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盐雾试验标准1、使用范围1.1本标准规程包括产生和维持盐雾实验环境所要求的仪器和程序，可能用到的合适的仪器在附录X1里说明。
1.2本规程并不指定试验的样本类型，或特殊产品的喷雾时间，也不对试验结果作出解释。
1.3以SI为单位的数据是标准的，括号内的数据仅供参考。
1.4本标准并不旨在涵盖所有的安全性问题，如果有，也是与它的使用方法有关系。
本标准的使用者有责任来建立合适的安全及健康操作程序，并在使用前决定规程限制的适用性。
2、参考文献2.1 ASTM标准2B368 用以加速铜腐蚀的醋酸-盐雾试验方法（CASS试验）D609 测试冷扎钢板喷涂、清漆、化学涂层和其他相关涂层产品的制剂D1193 试剂水说明D1654 在腐蚀环境下，样本喷涂估算的试验方法E70 玻璃电极水溶液PH值的试验方法E691 开展实验室间研究，以确定试验方法精密度的规程G85 更新的盐雾试验规程3、意义及作用3.1本规程提供了一种可控的腐蚀环境，金属及涂装金属在给定的试验房间里产生相关的防腐蚀信息。
3.2在自然环境下对其性能的预测值，与单独作为数据的盐雾试验结果很少有关联。
3.2.1建立在这种规程试验环境下，其腐蚀性能的关联值和外延值并不总是可预测的。
3.2.2只有在证实进行了适宜的长期自然环境的暴露以后，才应当考虑关联值和外延值。
3.3盐雾试验结果的可重复性，在很大程度上依赖于试验的样品和所选择的标准，也依赖于对操作变量的控制。
在一些测试程序中，应当考虑到大量的数据采集次数，以建立试验结果的可变性。
即使试验条件相似，测试的浓度范围一样，在不同的盐雾实验室内，相似的样本其试验结果也不一样。
4、装置4.1盐雾试验所要求的装置，包括一个盐雾室，盐溶液储罐、适当的压缩空气供应装置、一个或多个喷嘴、样品支撑架、盐雾室加热装置和其他必要的控制部件。
装置的尺寸和详细的结构是可选择的，只要能提供本规程所要求的环境即可。
4.2盐雾室内顶部或盖板上聚集的液滴不允许滴落在暴露的样本上。
盐雾试验标准astmb117ASTM B117 是美国材料和试验协会标准化技术委员会发布的盐雾试验标准，是一项重要的评估材料耐腐蚀性能的试验方法。
在日常生产和使用中，物资和设备受到环境因素的影响非常大，特别是进入海洋环境后，各种材料和设备都面临着严峻的腐蚀和氧化问题。
为了提高材料的质量和性能，B117 标准建立了实验室模拟海洋环境的盐雾湿度测试机，为材料的质量控制和生产提供了标准化的测试方法。
一、范围B117 标准适用于任何材料的耐盐雾性能测试，适用于开放或密封材料，如涂层、金属、合金、塑料、橡胶等。
通过盐雾试验，可以评估材料的耐腐蚀程度，判断其采用于海洋环境或其他恶劣环境的可行性。
二、材料2.1 标准试样试验的标准试样应当符合标准规定的要求。
2.2 试样的准备和测定三、试验方法试验方法分为三种：盐雾试验、腐蚀波动试验和周期腐蚀试验。
3.1 盐雾试验试样应当架设在 salt-spray test 试验设备中，并通过加热器、喷雾器等控制温度和湿度，使其处于适宜的条件下。
设备内应当保存一定的水平，以保证试样的稳定性。
试验时间为 240 小时，但也可以调整传递量和盐度，延长或缩短测试时间。
3.2 腐蚀波动试验腐蚀波动试验是将试样放置于一个不断变化的盐水浴中，并通过加热、冷却等控制水温的变化。
设备内的温度应当逐渐升高和降低，但不应当超过试样能够承受的极限。
周期腐蚀试验旨在模拟实际环境下的腐蚀形式，包括氧化、重组、氯化等周期组合，通过循环的变化，模拟出材料在实际环境中出现的各种腐蚀形式。
通过三种试验方法，可以全面评估材料的腐蚀等级和耐腐蚀性能，以便为生产和制造提供更好的保护和质量控制。
四、结果和分析在试验完成后，对试样进行外观变化、损失率、金属质量等方面进行评估和分析，通过比较不同试样之间的差异，得出材料的腐蚀等级和使用建议。
五、注意事项5.1 试验室环境在进行盐雾试验的时候，需要保持试验室的相对湿度在 85%-95% 之间，温度在35℃±2℃，空气流通应保持恰当，以避免水外的环境影响。
astm b117-19标准
ASTM B117-19是美国材料和试验协会（ASTM International）发布的一项标准，它规定了盐雾腐蚀试验的测试方法和评估标准。
下面将从以下几个方面对这个标准进行详细的介绍。
一、标准的适用范围
ASTM B117-19标准适用于金属和涂层材料的盐雾腐蚀试验。
它可以用于评估材料的耐腐蚀性能，以及涂层的附着力和耐腐蚀性能。
二、测试方法
ASTM B117-19标准规定了盐雾腐蚀试验的测试方法。
在测试过程中，将试样暴露在盐雾环境中，通过观察试样的腐蚀情况来评估材料的耐腐蚀性能。
测试时间和温度可以根据需要进行调整。
三、评估标准
ASTM B117-19标准规定了评估材料腐蚀程度的标准。
根据试样的腐蚀情况，将其分为不同的等级，从而评估材料的腐蚀性能。
这些等级包括：无腐蚀、轻微腐蚀、中等腐蚀和严重腐蚀。
四、注意事项
在进行盐雾腐蚀试验时，需要注意一些事项。
