1、Designation: A1091/A1091M 16Standard Specification forSteel Castings, Creep-Strength Enhanced Ferritic Alloy, forPressure-Containing Parts, Suitable for High TemperatureService1This standard is issued under the fixed designation A1091/A1091M; the number immediately following the designation indicate
2、s theyear of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers creep-strength enhan
3、ced alloysteel castings for valves, flanges, fittings, and other pressure-containing parts intended primarily for high-temperature ser-vice (see Note 1). However, they are not restricted to suchapplications, and the castings may be used for other applica-tions for which the attributes of the materia
4、l, as defined by thisspecification, are suitable.1.2 One grade of martensitic alloy steel, Grade C91, iscovered (see Note 2). It is provided in two classes, differenti-ated by the type of heat treatment after weld repairs. This andsimilar steels are characterized by a predominantly temperedmartensit
5、ic or tempered Bainitic microstructure that is stabi-lized by the precipitation of temper-resistant particles atvarious precipitate nucleation sites in the microstructure. Suchsteels are designed to have creep-rupture strengths significantlysuperior to those of alloys of nominally similar compositio
6、ns,but in which the precipitates or nucleation sites are absent.Since this crucial difference cannot be revealed by room-temperature mechanical property tests, these alloys requiretighter controls on manufacturing and processing.NOTE 1The grades covered by this specification represent materialsthat
7、are generally suitable for assembly with other castings or wroughtsteel parts by fusion welding. It is not intended to imply that these gradespossess equal degrees of weldability; therefore, it is the responsibility ofthe purchaser to establish a suitable welding technique. Since these gradespossess
8、 varying degrees of suitability for high-temperature service, it isalso the responsibility of the purchaser to determine which grade shall befurnished, due consideration being given to the requirements of theapplicable construction codes.NOTE 2The committee formulating this specification has include
9、d onegrade of material that is considered to represent a type of ferritic alloysteel suitable for valves, flanges, fittings, and other pressure-containingparts. Additional alloy steels will be considered for inclusion in thisspecification by the committee as the need becomes apparent.1.3 The values
10、stated in either SI 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.
11、 Referenced Documents2.1 ASTM Standards:2A335/A335M Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature ServiceA703/A703M Specification for Steel Castings, GeneralRequirements, for Pressure-Containing PartsA802/A802M Practice for Steel Castings, Surface Accep-tance Standards, V
12、isual ExaminationA985/A985M Specification for Steel Investment CastingsGeneral Requirements, for Pressure-Containing PartsA999/A999M Specification for General Requirements forAlloy and Stainless Steel Pipe2.2 ANSI Standards3ANSI B46.1 Surface Texture2.3 ASME Boiler and Pressure Vessel Code4ASME Boil
13、er and Pressure Vessel Code Section IASME Boiler and Pressure Vessel Code Section IIIASME Boiler and Pressure Vessel Code Section IVASME Boiler and Pressure Vessel Code Section VIIIASME Boiler and Pressure Vessel Code Section IXASME Boiler and Pressure Vessel Code Section XII2.4 Other ASME Codes4B16
14、.34 Valves Flanged, Threaded and Welding EndB31.1 Power PipingB31.3 Process Piping1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.18 on Castings.Current edition approved May 1, 2016. P
15、ublished May 2016. DOI: 10.1520/A109116.2For 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 ASTM website.3Available from Ameri
16、can National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Two Park Ave., New York, NY 10016-5990, http:/www.asme.org.Copyright ASTM International, 100 Barr
17、 Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.5 AWS Specifications5A5.5/A5.5M Low Alloy Steel Electrodes for Shielded MetalArc WeldingA5.23/A5.23M Low Alloy Steel Electrodes and Fluxes forSubmerged Arc WeldingA5.28/A5.28M Low Alloy Steel Electrodes and Rods forGas Shi
18、elded Arc WeldingA5.29/A5.29M Low Allow Steel Electrodes for Flux CoredArc Welding3. General Conditions for Delivery3.1 Except for investment castings and centrifugally castpipe, castings furnished to this specification shall conform tothe requirements of Specification A703/A703M, including anysuppl
19、ementary requirements that are indicated in the purchaseorder. Failure to comply with the general requirements ofSpecification A703/A703M constitutes nonconformance withthis specification. In case of conflict between the requirementsof this specification and Specification A703/A703M, thisspecificati
