1、Designation: A646/A646M 06 (Reapproved 2016)A646/A646M 17Standard Specification forPremium Quality Alloy Steel Blooms and Billets for Aircraftand Aerospace Forgings1This standard is issued under the fixed designation A646/A646M; the number immediately following the designation indicates the yearof o
2、riginal adoption or, in the case 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.1. Scope*1.1 This specification covers premium quality alloy steel semif
3、inished rolled or forged blooms and billets for reforging intocritical parts such as aircraft landing-gear forgings.1.2 Blooms and billets, hereinafter referred to as blooms, are semifinished steel products, hot rolled or forged to approximatecross-sectional dimensions. Blooms may be square, round,
4、hexagonal, octagonal, or rectangular in section. For the purposes of thisspecification, minimum bloom section size will be 16 in.2 103 cm2.1.3 This specification covers two basic classifications of steel:1.3.1 Class IVacuum-induction melted or consumable-electrode vacuum melted, or other suitable pr
5、ocesses which will satisfythe quality requirements of this specification.1.3.2 Class IIAir-melted vacuum degassed.1.3.3 Class IIIAir melted electric furnace ladle refined and vacuum degassed.1.4 The values stated in either inch-pound or SI (metric) units are to be regarded separately as standards. W
6、ithin the text andtables, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shallbe used independently of the other. Combining values from the two systems may result in nonconformance with the specification.1.5 Unless the order spe
7、cifies the applicable “M” specification the material shall be furnished to the inch-pound units.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Stan
8、dards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A255 Test Methods for Determining Hardenability of SteelA388/A388M Practice for Ultrasonic Examination of Steel ForgingsA788/A788M Specificat
9、ion for Steel Forgings, General RequirementsA604/A604M Practice for Macroetch Testing of Consumable Electrode Remelted Steel Bars and BilletsE45 Test Methods for Determining the Inclusion Content of SteelE114 Practice for Ultrasonic Pulse-Echo Straight-Beam Contact TestingE127 Practice for Fabricati
10、on and Control of Aluminum Alloy Ultrasonic Standard Reference BlocksE214 Practice for Immersed Ultrasonic Testing by the Reflection Method Using Pulsed Longitudinal Waves (Withdrawn 2007)3E381 Method of Macroetch Testing Steel Bars, Billets, Blooms, and ForgingsE428 Practice for Fabrication and Con
11、trol of Metal, Other than Aluminum, Reference Blocks Used in Ultrasonic Testing2.2 AMS Standards: 4AMS 2300 Steel Cleanliness, Premium-QualityAMS 2301 Steel Cleanliness, Aircraft-Quality1 This specification is under the jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloys an
12、d is the direct responsibility of Subcommittee A01.06on Steel Forgings and Billets.Current edition approved March 1, 2016Nov. 15, 2017. Published April 2016December 2017. Originally approved in 1971. Last previous edition approved in 20112016as A646/A646M 06 (2011).(2016). DOI: 10.1520/A0646_A0646M-
13、06R16.10.1520/A0646_A0646M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of
14、this historical standard is referenced on www.astm.org.4 Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096, http:/www.sae.org.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 ma
15、de to the previous version. Becauseit may not be technically possible 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
16、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 States1AMS 2304 Steel Cleanliness, Special Aircraft-Quality3. Terminology3.1 In addition to the terminology requirements of Specifi
17、cation A788/A788M, the following terms that are specific to thisspecification apply:3.2 Definitions:3.2.1 air-melted vacuum-degassed steelarc- or induction-furnace-melted steel that is vacuum treated immediately prior to orduring the operation of pouring the ingot.3.2.2 consumable-electrode vacuum-r
18、emelted steelmetal that has been remelted into a crucible in vacuum from single ormultiple electrodes.3.2.3 electroslag-melted steelmetal that has been remelted into a crucible from single or multiple electrodes utilizing anelectrical discharge through molten slag as a source of heat.3.2.3.1 Discuss
19、ionFor the purposes of this specification the parent heat from which any electrode for remelting by the electroslag process has beenproduced shall have been either melted under vacuum or vacuum degassed immediately prior to or during pouring of the heat.3.2.4 vacuum induction melted steelmetal that
20、has been melted, refined, and poured from an induction furnace operating undervacuum.4. Ordering Information and General Requirements4.1 Material supplied to this specification shall conform to the requirements of Specification A788/A788M, which outlinesadditional ordering information, manufacturing
21、 requirements, testing and retesting methods and procedures, marking, certification,product analysis variations, and additional supplementary requirements.4.1.1 If the requirements of this specification are in conflict with the requirements of Specification A788/A788M, therequirements of this specif
22、ication shall prevail.4.2 In addition to the ordering requirements of Specification A788/A788M, the following information should be supplied by thepurchaser:4.2.1 Class designation (see 1.3),4.2.2 Quality level (Table 21), grade designation (Table 12), or detailed chemistry for nonstandard grades,4.
