Table 1, andAs = Stress area, square inches, as shown in ASME B1.1 or calculated as follows:As5
40、0.785 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. Class 1, 1A, and 2 austenitic steels for temperatures above-325 F -200 C; Class 1 and 1A austenitic Gr
41、ades 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 SupplementaryRequirement S1 is specified in the purchase order (see 1.4). All other material furnished under this specificat
42、ion 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 absorption of 40 ft lbf 54 J at the test temperature when testedby the procedure specified in the applicab
43、le 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 for ferritic gradesare listed in Table 4. Exceptions to this requirement are permissible, and the impact
44、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 marked to identify the reported test temperature. When impact testing is required for austenitic grades, t
45、estcriteria 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 Tests:6.2.2.1 The test requirements for heat-treated bars are given in 6.1.2.1.6.2.2.2 For test requiremen
46、ts 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 Test SpecimensFor sections 1 in. 25 mm or less in diameter, test specimens shall be taken at the axis; f
47、or 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 testing shall be performed in accordancewith either Specification A962/A962M or with Test Methods F606F606/F
48、606M.A320/A320M 173TABLE 3 Chemical Requirements (Composition, %)AType . . . . . . FerriticSteelsGradeSymbol . . . . . L7, L7M, L70 L7A, L71 L7B, L72 L7C, L73 L43 L1Description . . . Chromium-MolybdenumBCarbon-Molybdenum(AISI 4037)Chromium-Molybdenum(AISI 4137)Nickel-Chromium-Molybdenum(AISI 8740)Ni
49、ckel-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 0.700.900.03 0.751.000.04 0.600.850.03 0.701.400.04Phosphorus,max0.035 0.005over0.035 0.005ov
