1、Designation: A 767/A 767M 05Standard Specification forZinc-Coated (Galvanized) Steel Bars for ConcreteReinforcement1This standard is issued under the fixed designationA767/A 767M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the
2、 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 specification covers
3、steel reinforcing bars withprotective zinc coatings applied by dipping the properlyprepared reinforcing bars into a molten bath of zinc.1.2 This specification is applicable for orders in eitherinch-pound units (as Specification A 767) or SI units (asSpecification A 767M).1.3 The values stated in eit
4、her SI or inch-pound units are tobe regarded as standard. Within the text, the inch-pound unitsare shown in brackets. The values stated in each system are notexact equivalents. Therefore, each system must be used inde-pendently of the other. Combining values from the two systemsmay result in nonconf
5、ormance with this specification.2. Referenced Documents2.1 ASTM Standards:2A 90/A 90M Test Method for Weight Mass of CoatingIron With Zinc or Zinc-Alloy CoatingA 615/A 615M Specification for Deformed and PlainCarbon-Steel Bars for Concrete ReinforcementA 706/A 706M Specification for Low-Alloy Steel
6、De-formed and Plain Bars for Concrete ReinforcementA 780/A 780M Practice for Repair of Damaged and Un-coated Areas of Hot-Dip Galvanized CoatingsA 996/A 996M Specification for Rail-Steel and Axle-SteelDeformed Bars for Concrete ReinforcementB6 Specification for ZincE 376 Practice for Measuring Coati
7、ng Thickness byMagnetic-Field or Eddy-Current (Electromagnetic) Exami-nation Methods2.2 American Concrete Institute Specification:3ACI 301 Specifications for Structural Concrete3. Ordering Information3.1 It shall be the responsibility of the purchaser to specifyall requirements that are necessary fo
8、r material ordered to thisspecification. Such requirements shall include, but are notlimited to the following:3.1.1 Quantity of bars,3.1.2 Size of bars,3.1.3 Reinforcing bar specification (ASTM designation andyear of issue) and grade,3.1.4 Class of coating,3.1.5 Galvanization before or after fabrica
9、tion, andNOTE 1A typical ordering description is as follows: Deformed Grade420 bars to ASTM A 615M-_; 1600 m, No. 19, 8 m long in securedlifts; zinc-coated (galvanized) to ASTM A 767M-_; including Class 1coating, and galvanization after fabrication.Deformed Grade 60 bars to ASTM A 615-_; 4000 linear
10、 ft, No. 6,20 ft, 0 in. long in secured lifts; zinc-coated (galvanized) to ASTMA 767-_, including Class 1 coating, and galvanization after fabrica-tion.4. Galvanizing4.1 Handling:4.1.1 The galvanizer shall be permitted to subject the newlycoated steel reinforcing bars to air or steam wiping to remov
11、eexcess zinc from the bars. After the wiping, the coated steelreinforcing bars shall meet the minimum coating massweight.NOTE 2During the wiping process care should be taken to maintain auniformly thick coating around the perimeter of the bar.4.1.2 It shall be the responsibility of the galvanizer to
12、maintain identity of the reinforcing bars throughout the galva-nizing process and to the point of shipment.4.2 Mass Weight of Coating and Test:1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel, and Related Alloys and is the direct responsibility of Subcommi
13、tteeA01.05 on Steel Reinforcement.Current edition approved March 1, 2005. Published March 2005. Originallyapproved in 1979. Last previous edition approved in 2000 as A 767/A 767M 00b.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
14、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Concrete Institute, 38800 Country Club Dr., Farm-ington Hills, MI 48331.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM
15、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2.1 This specification includes two classes of coatingmass weight. The mass weight of zinc coating based onactual area of the bar, shall conform to the requirements shownin Table 1.NOTE 3The nominal
16、 diameter of a deformed bar is equivalent to thatof a plain round bar having the same mass per metre weight per foot asthe deformed bar. Coating mass weight shown in Table 1 is based on anassumed area ratio of 1.2:1 (actual to nominal surface area of the steelreinforcing bar).4.2.2 Magnetic Thicknes
17、s MeasurementsThe massweight of the coating shall be determined by magneticthickness gage measuremens in accordance with PracticeE 376. The thickness measurement is used to calculate themass weight by multiplying it by the surface area of coatedbar and by the zinc density. One or more of the followi
18、ngmethods shall be permitted to be used to referee the resultsobtained by magnetic thickness measurments.4.2.2.1 Stripping MethodThe mass weight shall be de-termined by stripping the coating from the steel reinforcing barsection in accordance with Test Method A 90/A 90M.NOTE 4This is a destructive t
