Designation: A 508/A 508M 03 An American National Standard

Standard Specification forQuenched and Tempered Vacuum-Treated Carbon and AlloySteel Forgings for Pressure Vessels 1

This standard is issued under the fixed designation A 508/A 508M; the number immediately following the designation indicates the yearof original 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 (e) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the Department of Defense.

1. Scope

1.1 This specification2 covers quenched and temperedvacuum treated carbon and alloy steel forgings for pressurevessels such as those used in reactor systems. Specifically, itcovers forgings for vessel closures, shells, flanges, tube sheets,rings, heads, and similar parts.

1.2 All grades are considered weldable under proper condi-tions. Welding technique is of fundamental importance, and itis presupposed that welding procedure and inspection will be inaccordance with approved methods for the grade of materialused.

1.3 The values stated in either inch-pound units or SI(metric) units are to be regarded separately as standards.Within the text and the tables, the SI units are shown inbrackets. The values stated in each system are not exactequivalents; therefore, each system must be used independentof the other. Combining values from the two systems mayresult in nonconformance with the specification.

1.4 Unless the order specifies the applicable M specifica-tion designation, the material shall be furnished to the inch-pound units.

NOTE 1Grades 1 and 1A are composed of different chemistries buthave the same mechanical requirements.

NOTE 2Designations have been changed as follows:

Current FormerlyGrade 1 Class 1Grade 1A Class 1AGrade 2 Class 1 Class 2Grade 2 Class 2 Class 2AGrade 3 Class 1 Class 3Grade 3 Class 2 Class 3AGrade 4N Class 1 Class 4Grade 4N Class 2 Class 4AGrade 4N Class 3 Class 4BGrade 5 Class 1 Class 5Grade 5 Class 2 Class 5A

Grade 22 Class 3 Class 22BGrade 3V Class 3VGrade 6 Classes 1, 2, 3, and4

N/A

2. Referenced Documents

2.1 ASTM Standards:A 275/A 275M Test Method for Magnetic Particle Exami-

nation of Steel Forgings3

A 370 Test Methods and Definitions for Mechanical Testingof Steel Products4

A 388/A 388M Practice for Ultrasonic Examination ofHeavy Steel Forgings3

A 788 Specification for Steel Forgings, General Require-ments3

E 208 Test Method for Conducting Drop-Weight Test toDetermine Nil-Ductility Transition Temperature of FerriticSteels5

E 428 Practice for Fabrication and Control of Steel Refer-ence Blocks Used in Ultrasonic Inspection6

2.2 American Society of Mechanical Engineers Standard:Boiler and Pressure Vessel CodeSection III, Articles

NB 2300, NC 2300, ND 2300, NE 2300, NF 2300, NG23007

3. Ordering Information

3.1 Purchase OrderIn addition to the ordering informa-tion required by Specification A 788, the purchaser shallinclude with the inquiry and order a detailed drawing thatlocates the areas of significant loading in the forging (whenrequired), the method of selecting test locations (see 6.1.5 and6.1.6), and purchase options (see 4.2.2, 6.2.1, and 10.1) andany supplementary requirements desired.

3.2 Forging DrawingEach forging shall be manufacturedin accordance with a purchaser-approved drawing showing theprequenched dimensions, the finished dimensions, the surfaces

1 This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel, and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.

Current edition approved April 10, 2003. Published July 2003. Originallyapproved in 1964. Last previous edition approved in 1999 as A 508/A 508M 95(1999).

2 For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-508/SA-508M in Section II of that Code.

3 Annual Book of ASTM Standards, Vol 01.05.4 Annual Book of ASTM Standards, Vol 01.03.5 Annual Book of ASTM Standards, Vol 03.01.6 Annual Book of ASTM Standards, Vol 03.03.7 Available from American Society of Mechanical Engineers, 345 E. 47th St.,

New York, NY 10017.

1

Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.

that will be subjected to significant loading, and the locationsof mechanical test specimens.

3.3 Material supplied to this specification shall conform tothe requirements of Specification A 788, which outlines addi-tional ordering information, manufacturing requirements, test-ing and retesting methods and procedures, marking, certifica-tion, product analysis variations, and additional supplementaryrequirements.

3.4 If the requirements of this specification are in conflictwith the requirements of Specification A 788, the requirementsof this specification shall prevail.

