ASTM_D_1730_-_09_2014.pdf

Designation:D173009(Reapproved 2014)Standard Practices forPreparation of Aluminum and Aluminum-Alloy Surfaces forPainting1This standard is issued under the fixed designation D1730;the number immediately 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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 These practices cover four types of treatment for prepa-ration of aluminum and aluminum-alloy surfaces for painting,as follows:1.1.1 Type ASolvent Cleaning.1.1.2 Type BChemical Treatments.1.1.3 Type CAnodic Treatments.1.1.4 Type DMechanical Treatments.These four typescover a number of procedures,as described herein.1.2 Variations in surface treatment produce end conditionswhich differ,and which do not necessarily yield identicalresults when paints are applied.Service conditions will dictatethe type of surface preparation that should be selected,al-though the quality produced by any individual method mayvary with different alloys.1.3 This standard may involve hazardous materials,operations,and equipment.This standard does not purport toaddress all of the safety concerns,if any,associated with itsuse.It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint,Varnish,Conversion Coatings,andRelated Coating Products2.2 Military Standards:3MIL-A-8625 Anodic Coatings forAluminum andAluminumAlloysMIL-DTL-5541 Chemical Conversion Coatings on Alumi-num and Aluminum AlloysMIL-M-10578B Metal Conditioner and Rust Remover(Phosphoric Acid Type)MIL-P-15328bB Coating Compound Metal PretreatmentResin Resistant2.3 Federal Specification:3TT-C-490 Chemical Conversion Coatings and Pretreatmentsfor Ferrous Surfaces(Base for Organic Coatings)3.Type ASolvent Cleaning3.1 Solvent cleaning does not disturb the natural oxide filmon the metal and may prove adequate for some applications,such as ambient indoor or very mild service conditions.Threemethods may be employed,as follows:3.1.1 Method 1,Manual Swabbing or Dip-Washing,with asolvent such as mineral spirits or high-flask solvent naphtha.With this method it is extremely difficult to prevent accumu-lation of contaminants on the swab or in the solvent.Thismethod is only recommended when other treatments areimpractical.3.1.2 Method 2,Solvent Spray Cleaning,in accordancewith Method A,Procedure 1 of Practice D609.3.1.3 Method 3,Vapor Degreasing,in special equipmentemploying trichloroethylene vapor,in accordance with MethodA,Procedure 2 of Practice D609.4.Type BChemical TreatmentsNOTE1Materials and procedures employed in these methods oftreatment are available from a number of sources as proprietary com-pounds or methods.Selection may be made from available sources.Thehexavalent chromium methods given are not recommended as hexavalentchromium is a known carcinogen.4.1 Method 1,Alkaline CleanersAlkaline solutions,suchas caustic soda,etch the metal,thus destroying the naturaloxide film.They are followed by an acid treatment,preferablynitric acid or phosphoric acid.They shall not be used onassembled structures.Inhibited alkaline cleaners are sometimesemployed as a pretreatment to remove grease and oil prior to anacid treatment.Inhibited alkaline cleaners do not etch the1These practices are under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of B08.07ConversionCoatings on Chromate Conversion Coatings.Current edition approved Nov.1,2014.Published November 2014.Originallyapproved in 1960.Last previous edition approved in 2009 as D1730-09.DOI:10.1520/D1730-09R14.2For 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.3Available from Standardization Documents Order Desk,DODSSP,Bldg.4,Section D,700 Robbins Ave.,Philadelphia,PA 19111-5098Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 surface.They are not generally recommended unless followedby a conversion treatment,such as described in Methods 4,5,6,or 7.4.2 Method 2,Sulfuric Acid,Chromium Trioxide EtchThis treatment provides a clean and uniform surface withoutundue etching,and is effective for removing oil and waterstains and any film formed during heat-treatment.The etchingsolution is prepared by adding 1 gal(3.78 L)of concentratedsulfuric acid and 45 oz(1.28 kg)of chromium trioxide to 9 gal(34 L)of water.It is used at a temperature of 160 to 180F(71to 82C)(depe