1、Designation: A350/A350M 18Standard Specification forCarbon and Low-Alloy Steel Forgings, Requiring NotchToughness Testing for Piping Components1This standard is issued under the fixed designation A350/A350M; the number immediately following the designation indicates the yearof original adoption or,
2、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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scop
3、e*1.1 This specification2covers several grades of carbon andlow-alloy steel forged or ring-rolled flanges, forged fittings andvalves intended primarily for low-temperature service andrequiring notch toughness testing. They are made to specifieddimensions, or to dimensional standards, such as the ASM
4、Eand API Specifications referenced in Section 2. Although thisspecification covers some piping components machined fromrolled bar and seamless tubular materials (see 5.3.3), it does notcover raw material produced in these product forms.1.2 No limitation on size is intended beyond the ability ofthe m
5、anufacturer to obtain the specified requirements.However, Class 3 of Grade LF787 is only available in thequenched-and-precipitation heat treated condition.1.3 Supplementary requirements are provided for use whenadditional testing or inspection is desired. These shall applyonly when specified by the
6、purchaser in the order.1.4 This specification is expressed in both inch-pound unitsand in SI units. However, unless the order specifies theapplicable “M” specification designation (SI units), the mate-rial shall be furnished to inch-pound units.1.5 The values stated in either SI units or inch-pound
7、unitsare to be regarded separately as standard. Within the text, theSI units are shown in brackets. The values stated in eachsystem may not be exact equivalents; therefore, each systemshall be used independently of the other. Combining valuesfrom the two systems may result in non-conformance with th
8、estandard.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalB
9、arriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3A788/A788M Specification for Steel Forgings, General Re-quirementsA961/A961M Specification for Common Requirements forSteel Flanges, Forged Fittings, Valves, and Parts forPiping Applications2.2 ASME Standards:B 16.5 Steel Pi
10、pe Flanges and Flanged Fittings4B 16.9 Factory-Made Wrought Steel Butt-Welding Fittings4B 16.10 Face-to-Face and End-to-End Dimensions of Fer-rous Valves4B 16.11 Forged Steel Fittings, Socket-Welding andThreaded4B 16.30 Unfired Pressure Vessel Flange Dimensions4B 16.34 Valves-Flanged, Threaded, and
11、Welding End4B 16.47 Large Diameter Steel Flanges42.3 ASME Boiler and Pressure Vessel Code:Section IX22.4 AWS Standards:A 5.1 Mild Steel Covered Arc-Welding Electrodes5A 5.5 Low-Alloy Steel Covered Arc-Welding Electrodes52.5 API Standards:6600 Steel Gate Valves with Flanged or Butt-Welding Ends602 Co
12、mpact Design Carbon Steel Gate Valves for RefineryUse605 Large Diameter Carbon Steel Flanges1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.22 on Steel Forgings and Wrought Fittings fo
13、r Piping Applications and BoltingMaterials for Piping and Special Purpose Applications.Current edition approved May 1, 2018. Published June 2018. Originallyapproved in 1952. Last previous edition approved in 2017 as A350/A350M 17.DOI: 10.1520/A0350_A0350M-18.2For ASME Boiler and Pressure Vessel Code
14、 applications see related Specifi-cation SA-350 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
15、 ASTM website.4Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Two Park Ave., New York, NY 10016-5990, http:/www.asme.org.5Available from American Welding Society (AWS), 550 NW LeJeune Rd.,Miami, FL 33126, http:/www.aws.org.6Available from American Pet
16、roleum Institute (API), 1220 L. St., NW,Washington, DC 20005-4070, http:/api-ec.api.org.*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 StatesThis international standard was de
17、veloped in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13. Ordering Info
18、rmation3.1 It is the purchasers responsibility to specify in thepurchase order information necessary to purchase the neededmaterial. In addition to the ordering information guidelines inSpecification A961/A961M, orders should include the follow-ing information:3.1.1 The number of test reports requir
19、ed (see Section 14).3.1.2 Additional requirements (see Table 1 footnotes).3.1.3 Options in the specification. See 5.4.2.1.4. General Requirements4.1 Product furnished to this specification shall conform tothe requirements of Specification A961/A961M, including anysupplementary requirements that are
