1、Designation: A723/A723M 10Standard Specification forAlloy Steel Forgings for High-Strength Pressure ComponentApplication1This standard is issued under the fixed designation A723/A723M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision
2、, 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 specification2covers requirements for high-strength quenched and tempered alloy steel forgings for
3、 pres-sure vessels, isostatic presses, shock tubes, and similar com-ponents.1.2 These materials are not intended for welded construc-tion.1.3 Three grades of nickel-chromium-molybdenum steelsand six classes of increasing tensile strength are included. Thestrength class, section size, and configurati
4、on of the forgingwill largely dictate the applicable type(s) of steel.1.4 The values stated in either inch-pound units or SI(metric) units are to be regarded separately as the standard.Within the text and tables, the SI units are shown in brackets.The values stated in each system are not exact equiv
5、alents;therefore, each system must be used independently of the other.Combining values from the two systems may result in noncon-formance with the specification.1.5 Unless the order specifies the applicable “M” specifica-tion designation, the material shall be furnished to the inch-pound units.2. Re
6、ferenced Documents2.1 ASTM Standards:3A275/A275M Practice for Magnetic Particle Examinationof Steel ForgingsA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA388/A388M Practice for Ultrasonic Examination of SteelForgingsA788/A788M Specification for Steel Forgings, General Re-
7、quirements2.2 Other Standards:ASME Boiler and Pressure Vessel Code43. Ordering Information and General Requirements3.1 In addition to the ordering information required bySpecification A788/A788M, the purchaser shall include withthe inquiry and order a detailed drawing, sketch, or writtendescription
8、of the forging and the method of selecting testlocation (see 6.2). When appropriate, the areas of significantloading in the forging shall be designated. The purchaser mayalso include appropriate supplementary requirements fromSpecification A788/A788M as well as from this specification.3.2 Material s
9、upplied to this specification shall conform tothe requirements of Specification A788/A788M, which out-lines additional ordering information, manufacturing require-ments, testing and retesting methods and procedures, marking,certification, product analysis variations, and additional supple-mentary re
10、quirements.3.3 If the requirements of this specification are in conflictwith the requirements of Specification A788/A788M, therequirements of this specification shall prevail.3.4 When forgings are required to be in compliance withDivision 3 of the ASME Boiler and Pressure Vessel Code,Supplementary R
11、equirement S6 should be specified.4. Materials and Manufacture4.1 Melting PracticeThe steel melting procedures ofSpecification A788/A788M shall apply except that the open-hearth process shall not be used, and that the steel shall bevacuum degassed prior to or during the pouring of the ingot, inorder
12、 to remove objectionable gases, particularly hydrogen.4.1.1 Use of secondary remelting or refining operations maybe considered for particularly demanding applications.4.2 DiscardSufficient discard shall be taken from eachingot to secure freedom from piping and excessive segregation.4.3 Heat Treatmen
13、t:4.3.1 Forgings shall be rough-machined prior to final heattreatment if it is necessary to reduce the mass to ensure fullhardening or to meet the requirements of 6.2. The risk of1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is th
14、e direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved Nov. 1, 2010. Published December 2010. Originallyapproved in 1975. Last previous edition approved in 2008 as A723/A723M 08.DOI: 10.1520/A0723_A0723M-10.2For ASME Boiler and Pressure Vessel Code appli
15、cations see related Specifi-cation SA723/SA723M 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
16、 ASTM website.4Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C
17、700, West Conshohocken, PA 19428-2959, United States.cracking during heat treatment with high-hardenability steelsof the type covered by this specification should be borne inmind when deciding on the degree of surface preparationbefore heat treatment.4.3.2 Heat Treatment for Mechanical PropertiesHea
18、ttreatment shall consist of normalizing (which may be part ofthe preliminary treatment), reaustenitization, liquid quenching,and tempering. The forgings shall be quenched in a suitableliquid medium by spraying or immersion. Quenching shall befollowed by tempering at a minimum temperature of 1000F540
