ASTM A770 A770M-2003 Standard Specification for Through-Thickness Tension Testing of Steel Plates for Special Applications.pdf

1、Designation: A 770/A770M 03Standard Specification forThrough-Thickness Tension Testing of Steel Plates forSpecial Applications1This standard is issued under the fixed designation A 770/A770M; the number immediately following the designation indicates the yearof original adoption or, in the case of r

2、evision, 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 specifica

3、tion2covers the procedures and accep-tance standards for the determination of reduction of area usinga tension test specimen whose axis is perpendicular to therolled surfaces of steel plates 1 in. 25 mm and greater inthickness. The principal purpose of the testing is to provide ameasure of the resis

4、tance of a steel plate to lamellar tearing.(See Appendix X1.)1.2 The values stated in either inch-pound units or SI unitsare to be regarded as standard. Within the text, the SI units areshown in brackets. The values stated in each system are notexact equivalents; therefore, each system must be used

5、inde-pendently of the other. Combining values from the two systemsmay result in nonconformance with the specification.1.3 This specification is expressed in both inch-pound andSI units. However, unless the order specifies the applicable“M” specification designation (SI units), the material shall bef

6、urnished to inch-pound units.2. Referenced Documents2.1 ASTM Standards:A 370 Test Methods and Definitions for Mechanical Testingof Steel Products33. Ordering Information3.1 The inquiry and order shall include the following, ifrequired:3.1.1 Supplementary requirements that are available to meetend us

7、e requirements (see S1 through S5).3.1.2 Special requirements agreed upon between the manu-facturer and the purchaser.4. Tension Tests4.1 Number of Tests:4.1.1 Two tests shall be required from each plate-as-rolled,except for plates subjected to heat treatment by quenching andtempering. Two tests sha

8、ll be required from each quenched-and-tempered plate. The tests shall be representative of theplate in its final condition.4.1.2 When plates are furnished by the manufacturer in anunheat-treated condition and qualified by heat-treated speci-mens (including normalized, normalized and tempered, andque

9、nched and tempered), two tests shall be required from eachplate-as-rolled.NOTE 1The term “plate-as-rolled refers to the unit plate rolled froma slab or directly from an ingot. It does not refer to the condition of theplate.4.2 Location of Test CouponsTake one test coupon at eachend of each plate as

10、defined in 4.1. Take the test coupons fromthe center of the plate width.4.3 Orientation of Test SpecimensThe longitudinal axis ofthe reduced section of the test specimens shall be perpendicularto the rolled surface of the plate.4.4 Preparation of Test Specimens:4.4.1 Welded ProlongationsWhen require

11、d, join weldedprolongations to the surface(s) of the plate being tested. Thejoining method used shall be one which results in a minimalheat-affected zone in the portion of the plate to be tested.Shielded metal arc, friction, stud, or electron-beam weldingmethods have proven to be suitable.4.4.2 Stan

12、dard Test Specimens:4.4.2.1 Three types of standard round tension test specimensare shown in Fig. 1 and Table 1. For Types 1 and 2 specimens,locate the center of the length of the reduced section at theapproximate mid-point of the plate thickness. For Type 3specimens, locate the weld fusion line of

13、one plate surfacewithin14 in. 6 mm of one end of the reduced section.4.4.2.2 For plates from 1 in. 25 mm to 114 in. 32 mminclusive in thickness, use either the 0.350-in. 8.75-mm Type1 specimen or the 0.500-in. 12.5-mm Type 2 specimen.4.4.2.3 For plates over 114 in. to 2 in. 50 mm inclusive inthickne

14、ss, use the 0.500-in. 12.5-mm Type 2 specimen.4.4.2.4 For plates greater than 2 in. 50 mm in thickness,use the Type 3 specimen.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel, and Related Alloys and is the direct responsibility of SubcommitteeA01.11 on St

15、eel for Boilers and Pressure Vessels.Current edition approved May 10, 2003. Published July 2003. Originallyapproved in 1980. Last previous edition approved in 2001 as A 770 86 (2001).2For ASME Boiler and Pressure Vessel Code applications, see related Specifi-cation SA-770/SA-770M in Section II of th

16、at Code.3Annual Book of ASTM Standards, Vol 01.03.1*A Summary of Changes 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.4.4.3 Alternative Test SpecimensThe alternative testspecimens in Fig.