例如，试样的准备和处理、试验室环境的控制、试验设备的维护等等。
这些因素都可能会影响测试结果，因此需要严格遵守标准的要求。
总之，ASTM B117-19标准是一项非常重要的标准，它可以用于评估材料和涂层的耐腐蚀性能。
在进行盐雾腐蚀试验时，需要严格遵守标准的要求，以确保测试结果的准确性和可靠性。
常用盐雾试验标准及相关结果评价【标题】常用盐雾试验标准及相关结果评价：深度剖析常见问题与优化方法【引言】在物质的日常使用中，我们经常会遇到很多与腐蚀有关的问题。
为了保证产品的质量和耐久性，盐雾试验作为一种常用的检测手段，被广泛运用于各个行业。
然而，由于标准和结果评估的多样性，我们需要深入了解常见的盐雾试验标准并探讨相关结果的评价方法，以便更好地使用和解读这些试验结果。
【正文】一、常见的盐雾试验标准1. ASTM B117ASTM B117是美国材料和试验协会（ASTM）所制定的盐雾试验标准，该标准以其广泛应用和严格性而闻名。
它要求在特定条件下，将试验样品放置于盐水喷洒环境中，并对其进行长时间暴露和观察。
该标准主要用于金属及金属覆盖物的测试，评估其耐腐蚀性能。
2. ISO 9227ISO 9227是国际标准化组织（ISO）实施的盐雾腐蚀试验标准。
与ASTM B117标准相比，ISO 9227更注重试验设备和试验方法的一致性，以提高试验结果的可比性。
该标准适用于各种材料和产品，包括涂层、电镀、油漆和塑料等。
3. JIS Z 2371JIS Z 2371是日本工业标准所制定的盐雾试验标准。
作为亚洲地区应用最广泛的标准之一，它在盐雾试验的环境参数、试验时间以及观察和评定结果等方面都进行了详细规定。
该标准主要适用于电子、汽车、航空航天和光学等领域。
二、盐雾试验结果的评价方法1. 腐蚀程度评价在进行盐雾试验时，需对试样表面进行腐蚀程度的评估。
常见的评价方法包括比色法、光学显微镜法和电化学测试等。
比色法通过颜色鉴定试样的腐蚀程度，通常采用灰度卡来进行比对。
光学显微镜法则通过放大观察试样表面的细微腐蚀情况。
而电化学测试则可定量测量试样表面的腐蚀速率。
2. 腐蚀产物分析盐雾试验会在试样表面形成腐蚀产物。
分析腐蚀产物的组成和结构可以帮助我们更详细地了解腐蚀机理，并找到应对腐蚀的有效方法。
常用的分析方法包括扫描电子显微镜（SEM）、能谱仪（EDX）和X 射线衍射（XRD）等。
镀锡盐雾试验标准镀锡盐雾试验是一种常用于评估金属表面镀锡层的耐腐蚀性能的方法。
该试验可以模拟出真实环境中的盐雾腐蚀环境，通过观察和分析金属表面锡层的变化情况，从而评估其耐腐蚀性能的好坏。
下面将介绍一种常见的镀锡盐雾试验标准——ASTM B117。
ASTM B117是美国材料测试协会（ASTM）制定的一项标准，其全称为“ASTM B117-16 Standard Practice for Operating Salt Spray (Fog) Apparatus”。
该标准规定了使用盐雾试验设备进行镀锡层腐蚀测试的具体要求和步骤，有效保证了试验的准确性和可重复性。
首先，ASTM B117规定了试验设备的基本要求。
盐雾试验设备应具备恒温恒湿的能力，并且能够持续稳定地生成盐雾气雾。
设备内部的湿度应保持在95%RH（相对湿度）±3%的范围内，温度应保持在35±2℃。
设备的操作和控制系统应具备自动控温、控湿的功能，能够精确调控试验的时间和条件。
其次，在样品的准备方面，ASTM B117规定了一系列准备工作。
首先，试样的表面应彻底清洁，确保没有任何灰尘、油脂或其他污染物。
然后，将试样固定在试验架上，并使用适当的方法保证样品的完整性和稳定性。
试样的尺寸和形状应符合标准的要求，以确保试验结果的可靠性。
试验的进行过程中，ASTM B117规定了盐雾试验的时间长度和观察周期。
标准试验时间为48小时，但根据实际需要，也可以进行长期试验，例如240小时或更长。
试验周期内应进行定期观察和记录，通常每24小时观察一次，并记录试样的变化情况。
观察时应注意试样是否出现锡层的剥落、氧化、锈蚀等现象，并进行详细记录。
最后，在试验结束后，ASTM B117规定了进行试样评估和结果判定的方法。
通常情况下，根据试样表面的腐蚀程度，结合试样的应用需求，进行定性或定量评估。
评估常用的方法有目视评估、显微镜观察、重量损失测定等。
ASTM B117 －2011：操作盐雾测试机1 的标准实验方法本标准是在以固定称呼B117 来发行，而跟随在称呼之后的数字则表示为最早发行之年版或是最后发行年版，括号内之号码则表示该版本经确认之最后年版，如果后面又加上括号内并含一希腊字母时则代表在最后版本确认后还有编辑上的修改。
本标准已由国防部核准使用。
1. 范围1.1 本实验方法包含了仪器、程序以及为了建立与保持盐水喷雾试验环境所要求之条件。
附录X1描述可被使用之适合的试验机。
1.2 本实验没有指定试验样品的种类或者对于特定产品所需的曝露时间，也不对结果作说明。
1.3 以SI(国际公制单位)数据单位来表示被视为标准。
英吋-磅单位以括号表示是为了提供资讯且可能是相等的。
1.4 本标准并未指明试验方法上所产生之任何安全问题，该安全问题是引用本标准之使用者的责任。
