1、Designation:A96705 2 A967/A967M13 Standard Specication for Chemical Passivation Treatments for Stainless Steel Parts 1 ThisstandardisissuedunderthexeddesignationA967;A967/A967M;thenumberimmediatelyfollowingthedesignationindicatesthe year of original adoption or, in the case of revision, the year of
2、last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense. e 1 NOTESection 6.1.1.1 was editorially correc
3、ted in July 2007. e 2 NOTESection references were editorially corrected in Section 22.1 in March 2010. 1. Scope* 1.1 This specication covers several different types of chemical passivation treatments for stainless steel parts. It includes recommendations and precautions for descaling, cleaning, and
4、passivation of stainless steel parts. It includes several alternative tests, with acceptance criteria, for conrmation of effectiveness of such treatments for stainless steel parts. 1.2 Practices for the mechanical and chemical treatments of stainless steel surfaces are discussed more thoroughly in P
5、ractice A380. 1.3 Several alternative chemical treatments are dened for passivation of stainless steel parts. Appendix X1 gives some nonmandatory information and provides some general guidelines regarding the selection of passivation treatment appropriate to particular grades of stainless steel. It
6、makes no recommendations regarding the suitability of any grade, treatment, or acceptance criteria for any particular application or class of applications. 1.4 Thetestsinthisspecicationareintendedtoconrmtheeffectivenessofpassivation,particularlywithregardtotheremoval of free iron and other exogenous
7、 matter. These tests include the following practices: 1.4.1 Practice AWater Immersion Test, 1.4.2 Practice BHigh Humidity Test, 1.4.3 Practice CSalt Spray Test, 1.4.4 Practice DCopper Sulfate Test, 1.4.5 Practice EPotassium FerricyanideNitric Acid Test, and 1.4.6 Practice FFree IronDamp Cloth Test.
8、NOTE 1Free iron denotes iron present on the surface of the parts, including but not limited to iron contamination, iron-tool marks, residual-iron salts from pickling solutions, iron dust, atmospheric exposure, iron deposits in welds, embedded iron and iron oxide. 1.5 The values stated in either SI u
9、nits or inch-pound units are to be regarded separately as the standard. The SI units given in parentheses are for information only. values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may re
10、sult in non-conformance with the standard. 1.6 The following precautionary caveat pertains only to the test method portions, SectionsSection 14 through 18 of this specication:This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibili
11、ty of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: 2 A380Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Sy
12、stems B117Practice for Operating Salt Spray (Fog) Apparatus B254Practice for Preparation of and Electroplating on Stainless Steel 1 ThisspecicationisunderthejurisdictionofASTMCommitteeA01onSteel,StainlessSteelandRelatedAlloysandisthedirectresponsibilityofSubcommitteeA01.14 on Methods of Corrosion Te
13、sting. Current edition approved Sept. 1, 2005Feb. 15, 2013. Published September 2005March 2013. Originally approved in 1996. Last previous edition approved in 20012005 as A96701A96705 e1e2 . DOI: 10.1520/A0967-05E01.10.1520/A0967-13. 2 ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orco
14、ntactASTMCustomerServiceatserviceastm.org.ForAnnualBookofASTMStandards volume information, refer to the standards Document Summary page on the ASTM website. This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made t
15、o the previous version. Because it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version of the standard as published by ASTM is to be considered the official document. *ASu
16、mmary 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 12.2 Federal Specication: 3 QQ-P-35CPassivation Treatments for Corrosion-Resistant Steels 3. Terminology 3.1 Denition of Term
17、 Specic to This StandardIt is necessary to dene which of the several commonly used denitions of the term passivation will be used in this specication. (See Discussion.) 3.1.1 DiscussionStainless steels are autopassivating in the sense that the protective passive lm is formed spontaneously on exposur
18、e to air or moisture. The presence of exogenous surface contamination, including dirt, grease, free iron from contact with steel tooling, and so forth, may interfere with the formation of the passive lm. The cleaning of these contaminants from the stainlesssteelsurfacewillfacilitatethespontaneouspas
