1、Designation: A 770/A 770M 03 (Reapproved 2007)Standard Specification forThrough-Thickness Tension Testing of Steel Plates forSpecial Applications1This standard is issued under the fixed designation A 770/A 770M; the number immediately following the designation indicates the yearof original adoption
2、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. Scop
3、e1.1 This specification2covers 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 am
4、easure of the resistance 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 s
5、ystem must be used 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
6、 material shall befurnished to inch-pound units.2. Referenced Documents2.1 ASTM Standards:3A 370 Test Methods and Definitions for Mechanical Testingof Steel Products3. Ordering Information3.1 The inquiry and order shall include the following, ifrequired:3.1.1 Supplementary requirements that are avai
7、lable to meetend use 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 andtempe
8、ring. Two tests shall 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 a
9、nd tempered, andquenched 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 eachen
10、d of each plate as 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 Prolon
11、gationsWhen required, 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
12、suitable.4.4.2 Standard 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 31This specification is
13、under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.11 on Steel Plates for Boilers and Pressure Vessels.Current edition approved Nov. 1, 2007. Published March 2008. Originallyapproved in 1980. Last previous edit
14、ion approved in 2003 as A 770/A 770M 03.2For ASME Boiler and Pressure Vessel Code applications, see related Specifi-cation SA-770/SA-770M 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 Bo
15、ok of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.specimens, locate the weld fusion line of one plate surfacewithin14 in. 6 mm of o
16、ne 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 inthickness, use the 0.500-in. 12.5-mm Type 2 sp
17、ecimen.4.4.2.4 For plates greater than 2 in. 50 mm in thickness,use the Type 3 specimen.4.4.3 Alternative Test SpecimensThe alternative testspecimens in Fig. 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, TypeAorTyp
18、e B specimens may be used. The TypeAspecimen providesa reduced section length greater than the plate thickness. TheType B specimen provides a reduced section length of 214 in.57 mm with its center at the mid-thickness of the plate. Overa minimum plate thickness determined by the specimen endconfigur
19、ation, 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 plates 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 co
20、ver the full thickness of the plate. Thenumber of tests required will depend upon the thickness of theplate being tested and the reduced section length selected.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 specime
21、n type to be used, Type D, Type E, orType F, is determined by the nominal plate thickness asdescribed in Table 2.Aseries of two or more Type F specimensmay 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 lengt
22、h of the reduced section excluding themachined radius (R). Within the plate thickness dimensionspecified for each test specimen type, either the button-headthickness, the reduced section length, or the machined radiusmay be varied. In all cases, the minimum length of the reducedsection must be as sp
23、ecified 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 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 ofNOTEFor
24、 Type 3 only one welded prolongation may be 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, mini
25、mum (R)14 638 1038 10Length of reduced section (A)134 45 214 60 214 60ASee Test Methods and DefinitionsA 370 (Fig. 5 for further details and Fig. 6 forvarious types of ends).FIG. 2 Alternative Tension Test SpecimensA 770/A 770M 03 (2007)2area of one of the two tests from a plate is less than 20 %, o
26、neretest of two additional specimens taken from a locationadjacent to the specimen that failed may 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-tes
27、t,” and anadditional specimen shall be tested.6. Marking6.1 Plates accepted in accordance with this specificationshall be identified by stamping or stenciling ZT adjacent to themarking required by the applicable product specification.7. Keywords7.1 lamellar tearing; special steel-making processes; s
28、teelplate; through-thickness tension testingSUPPLEMENTARY REQUIREMENTSThese requirements apply only when specified by the purchaser.S1. Tensile Strength RequirementsS1.1 Tensile strength shall conform to a minimum valuewhich is subject to agreement between the manufacturer andpurchaser.S2. Yield Str
