1、Designation: G 85 02e1Standard Practice forModified Salt Spray (Fog) Testing1This standard is issued under the fixed designation G 85; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in parenthes
2、es indicates the year of last reapproval. A superscriptepsilon (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.e1NOTEEditorial changes were made in the Appendix for clarity August 2003.1. Scope1.
3、1 This practice sets forth conditions for five modificationsin salt spray (fog) testing for specification purposes. These arein chronological order of their development:1.1.1 Annex A1, acetic acid-salt spray test, continuous.1.1.2 Annex A2, cyclic acidified salt spray test.1.1.3 Annex A3, seawater a
4、cidified test, cyclic (SWAAT).1.1.4 Annex A4,SO2salt spray test, cyclic.1.1.5 Annex A5, dilute electrolyte cyclic fog dry test.1.2 This practice does not prescribe the type of modifica-tion, test specimen or exposure periods to be used for a specificproduct, nor the interpretation to be given to the
5、 results.1.3 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 consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to
6、use.2. Referenced Documents2.1 ASTM Standards:B 117 Practice for Operating Salt Spray (Fog) Apparatus2D 609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, andRelated Coating Products3D 1141 Practice for the Preparation of Substitute OceanWater4D
7、1193 Specification for Reagent Water5D 1654 Test Method for Evaluation of Painted or CoatedSpecimens Subjected to Corrosive Environments3E 70 Test Method for pH of Aqueous Solutions with theGlass Electrode63. Significance and Use3.1 This practice is applicable to ferrous and nonferrousmetals; also o
8、rganic and inorganic coatings. The variationsdescribed herein are useful when a different or more corrosiveenvironment than the salt fog described in Practice B 117 isdesired.4. Apparatus4.1 Cabinet:4.1.1 The apparatus required for salt spray (fog) testingconsists of a fog chamber, a salt solution r
9、eservoir, a supply ofsuitably conditioned compressed air, one or more atomizingnozzles, specimen supports, provision for heating the chamber,and necessary means of control. The size and detailed con-struction of the cabinet are optional, provided the conditionsobtained meet the requirements of this
10、practice. The material ofconstruction shall be such that it will not affect the corrosive-ness of the fog. Suitable apparatus that may be used to obtainthese conditions is described in Appendix A1 of Practice B 117with necessary modifications described in each annex.4.1.2 Design the cabinet so that
11、drops of solution thataccumulate on the ceiling or cover of the chamber do not fallon the specimens being tested. Do not return drops of solutionthat fall from the specimens to the solution reservoir forrespraying.4.1.3 Equip the cabinet with one or more timing devices toprovide for intermittent spr
12、aying or periodic introduction of agas, or both.4.2 Air Supply:4.2.1 Make sure the compressed air supply to the nozzle ornozzles for atomizing the salt solution is free of oil and dirt andmaintain the air supply between 69 and 172 kPa (10 and 25psi).NOTE 1The air supply may be freed of oil and dirt
13、by passing itthrough a water scrubber or at least 610 mm (2 ft) of suitable cleaningmaterial such as asbestos, sheeps wool, or activated alumina.4.2.2 Temperature in the saturator tower (bubble tower)varies depending on the test method used.4.3 Conditions in Salt-Spray Chamber:1This practice is unde
14、r the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.Current edition approved October 10, 2002. Published February 2003. Originallyapproved in 1985. Last previous edition approved in 1998 as G 85 98.2Annua
15、l Book of ASTM Standards, Vol 03.02.3Annual Book of ASTM Standards, Vol 06.01.4Annual Book of ASTM Standards, Vol 11.02.5Annual Book of ASTM Standards, Vol 11.01.6Annual Book of ASTM Standards, Vol 15.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2
16、959, United States.4.3.1 TemperatureThe temperature in the exposure zonevaries with the test method used. For recommended exposurezone temperatures for the various methods see the Annex. Eachset point and its tolerance represents an operational controlpoint for equilibrium conditions at a single loc
17、ation in thecabinet which may not necessarily represent the uniformity ofconditions throughout the cabinet. Record the temperaturewithin the exposure zone of the closed cabinet at least twice aday at least 7 h apart (except on weekends and holidays, whenthe salt spray test is not interrupted for exp
18、osing, rearranging,or removing test specimens or to check and replenish thesolution in the reservoir).NOTE 2Suitable methods to record the temperature are a continuousrecording device or a thermometer which can be read from outside theclosed cabinet. Obtain the recorded temperature with the salt spr
