1、Designation: A1079 12Standard Specification forSteel Sheet, Complex Phase (CP), Dual Phase (DP) andTransformation Induced Plasticity (TRIP), Zinc-Coated(Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) bythe Hot-Dip Process1This standard is issued under the fixed designation A1079; the number im
2、mediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 Th
3、is specification covers steel sheet, complex phase(CP) grade, dual phase (DP) grade, and transformation inducedplasticity (TRIP) grade, zinc-coated (galvanized) or zinc-ironalloy-coated (galvannealed) by the hot-dip process in coils andcut lengths.1.2 The product is produced in various zinc or zinc-
4、ironalloy-coating masses or coating designations as shown in Table1.1.3 Product furnished under this specification shall conformto the applicable requirements of the latest issue of Specifica-tion A924/A924M, unless otherwise provided herein.1.4 The product is available in a number of designations a
5、ndgrades with mandatory chemical requirements and mandatorymechanical properties that are achieved through thermal orthermal-mechanical treatments, and are designed to be com-patible with automotive application requirements.1.5 The grade designation nomenclature of the productdiffers from other hot-
6、dip sheet products having mandatorymechanical properties in that ordering is to tensile, rather thanyield strength values.1.6 The values stated in SI units are to be regarded as thestandard.1.7 The text of this specification references notes andfootnotes that provide explanatory material. These note
7、s andfootnotes, excluding those in tables and figures, shall not beconsidered as requirements of this specification.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate
8、 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A90/A90M Test Method for Weight Mass of Coating onIron and Steel Articles with Zinc or Zinc-Alloy CoatingsA370 Test Methods and Definitions for Mechanical T
9、estingof Steel ProductsA902 Terminology Relating to Metallic Coated Steel Prod-uctsA924/A924M Specification for General Requirements forSteel Sheet, Metallic-Coated by the Hot-Dip ProcessD7396 Guide for Preparation of New, Continuous Zinc-Coated (Galvanized) Steel Surfaces for PaintingE646 Test Meth
10、od for Tensile Strain-Hardening Exponents(n -Values) of Metallic Sheet Materials3. Terminology3.1 DefinitionsSee Terminology A902 for definitions ofgeneral terminology relating to metallic-coated hot-dip prod-ucts.3.2 Definitions of Terms Specific to This Standard:3.2.1 complex phase (CP) steel, nst
11、eel sheet with aferritic/bainitic matrix containing small amounts of retainedaustenite, austenite, and/or pearlite where significant grainrefinement is caused by retarded crystallization or precipitationof microalloying elements.3.2.2 dual phase (DP) steel, nsteel sheet with a ferriticmatrix contain
12、ing a martensitic phase present in the form ofislands.3.2.3 transformation induced plasticity (TRIP) steel,nsteel sheet with a mainly ferritic matrix containing retainedaustenite where, during the forming process, retained austenitecan transform to martensite.3.2.4 zinc-iron alloy, na dull grey coat
13、ing with no spanglepattern that is produced on hot-dip zinc-coated steel sheet.1This test method is under the jurisdiction of ASTM Committee A05 onMetallic-Coated Iron and Steel Products and is the direct responsibility ofSubcommittee A05.11 on Sheet Specifications.Current edition approved Sept. 1,
14、2012. Published September 2012. DOI:10.1520/A1079-122For 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.Copyright
15、 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.4.1 DiscussionZinc-iron alloy coating is composedentirely of inter-metallic alloys. It is typically produced bysubjecting the hot-dip zinc-coated steel sheet to a thermaltreatment after it em
16、erges from the molten zinc bath. This typeof coating is suitable for immediate painting without furthertreatment except normal cleaning (refer to Guide D7396). Thelack of ductility of the alloy coating presents a potential forpowdering.4. Classification4.1 The material is available in several design
17、ations andgrades as follows:4.1.1 Complex phase (CP) steel (Grades 600T/350Y, 780T/500Y, and 980T/700Y),4.1.2 Dual phase (DP) steel (Grades 440T/250Y, 490T/290Y, 590T/340Y, 780T/420Y, and 980T/550Y), and4.1.3 Transformation induced plasticity (TRIP) steel(Grades 690T/410Y and 780T/440Y).4.2 The mate
18、rial is available as either zinc-coated or zinc-iron alloy-coated in several coating masses or coating desig-nations as shown in Table 1.4.2.1 The material is available with the same or differentcoating designations on each surface.5. Ordering Information5.1 Zinc-coated or zinc-iron alloy-coated she
19、et in coils andcut lengths is produced to thickness requirements expressed to0.01 mm. The thickness of the sheet includes both the basemetal and the coating.5.2 Orders for product to this specification shall include thefollowing information, as necessary, to adequately describe thedesired product:5.