4. Materials and Manufacture

4.1 Melting Process:4.1.1 The steel shall be made by the basic electric-furnace

process except when secondary ladle refining or the remeltingprocess is employed, in which case the melting processes ofSpecification A 788 are permitted.

4.1.2 The molten steel shall be vacuum treated in accor-dance with the methods described in Specification A 788, priorto or during the pouring of the ingot, in order to removeobjectionable gases, particularly hydrogen.

Grade 6 shall be produced to a fine grain melting practicewhich has been shown to result in a prior austenitic grain sizeof five or finer for Classes 1, 2, 3 and 4.

4.1.3 DiscardSufficient discard shall be made from eachingot to secure freedom from piping and excessive segregation.

4.2 Heat Treatment:4.2.1 Preliminary Heat TreatmentAfter forging and be-

fore reheating, the forgings shall be cooled to provide substan-tially complete transformation of austenite. Preliminary heattreatment may be applied to improve machinability and toenhance subsequent heat treatments.

4.2.2 Heat Treatment for Mechanical PropertiesThe forg-ings shall be heated to a temperature which produces anaustenitic structure and then quenched in a suitable liquidmedium by spraying or immersion. For Grade 4N, Classes 1and 3, the austenitizing temperature shall be 1540F [840C]min to 1640F [895C] max. Quenching shall be followed bytempering at a subcritical temperature and holding at thistemperature for a minimum time of one-half hour per inch of

maximum section thickness. Except when Supplementary Re-quirement S 13 is specified for Grades 2 and 3, the minimumtempering temperatures shall be as follows:

Grades 1, 1A, 2 Class 2, and 3 Class 2 1150F [620C]Grades 2 Class 1 and 3 Class 1 1200F [650C]Grades 4N Classes 1 and 2, and 5

Classes 1 and 21100F [595C]

Grade 4N Class 3 1125F [600C]Grades 3V and 3VCb 1250F [675C]Grade 22, Class 3 1200F [650C]Grade 6, Classes 1, 2, 3, and 4 1200F [650C]

Specific cooling rates from the tempering temperature shallbe applied if Supplementary Requirement S14 is specified.

4.3 For Grades 1, 1A, 2, 2A, 3, or 3A, a multiple stageaustenitizing procedure may be used whereby the forging isfirst fully austenitized and liquid quenched, followed byreheating within the intercritical temperature range to partiallyreaustenitize and again liquid quenched. On completion of theaustenitizing/quenching cycles, the forgings shall be temperedat a subcritical temperature as described in 4.2.2.

5. Chemical Composition

5.1 Heat AnalysisThe heat analysis obtained from sam-pling in accordance with Specification A 788 shall comply withTable 1 except that the additional features of SupplementaryRequirements S7, S8, S9, and S11 shall also apply as individu-ally specified in the ordering information.

5.2 Product AnalysisThe manufacturer shall use the prod-uct analysis provision of Specification A 788 to obtain aproduct analysis from a forging representing each heat ormultiple heat. The permissible variations provided in the tableon Permissible Variations in Product Analysis for Killed Steelin Specification A 788 apply for manganese, nickel, chromium,molybdenum and vanadium only. Boron is not subject toproduct analysis. The purchaser may also make this determi-nation in accordance with Specification A 788.

6. Mechanical Properties

6.1 Tension Test:6.1.1 The steel shall conform to the requirements of Table 2.6.1.2 The location and number of tension test specimens for

each forging or multiple forging shall be as follows:

TABLE 1 Chemical Requirements

Composition, %

Grade 1 Grade 1A Grade 2 Grade 3 Grade 4N Grade 5 Grade 22 Grade 3V Grade 3VCb Grade 6