19、sivationbyallowingtheoxygenuniformaccesstothesurface.Thepassive lm may be augmented by chemical treatments that provide an oxidizing environment for the stainless steel surface. 3.1.1.1 Inthisspecication,passivation,unlessotherwisespecied,isdenedasthechemicaltreatmentofastainlesssteelwith a mild oxi
20、dant, such as a nitric acid solution, for the purpose of the removal of free iron or other foreign matter, but which is generallynoteffectiveinremovalofheattintoroxidescaleonstainlesssteel.Inthecaseofstainlesssteelswithadditionsofsulfur for the purpose of improved machinability, passivation may also
21、 include the removal of suldes from the surface of the metal for the purpose of maximizing corrosion resistance. 3.1.1.2 The formation of the protective passive lm on a stainless steel, also called passivation in a more general context, will occur spontaneously in air or other oxygen-containing envi
22、ronment when the stainless steel surface is free of oxide scale and exogenous matter. 3.1.1.3 Chemical treatments, such as sodium dichromate solutions, may facilitate the more rapid formation of the passive lm on a stainless steel surface already free of scale or foreign matter. Such treatments, als
23、o sometimes called passivation in common usage, are designated as post-cleaning treatments in this specication in order to distinguish them from chemical treatments capable of removing free iron from stainless steels. 3.1.1.4 The chemical treatments capable of removing heat tint or oxide scale from
24、stainless steel and capable of dissolving the stainless steel itself, typically called pickling, are substantially more aggressive than treatments used for passivation, as dened in 3.1.1.1. The surface of stainless steel that has been pickled is free of scale, free iron, and exogenous foreign matter
25、, and does not require a separate treatment for passivation as dened in 3.1.1.1. The passivation process dened in 3.1.1.2 will occur without further chemical treatment but may be augmented and improved by the post-cleaning treatments dened in 3.1.1.3. 3.1.1.5 Electrochemical treatments, including el
26、ectropickling and electropolishing capable of removing heat tint or oxide scale from stainless steel and capable of dissolving the stainless steel itself, are substantially more aggressive than treatments used for passivation, as dened in 3.1.1.1. The surface of stainless steel resulting from these
27、treatments is free of scale, free iron, and exogenous foreign matter, and does not require a separate treatment for passivation as dened in 3.1.1.1. The passivation process dened in 3.1.1.2 will occur without further chemical treatment, but may be augmented and improved by the post-cleaning treatmen
28、ts dened in 3.1.1.3. Statements regarding chemical treatments, unless otherwise specied, are taken to include electrochemical treatments. 4. Ordering Information 4.1 It is the responsibility of the purchaser to specify a test practice appropriate to any particular material and application.This speci
29、cation was written for the purpose of providing an alternative to United States Federal Specication QQ-P-35C. Determination of the suitability of this specication for that purpose is the responsibility of the purchaser. 4.2 Unless specied by the purchaser, the chemical treatment applied to the stain
30、less steel parts shall be selected by the seller from among the listed passivation treatments. 4.3 Unless specied by the purchaser, the test practice applied to the stainless steel parts shall be selected by the seller from among the listed test practices. 5. Materials and Preparation for Passivatio
31、n Treatments 5.1 The passivation treatments shall be of one or more of the following types. The effectiveness of a particular treatment for a particular grade of stainless steel in a particular application is demonstrated by meeting the specied testing requirements: 5.1.1 Treatments in nitric acid,
32、acid solutions (see Section 6), 5.1.2 Treatments in citric acid, acid solutions (see Section 7), 5.1.3 Other chemical treatments, including electrochemical treatments, Treatments in other chemical solutions, including electrochemical treatments (see Section 8), 5.1.4 Neutralization, and Rinsing and
33、neutralization (see Section 9), and 5.1.5 Post-cleaning treatments. treatments (see Section 10). 5.2 Materials: 3 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. A967/A967M13 25.2.1 Thechemicalsusedforpassivationtreatmentsshallproducepassivatedsurfa
34、cesthatmeettherequirementsofoneormore of the tests of this specication.Attention shall be given to maintaining adequate volume, concentration, purity, and temperature control appropriate to the size and amount of stainless steel to be treated. 5.2.2 The processor shall maintain a record with regard