23、2.3 Desired billet or bloom size,4.2.4 Weight or quantity and length,4.2.5 Minimum forging reduction required if ordered size exceeds 225 in.2 1450 cm2 (see 5.2.2),4.2.6 Annealing, if required (see 5.3.2),4.2.7 Macroetch standards of acceptance (see 7.1),4.2.8 Microcleanliness standards of acceptanc
24、e (see 7.2),4.2.9 Specific ultrasonic examination requirements, such as transducer type and size, whether contact or immersion preferred,level of reportable discontinuities and any special surface finish requirements.4.2.10 Hardenability standards of acceptance (see 8.1), and4.2.11 Any supplementary
25、 requirements desired.5. Manufacture5.1 Melting Practice:5.1.1 The steel making provisions of Specification A788/A788M shall apply, except for the following modifications;TABLE 1 Maximum Permissible Discontinuities in UltrasonicExaminationQualityLevelResponse,in. mm Stringers,Length in. mmSingleDisc
26、ontinuitiesMultipleDiscontinuitiesAA 364 1.0 264 0.8 264 12 1.012.0A 564 2.0 364 1.0 364 1 1.025B 864 3.0 564 2.0 564 1 2.025C 1264 5.0 864 3.0 864 1 3.025A646/A646M 1725.1.1.1 Class I material shall be manufactured by the vacuum-induction-melting process or by the consumable-electrodevacuum-melting
27、 (VAR) process. By agreement other processes such as electroslag or electron-beam melting may be consideredacceptable.5.1.1.2 Class II material shall be manufactured by an electric-furnace vacuum-degassed process.5.1.1.3 Class III material shall be manufactured by the electric furnace process with l
28、adle refining and vacuum degassing.5.2 Hot-Working Procedure:5.2.1 Blooms may be either hot rolled or forged.5.2.2 Blooms having cross-sectional areas ranging from 16 to 225 in.2 100 to 1450 cm2 when made from air-melt ingots shallhave at least 2 to 1 reduction of area from ingot to bloom. On blooms
29、 exceeding 225 in.2 1450 cm2 forging reductionrequirements shall be by agreement. Ingot-to-final forging reduction is not included in this requirement.5.3 Heat Treatment:5.3.1 Unless otherwise specified all material purchased to this specification will be furnished in the as forged or rolled(untreat
30、ed) condition. In this condition some grades may not be soft enough for cold sawing, and may be prone to cracking.5.3.2 When specified, the material may be ordered annealed or normalized and tempered to a maximum Brinell Hardness, asspecified in Table 2 or by agreement.5.3.3 Material shall be furnis
31、hed in condition to withstand, for an indefinite time, exposure to all climatic conditions withoutdeveloping any external or internal cracks. The method of cooling after hot working or of heat treatment before shipment shall beoptional with the manufacturer, who shall be responsible (in the same man
32、ner as for discontinuities disclosed after delivery) forcracks which may develop before material is subjected to reheating. When a specific heat treatment or conditioning of materialis specified by the purchaser, the manufacturer shall be responsible only for carrying out those specific operations a
33、nd not for anycracking that may subsequently develop.6. Chemical Requirements6.1 General Requirements:6.1.1 Table 12 lists standard grades of alloy steel that are currently produced in premium quality; however, it is not the intentof this specification to restrict application only to the materials l
34、isted in Table 12.TABLE 2 Chemical and Hardness RequirementsAComposition, %ProprietaryName orGradeGradeNo. Carbon Manga-nesePhos-phorus Sulfur Silicon NickelChro-miumMolyb-denumVana-dium OthersMaximumAnnealedBrinellHardness3310 1 0.080.13 0.450.60 0.015max 0.012 max 0.200.35 3.253.75 1.401.75 . . .
35、. . . . . . 2629310 2 0.080.13 0.450.65 0.015 max 0.012 max 0.200.35 3.003.50 1.001.40 0.080.15 . . . . . . 2624620 3 0.170.22 0.450.65 0.015 max 0.012 max 0.200.35 1.652.00 . . . 0.200.30 . . . . . . 2298620 4 0.180.23 0.700.90 0.015max 0.012 max 0.200.35 0.400.70 0.400.60 0.150.25 . . . . . . 2294
36、330 Mod. 5 0.280.33 0.751.00 0.015 max 0.012 max 0.200.35 1.652.00 0.700.95 0.350.50 0.050.10 . . . 2854335 Mod. 6 0.330.38 0.600.90 0.015 max 0.012 max 0.400.60 1.652.00 0.650.90 0.300.40 0.170.23 . . . 2854340 7 0.380.43 0.650.85 0.015 max 0.012 max 0.200.35 1.652.00 0.700.90 0.200.30 . . . . . .