Carbon 0.35 max 0.30 max 0.27 max 0.25 max 0.23 max 0.23 max 0.110.15 0.100.15 0.100.15 0.280.33Manganese 0.401.05 0.701.35 0.501.00 1.201.50 0.200.40 0.200.40 0.300.60 0.300.60 0.300.60 0.751.15Phosphorus 0.025 max 0.025 max 0.025 max 0.025 max 0.020 max 0.020 max 0.015 max 0.020 max 0.020 max 0.025 maxSulfur 0.025 max 0.025 max 0.025 max 0.025 max 0.020 max 0.020 max 0.015 max 0.020 max 0.010 max 0.025 maxSiliconA 0.150.40 0.150.40 0.150.40 0.150.40 0.150.40 0.30 max 0.50 max 0.10 max 0.10 max 0.150.35Nickel 0.40 max 0.40 max 0.501.00 0.401.00 2.83.9 2.83.9 0.25 max . . . 0.25 max 0.750.95Chromium 0.25 max 0.25 max 0.250.45 0.25 max 1.502.00 1.502.00 2.002.50 2.83.3 2.73.3 0.701.00Molybdenum 0.10 max 0.10 max 0.550.70 0.450.60 0.400.60 0.400.60 0.901.10 max 0.901.10 0.901.10 0.300.45Vanadium 0.05 max 0.05 max 0.05 max 0.05 max 0.03 max 0.08 max 0.02 max 0.200.30 0.200.30 0.05 maxColumbium . . . . . . . . . . . . . . . . . . . . . . . . 0.0150.070 0.01 maxB

Copper . . . . . . . . . . . . . . . . . . . . . . . . 0.25 max ...Calcium . . . . . . . . . . . . . . . . . . . . . . . . 0.00050.0150 ...Boron . . . . . . . . . . . . . . . . . . . . . 0.0010.003 . . . ...Titanium . . . . . . . . . . . . . . . . . . . . . 0.0150.035 0.015 max B

Aluminum ... ... ... ... ... ... ... ... ... 0.05 maxA When vacuum carbon-deoxidation is required by Supplementary Requirement S 11, the silicon content shall be 0.10 % maximum.BInternational addition of Cb and Ti not permitted.

A 508/A 508M 03

2

TAB

LE2

Tens

ileR

equi

rem

ents

Gra

des

1an

d1a

Gra

des

2C

lass

1an

d3

Cla

ss1

Gra

des

2C

lass

2an

d3

Cla

ss2

Gra

des

4NC

lass

1an

d5

Cla

ss1

Gra

des

4NC

lass

2an

d5

Cla

ss2

Gra

de4N

Cla

ss3

Gra

de22

Cla

ss3

Gra

des

3Van

d3V

Cb

Gra

de6

Cla

ss1

Gra

de6

Cla

ss2

Gra

de6

Cla

ss3

Gra

de6

Cla

ss4

Tens

ilest

reng

th,

ksi[

MP

a]

70to

95[4

85to

655]

80to

105

[550

to72

5]90

to11

5[6

20to

795]

105

to13

0[7

25to

895]

115

to14

0[7

95to

965]

90to

115

[620

to79

5]

85to

110

[585

to76

0]85

to11

0[5

85to

760]

85to

110

[655

to82

5]95

to12

0[6

55to

825]

100

to12

5[6

90to

760]

105

to13

0[7

25to

895]

Yie

ldst

reng

th,

min

[0.2

%of

fset

],ks

i[M

Pa]

36[2

50]

50[3

45]

65[4

50]

85[5

85]

100[

690]

70[4

85]

55[3

80]

60[4

15]

75[4

15]

75[5

15]

80[5

50]

85[5

85]

Elo

ngat

ion

in2 in

.or

50m

m, min

,%

2018

1618

1620

1818

1818

1818

Red

uctio

nof

area

,m

in,

%

3838

3545

4548

4545

3535

3535

A 508/A 508M 03

3

6.1.2.1 Multiple Forgings Separated into Identical Indi-vidual Forgings with Rough Machined Weights not Exceeding1000 lb [455 kg] Prior to Quenching and TemperingTreatmentAt least one individual forging from each multipleforging in each heat-treating lot shall be tested using the testspecimen locations of 6.1.5 or 6.1.6 as specified on thepurchase orders, except that test specimens located atmidlength may be closer to the ends of the production forgingthan the specified distance to the second surfaces. All forgingsshall be quenched and tempered in the same furnace charge. Allforgings from the multiple shall be Brinell hardness tested afterheat treatment and forgings not tested for mechanical proper-ties shall have a Brinell Hardness within 20 points of theBrinell Hardness of the forging that has been tested formechanical properties.

6.1.2.2 Forgings or Multiple Forgings (Note 2) with RoughMachined Weights Less than 10 000 lb [4540 kg] and Havinga Heat-Treated Length (Exclusive of Test Prolongation) of 80in. [2032 mm] or LessA test prolongation (Note 3) shall belocated at one end. One tension test specimen shall be takenfrom the test prolongation.