20、indicated in the purchaseorder. Failure to comply with the general requirements ofSpecification A961/A961M constitutes nonconformance withthis specification. In case of conflict between the requirementsof this specification and Specification A961/A961M, thisspecification shall prevail.5. Manufacture
21、5.1 Melting ProcessThe steel shall be produced by any ofthe following primary processes: open-hearth, basic oxygen,electric-furnace, or vacuum-induction melting (VIM). Theprimary melting may incorporate separate degassing orrefining, and may be followed by secondary melting usingelectroslag remeltin
22、g (ESR), or vacuum-arc remelting (VAR).5.1.1 The steel shall be fully killed, fine-grain practice.5.1.2 The molten steel may be vacuum treated prior to orduring pouring of the ingot.5.2 DiscardA sufficient discard shall be made to securefreedom from injurious piping and undue segregation.5.3 Forging
23、 Process:5.3.1 Material for forgings shall consist of ingots, or forged,rolled, or strandcast blooms, billets, slabs, or bars.5.3.2 The finished product shall be a forging as defined inthe Terminology section of Specification A788/A788M.5.3.3 Except for flanges of all types, hollow, cylindrically-sh
24、aped parts may be machined from rolled bar or seamlesstubular materials provided that the axial length of the part isapproximately parallel to the metal flow lines of the stock.Other parts, excluding flanges of all types, may be machinedfrom hot-rolled or forged bar up through and including NPS4.Elb
25、ows, return bends, tees, and header tees shall not bemachined directly from bar stock.5.4 Heat Treatment:5.4.1 After hot working and before reheating for heattreatment, the forging shall be allowed to cool substantiallybelow the transformation range.5.4.2 Forgings of grades other than Grade LF787 sh
26、all befurnished in the normalized, or normalized and tempered, orquenched and tempered condition. At the option of themanufacturer, forgings furnished in the quenched and temperedcondition may be normalized prior to the austenitize/quenchoperation.5.4.2.1 Quenching shall consist of either:(1) fully
27、austenitizing the forgings followed by quenchingin a suitable liquid medium, or(2) using a multiple stage procedure whereby the forging isfirst fully austenitized and rapidly cooled, then reheated topartially re-asutenitize, followed by quenching in a suitableliquid medium.(3) Unless otherwise speci
28、fied by the purchaser, the choiceof (1)or(2) shall be at the option of the manufacturer.5.4.2.2 All quenched forgings shall be tempered to 5.4.2.35.4.2.3 Forgings, when tempered, shall be tempered at1100 F 590 C, minimum, holding at temperature a mini-mum of 30 min/in. 30 min/25 mm of maximum thickn
29、ess, butin no case less than 30 min.5.4.3 Grade LF787 forgings shall be furnished in either thenormalized-and-precipitation heat treated condition or in thequenched-and-precipitation heat treated condition. The heattreatment procedures shall be as follows:5.4.3.1 Normalized-and-Precipitation Heat Tr
30、eatedAustenitize in the range from 1600 to 1725 F 870 to 940 CTABLE 1 Chemical RequirementsElementComposition, wt. %Grade LF1 Grade LF2 Grade LF3 Grade LF5 Grade LF6 Grade LF9 Grade LF787Carbon, max 0.30 0.30 0.20 0.30 0.22 0.20 0.07Manganese 0.601.35 0.601.35 0.90 max 0.601.35 1.151.50 0.401.06 0.4
31、00.70Phosphorus,max0.035 0.035 0.035 0.035 0.025 0.035 0.025Sulfur, max 0.040 0.040 0.040 0.040 0.025 0.040 0.025SiliconA0.150.30 0.150.30 0.200.35 0.200.35 0.150.30 . 0.40 maxNickel 0.40 maxB0.40 maxB3.33.7 1.02.0 0.40 maxB1.602.24 0.701.00Chromium 0.30 maxB,C0.30 maxB,C0.30 maxC0.30 maxC0.30 maxB,
32、C0.30 maxC0.600.90Molybdenum 0.12 maxB,C0.12 maxB,C0.12 maxC0.12 maxC0.12 maxB,C0.12 maxC0.150.25Copper 0.40 maxB0.40 maxB0.40 max 0.40 max 0.40 maxB0.751.25 1.001.30NiobiumE0.02 maxD0.02 maxD0.02 max 0.02 max 0.02 max 0.02 max 0.02 minVanadium 0.08 max 0.08 max 0.03 max 0.03 max 0.040.11 0.03 max 0
33、.03 maxNitrogen . . . . . . . . . . . . 0.010.030 . . . . . .AWhen vacuum carbon-deoxidation is required by Supplementary Requirement S4, the silicon content shall be 0.12 % maximum.BThe sum of copper, nickel, chromium, vanadium and molybdenum shall not exceed 1.00 % on heat analysis.CThe sum of chr
34、omium and molybdenum shall not exceed 0.32 % on heat analysis.DBy agreement, the limit for niobium (columbium) may be increased up to 0.05 % on heat analysis and 0.06 % on product analysis.ENiobium and columbium are interchangeable names for the same element and both names are acceptable for use in