19、C. The minimum time at tempering temperature shall be12 h/in. 12 h/25 mm of maximum section thickness, unlessotherwise agreed between supplier and purchaser.5. Chemical Composition5.1 Heat AnalysisThe heat analysis obtained from sam-pling in accordance with Specification A788/A788M shallcomply with
20、Table 1.5.1.1 Temper Embrittlement ControlThe purchasers at-tention is drawn to Supplementary Requirement S24 in Speci-fication A788/A788M for application of the J Factor whichmay be of assistance in the control of temper embrittlement inforgings produced to Specification A723/A723M.5.2 Product Anal
21、ysisThe manufacturer shall use the prod-uct analysis provision of Specification A788/A788M to obtaina product analysis from a forging representing each heat ormultiple heat. The purchaser may also make this determinationin accordance with Specification A788/A788M.6. Mechanical Properties6.1 General
22、RequirementsThe forging shall conform tothe requirements of Table 2 and Table 3. The largest obtainabletension test specimen as specified in Test Methods and Defi-nitions A370 (that is, standard round 0.500-in. 12.5-mmdiameter specimen) shall be used. Charpy V-notch Type Aimpact specimens, as shown
23、in Test Methods and DefinitionsA370, shall be used.6.2 SamplingThe mid-point of the gage length of tensiontest specimens and the area under the notch of impact speci-mens shall be located in accordance with one of the followingmethods as specified by the purchaser, or suggested by thesupplier and ap
24、proved by the purchaser. Wherever practical, alltesting shall be from integral prolongations of the forging.6.2.1 Method 1This method shall always be used whenthe maximum quenched thickness does not exceed 4 in. 100mm. Datum points of the specimens, as described in 6.2, shallbe located in the forgin
25、g or test forging (6.2.4) at mid-thicknessand at least23 T (T is the maximum heat-treated thickness)from the quenched end surface or nearest adjacent surfaces.6.2.2 Method 2t by 2t, where t is the distance from thearea of significant loading (3.1) to the nearest quenchedsurface. However, the datum p
26、oints of the specimens asdescribed in 6.2 shall not be nearer to one quenched surfacethan34 in. 20 mm and to the second quenched surface than 112 in. 40 mm. When this method of testing is employed,forgings are usually manufactured in accordance with apurchaser-approved drawing showing prequenched di
27、mensionsand the location of mechanical test specimens. It is commonlyused for disk-type forgings such as tube sheets and covers.6.2.3 Method 3For maximum quenched thicknesses inexcess of 4 in. 100 mm as heat treated. Where this method oftesting is employed, the datum points of the test specimen, asd
28、escribed in 6.2, shall be removed14 T from the nearestquenched surface and23 T from the quenched end surface ornearest adjacent surface.6.2.4 Method 4Test specimens shall be taken from arepresentative separate test forging made from the same heat ofsteel, which shall receive substantially the same r
29、eduction andtype of hot working, and have a cross section not less than theproduction forgings which it represents. It shall be heat treatedin the same furnace charge and under the same conditions asthe production forgings. The test specimen shall be removedusing the Method 3 procedure.6.3 Thermal B
30、uffers:6.3.1 Thermal buffer rings, at least T by T in cross section orsections of such a ring at least 3 T in length, shall be welded tothe test end(s) of a forging prior to heat treatment formechanical properties. The buffer material may be any weld-able carbon or low-alloy steel and shall be joine
31、d to the forgingwith a partial penetration-type weld which completely seals thebuffered surface. The test coupons shall be removed from theforging in the region buffered by the ring or ring segments. Ifthe latter are used, the test coupons shall be removed from theforging in the area under the cente
32、r13 of the buffer ringsegment length. In either case, the test specimens shall belocated at a minimum distance of12 in. 13 mm from thebuffered surface of the forging and at least14 T from aquenched surface of the forging. Buffered weld areas must beat least 1 in. 25 mm from any finished machining su
33、rface ofthe complete forging.6.3.2 Bearing in mind the characteristics of the base mate-rials included in this specification, precautions should be taken,such as the use of pre- and post-weld heating and austeniticweld metal, to minimize the occurrence of crack-like defects.6.3.3 Approval of the pur
34、chaser should be obtained for theuse of this method.6.4 Samples shall be removed from the forgings afterquenching and tempering.6.5 OrientationFor upset disk forgings, the longitudinalaxis of all test specimens shall be oriented in the tangential orradial direction. For all other forgings, the longi