6.1.2.3 Forgings or Multiple Forgings with Rough Ma-chined Weights Less than 10 000 lb [4540 kg] and Having aHeat-Treated Length (Exclusive of Test Prolongations) Exceed-ing 80 in. [2032 mm] A test prolongation shall be located ateach end. One tension test specimen shall be taken from eachtest prolongation. An orientation of 180 shall be establishedbetween the two tension test specimens.

6.1.2.4 Forgings or Multiple Forgings with Rough Ma-chined Weights Over 10 000 lb [4540 kg] and Having aHeat-Treated Length (Exclusive of Test Prolongation) of 80 in.[2032 mm] or LessA test prolongation shall be located at oneend. Two tension test specimens shall be taken from the testprolongation and shall be oriented 180 apart.

6.1.2.5 Forgings or Multiple Forgings with Rough Ma-chined Weights Over 10 000 lb [4540 kg] and Having aHeat-Treated Length (Exclusive of Test Prolongations) Exceed-ing 80 in [2032 mm]A test prolongation shall be located ateach end. The tension test specimens oriented 180 apart fromeach other shall be taken from each test prolongation. The twotension specimens located in one test prolongation shall beoriented 90 in relation to the two tension specimens located inthe other test prolongation.

NOTE 3Multiple forgings in 6.1.2.2 through 6.1.2.5 are those whichwill be separated after the quench and temper treatment.

NOTE 4A test prolongation is defined as that integral test metallocated at an end of the forging or forging multiples.

6.1.3 Samples for mechanical test specimen shall be re-moved from forgings after the quenching and tempering heattreatment. The sample material shall be subjected to a simu-lated post weld heat treatment if Supplementary RequirementS1 is specified.

6.1.4 For upset disk forgings, the longitudinal axis of thetest specimens shall be in the tangential direction. For all otherparts, the longitudinal axis of the specimens shall be parallel tothe direction of major working of the forging.

6.1.5 Each forging shall be manufactured in accordancewith a purchaser-approved drawing, showing the prequenched

dimensions, the finished dimensions, the surfaces that will besubjected to critical stresses, and the location of mechanicaltest specimens.

6.1.6 The tension test specimens shall be positioned so thatthe longitudinal axis and mid-length is in accordance with oneof the following methods:

6.1.6.1 Method 1t by 2t, wheret is the distance from thearea of significant loading (see 3.1) to the nearest quenchedsurface. However, they shall not be nearer to one quenchedsurface than34 in. [20 mm] and to the second quenched surfacethan 112 in. [40 mm].

6.1.6.2 Method 214 T by T, where T is the maximumthickness of the forging as heat treated. Where this method oftesting is employed, the following limitations for as-treatedthickness shall generally apply:Grades 1 and 1a 3 in. [75 mm], maxGrades 2 Class 2 and 3 Class 2 6 in. [150 mm], maxGrades 2 Class 1 and 3 Class 1 8 in. [205 mm], maxGrade 4N Class 2 and 5 Class 2 16 in. [405 mm], maxGrade 4N Class 1 and 5 Class 1 30 in. [760 mm], maxGrade 4N Class 3 40 in. [1015 mm], maxGrades 3V and 3VCb 20 in. [510 mm], maxGrade 22 Class 3 20 in. [510 mm], maxGrade 6 Classes 1, 2, 3, and 4 6 in. [150 mm], max

6.1.6.3 Method 3Test specimens shall be taken from arepresentative separate test forging made from the same heat ofsteel and shall receive substantially the same reduction andtype of hot working as the production forgings that it representsand shall be of the same nominal thickness as the as-quenchedproduction forgings. The separate test forging shall be heattreated in the same furnace charge and under the sameconditions as the production forgings. Test specimens shall beremoved from the region midway between the mid-thicknessand the surface, and not closer thanT to a second heat treatedsurface with the same limitation on forging thickness as in6.1.6.2. This method shall be limited to forgings with a roughmachined weight of not more than 1000 lb [455 kg].

6.1.6.4 Method 4A thermal buffer ring, at leastT by T incross section, or segments of such a ring at least 3T in length,shall be welded to the test end of a forging prior to heattreatment for mechanical properties. The buffer material maybe any weldable carbon or low-alloy steel and shall be joinedto the forging with a partial-penetration type weld whichcompletely seals the buffered surface. The test coupons shall beremoved from the forging in the region buffered by the ring orring segments. If ring segments are used, the test coupons shallbe removed from the forging in the area under the buffer ringsegment at a minimum distance ofT from each end of thatsegment. In either case, the test specimens shall be located ata minimum distance of12 in. [13 mm] from the bufferedsurface of the forging, and at least14 T from a quenchedsurface of the forging.