37、285300 M 8 0.380.43 0.650.90 0.012 max 0.012 max 1.451.80 1.652.00 0.700.95 0.350.45 0.050.10 . . . 285D6AC 9 0.450.50 0.600.90 0.010 max 0.010 max 0.150.30 0.400.70 0.901.20 0.901.10 0.080.15 . . . 285H-11 10 0.380.43 0.200.40 0.015 max 0.015 max 0.801.00 . . . 4.755.25 1.201.40 0.400.60 . . . 2354
38、130 11 0.280.33 0.400.60 0.015 max 0.012 max 0.200.35 . . . 0.801.10 0.150.25 . . . . . . 2294140 12 0.380.43 0.751.00 0.015 max 0.012 max 0.200.35 . . . 0.801.10 0.150.25 . . . . . . 23598BV40 13 0.400.46 0.751.00 0.015 max 0.012 max 0.500.80 0.600.90 0.801.05 0.450.60 0.010.06 0.0005 min, 285Boron
39、6150 14 0.480.53 0.700.90 0.015 max 0.012 max 0.200.35 . . . 0.801.10 . . . 0.15 min . . . 23552100 15 0.981.10 0.250.45 0.015 max 0.010 max 0.200.35 . . . 1.301.60 . . . . . . . . . 302HP 9-4-20 16 0.170.23 0.200.40 0.010 max 0.010 max 0.10 max 8.59.5 0.650.85 0.901.10 0.060.12 Co 4.254.75 341HP 9-
40、4-30 17 0.290.34 0.100.35 0.010 max 0.010 max 0.10 max 7.08.0 0.901.10 0.901.10 0.060.12 Co 4.254.75 341Marage20018 0.03 max 0.10 max 0.010 max 0.010 max 0.10 max 17.019.0 . . . 3.03.50 . . . Co 8.09.0Ti 0.100.25Al 0.050.15B, Zr, Ca added321Marage25019 0.03 max 0.10 max 0.010 max 0.010 max 0.10 max
41、17.019.0 . . . 4.65.2 . . . Co 7.08.5Ti 0.300.50Al 0.050.15B, Zr, Ca added321Marage30020 0.03 max 0.10 max 0.010 max 0.010 max 0.10 max 18.019.0 . . . 4.75.2 . . . Co 8.59.5Ti 0.500.80Al 0.050.15B, Zr, Ca added321Nit. 135 21 0.380.43 0.500.70 0.015 max 0.012 max 0.200.40 . . . 1.401.80 0.300.40 . .
42、. Al 0.951.30 285A If any of the following elements are not specified, the following maximum limits shall apply: Nickel 0.35 %; Chromium 0.20 %; Molybdenum 0.06 %; Copper 0.35 %.A646/A646M 1736.1.2 When a standard grade is ordered, the analysis shall conform to the requirements as to chemical compos
43、ition prescribedin Table 12 for the ordered grade.6.1.3 The steel, when ordered to other than a standard analysis, shall conform to the requirements of the order.6.2 Heat Analysis:6.2.1 The heat analysis obtained from sampling in accordance with Specification A788/A788M shall comply with Table 12 fo
44、rstandard grades, or to the requirements of the order.A646/A646M 1746.3 Product Analysis:6.3.1 The purchaser may use the product analysis provision of Specification A788/A788M to obtain a product analysis from abillet or bloom representing each heat or multiple heat.7. Quality Evaluation Tests7.1 Ma
45、croetchMacroetch inspection shall be required for all material furnished to this specification. Samples representing thetop and bottom of each ingot shall be examined. Macroetching shall be performed in accordance with Method E381 and TestMethod Practice A604/A604M, as applicable. Standards of accep
46、tance shall be specified by the purchaser in the order.7.2 MicrocleanlinessAll material furnished to this specification shall be inspected for microcleanliness. At least one sampleshall be removed from a location midway between the center and outside surface representing the top and bottom of the fi
47、rst andlast ingots of each heat or from an ingot from each plate for bottom poured ingots. For blooms produced from continually castmaterial the samples shall represent the beginning and end of each strand produced from the heat. The specimens shall be preparedand rated by the procedure described in
48、 Method A of Test Methods E45. The polished face shall be longitudinal to the directionof maximum hot working. All specimens shall be prepared and rated in accordance with Test Methods E45, using Method D(Modified JK Chart) for Class I steel and Method A (JK Chart) for ClassrsClasses II and III stee
49、l. Standards of acceptance shallbe specified by the purchaser in the order.7.3 Nondestructive Testing, Ultrasonic Inspection:7.3.1 General:7.3.1.1 All material ordered to this specification shall be subjected to ultrasonic examination. Inspection may be performed byeither the immersion or the contact method providing that the manufacturer can ensure adequate resolution of the applicablerefe