20、on shall prevail.3.2 Investment castings furnished to this specification shallconform to the requirements of Specification A985/A985Mincluding any supplementary requirements that are indicated inthe purchase order. Failure to comply with the general require-ments of Specification A985/A985M constitu
21、tes nonconfor-mance with this specification. In case of conflict between therequirements of this specification and Specification A985/A985M, Specification A985/A985M shall prevail.3.3 Centrifugally cast pipe furnished under this specificationshall conform to the requirements of Specification A999/A9
22、99M, including any supplementary requirements that areindicated in the purchase order. Failure to comply with thegeneral requirements of Specification A999/A999M consti-tutes nonconformance with this specification. In case of con-flict between the requirements of this specification and Speci-ficatio
23、n A999/A999M, this specification shall prevail.4. Ordering Information4.1 Orders for material under this specification shall includethe following, as required, to describe the desired materialadequately:4.1.1 Except for centrifugally cast pipe,4.1.1.1 A description of the casting by pattern number o
24、rdrawing (dimensional tolerances shall be included on thecasting drawing),4.1.1.2 Grade and Class of steel,4.1.1.3 Options in the specification (see 5.1.5, 5.2, 7.1.4,8.4, 10.3.5, and 10.3.7, 10.3.8.2, and 10.3.8.3),4.1.1.4 Whether the castings are to be produced using theinvestment casting process,
25、 and4.1.1.5 The supplementary requirements desired includingthe standards of acceptance.4.1.2 Centrifugally cast pipe,4.1.2.1 Quantity (feet, centimeters, or number of lengths),4.1.2.2 Name of material (centrifugally cast pipe),4.1.2.3 Grade of steel,4.1.2.4 Size (outside or inside diameter and mini
26、mum wallthickness),4.1.2.5 Length (specific or random) (Section on PermissibleVariations in Length of Specification A999/A999M),4.1.2.6 End finish (Section on Ends of Specification A999/A999M),4.1.2.7 Options in the specification (see 5.1.5, 5.2, 7.1.4,8.4, 10.3.5, and 10.3.7, 10.3.8.2, and 10.3.8.3
27、),4.1.2.8 Whether the castings are to be used in ASME Boileror in ASME Codes B16.34, B31.1, B31.3, orother ASME construction codes,and,4.1.2.9 The supplementary requirements desired.5. Materials and Manufacture5.1 Heat-TreatmentCastings shall be furnished in theaustenitized and tempered condition.5.
28、1.1 Before heat treatment, castings shall be allowed tocool to a temperature below the transformation range.5.1.2 Castings shall be heat treated by heating to a tempera-ture range of 1900 to 1975F 1040 to 1080C and either aircooled or accelerated cooled from the austenitizing tempera-ture by air bla
29、sting or liquid quenching, to a temperature of200F 95C or below, followed by tempering at 1350 to1470F 730 to 800C.5.1.3 Compliance with the temperature ranges specified in5.1.2, for castings heat treated singly, shall be verified by athermocouple or thermocouples placed directly on the castings.5.1
30、.4 Compliance with the temperature ranges specified in5.1.2, for castings heat treated in batches, shall be verified bythermocouples placed on selected castings in each batch.5.1.5 Unless specified by the purchaser, the number andlocations of thermocouples to be placed on each casting, or oncastings
31、 in each heat-treatment batch, shall be at the discretionof the producer.5.1.6 A record of the final austenitizing and tempering heattreatment, and, if specified in the order (see 10.3.7), of any andall subsequent sub-critical heat treatments, shall be made andshall be shown on the material test rep
32、ort. The record shallinclude both the number and locations of thermocouplesapplied to each casting, or to each heat-treatment batch ofcastings.5.2 MachiningCentrifugally cast pipe shall be machinedon the inner and outer surfaces to a roughness value no greaterthan 250 in. 6.35 m arithmetical average
33、 deviation (AA)from the mean line unless otherwise specified as in ANSIB46.1.6. Chemical Composition6.1 Heat AnalysisAn analysis of each heat shall be madeby the manufacturer to determine the weight percentages ofelements specified in Table 1. The analysis shall be made on atest sample taken from th
34、e ladle. The chemical compositionthus determined shall conform to the requirements specified inTable 1 (see Note 3).NOTE 3The role of alloying elements in the development of Grade5Available from American Welding Society (AWS), 8669 NW 36 St., #130,Miami, FL 33166-6672, http:/www.aws.org.A1091/A1091M