NOTE 5For forgings with a maximum thickness of 2 in. [50 mm], thespecimens shall be taken at midthickness and at least 2 in. from a secondsurface. This provision is applicable to all four methods in 6.1.6.

6.1.7 Tension specimens shall be the standard 0.5 in. [12.5mm] round by 2 in. [50 mm] gage length, as shown in TestMethods and Definitions A 370.

6.2 Impact Test:

A 508/A 508M 03

4

6.2.1 The steel shall conform to the requirements of Table 3,or Supplementary Requirement S10 may be specified insteadof these requirements.

6.2.2 Number, Location, and Orientation of Specimens:6.2.2.1 One set of three Charpy V-notch specimens shall be

taken from each tensile specimen location required in 6.1.2.Orientation shall be the same as in 6.1.4. When S10 isspecified, the required number of tests shall be governed byNB, NC, ND, NE, NF, or NG 2300, as applicable.

6.2.2.2 The requirements of 6.1.3 also apply to impactspecimens.

6.2.2.3 The longitudinal axis and mid-length of the impactspecimen shall be located similarly to the longitudinal axis ofthe tension test specimens as defined in 6.1.6. The axis of thenotch shall be normal to the nearest heat-treated surface of theforging. When S10 is specified the orientation shall be gov-erned by NB, NC, ND, NE, NF, or NG 2300.

6.2.3 Impact specimens shall be Charpy V-notch as shownin Test Methods and Definitions A 370.

7. Workmanship and Quality Level Requirements

7.1 See requirements in 8.1, 8.2.2, 8.3.1.1, and 8.3.2.2.

8. Nondestructive Inspection Requirements

8.1 General RequirementsDimensional and visual inspec-tions, and magnetic particle and ultrasonic inspection shall beconducted by the manufacturer. Forgings shall be free ofcracks, thermal ruptures, or other injurious indications.

8.2 Magnetic Particle Inspection:8.2.1 Following final machining by the manufacturer all

accessible surfaces of each forging shall be examined by thecontinuous current magnetic particle method in accordancewith Test Method A 275/A 275M.

8.2.2 The following conditions are subject to rejection orremoval:

8.2.2.1 Indications with major dimension exceeding316 in.[4.8 mm].

8.2.2.2 Four or more indications exceeding116 in. [1.6 mm]in major dimensions that are aligned and separated by116 in.[1.6 mm] or less end to end.

8.2.2.3 Ten or more indications exceeding116 in. [1.6 mm]in major dimensions contained in any 6 in.2 [39 cm2] ofsurface, with the major dimension of this area not to exceed 6in. [150 mm]. The area shall be taken in the most unfavorablelocation relative to the indications being evaluated.

8.3 Ultrasonic InspectionForgings shall be ultrasonicallyinspected in accordance with the procedures of Practice A 388/A 388M.

8.3.1 Longitudinal Wave Inspection:8.3.1.1 Unless otherwise specified by Supplementary Re-

quirement S2, the back reflection method of tuning shall beused in accordance with 7.2.2.1 of Practice A 388/A 388M. Inaddition to the reportable conditions in Section 7 of PracticeA 388/A 388M, indications exceeding the resultant back re-flection shall be recorded. The following conditions are con-sidered rejectable:

8.3.1.2 Complete loss of back reflection not associated withforging configuration or surface and accompanied by an

indication of a discontinuity. For this purpose, a back reflectionless than 5 % of full screen height shall be considered completeloss of back reflection.

8.3.1.3 Indications whose amplitude equals or exceeds thatof the back reflection established in an indication-free area ofthe forging.

8.3.2 Angle Beam Inspection:8.3.2.1 Calibration notches shall be cut into the inside- and

outside-diameter surfaces with a depth equal to 3 % of thenominal section thickness (or38 in. [9.5 mm], max), a length ofapproximately 1 in. [25 mm], and a width not greater thantwice its depth. Adjust instrument controls to obtain anindication from the inside-diameter notch approximately 75 %of full screen height. Measure the amplitude of indication fromthe outside-diameter notch. Draw a straight line on the shield infront of the cathode ray tube from this peak to that of theinside-diameter notch and continue it as a horizontal line to theinitial pulse. This line constitutes the angle beam referenceline.