19、aychamber closed to avoid a false low reading because of wet-bulb effectwhen the chamber is open.4.3.2 Atomization and Quantity of FogPlace at least twoclean fog collectors within the exposure zone so that no dropsof solution from the test specimens or any other source can becollected. Position the
20、collectors in the proximity of the testspecimens, one nearest to any nozzle and the other farthestfrom all nozzles. Make sure that for each 80 cm2of horizontal-collecting area fog accumulates in each collector from 1.0 to2.0 mL of solution per hour based on an average run of at least16 h continuous
21、spray.NOTE 3Suitable collecting devices are glass funnels with the stemsinserted through stoppers into graduated cylinders or crystallizing dishes.Funnels and dishes with a diameter of 100 mm have an area of about 80cm2.4.3.3 Direct or baffle the nozzle or nozzles so that none ofthe spray can imping
22、e directly on the test specimens.5. Test Specimens5.1 Define the type and number of test specimens to be used,as well as the criteria for the evaluation of the test results in thespecifications covering the material or product being tested orupon mutual agreement between the purchaser and the seller
23、.5.2 Preparation of Test Specimens:5.2.1 Clean metallic and metallic-coated specimens. Thecleaning method is optional depending on the nature of thesurface and the contaminants; however, when using a cleaningmethod do not include in the contents abrasives other than apaste of pure magnesium oxide no
24、r of solvents which mayform corrosive or inhibitive films. The use of nitric acidsolution for the chemical cleaning, or passivation, of stainlesssteel specimens is permissible when agreed upon between thepurchaser and the seller. Take care that specimens are notrecontaminated after cleaning by exces
25、sive or careless han-dling.5.2.2 Prepare specimens for evaluation of paints and otherorganic coatings in accordance with applicable specification(s)for the material(s) being tested, or as agreed upon between thepurchaser and supplier. Otherwise, make sure the test speci-mens consist of steel meeting
26、 the requirements of PracticeD 609; clean and prepare the specimens for coating in accor-dance with applicable procedure of Practice D 609.5.2.3 Whenever it is desired to determine the developmentof corrosion from an abraded area in the paint or organiccoating, make a scratch or scribed line through
27、 the coating witha sharp instrument so that the underlying metal is exposedbefore testing. Use the conditions of making the scratch asdefined in Test Method D 1654, unless otherwise agreed uponbetween the purchaser and seller.5.2.4 Protect the cut edges of plated, coated, or duplexmaterials and area
28、s that contain identification marks or that arein contact with the racks or supports with a suitable coating thatis stable under the conditions of the test, such as ceresin wax,unless otherwise specified.NOTE 4Should it be desirable to cut test specimens from parts or frompreplated, painted, or othe
29、rwise coated-steel sheet, protect the cut edgesby coating them with paint, wax, tape, or other effective media so that thedevelopment of preferential attack or a galvanic effect between such edgesand the adjacent plated or otherwise coated-metal surfaces, is prevented.6. Salt Solutions6.1 Make the s
30、alt solutions by using either synthetic sea saltin accordance with Practice D 1141 or sodium chloride inaccordance with Practice B 117, unless otherwise specified inthe appropriate annex. Make-up water shall be distilled ordeionized water conforming to Type IV water in SpecificationD 1193 (except th
31、at for this practice, limits for chlorides andsodium may be ignored).6.2 Synthetic Sea Salt Solution:6.2.1 Make the salt solution so that it consists of 42 g ofsynthetic sea salt in accordance with Practice D 1141 per litreof solution (see Note 5).6.3 Sodium Chloride Solution:6.3.1 Prepare the salt
32、solution by dissolving 5 6 1 parts byweight of sodium chloride in 95 parts of distilled water orwater containing not more than 200 ppm of total solids (seeNote 5). The sodium chloride shall be substantially free ofnickel and copper and shall contain on the dry basis not morethan 0.1 % of sodium iodi
33、de and not more than 0.3 % of totalimpurities. Some salts contain additives that may act ascorrosion inhibitors; careful attention should be given to thechemical content of the salt. Upon agreement between pur-chaser and seller, analysis may be required and limits estab-lished for elements or compou
34、nds not specified in the chemicalcomposition given above.NOTE 5A solution having a specific gravity of 1.0255 to 1.0400 at25C (77F) will meet the concentration requirement of 6.2.1 and 6.3.1. Itis suggested that a daily check be made.6.4 The pH of the salt solutions will vary depending on thetest me