20、2.1 Name of product steel sheet, zinc-coated (galvanized)or zinc-iron alloy-coated (galvannealed),5.2.2 Designation of sheet CP (Grades 600T/350Y, 780T/500Y, or 980T/700Y), DP (Grades 440T/250Y, 490T/290Y,590T/340Y, 780T/420Y, or 980T/550Y), or TRIP (Grades690T/410Y or 780T/440Y).5.2.3 ASTM designat
21、ion number and year of issue, asA1079.5.2.4 Coating designation (see 8.1.3),5.2.5 Minimized spangle (if required),5.2.6 Chemically treated or not chemically treated,5.2.7 Oiled or not oiled,5.2.8 Extra smooth (if required),5.2.9 Phosphatized (if required),5.2.10 Dimensions (show thickness, minimum o
22、r nominal,width, flatness requirements, and length, (if cut lengths).5.2.11 Coil size requirements (specify maximum outsidediameter (OD), acceptable inside diameter (ID), and maximummass),5.2.12 Packaging,5.2.13 Certification, if required, heat analysis and mechani-cal property report,5.2.14 Applica
23、tion (part identification and description), and5.2.15 Special requirements (if any).NOTE 1Typical ordering descriptions are as follows: steel sheet,zinc-iron alloy-coated, DP Grade 590T/340Y, ASTM A1079, CoatingDesignation 45A45A, not chemically treated, oiled, minimum 1.00 by1200 mm by coil, 1520 m
24、m maximum OD, 600 mm ID, 10 000 kgmaximum, for B side pillar.NOTE 2The purchaser should be aware that there are variations inmanufacturing practices among the producers and therefore is advised toestablish the producers standard (or default) procedures for thicknesstolerances.6. Chemical Composition
25、6.1 Base Metal:6.1.1 The heat analysis of the base metal shall conform tothe requirements shown in Table 2.6.1.2 Each of the elements listed in Table 2 shall be includedin the report of heat analysis, including each element incolumns with grouped elements. When the amount of copper,nickel, chromium,
26、 or molybdenum is less than 0.02 %, reportthe analysis as either 0.02 % or the actual determined value.When the amount of vanadium, titanium, or columbium is lessthan 0.008 %, report the analysis as either 0.008 % or theactual determined value.6.1.3 See Specification A924/A924M for chemical analysis
27、procedures and product analysis tolerances.6.2 Zinc Bath AnalysisThe bath metal used in continuoushot-dip galvanizing shall contain not less than 99 % zinc.TABLE 1 Mass of Coating RequirementsANOTE 1Use the information provided in 8.1.2 to obtain the approximate coating thickness per side from the c
28、oating mass.Single Spot/Single Side Coating MassCoating Designation Minimum, g/m2Maximum, g/m2Zinc 20G 20 7030G 30 8040G 40 9045G 45 9550G 50 10055G 55 10560G 60 11070G 70 12090G 90 160100G 100 200Zinc-Iron Alloy 30A 30 8040A 40 7045A 45 7550A 50 80AThe coating designation is the term by which the m
29、inimum single spot/single side coating mass is specified for each side.A1079 122NOTE 3To control alloy formation and promote adhesion of the zinccoating with the steel base metal, the molten coating metal compositionnormally contains a percentage of aluminum usually in the range from0.05 to 0.25. Th
30、is aluminum is purposely supplied to the molten coatingbath, either as a specified ingredient in the zinc spelter or by the additionof a master alloy containing aluminum.7. Mechanical Properties7.1 All designations and grades shall conform to the me-chanical property requirements in Table 3.7.1.1 Al
31、l designations and grades shall conform to bakehardening index requirements included in Table 3. The mini-mum increase in yield strength is based on the lower yieldstress, after a prestrained specimen has been exposed to astandard bake cycle of 170C for 20 minutes. The method formeasuring the bake h
32、ardening index is described in the AnnexA1.7.2 Mechanical property tests shall be conducted in accor-dance with the methods specified in Specification A924/A924M, or those prescribed by the purchaser.7.3 Bending Properties Minimum Cold Bending RadiiHigh-strength sheet steels are commonly fabricated
33、by coldbending. There are many interrelated factors that affect theability of a steel to cold form over a given radius under shopconditions. These factors include thickness, strength level,degree of restraint, relationship to rolling direction, chemistry,and base metal microstructure. The table in A
34、ppendix X1 liststhe suggested minimum inside radius for 90 cold bending forthe grades steel of steel in this specification. They presuppose“hard way” bending (bend axis parallel to rolling direction) andreasonably good shop forming practices. Where possible, theuse of larger radii or “easy way” bend