8.3.2.2 A forging containing a discontinuity which results inan indication exceeding the amplitude of the reference line issubject to rejection.

NOTE 6Signals from discontinuities within approximately14 in. [6.4mm] of inside and outside surfaces are reinforced by wave trapping duringangle beam inspection; they are therefore amplified in respect to internaldiscontinuities.

8.3.3 The report of the ultrasonic inspection shall be incompliance with Section 8 of Practice A 388/A 388M.

8.3.4 Additional nondestructive inspection or trepanningmay be employed to resolve questions of interpretation ofultrasonic indications. The manufacturer shall accept respon-sibility for injurious indications which will not be removed infinal machining.

9. Repair Welding

9.1 Repair welding of forgings may be permitted, but onlyat the option of the purchaser.

9.2 If repair welding is performed, welders and weld pro-cedures shall be qualified in accordance with Section IX of theASME Boiler and Pressure Vessel Code.

10. Certification and Reports

10.1 In addition to items to be reported by SpecificationA 788, the following items shall also be reported:

10.1.1 Product chemical analysis,10.1.2 The method used for locating test specimens, and10.1.3 Sketches showing the locations of all recordable

indications in the report of all nondestructive examinations.10.1.4 Details of the heat treatment cycle, as listed in

Specification A 788.

11. Product Marking

11.1 The purchaser may specify additional identificationmarking and the location of the stamping. The type of stampsto be used when impression stamping is performed shall beround-nosed or interrupted-dot die stamps having a mini-mum radius of132 in. [0.8 mm].

A 508/A 508M 03

5

TAB

LE3

Cha

rpy

Impa

ctR

equi

rem

ents

Gra

des

1an

d1a

(at

+40

F[4

.4C

])

Gra

des

2C

lass

1an

d3

Cla

ss1

(at

+40

F[4

.4C

])

Gra

des

2C

lass

2an

d3

Cla

ss2

(at

+70

F[2

1C

])

Gra

des

4N(a

llcl

asse

s)an

d5

(all

clas

ses)

(at

20

F[

29C

])

Gra

des

22C

lass

es3,

3V,

and

3VC

b(a

t0

F[

18C

])

Gra

de6

Cla

sses

1,2,

3,an

d4

(at

75F

[59

C])

Min

imum

aver

age

valu

eof

set

ofth

ree

spec

imen

s,ft

lbf

(J)A

15[2

0]30

[41]

35[4

8]35

[48]

40[5

5]20

[27]

Min

imum

valu

eof

one

spec

imen

,ft

lbf

(J)

10[1

4]25

[34]

30[4

1]30

[41]

35[5

0]15

[20]

AN

otm

ore

than

one

spec

imen

from

ase

tm

aybe

belo

wth

isva

lue.

A 508/A 508M 03

6

12. Keywords12.1 chromium-molybdenum steel; nickel-chromium-

molybdenum alloy steels; pressure vessel service; quenchedand tempered steels; steel forgingsalloy; steel forgingscarbon; vacuum-treated steels

SUPPLEMENTARY REQUIREMENTS

One or more of the following supplementary requirements shall apply only when specified by thepurchaser in the inquiry or order. Details of these supplementary requirements shall be agreed uponbetween the manufacturer and the purchaser.

S1. Simulated Post-Weld Heat Treatment of MechanicalTest Samples

S1.1 All test coupons shall be subjected to single or multipleheat treatments at subcritical temperatures prior to testing.Such treatments are intended to simulate post-weld or othertreatments to which the forgings will be subjected duringsubsequent fabrication. The purchaser shall furnish the manu-facturer with details of the desired heat treatment for the testcoupons, including temperatures, timers, and cooling rates.

S2. Ultrasonic Testing-Reference Block Calibration (forexamining sections 24-in. [610 mm] thick or less)

S2.1 Reference blocks of acoustically similar metal shall beused for calibration. Blocks shall meet one of the followingrequirements:

S2.1.1 A comparison of the back reflections betweenequivalent thicknesses of the reference block material and theactual forging to be tested, without change in instrumentsetting shall not show a variation in excess of 25 %.

S2.1.2 The reference blocks shall be manufactured fromsteel that is similar in chemistry and processing history to theproduction forging being tested. The reference blocks shall befabricated in accordance with the procedures of Practice E 428.