使用者应自行建立适当之安全卫生操作方法，并且在使用前决定应有的使用限制规定。
2. 参考文件2.1 ASTM 标准B 368－醋酸铜盐水喷雾试验方法(CACC试验) . D 1193－试剂水4(Reagent Water)的规范.D 1654－涂漆或有镀层的试片在腐蚀环境3下之评估方法.E 70－使用玻璃电极5量测含水溶液的pH值之试验方法.E 691－决定试验方法的正确性6.G 85－修正盐水喷雾试验的实验73. 重要性以及使用3.1 本实验提供一个受控制之腐蚀环境，该环境被利用来让金属与镀金属的试件暴露于一特定试验室中而产生相关防腐蚀的讯息。
3.2 当使用独立的数据时，在自然环境中试验的预估很少与盐水喷雾的结果有所关连。
3.2.1 基于暴露于本实验所提供的试验环境，腐蚀发生的关系与推测并不常是可预料的。
3.2.2 只有在适当的确定长期环境暴露已被采用时，相互关系与推测应被考虑。
2/153.3 暴露于盐水喷雾结果的再现性是高度取决于试验试件的种类所选择的评估准则，以及操作变异的控制。
在任何试验程序中，在建立结果的变异应包括充分的复制。
ASTM B117 ,1788_美国盐雾试验标准美国材料试验标准(ASTM)代码：B 117—02盐雾试验仪的标准操作规程本标准已被批准供国防部下属司，局使用。
1．适用范围1.1本规程将说明产生和维持盐雾试验环境所要求的仪器，方法和条件。
可以使用的合适仪器将在附录Ⅺ中说明。
1。
2本规程没有规定试样类型或特定产品的盐雾接触时间，也没有规定对试验结果应做的解释。
1。
3用公制单位表示的数据将被认为是标准数据。
英制单位数据被标在括号内供参考，并且可能是近似值。
同1。
4本标准应用有关的一切安全问题不是本标准的重点.本标准的使用者有责任在应用前建立适宜的安全，卫生规程以及确定允许限定值的适用范围。
2．参考文献2.1ASTM标准：B 368用以加快铜腐蚀的醋酸—盐雾试验方法（CASS试验）。
D 609供测试涂料,清漆，更换贴面以及相关贴面产品用的冷轧钢板制备规程.D 1193试剂水规格。
D 1654在腐蚀性环境使用的涂装或贴面试样鉴定用试验方法。
E 70玻璃电极水溶液的pH值测试方法.E 691开展实验室间研究，以确定测试方法精度所适用的规程。
G 85改进的盐雾试验规程。
3．意义和用途3。
1本规程提出一种受控的腐蚀性环境，金属及涂装的金属试样在规定的测试室这种腐蚀性环境下将产生相应的抗腐蚀数据。
3。
2在自然环境下的性能预测值与单独使用的盐雾试验结果几乎没有关联.3。
2.1以本规程提出的测试环境为基础得出的腐蚀性能相关性和外推值并不总是可以用来做预测。
3.2。
2只有在进行了适宜的长期大气暴露验证之后才可考虑关联性和外推值。
3.3盐雾暴露试验结果的重复性主要取决于被测试样的类型和选定的鉴定标准，以及操作参数的控制。
任一测试项目都应搞足够的重复试验，以便了解结果的波动性。
即使测试条件通常类似，并且处在本规程规定的范围内,在不同的盐雾室测试类似的试样，仍获得不同的结果.4．仪器4。
1盐雾暴露试验所要求的仪器由以下构件组成：盐雾室，盐溶液储罐，经适当空调的压缩空气的供应管道，一个或多个雾化喷嘴,试样支架,盐雾室加热装置和必要的控制器.这种仪器的尺寸和具体结构可以任选，只是产生的条件应满足本规程的要求。
Designation:B117–03Standard Practice forOperating Salt Spray(Fog)Apparatus1This standard is issued under thefixed designation B117;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the 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.Scope1.1This practice covers the apparatus,procedure,and conditions required to create and maintain the salt spray(fog) test environment.Suitable apparatus which may be used is described in Appendix X1.1.2This practice does not prescribe the type of test speci-men or exposure periods to be used for a specific product,nor the interpretation to be given to the results.1.3The values stated in SI units are to be regarded as standard.The inch-pound units in parentheses are provided for information and may be