1、Designation: A 723/A 723M 08Standard Specification forAlloy Steel Forgings for High-Strength Pressure ComponentApplication1This standard is issued under the fixed designation A 723/A 723M; the number immediately following the designation indicates the yearof original adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) 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 forging
3、s for 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 config
4、uration 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
5、equivalents;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.
6、2. Referenced Documents2.1 ASTM Standards:3A 275/A 275M Practice for Magnetic Particle Examinationof Steel ForgingsA 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 388/A 388M Practice for Ultrasonic Examination ofHeavy Steel ForgingsA 788/A 788M Specification for Steel For
7、gings, GeneralRequirements3. Ordering Information and General Requirements3.1 In addition to the ordering information required bySpecification A 788/A 788M, the purchaser shall include withthe inquiry and order a detailed drawing, sketch, or writtendescription of the forging and the method of select
8、ing testlocation (see 6.2). When appropriate, the areas of significantloading in the forging shall be designated. The purchaser mayalso include appropriate supplementary requirements fromSpecification A 788/A 788M as well as from this specification.3.2 Material supplied to this specification shall c
9、onform tothe requirements of Specification A 788/A 788M, which out-lines additional ordering information, manufacturing require-ments, testing and retesting methods and procedures, marking,certification, product analysis variations, and additional supple-mentary requirements.3.3 If the requirements
10、of this specification are in conflictwith the requirements of Specification A 788/A 788M, therequirements of this specification shall prevail.4. Materials and Manufacture4.1 Melting PracticeThe steel melting procedures ofSpecification A 788/A 788M shall apply except that the open-hearth process shal
11、l not be used, and that the steel shall bevacuum degassed prior to or during the pouring of the ingot, inorder 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 d
12、iscard shall be taken from eachingot to secure freedom from piping and excessive segregation.4.3 Heat Treatment: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 ofcracking du
13、ring 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 PropertiesHeattreatment shall consist of normalizing (which may be part ofthe
14、 preliminary treatment), reaustenitization, liquid quenching,and tempering. The forgings shall be quenched in a suitableliquid medium by spraying or immersion. Quenching shall be1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the
15、 direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved March 1, 2008. Published March 2008. Originallyapproved in 1975. Last previous edition approved in 2002 as A 723/A 723M 02.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-ca
16、tion 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 ASTM website.1*A Summary of C
17、hanges section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.followed by tempering at a minimum temperature of 1000F540C. The minimum time at tempering temperature shall be12 h/in. 12 h/25 mm of m
18、aximum section thickness, unlessotherwise agreed between supplier and purchaser.5. Chemical Composition5.1 Heat AnalysisThe heat analysis obtained from sam-pling in accordance with Specification A 788/A 788M shallcomply with Table 1.5.1.1 Temper Embrittlement ControlThe purchasers at-tention is draw
19、n to Supplementary Requirement S24 in Speci-fication A 788/A 788M for application of the J Factor whichmay be of assistance in the control of temper embrittlement inforgings produced to Specification A 723/A 723M.5.2 Product AnalysisThe manufacturer shall use the prod-uct analysis provision of Speci
20、ficationA 788/A 788M to obtaina product analysis from a forging representing each heat ormultiple heat. The purchaser may also make this determinationin accordance with Specification A 788/A 788M.6. Mechanical Properties6.1 General RequirementsThe forging shall conform tothe requirements of Table 2
21、and Table 3. The largest obtainabletension test specimen as specified in Test Methods and Defi-nitions A 370 (that is, standard round 0.500-in. 12.5-mmdiameter specimen) shall be used. Charpy V-notch Type Aimpact specimens, as shown in Test Methods and DefinitionsA 370, shall be used.6.2 SamplingThe
22、 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 approved by the purchaser. Wherever practical, alltesting shall be f
23、rom 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 forging or test forging (6.2.4) at mid-thicknessand at least23 T (T is t
24、he 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 points of the specimens asdescribed in 6.2 shall not be nearer to o