35、A01.22 specifications.A350/A350M 182for not less than12 h, and remove from the furnace and cool inair. Subsequently, artificially age in the range from 1000 to1200 F 540 to 650 C for not less than12 h, and cool at anyconvenient rate.5.4.3.2 Quenched-and-Precipitation Heat TreatedAustenitize in the r
36、ange from 1600 to 1725 F 870 to 940 Cfor not less than12 h and quench in a suitable liquid mediumby immersion; artificially age in the range from 1000 to1225 F 540 to 665 C for not less than12 h, and cool at anyconvenient rate.6. Chemical Composition6.1 Heat Analysis:6.1.1 A chemical heat analysis i
37、n accordance with Specifi-cation A961/A961M shall be made and conform to therequirements as to chemical composition prescribed in Table 1.Leaded steels shall not be permitted.6.2 Product Analysis:6.2.1 The purchaser may make a product analysis on prod-ucts supplied to this specification in accordanc
38、e with Specifi-cation A961/A961M.7. Mechanical Properties7.1 Tension Tests:7.1.1 RequirementsThe material shall conform to require-ments for tensile properties in Table 2.7.1.1.1 The test specimen shall be obtained from a rough orfinished forging, or prolongation thereof. For forgings under10 000 lb
39、s, at time of heat treatment, it may be obtained fromseparately forged test blanks from the same heat of steel as theproduction forgings. The test blank shall be reduced by forgingin a manner similar to that for the products represented, andshall receive approximately the same hot working and reduc-
40、tion and the same heat treatment as the finished productsrepresented. The test material shall be treated in the samefurnace at the same time as the forging it represents, subject tothe requirements of 7.1.2.1.7.1.1.2 The test specimen shall represent all forgings fromthe same heat and heat-treatment
41、 load whose maximum thick-nesses do not exceed the thickness of the test forging or blankby more than14 in. 6 mm.7.1.2 Number of TestsOne tension test at room tempera-ture shall be made in accordance with 7.1.1.2 from each heat ineach heat-treatment load.7.1.2.1 If heat treatment is performed in eit
42、her a continuousor a batch-type furnace controlled within 625 F 614 C ofthe required heat-treatment temperature and equipped withrecording pyrometers so that complete records of heat treat-ment are available and if the same heat-treating cycles are usedon the forgings represented by the tension test
43、, then one tensiontest from each heat shall be required, instead of one tension testfrom each heat in each heat treatment load in accordance with7.1.1.2.7.1.3 Test Locations and OrientationsThe test specimenshall be removed from the heaviest section of the forging ortest blank, at locations describe
44、d in 7.1.3.1, 7.1.3.2, 7.1.3.5 oras close to these locations as practical, subject to forging sizeand geometry.7.1.3.1 For forgings or test blanks having a maximumheat-treated thickness, T, of 2 in. 50 mm or less, thelongitudinal axis of the test specimen shall be taken atmid-thickness and its mid-l
45、ength shall be at least 2 in. 50 mmfrom all other heat treated surfaces, exclusive of the Tdimension surfaces. (This is normally referred to as12 T by 2in. 50 mm). See Fig. 1 for test specimen location in separatelyforged test blanks.7.1.3.2 For forgings or test blanks having a maximumheat-treated t
46、hickness, T, greater than 2 in. 50 mm:TABLE 2 Tensile Properties at Room TemperatureAGradesLF1 and LF5Class 1LF2Classes1 and 2LF3Classes 1and 2LF5Class 2LF6 LF9 LF787Class 1 Classes 2and 3Class 2 Class 3Tensile strength, ksi MPa 60854155857095485655709548565566914556307510051569063884356056585450585
47、7595515655Yield strength, min, ksi MPaB30 205 36 250 37.5 260 52 360 60 415 46 315 55 380 65 450Elongation:Standard round specimen, orsmall proportional specimen,min % in 4D gauge length25 22 22 22 20 25 20 20Strip specimen for wall thickness516 in. 7.94 mm and overand for all small sizes testedin f
48、ull section; min % in 2 in.50 mm28 30 30 30 28 28 28 28Equation for calculating minelongation for strip specimensthinner than516 in. 7.94 mm;min % in 2 in. 50 mmt = actual thickness in inches48t +13 48t +15 48t +15 48t +15 48t +13 48t +13 48t +13 48t +13Reduction of area, min, %C38 30 35 40 40 38 45
49、 45ASee 7.3 for hardness tests.BDetermined by either the 0.2 % offset method or the 0.5 % extension under load method.CFor round specimens only.A350/A350M 183(1) Except as stated in 7.1.3.2 (2) and 7.1.3.2 (3), thecentral axis of the test specimen shall be taken at least14 Tfrom the nearest heat-treated surface and its mid-length shall beat least 2 in. 50 mm from all other heat treated surfaces,exclusive of the T dimension surfaces. See Fig. 2