29、ength 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 manufacturer and purchaser.S3. Reduction of Area RequirementsS3.1 A minimum reduction of area limit higher than that in5.1 may be specified su
30、bject 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 agreement between the manufacturer andpurchaser.S5. Location of Test CouponsS5.1 Test coupons from locations in addition to thosespecified in
31、4.2 may be specified subject to agreement betweenthe manufacturer and purchaser.TABLE 2 Schedule of Alternative Test Specimens, Inches MillimetresSpecimen TypeAABACBDEFPlate thickness (t)2t 50 t2t 50 t414 t 108 t1# t # 134 25 # t# 45134 t # 212 45 # t# 64212 t 64 tDiameter (D) 0.500 12.5 0.500 12.5
32、0.500 12.5 0.250 6.25C6 0.0050.100.350 8.75C6 0.0070.180.500 12.5C6 10.0100.25Radius, min (R)38 1038 10116 2 optional optional optionalLength of reducedsection, min(A)t +14 min t +6 214 60 t 112 t 38 0.625 16 0.875 22 1.250 32ASee Test Methods and Definitions A 370 (Fig. 5 for further details and Fi
33、g. 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/A 770M 03 (2
34、007)3APPENDIXES(Nonmandatory Information)X1. LAMELLAR TEARING ADJACENT TO WELDSX1.1 IntroductionX1.1.1 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
35、the weld deposit and by the restraintimposed by the components that comprise the weldment. 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
36、Characteristics of Lamellar TearingX1.2.1 Lamellar tearing normally occurs in susceptiblematerial 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”
37、 (cracks running parallel to the platesurface) and “walls” (cracks which connect the individualterraces). The tearing may remain completely subsurface orappear at plate edges or at weld toes.X1.3 InclusionsX1.3.1 The step-like cracking characteristic of lamellartearing is usually considered to resul
38、t from small elongatednonmetallic inclusions that are normally present in the steel.Strains in the through-thickness direction can cause individualinclusions to fractures or decohere from the surrounding steelmatrix, thus initiating a void. Further strain can cause theremaining metallic ligaments to
39、 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 steelsurface. On the other hand, a reduction in the magnitude andconcentration of these inclusions to a low level ten
40、ds 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 inclusions depends on thetype of steel. In silicon semikilled or fully killed steels, theseinclusions are primarily oxi
41、des (present as silicates) andsulfides (present as manganese sulfides). For aluminum-siliconkilled steels, these inclusions are primarily sulfides (manganesesulfides). To improve the through-thickness ductility and thusthe resistance of the steel to lamellar tearing, it is necessary toreduce the lev
42、el 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 the steel to very low levels.X1.4 Steel Manufacturing ProcessesX1.4.1 Special steel-making processes are available f
43、orimproving the through-thickness ductility. The more commonprocesses, used singly or in combination, are: (1) low sulfurpractices; (2) inclusion shape control; (3) electroslag orvacuum arc remelting; and (4) vacuum degassing. The steel-making processes are not all intended for the same purpose, but
44、will improve the through-thickness ductility to various degreesdepending on the process used.X1.5 Through-Thickness Ductility RequirementsX1.5.1 Susceptibility to lamellar tearing depends on manyfactors (for example, restraint, welding conditions, etc.) and,consequently a specific through-thickness
45、ductility require-ment does not provide a guarantee against lamellar tearing. Themost widely accepted method of measuring the materialductility factor of susceptibility to lamellar tearing is thereduction of area of a round tension test specimen orientedperpendicular to the rolled surface of a plate
46、.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 reduction of area determination as provided for inthis specification, are subject to substantially greater scatterthan would
47、 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 thedistribution of the nonmetallic inclusions discussed in X1.3.For example, those nonmetallic inclusions that form durin
48、g 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 thetest results. Some of these factors are discussed in X2.2.Operator technique will also be a factor in increasing sca
49、tter,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 quitedifferent than the classical cup-cone fractures common toA 770/A 770M 03 (2007)4longitudinal and transverse tension testing. For those materialswith approximately 20 % reduction of area, the final diametermeasurement may require a substantial amount of judgment