35、to concentration and temperature of the passivation solution sufficient todemonstratethatthespeciedpassivationconditionsweremaintainedforeachlotofstainlesssteelpartsprocessed.Suchrecords shall be available for inspection when specied in the purchase order. The processor is not required to reveal the
36、 precise composition of proprietary chemical mixtures but shall maintain a unique identication of the mixture that will ensure its accurate representation for subsequent use. 5.2.3 The processor shall be responsible for the safe disposal of all material generated by this process. 5.3 Preparation for
37、 Passivation Treatments: 5.3.1 The pretreatment methods and procedures used prior to the passivation treatment, including mechanical and chemical methods, singly or in combination, for descaling and pickling, shall be in accordance with Practice A380. When electrochemical cleaning is required, it sh
38、all be performed in accordance with Practice B254. 5.3.2 The resulting pretreated surface shall be substantially free of oil, grease, rust, scale, and other foreign matter. 5.3.3 When the nal pretreatment of a part includes pickling of the entire surface of the part, no further passivation treatment
39、 is required prior to testing of the surface unless specied by the purchaser. 6. Treatments in NitricAcid Solutions 6.1 Passivation Treatment: 6.1.1 Stainless steel parts shall be treated in one of the following aqueous solutions and maintained within the specied temperature range for the specied ti
40、me. 6.1.1.1 Nitric 1The solution shall contain 20 to 25 volume percent of nitric acid and 2.5 6 0.5 weight percent of sodium dichromate. The parts shall be immersed for a minimum of 20 min at a temperature in the range from 12050 to 130F (4955C 120 to 54C).130F. 6.1.1.2 Nitric 2The solution shall co
41、ntain 20 to 45 volume percent of nitric acid.The parts shall be immersed for a minimum of 30 min at a temperature in the range from 7020 to 90F (2130C 70 to 32C).90F. 6.1.1.3 Nitric 3The solution shall contain 20 to 25 volume percent nitric acid. The parts shall be immersed for a minimum of 20 min a
42、t a temperature in the range from 12050 to 140F (4960C 120 to 60C).140F. 6.1.1.4 Nitric 4The solution shall contain 45 to 55 volume percent of nitric acid.The parts shall be immersed for a minimum of 30 min at a temperature in the range from 12050 to 130F (4955C 120 to 54C).130F. 6.1.1.5 Nitric 5Oth
43、er combinations of temperature, time, and concentration of nitric acid, with or without other chemicals, including accelerants, inhibitors, or proprietary solutions, capable of producing parts that pass the specied test requirements. 6.2 Water RinseImmediately after removal from the passivating solu
44、tion the parts shall be thoroughly rinsed, using stagnant, countercurrent,orspraywashessinglyorincombination,withorwithoutaseparatechemicaltreatmentforneutralization(see9.1) ofthepassivationmedia,media(seeSection9),withanalrinsebeingcarriedoutusingwaterwithamaximumtotalsolidscontent of 200 ppm. NOTE
45、 2Each of the nitric acid solution treatments listed are recommended for different grades of stainless steel. See X1.3. 7. Treatments in CitricAcid Solutions 7.1 Passivation Treatment: 7.1.1 Stainless steel parts shall be treated in one of the following aqueous solutions and maintained within the sp
46、ecied temperature range for the specied time. 7.1.1.1 Citric 1The solution shall contain 4 to 10 weight percent of citric acid. The parts shall be immersed for a minimum of 4 min at a temperature in the range from 14060 to 160F (6070C 140 to 71C).160F. 7.1.1.2 Citric 2The solution shall contain 4 to
47、 10 weight percent of citric acid. The parts shall be immersed for a minimum of 10 min at a temperature in the range from 12050 to 140F (4960C 120 to 60C).140F. 7.1.1.3 Citric 3The solution shall contain 4 to 10 weight percent of citric acid. The parts shall be immersed for a minimum of 20 min at a
48、temperature in the range from 7020 to 120F (2150C 70 to 49C).120F. 7.1.1.4 Citric 4Other combinations of temperature, time, and concentration of citric acid, with or without other chemicals to enhance cleaning, including accelerants, inhibitors, or proprietary solutions capable of producing parts th
49、at pass the specied test requirements. 7.1.1.5 Citric 5Other combinations of temperature, time, and concentrations of citric acid, with or without other chemicals to enhance cleaning, including accelerants, inhibitors, or proprietary solutions capable of producing parts that pass the specied test requirements. Immersion bath to be controlled at a pH of 1.82.2. A967/A967M13 37.2 Water RinseImmediately after removal from the passivating solution, the parts shall b