25、ne 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 dimensionsand the location of mechanical test specimens. It is commo
26、nlyused 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, asdescribed in 6.2, shall be removed14 T from the nearestquenched sur
27、face 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 reduction andtype of hot working, and have a cross section not less
28、 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 Buffers:6.3.1 Thermal buffer rings, at least T by T in cross sectio
29、n 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 joined to the forgingwith a partial penetration-type weld which complet
30、ely 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 center13 of the buffer ringsegment length. In either case, the test spe
31、cimens 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 surface ofthe complete forging.6.3.2 Bearing in mind the characteris
32、tics 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 purchaser should be obtained for theuse of this method.6.4 Samples sh
33、all 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 longitudinal axis ofthe specimens shall be oriented in the direction of
34、 maximumworking of the forging, or as agreed between manufacturer andpurchaser.6.6 Number of Tests:6.6.1 For forgings weighing 1000 lb 455 kg or less, 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) sh
35、all be taken to represent each heat in eachheat-treatment charge. This testing shall be repeated at theopposite end of the same test forging, if the heat-treated lengthexcluding test material exceeds 80 in. 2030 mm. When heatTABLE 1 Chemical RequirementsComposition, %Grade 1 Grade 2 Grade 3Carbon, m
36、ax 0.35 0.40 0.40Manganese, max 0.90 0.90 0.90Phosphorus, max 0.015 0.015 0.015Sulfur, 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 0.20A
37、 723/A 723M 082treatment 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 considered as any continuousrun not exceeding8hinduration.6.6.2 Forgings
38、 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 of the forging exceeds 80 in. 2030 mm thistesting shall be repe
39、ated 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 locations, 180 apart. For forgings with lengthsexceeding 80 in. 2030 mm
40、 this testing shall be repeated at theopposite end of the forging.7. Nondestructive Examination Requirements NondestructiveExamination Requirements7.1 Ultrasonic Examination:7.1.1 Forgings shall be ultrasonically examined in accor-dance with the procedures of Practice A 388/A 388M.7.1.1.1 Straight-B
41、eam Examination:(a) Unless otherwise specified, the back-reflection methodof tuning shall be used in accordance with Practice A 388/A 388M.(b) In addition to the reportable conditions of PracticeA 388/A 388M, indications exceeding the resultant back-reflection shall be recorded.(c) A forging shall b
42、e unacceptable when one or morereflections are present producing indications accompanied by acomplete loss of back-reflection, 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 l
43、oss of back-reflection.7.1.1.2 Angle-Beam Examination:(a) Calibration notches shall be cut into the inside diameterand outside diameter surfaces in accordance with PracticeA 388/A 388M.(b) A forging that contains a discontinuity which results inan indication exceeding the amplitude of the reference
44、line issubject to rejection.(c) The report of the ultrasonic test shall be in compliancewith Practice A 388/A 388M.(d) Additional nondestructive examination or trepanningmay be employed to resolve questions of interpretation ofultrasonic indications. The manufacturer shall accept respon-sibility for
45、 injurious defects that will not be removed in finalmachining.7.2 Magnetic Particle Examination:7.2.1 Each forging shall be examined by magnetic particlemethods described in Practice A 275/A 275M. Acceptance andrejection standards shall be as follows: Only indications withmajor dimensions greater th
46、an116 in. 1.6 mm shall beconsidered relevant. The following relevant indications areunacceptable:7.2.1.1 Any linear indications 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
47、mm long for materials 2 in. 50mm thick and greater. A linear indication is defined as onewhose length is three times its width.7.2.1.2 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 andgre
48、ater.7.2.1.3 Four or more relevant indications in a line separatedby116 in. 1.6 mm or less, edge to edge.7.2.1.4 Ten or more relevant indications in any 6 in.23870mm2 of surface with the major dimension of this area not toexceed 6 in. 150 mm when it is taken in the most unfavorableorientation relati
49、ve to the indications being evaluated.8. Rework and Retreatment8.1 Repair welding shall not be permitted. For retreatment,see 7.2.1.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, ksi MPa 100 690 120 825 130 895 140 965 160 1105 180 1240Elongation in 2 in. or 50 mm, min, % 16 14 13.5 13 12 10Reduction of area