35、 162C91has been extensively investigated. V and Cb (Nb) contribute toprecipitation strengthening by forming fine and coherent precipitation ofM(C, N)X carbo-nitrides in the ferrite matrix. V also precipitates as VNduring tempering or during creep. The two elements are more effective incombination. T
36、herefore, the addition of strong nitride-forming elements,those with a stronger affinity for nitrogen than Cb (Nb) and V, asde-oxidation agents, interferes with these high-temperature strengtheningmechanisms.67. Mechanical Properties7.1 Tensile Testing7.1.1 One tension test shall be made from each h
37、eat per heattreatment lot. Test results shall conform to the tensile require-ments specified in Table 2.7.1.2 If a specimen is machined improperly or if flaws arerevealed by machining or during testing, the specimen may bediscarded and another substituted from the same heat.7.1.3 Except as permitted
38、 by 7.1.4, and except for invest-ment castings, test coupons from which tension test specimensare prepared shall be removed from heat-treated castingprolongations.7.1.4 When agreed upon between the manufacturer and thepurchaser, test coupons from which test specimens are pre-pared shall be cast as s
39、eparate blocks from the same heat as thecasting represented. The test blocks shall be heat treated in thesame manner as the casting represented.7.2 Hardness TestingEach casting shall be Brinell hard-ness tested in accordance with Supplementary RequirementS13 of A703/A703M; or, for investment casting
40、s, Supplemen-tary Requirement S13 of A985/A985M; or, for centrifugallycast pipe, 14.3.2 of A335/A335M, and shall have a Brinellhardness of 185 to 248 HBW.8. Quality8.1 All accessible surfaces of the castings shall be examinedvisually and shall be free of adhering sand, scale, cracks, andhot tears. O
41、ther surface discontinuities shall meet the visualacceptance standards specified in the order. Practice A802/A802M or other visual standards may be used to defineacceptable surface discontinuities and finish. Unacceptablevisual surface discontinuities shall be removed and theirremoval verified by vi
42、sual examination of the resultant cavi-ties. When methods involving high temperature are used in theremoval of discontinuities, castings shall be preheated to atleast 400F 200C.8.2 Except for centrifugally cast pipe, hollow castings largerthan NPS 4 DN 100, and whose internal surfaces are notaccessi
43、ble to the visual examination in 8.1, shall be examinedby the ultrasonic examination prescribed in SupplementaryRequirement S7 of A703/A703M; or for investment castings,of Supplementary Requirement S7 of A985/A985M.8.2.1 Castings producing a signal equal to or greater thanthe lowest signal produced
44、by the referenced discontinuitiesshall be considered to contain defects, and they shall beidentified and separated from the acceptable castings. The areaproducing the signal may be re-examined.8.2.2 Castings containing defects shall be rejected if the testsignals were produced by imperfections that
45、cannot be identi-fied or were produced by cracks or crack-like imperfections.8.2.3 Castings containing defects may be repaired. To beaccepted, a repaired casting shall pass the ultrasonic examina-tion and shall meet the minimum wall thickness requirementsof the purchase order.6Viswanathan, R. and Ba
46、kker, W. T., Materials for Ultra Supercritical FossilPower Plants, EPRI, Palo Alto, CA, 2000. TR-114750.TABLE 1 Chemical RequirementsComposition, %Grade Identification Symbol C91UNS Number J84090Carbon 0.08-0.12Manganese 0.300.60Phosphorus 0.025Sulfur 0.010Silicon 0.200.50Nickel 0.40Chromium 8.09.5M
47、olybdenium 0.851.05ColumbiumA(Niobium)A0.0600.10Nitrogen 0.0300.070Vanadium 0.180.25Aluminum 0.02Titanium 0.01Zirconium 0.01AColumbium (Cb) and Niobium (Nb) refer to the same Element 41.TABLE 2 Tensile RequirementsGrade TensileStrength, ksiMPaYieldStrengthA,min, ksi MPaElongation in 2 in.50 mm., min
48、, %BReduction ofArea, min, %C91 85 585 to11076060 415 18 45ADetermined by 0.2 % offset method.BWhen ICI test bars are used in tensile testing as provided for in SpecificationA703/A703M, the gauge length-to-reduced section diameter ratio shall be 4 to 1.A1091/A1091M 1638.3 Each length of centrifugall
49、y cast pipe shall be ultrasoni-cally examined in accordance with A999/A999M.8.4 When additional inspection is desired, SupplementaryRequirements S4, S5, S6, and S10, of A703/A703M; or, forinvestment castings, A985/A985M, may be ordered.9. Permissible Variations in Dimensions of CentrifugallyCast Pipe9.1 ThicknessThe wall thickness of centrifugally cast pipeshall not vary over that specified by more than18 in. 3 mm.There shall be no variation under the specified wall thickness.10. Rework, Weld Repair, and Retreatment10.1 Defect