S2.2 For test sections up to 12 in. [305 mm] thick, thereference blocks shall contain a14-in. [6.4-mm] diameterflat-bottom hole; for over 12 to 18 in. [305 to 457 mm], thehole diameter shall be38 in. [9.5 mm]; and for over 18 to 24 in.[457 to 610 mm], it shall be12 in. [13 mm].

S2.3 A distance-amplitude correction curve shall be estab-lished for the proper grade of steel and specified hole size.

S2.4 A forging containing one or more indications equal inamplitude to that of the applicable reference hole, whenproperly corrected for distance, is subject to rejection.

S3. Charpy V-Notch Impact Transition Curve

S3.1 Sufficient impact tests shall be made from the forgingtest material to establish a temperature-absorbed energy curve.The test-temperature range shall be wide enough to establishthe upper and lower shelf foot-pound energies, with sufficienttesting at intermediate temperatures to permit plotting a rea-sonably smooth curve.

S4. Additional Charpy Data

S4.1 The percent shear fracture and mils of lateral expan-sion, defined in Test Methods and Definitions A 370, shall bereported for each Charpy specimen tested.

S5. Alternative Impact Test

S5.1 Charpy impact tests shall be made in accordance withthe provisions of 6.2 of the specification except that the testtemperature shall be lower than specified in Table 3. This testshall be instead of that specified in 6.2.

S6. Drop-Weight Test

S6.1 Drop-weight tests shall be conducted in accordancewith the requirements of Test Method E 208. The fracture planeof the specimens shall coincide with the location required forother mechanical test specimens as specified by the purchaserin accordance with 6.1.6. However, since the drop weightspecimen can be taken in any orientation, the fracture plane ofthe specimen when tested to Method 1 (6.1.6.1) shall be aminimum distance of716 in. [11 mm] from the nearestquenched surface, and 112 in. [38 mm] from any secondsurface. The purchaser may specify either duplicate no-breakperformance when tested 10F [6C] warmer than a specifiedtemperature or request a determination of the NDT tempera-ture.

S7. Restrictive Chemistry for Grades 4N and 5

S7.1 Phosphorus and sulfur limits for Grades 4N and 5 shallbe 0.015 % maximum heat and 0.018 % maximum product.

S8. Additional Vanadium

S8.1 The vanadium content for Grade 5 forgings shall be0.05 to 0.15 %.

S9. Restrictive Chemistry for Grades 2, 3, or 4N

S9.1 Grades 2, 3, or 4N shall be specified with restrictedphosphorus and copper limits, as follows:

S9.1.1 P 0.012 maximum heat and 0.015 maximum product;Cu 0.10 maximum heat and product, or

S9.1.2 P 0.015 maximum heat and 0.018 maximum product;Cu 0.15 maximum heat and product.

S9.2 Grades 2, 3, 4N shall be specified with restricted sulfurof 0.015 heat and 0.018 product.

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S10. Alternative Fracture Toughness Requirements

S10.1 The fracture toughness requirements (drop weightand Charpy impact tests) for materials of the ASME Boiler andPressure Vessel Code, Section III, Articles NB 2300, NC 2300,ND 2300, NE 2300, NF 2300, or NG 2300, as specified, shallbe used instead of the Charpy impact test requirements of thisspecification.

S11. Vacuum Carbon-Deoxidized Steels

S11.1 Material made to Grades 1, 1a, 2, 3, 4N, or 5 shall bevacuum carbon-deoxidized, in which case the silicon contentshall be 0.10 % max. The test report shall indicate that the steelwas vacuum carbon-deoxidized.

S12. Vacuum-Treated Basic Oxygen Furnace Steels

S12.1 For Grades 1, 1a, 2, or 3 material, vacuum-treatedbasic oxygen furnace steel shall be used.

S13. Minimum Tempering Temperature

S13.1 For Grades 2 Class 1 and 3 Class 1 the minimumtempering temperature shall be 1175F [635C] and the simu-lated post weld heat treatment temperature shall not exceed1150F [620C] when S1 is required.

S14. Cooling from the Tempering Temperature

S14.1 The purchaser shall provide specific cooling ratesfrom the tempering temperature.

S15. Product Analysis

S15.1 More than one forging per heat shall be subject toproduct analysis by either the manufacturer or purchaser. Thepurchaser shall indicate in the ordering information the numberof forgings to be tested, and whether the manufacturer,purchaser, or both shall perform the additional analyses.

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