35、s is recommended forimproved performance.8. Coating Properties8.1 Coating Mass:8.1.1 Coating mass shall conform to the requirements asshown in Table 1 for the specific coating designation.8.1.2 Use the following relationships to estimate the coatingthickness from the coating mass:8.1.2.1 7.14 g/m2co
36、ating mass = 1.00 m coating thickness.8.1.3 The ordering format for specifying the coating foreach surface shall be, for instance, 45A45A. In the case ofdifferentially coated product, the thicker (heavier) coating massside shall be specified first, for instance 50A30A.8.2 Coating Mass Tests:TABLE 2
37、Chemical RequirementsASteel Sheet Designations CP, DP, and TRIPComposition, %Heat Analysis Element, max (unless otherwise shown)Designation/GradeC Mn+Al+SiCPSCuBNi Cr+MoCV+Cb+TiCNCP600T/350Y 0.18 5.30 0.080 0.015 0.20 0.50 1.00 0.35 .780T/500Y 0.18 5.50 0.080 0.015 0.20 0.50 1.00 0.35 .980T/700Y 0.2
38、5 5.20 0.080 0.015 0.20 0.50 1.00 0.35 .DP450T/250Y 0.15 3.00 0.080 0.015 0.20 0.50 1.00 0.35 .490T/290Y 0.15 3.40 0.080 0.015 0.20 0.50 1.00 0.35 .590T/340Y 0.17 4.75 0.080 0.015 0.20 0.50 1.40 0.35 .780T/420Y 0.18 5.40 0.080 0.015 0.20 0.50 1.40 0.35 .980T/550Y 0.23 6.00 0.080 0.015 0.20 0.50 1.40
39、 0.35 .TRIP690T/410Y 0.32 6.20 0.12 0.015 0.20 0.50 0.60 0.40 .780T/440Y 0.32 6.70 0.12 0.015 0.20 0.50 0.60 0.40 .AWhere an ellipsis (.) appears in the table, there is no requirement but, the analysis shall be reported.BWhen copper is specified, the copper limit is a minimum requirement. When coppe
40、r steel is not specified, the copper limit is a maximum requirement.CThe producer shall report the individual composition of each element in the grouping.TABLE 3 Mechanical Property Requirements, Base Metal (Longitudinal) Steel Sheet Designations CP, DP, and TRIPADesignation Grade Yield Strength, mi
41、n,MPaTensile Strength,min, MPaElongation in 50mm, min, %n ValueBBake HardeningIndex, min, MPaLower YieldCP 600T/350Y 350 600 16 30780T/500Y 500 780 10 30980T/700Y 700 980 7 30DP 450T/250Y 250 450 27 $0.16 30490T/290Y 290 490 25 $0.15 30590T/340Y 340 590 21 $0.14 30780T/420Y 420 780 14 $0.11 30980T/5
42、50Y 550 980 8 30TRIP 690T/410Y 410 690 21 $0.19 30780T/440Y 440 780 19 $0.16 30AWhere an ellipsis (. . .) appears in this table, there is no requirement.Bn ValueStrain-hardening exponent as determined by Test Method E646, 10-20 % strain.A1079 1238.2.1 Coating mass tests shall be performed in accorda
43、ncewith the requirements of Specification A924/A924M.8.2.2 The referee method to be used shall be Test MethodA90/A90M.8.3 Coating Bend Test:8.3.1 The designations and grades in this specification arenot subject to coating bend tests.9. Retests and Disposition of Non-Conforming Material9.1 Retests, c
44、onducted in accordance with the requirementsof the section on Retests and Disposition of Non-ConformingMaterial of Specification A924/A924M, are permitted when anunsatisfactory test result is suspected to be the consequence ofthe test method procedure.9.2 Disposition of non-conforming material shall
45、 be subjectto the requirements of Specification A924/A924M.10. Dimensions and Permissible Variations10.1 All dimensions and permissible variations shall com-ply with the requirements of Specification A924/A924M.11. Keywords11.1 alloyed coating; complex phase steel; dual phase steel;minimized spangle
46、 coating; sheet steel; spangle; steel; steelsheet; transformation induced plasticity steel; zinc; zinc iron-alloy; zinc coated (galvanized); zinc iron-alloy coated (gal-vannealed)ANNEX(Mandatory Information)A1. BAKE HARDENABLE INDEXA1.1 Determination of Bake Hardening IndexA1.1.1 The bake hardening
47、index (BHI) is determined by atwo-step procedure using a standard longitudinal (rollingdirection) tensile-test specimen, prepared in accordance withTest Methods A370. The test specimen is first strained intension. The magnitude of this tensile “pre-strain” shall be 2 %(extension under load). The tes
48、t specimen is then removedfrom the test machine and baked at a temperature of 340F170C for a period of 20 minutes. Referring to Fig. A1.1, thebake hardening index (BHI) of the material is calculated asfollows:BHI 5 B 2 A (A1.1)where:A = flow stress at 2 % extension under load.B = yield strength uppe
49、r yield strength (BU) or lower yieldstress (BL) after baking at 340F 170C for 20minutes.A1.1.2 The original test specimen cross section (width andthickness) is used in the calculation of all engineering strengthsin this test.A1.1.3 The pre-straining of2%intension is intended tosimulate a modest degree of forming strain, while the subse-quent baking is intended to simulate a paint-curing or similartreatment. In the production of actual parts, forming strains andbaking treatments can differ from those employed here and, asa result; final prop