35、tudinal axis ofthe specimens shall be oriented in the direction of maximumworking of the forging, or as agreed between manufacturer andpurchaser.TABLE 1 Chemical RequirementsComposition, %Grade 1 Grade 2 Grade 3Carbon, max 0.35 0.40 0.40Manganese, max 0.90 0.90 0.90Phosphorus, max 0.015 0.015 0.015S
36、ulfur, max 0.015 0.015 0.015Silicon, max 0.35 0.35 0.35Nickel 1.5 to 2.25 2.3 to 3.3 3.3 to 4.5Chromium 0.80 to 2.00 0.80 to 2.00 0.80 to 2.00Molybdenum 0.20 to 0.40 0.30 to 0.50 0.40 to 0.80Vanadium, max 0.20 0.20 0.20A723/A723M 1026.6 Number of Tests:6.6.1 For forgings weighing 1000 lb 455 kg or l
37、ess, as heattreated but not exceeding 80 in. 2030 mm in length, exclud-ing test material, one tension test and one set of impact tests(three specimens) shall be taken to represent each heat in eachheat-treatment charge. This testing shall be repeated at theopposite end of the same test forging, if t
38、he heat-treated lengthexcluding test material exceeds 80 in. 2030 mm. When heattreatment is performed in continuous-type furnaces with suit-able temperature control and equipped with recording pyrom-eters so that complete heat-treatment records are available, aheat-treatment charge shall be consider
39、ed as any continuousrun not exceeding8hinduration.6.6.2 Forgings weighing over 1000 lb 455 kg but not over5000 lb 2270 kg as heat treated and not over 80 in. 2030mm in length excluding test material, one tension test and oneset of three impact tests shall be removed from each forging.When the length
40、 of the forging exceeds 80 in. 2030 mm thistesting shall be repeated at the opposite end of the forging.6.6.3 Forgings exceeding 5000 lb 2270 kg and not over 80in. 2030 mm in length, excluding test material, shall have onetension test and one set of three impact tests removed fromeach of two locatio
41、ns, 180 apart. For forgings with lengthsexceeding 80 in. 2030 mm this testing shall be repeated at theopposite end of the forging. Supplementary Requirement S6 isapplicable for forgings intended for use under the rules ofSection VIII, Division 3 of the ASME Boiler and PressureVessel Code.7. Nondestr
42、uctive Examination Requirements7.1 Ultrasonic Examination:7.1.1 Forgings shall be ultrasonically examined in accor-dance with the procedures of Practice A388/A388M.7.1.1.1 Straight-Beam Examination:(a) Unless otherwise specified, the back-reflection methodof tuning shall be used in accordance with P
43、ractice A388/A388M.(b) In addition to the reportable conditions of PracticeA388/A388M, indications exceeding the resultant back-reflection shall be recorded.(c) A forging shall be unacceptable when one or morereflections are present producing indications accompanied by acomplete loss of back-reflect
44、ion, not attributable to nor asso-ciated with the geometric configuration. For this purpose, aback-reflection of less than 5 % of full screen height shall beconsidered complete loss of back-reflection.7.1.1.2 Angle-Beam Examination:(a) Calibration notches shall be cut into the inside diameterand out
45、side diameter surfaces in accordance with PracticeA388/A388M.(b) A forging that contains a discontinuity which results inan indication exceeding the amplitude of the reference line issubject to rejection.(c) The report of the ultrasonic test shall be in compliancewith Practice A388/A388M.(d) Additio
46、nal nondestructive examination or trepanningmay be employed to resolve questions of interpretation ofultrasonic indications. The manufacturer shall accept respon-sibility for injurious defects that will not be removed in finalmachining.7.2 Magnetic Particle Examination:7.2.1 Each forging shall be ex
47、amined by magnetic particlemethods described in Practice A275/A275M. Acceptance andrejection standards shall be as follows: Only indications withmajor dimensions greater than116 in. 1.6 mm shall beconsidered relevant. The following relevant indications areunacceptable:7.2.1.1 Any linear indications
48、greater than116 in. 1.6 mmlong for materials less than58 in. 16 mm thick; greater than18 in. 3.2 mm long for materials from58 in. to under 2 in. 50mm thick; and316 in. 4.8 mm long for materials 2 in. 50mm thick and greater. A linear indication is defined as onewhose length is three times its width.7
49、.2.1.2 Rounded indications with dimensions greater than18 in. 3.2 mm for thicknesses less than58 in. 16 mm, andgreater than316 in. 4.8 mm for thicknesses58 in. 16 mm andgreater.7.2.1.3 Four or more relevant indications in a line separatedby116 in. 1.6 mm or less, edge to edge.TABLE 2 Tensile RequirementsClass 1 Class 2 Class 2a Class 3AClass 4BClass 5CTensile strength, min, ksi MPa 115 795 135 930 145 1000 155 1070 175 1205 190 1310Yield strength, 0.2 % offset, min, k