17、 2 and Table 2 may be used in place of thestandard specimens in Fig. 1 and Table 1.4.4.3.1 For plates over 2 in. 50 mm in thickness, Type A orType B specimens may be used. The Type A specimen providesa reduced section length greater than the plate thickness. TheType B specimen provides a reduced sec

18、tion length of 214 in.57 mm with its center at the mid-thickness of the plate. Overa minimum plate thickness determined by the specimen endconfiguration, no welded prolongations may be needed for theType B specimen. For plates over 414 in. 108 mm inthickness, the Type C specimen may be used. For pla

19、tes over 6in. 150 mm in thickness, a series of two or more Type A orType C specimens with reduced sections of 4 in. 100 mm orless may be used to cover the full thickness of the plate. Thenumber of tests required will depend upon the thickness of theplate being tested and the reduced section length s

20、elected.4.4.3.2 For plates over 1 in. 25 mm in thickness, a seriesof button-head specimens shown in Fig. 2 and Table 2 may beused. The test specimen type to be used, Type D, Type E, orType F, is determined by the nominal plate thickness asdescribed in Table 2. A series of two or more Type F specimen

21、smay be used to cover the full thickness of the plate. The lengthof the reduced section (A), as shown in Fig. 2 and specified inTable 2, is the length of the reduced section excluding themachined radius (R). Within the plate thickness dimensionspecified for each test specimen type, either the button

22、-headthickness, the reduced section length, or the machined radiusmay be varied. In all cases, the minimum length of the reducedsection must be as specified in Table 2 to maintain a minimumlength to diameter ratio (see Appendix X2.2).5. Acceptance Standards5.1 Each tension test shall have a minimum

23、reduction ofarea no less than 20 %. If the reduction of area of both tests isless than 20 %, no retest shall be permitted. If the reduction ofarea of one of the two tests from a plate is less than 20 %, oneretest of two additional specimens taken from a locationadjacent to the specimen that failed m

24、ay be made, and both ofthese additional specimens shall have a reduction of area of20 % or more.5.2 Failures occurring in the prolongations, the weld, or inthe fusion line shall be considered as a “no-test, and anadditional specimen shall be tested.NOTEFor Type 3 only one welded prolongation may be

25、needed,depending upon plate thickness.FIG. 1 Standard Round Tension Test SpecimensTABLE 1 Schedule of Standard Test Specimens, InchesMillimetresASpecimen Type123Plate thickness(t)1# t # 114 1t # 22tDiameter(D) 0.350 8.75 0.500 12.5 0.500 12.5Radius, minimum(R)14 638 1038 10Length of reducedsection(A

26、)134 45 214 60 214 60ASee Test Methods and Definitions A 370 (Fig. 5 for further details and Fig. 6 forvarious types of ends).FIG. 2 Alternative Tension Test SpecimensA 770/A770M 0326. Marking6.1 Plates accepted in accordance with this specificationshall be identified by stamping or stenciling ZT ad

27、jacent to themarking required by the applicable product specification.7. Keywords7.1 lamellar tearing; special steel-making processes; steelplate; through-thickness tension testingSUPPLEMENTARY REQUIREMENTSThese requirements apply only when specified by the purchaser.S1. Tensile Strength Requirement

28、sS1.1 Tensile strength shall conform to a minimum valuewhich is subject to agreement between the manufacturer andpurchaser.S2. Yield Strength RequirementsS2.1 Yield strength, for plates 2 in. 50 mm and over inthickness, shall conform to a minimum value which is subjectto agreement between the manufa

29、cturer and purchaser.S3. Reduction of Area RequirementsS3.1 A minimum reduction of area limit higher than that in5.1 may be specified subject to agreement between the manu-facturer and purchaser.S4. Number of TestsS4.1 A greater number of tests than indicated in 4.1 may bespecified subject to agreem

30、ent between the manufacturer andpurchaser.S5. Location of Test CouponsS5.1 Test coupons from locations in addition to thosespecified in 4.2 may be specified subject to agreement betweenthe manufacturer and purchaser.APPENDIXES(Nonmandatory Information)X1. LAMELLAR TEARING ADJACENT TO WELDSX1.1 Intro

31、ductionX1.1.1 Lamellar tearing is a particular type of cracking thatoccurs under the weld of a steel plate weldment. It is generallycaused by strain induced in the thickness direction resultingfrom shrinkage of the weld deposit and by the restraintimposed by the components that comprise the weldment

32、. Highrestraint increases the possibility of lamellar tearing. However,lamellar tearing is not solely confined to highly restrainedweldments. Lamellar tearing may also result from loads on theplate surface.X1.2 Characteristics of Lamellar TearingX1.2.1 Lamellar tearing normally occurs in susceptible

33、material underneath the weld, in a direction generally parallelto the plate surface and often slightly outside the heat-affectedzone. Lamellar tearing generally has a step-like appearanceconsisting of “terraces (cracks running parallel to the platesurface) and “walls (cracks which connect the indivi