19、est appropriate for small samples of aminimum of 2000 mm23 in.2 of surface area. It does note include themass weight of iron reacted with the zinc coating and may overestimatecoating mass weight by up to 10%.4.2.2.2 Weighing Before and After GalvanizingThe massweight shall be determined by weighing
20、steel reinforcing barsbefore and after galvanizing. The difference between the twomeasurements divided by the surfce area of the bars providesthe mass weight. The original weighing shall occur afterpickling and drying. The second weighing shall occur aftercooling to ambient temperature.4.2.2.3 Micro
21、scopyThe mass weight shall be deter-mined by cross-sectional and optical measurement in accor-dance with Test Method B 487. A cross-section sample of thesteel shall be polished and examined with an optical micro-scope to determine the coating thickness. The coating massweight shall be determined by
22、multiplying coating thicknessby the surface area of the coated sample and by the density ofzinc.4.2.3 Number of TestsFor determination of the coatingmass weight, three random samples shall be tested from eachlot. For each magnetic thickness measurement sample, five ormore measurements shall be made
23、at various points throughoutthe sample so as to represent the entire surface of the sample.A total of at least fifteen measurements shall be averaged toobtain the coating thickness. For the microscopy method, fivesamples shall be tested per lot. Each sample shall be measuredon four sides and the tot
24、al of twenty measurements shall beaveraged to obtain the coating thickness. For the strippingmethod and the weighing method, three samples per lot shallbe measured.NOTE 5A lot shall be as follows: All bars of one size furnished to thesame steel reinforcing bar specification that have been galvanized
25、 withina single production shift.4.2.4 RetestsIf the average zinc coating mass weightfails to meet the requirements of Table 1, six additional randomsamples from the lot shall be permitted to be tested. If theaverage zinc coating mass weight of the six samples con-forms to the requirements of Table
26、1, the lot shall be accepted.4.3 ChromatingThe galvanized coating shall be chromatetreated. This is to preclude a reaction between the bars andfresh portland cement paste. Proprietary chromating solutionsof equivalent strength are permitted in place of the genericchemical treatment specified.4.3.1 I
27、f the chromate treatment is performed immediatelyafter galvanizing, it may be accomplished by quenching thesteel reinforcing bars in a solution containing at least 0.2 masswt % of sodium dichromate in water (such as 2kg/m33 oz ofeach 10 gal of quench water) or by quench chromating in aminimum of 0.2
28、 % chromic acid solution. The solution shall beat least 32C 90F. The galvanized reinforcing bars shall beimmersed in the solution for at least 20 s.4.3.2 If the galvanized reinforcing bars are at ambienttemperature, the chromate treatment shall be the same asspecified in 4.3.1 except that 0.5 to 1.0
29、 % concentration ofsulfuric acid shall be added as an activator of the chromatesolution. In this case, there is no temperature requirement forthe activated chromate solution.5. General Requirements5.1 The steel reinforcing bars shall conform to one of thefollowing specifications: A 615M, A 706M, or
30、A 996M A 615,A 706, or A 996.5.2 The zinc used for coating shall be any grade thatconforms to Specification B6.6. Finish and Adherence of Coating6.1 The zinc coating shall have no bare spots. The coatingshall be free of blisters, flux spots or inclusions, dross, and acidor black spots. Bars that sti
31、ck together after galvanizing shallbe rejected. In addition, the presence of tears or sharp spikeswhich make the bar hazardous to handle shall be cause forrejection. A matte gray finish appearance shall not be itself acause for rejection.NOTE 6Specific concentrations of elements such as silicon, car
32、bon,and phosphorus in steel tend to accelerate the growth of the zinc-iron alloylayer so that the galvanized coating may have a matte finish with little orno free zinc outer layer. The mass, shape, and amount of cold working ofthe bar being galvanized may also affect this condition.6.2 The coating s
33、hall be adherent so it cannot be removedby any reasonable process of handling or erection.7. Fabrication7.1 Before Galvanizing:TABLE 1 Mass Weight of Zinc CoatingCoating ClassMass Weight of ZincCoating,min, g/m2oz/ft2 of SurfaceClass IBar Designation Size No. 10 3 915 3.00Bar Designation Size No. 13
34、 4 and Larger 1070 3.50Class IIBar Designation Size No. 10 3 and Larger 610 2.00A 767/A 767M 0527.1.1 Steel reinforcing bars that are bent cold prior togalvanizing shall be fabricated to a bend diameter equal to orgreater than those specified in Table 2.7.1.2 Steel reinforcing bars shall be permitte