35、thod used. Before the solution is atomized, free it ofsuspended solids (see Note 6). Take the pH measurementselectrometrically at 25C (77F) using a glass electrode with asaturated potassium chloride bridge in accordance with TestMethod E 70.NOTE 6The freshly prepared salt solution may be filtered or
36、 decantedbefore it is placed in the reservoir, or the end of the tube leading from thesolution to the atomizer may be covered with a double layer of cheeseclothor suitable nonmetallic filter cloth to prevent plugging of the nozzle.7. Procedure7.1 Position of Specimens During Test:G8502e127.1.1 Unles
37、s otherwise specified, support or suspend thespecimens between 6 and 45 from the vertical, and preferablyparallel to the principal direction of horizontal flow of fogthrough the chamber, based upon the dominant surface beingtested. Note that test severity increases as angle from thevertical increase
38、s.7.1.2 Do not allow contact of the specimens between eachother, between any metallic material, or between any materialcapable of acting as a wick.7.1.3 Place each specimen so as to permit free settling of fogon all specimens. A minimum spacing between specimens of30 mm is recommended.7.1.4 Do not p
39、ermit the salt solution from one specimen todrip on any other specimen.7.1.5 It is recommended that placement of replicate speci-mens be randomized to avoid possible bias caused by differ-ence in spray patterns. Individual specimens may also berotated daily for the same reason.7.1.6 Suitable materia
40、ls for the construction or coating ofracks and supports are glass, rubber, plastic, or suitably coatedwood. Do not use bare metal. Support specimens preferablyfrom the bottom or the side. Slotted wooden, laminated plastic,or inert plastic strips are suitable for the support of flat panels.Suspension
41、 from glass hooks or waxed string may be used aslong as the specified position of the specimens is obtained, and,if necessary, by means of secondary support at the bottom ofthe specimens.7.2 Continuity of Test:7.2.1 Unless otherwise specified, in the specifications cov-ering the material or product
42、being tested, allow the test to becontinuous for the duration of the entire test period. Continu-ous operation implies that the chamber be closed except for theshort daily interruptions necessary to inspect, rearrange, orremove test specimens, and to check and replenish the solutionin the reservoir.
43、 Schedule operations so that these interruptionsare held to a minimum.7.3 Period of Test:7.3.1 Designate the period of test in accordance with thespecifications covering the material or product being tested oras mutually agreed upon between the purchaser and the seller.Exposure periods of multiples
44、of 24 h are suggested.7.4 Cleaning of Tested Specimens:7.4.1 Unless otherwise specified in the specifications cov-ering the material or product being tested, at the end of the test,specimens may be gently washed or dipped in clean runningwater no warmer than 38C (100F) to remove salt depositsfrom th
45、eir surface, and then immediately dried. Dry with astream of clean, compressed air.NOTE 7Drying with compressed air may not be desirable for alumi-num specimens to be tested for exfoliation corrosion resistance.8. Evaluation of Results8.1 Make a careful and immediate examination for theextent of cor
46、rosion of the dry test specimens or for other failureas required by the specifications covering the material orproduct being tested or by agreement between the purchaserand the seller.9. Report9.1 Record the following information, unless otherwiseprescribed in the specifications covering the materia
47、l or prod-uct being tested:9.1.1 Type of salt and water used in preparing the saltsolution,9.1.2 All readings of temperature within the exposure zoneof the chamber,9.1.3 Weekly records of data obtained from each fog-collecting device including the following:9.1.3.1 Volume of salt solution collected
48、in millilitres perhour per 80 cm2,9.1.3.2 Concentration or specific gravity at 35C (95F) ofsolution collected, (see Note 8), and9.1.3.3 pH of collected solution,9.1.4 Type of specimen and its dimensions, or number ordescription of part,9.1.5 Method of cleaning specimens before and after test-ing,9.1
49、.6 Method of supporting or suspending article in the saltspray chamber,9.1.7 Description of protection used as required in 5.2.5,9.1.8 Exposure period,9.1.9 Interruptions in test, cause and length of time, and9.1.10 Results of all inspections.NOTE 8It is also advisable to record the concentration or specificgravity of any atomized salt solution that has not made contact with thetest specimen and that was returned to the reservoir.10. Keywords10.1 acidic salt spray; corrosion; salt sprayG8502e13ANNEXES(Mandatory Information)A1. ACETIC ACID-SALT SPRAY (FOG) TESTINGA1