34、dualterraces). The tearing may remain completely subsurface orappear at plate edges or at weld toes.TABLE 2 Schedule of Alternative Test Specimens, Inches MillimetresSpecimen TypeAABACBDEFPlate thickness(t)2t50 t2t50 t414 t108 t1 # t # 13425 # t # 45134 t # 21245 # t # 64212 t64 tDiameter(D) 0.500 1

35、2.5 0.500 12.5 0.500 12.5 0.250 6.25C60.005 0.100.350 8.75C60.007 0.180.500 12.5C6 l0.0100.25Radius, min(R)38 1038 10116 10 optional optional optionalLength of reduced sectionmin(A)t +14 mint +6214 60 t 112t 380.625 16 0.875 22 1.250 32ASee Test Methods and Definitions A 370 (Fig. 5 for further deta

36、ils and Fig. 6 for various types of ends).BSee Test Methods and Definitions A 370 (Fig. 6, specimen 3 for further details).CThe reduced section may have a gradual taper from the ends toward the center, with the ends not more than 1 % larger in diameter than the center (controllingdimension).A 770/A7

37、70M 033X1.3 InclusionsX1.3.1 The step-like cracking characteristic of lamellartearing is usually considered to result from small elongatednonmetallic inclusions that are normally present in the steel.Strains in the through-thickness direction can cause individualinclusions to fractures or decohere f

38、rom the surrounding steelmatrix, thus initiating a void. Further strain can cause theremaining metallic ligaments to shear or rupture, resulting inthe step-like fracture appearance.X1.3.2 A high or concentrated inclusion content in the steelproduces planar regions of poor ductility parallel to the s

39、teelsurface. On the other hand, a reduction in the magnitude andconcentration of these inclusions to a low level tends topreclude any easy fracture path along the low ductility inclu-sions and the steel exhibits improved ductility in a through-thickness direction.X1.3.3 The extent of nonmetallic inc

40、lusions depends on thetype of steel. In silicon semikilled or fully killed steels, theseinclusions are primarily oxides (present as silicates) andsulfides (present as manganese sulfides). For aluminum-siliconkilled steels, these inclusions are primarily sulfides (manganesesulfides). To improve the t

41、hrough-thickness ductility and thusthe resistance of the steel to lamellar tearing, it is necessary toreduce the level of the nonmetallic inclusions. To provide ahigh resistance to lamellar tearing may require the use ofspecial steel-making processes that can reduce the oxygen andsulfur contents in

42、the steel to very low levels.X1.4 Steel Manufacturing ProcessesX1.4.1 Special steel-making processes are available forimproving the through-thickness ductility. The more commonprocesses, used singly or in combination, are: (1) low sulfurpractices; (2) inclusion shape control; (3) electroslag orvacuu

43、m arc remelting; and (4) vacuum degassing. The steel-making processes are not all intended for the same purpose, butwill improve the through-thickness ductility to various degreesdepending on the process used.X1.5 Through-Thickness Ductility RequirementsX1.5.1 Susceptibility to lamellar tearing depe

44、nds on manyfactors (for example, restraint, welding conditions, etc.) and,consequently a specific through-thickness ductility require-ment does not provide a guarantee against lamellar tearing. Themost widely accepted method of measuring the materialductility factor of susceptibility to lamellar tea

45、ring is thereduction of area of a round tension test specimen orientedperpendicular to the rolled surface of a plate.X2. TESTING PARAMETERS AFFECTING REDUCTION OF AREA VALUESX2.1 Variability of Through-Thickness PropertiesX2.1.1 Through-thickness tension test results, and in par-ticular the reductio

46、n of area determination as provided for inthis specification, are subject to substantially greater scatterthan would normally be expected from standard tension tests ofa plate in the longitudinal or transverse direction. This scatterof test results is due in part to the inherent variability of thedi

47、stribution of the nonmetallic inclusions discussed in X1.3.For example, those nonmetallic inclusions that form during thesolidification phase of the steelmaking process tend to occurwith a higher frequency in the area of final solidification.X2.1.2 Test specimen design may also have an effect on the

48、test results. Some of these factors are discussed in X2.2.Operator technique will also be a factor in increasing scatter,particularly in the measurement of the final diameter of the testspecimen. Because of the effect of inclusions on the fractureprocess, the appearance of the final fracture may be

49、quitedifferent than the classical cup-cone fractures common tolongitudinal and transverse tension testing. For those materialswith approximately 20 % reduction of area, the final diametermeasurement may require a substantial amount of judgment onthe part of the test operator.X2.1.3 In view of the potential variability of the through-thickness reduction of area test results, it is recognized that twotests per plate are not sufficient to fully ch