35、d to be coldbent to tighter diameters than specified in Table 2 (limited tothe extent that the appropriate reinforcing bar specificationallows) if stress relieved at a temperature from 480 to 560C900 to 1050F for 1 h per 25 mm 1 in. of bar diameter.7.2 After Galvanizing:7.2.1 When galvanizing is per
36、formed before bending, somecracking and flaking of the galvanized coating in the area of thebend shall not be cause for rejection (Note 7).7.2.2 Damage to the coating as a result of fabrication shallbe repaired in accordance with Section 9.NOTE 7The tendency for cracking of the zinc coating increase
37、s withbar diameter and with severity and rate of bending.8. Inspection8.1 The inspector representing the purchaser shall haveaccess at all times, while work on the contract of the purchaseris being performed, to those areas of the galvanizers plantwhich concern the manufacture of the material ordere
38、d. Thegalvanizer shall afford the inspector all reasonable facilities tosatisfy him that the coating is being furnished in accordancewith this specification.8.2 The material shall be inspected at the galvanizers plantprior to shipment. However, if specified, the purchaser shallmake the tests which g
39、overn the acceptance or rejection of thematerials in his own laboratory or elsewhere.8.3 Visual inspection of materials ready for shipment shallbe made to determine conformity with the requirements of 6.1.For materials that fail inspection, it shall be permissible for thematerials to be stripped and
40、 regalvanized, and resubmitted forinspection. They shall conform to the requirements of thisspecification.9. Repair of Damaged Coating9.1 All coating damage due to fabrication or handling (tothepoint of shipment) shall be repaired with a zinc-rich formula-tion in accordance with Practice A 780/A780M
41、.9.2 Sheared ends shall be coated with a zinc-rich formula-tion.10. Certification10.1 Upon request of the purchaser in the contract or order,the galvanizers certification that the material was manufac-tured and tested in accordance with this specification, togetherwith the report of the tests result
42、s, shall be furnished at the timeof shipment.10.2 When Specification A 615/A615M steel is supplied, asilicon analysis shall be provided.10.3 A material test report, certificate of inspection, orsimilar document printed from or used in electronic form froman electronic data interchange (EDI) transmis
43、sion shall beregarded as having the same validity as a counterpart printed inthe certifiers facility. The content of the EDI transmitteddocument must meet the requirements of the invoked ASTMstandard(s) and conform to any existing EDI agreement be-tween the purchaser and the supplier. Notwithstandin
44、g theabsence of a signature, the organization submitting the EDItransmission is responsible for the content of the report.NOTE 8The industry definition as invoked here is: EDI is thecomputer-to-computer exchange of business information in a standardformat such as ANSI ASC X12.11. Keywords11.1 corros
45、ion resistance; galvanizing; steel reinforcingbars; zinc-coatedAPPENDIXES(Nonmandatory Information)X1. Guidelines for Job-Site PracticesX1.1 Specification A 767/A 767M is a product standard.Requirements for zinc-coated (galvanized) steel reinforcingbars from the point of shipment to the job-site and
46、 subsequentpractices at the job-site are not delineated in this productstandard.X1.2 The American Concrete Institute promulgates “Speci-fications for Structural Concrete ACI 301.” SpecificationsACI 301 is intended to be used in its entirety in the projectspecifications. An architect-engineer may cit
47、e Standard Speci-fications ACI 301 in the project specifications for any cast-in-place concrete construction project. Standard SpecificationsACI 301 include provisions for zinc-coated (galvanized) steelreinforcing bars.X1.3 The project specifications should prescribe require-ments for the zinc-coate
48、d (galvanized) steel reinforcing barsfrom the point of shipment to the job-site and subsequentpractices at the job-site. In the absence of these requirements inthe project specifications, the following guidelines for job-siteTABLE 2 Minimum Finished Bend DiametersBar No. Grade 28040Grade 35050Grade
49、42060Grade 5207510,13,16 3,4,5 6dA6d 6d .19 6 6d 6d 6d 6d22,25 7,8 6d 8d 8d 8d29,32 9,10 . . . . . . 8d 8d3611 . . 8d 8d43,57 14,18 . . . . . . 10d 10dAd = nominal diameter of the bar.A 767/A 767M 053practices are recommended:X1.3.1 When handling coated steel reinforcing bars, careshould be exercised to avoid bundle-to-bundle or bar-to-barabrasion.X1.3.2 Equipment for handling coated steel reinforcing barsshould have protected contact areas.X1.3.3 Coated st