approximate.1.4This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1ASTM Standards:B368Method for Copper-Accelerated Acetic Acid-Salt Spray(Fog)Testing(CASS Test)2D609Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint,Varnish,Conversion Coatings,and Related Coating Products3D1193Specification for Reagent Water4D1654Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments3E70Test Method for pH of Aqueous Solutions with the Glass Electrode5E691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method6G85Practice for Modified Salt Spray(Fog)Testing73.Significance and Use3.1This practice provides a controlled corrosive environ-ment which has been utilized to produce relative corrosion resistance information for specimens of metals and coated metals exposed in a given test chamber.3.2Prediction of performance in natural environments has seldom been correlated with salt spray results when used as stand alone data.3.2.1Correlation and extrapolation of corrosion perfor-mance based on exposure to the test environment provided by this practice are not always predictable.3.2.2Correlation and extrapolation should be considered only in cases where appropriate corroborating long-term atmo-spheric exposures have been conducted.3.3The reproducibility of results in the salt spray exposure is highly dependent on the type of specimens tested and the evaluation criteria selected,as well as the control of the operating variables.In any testing program,sufficient repli-cates should be included to establish the variability of the results.Variability has been observed when similar specimens are tested in different fog chambers even though the testing conditions are nominally similar and within the ranges speci-fied in this practice.4.Apparatus4.1The apparatus required for salt spray(fog)exposure consists of a fog chamber,a salt solution reservoir,a supply of suitably conditioned compressed air,one or more atomizing nozzles,specimen supports,provision for heating the chamber, and necessary means of control.The size and detailed con-struction of the apparatus are optional,provided the conditions obtained meet the requirements of this practice.4.2Drops of solution which accumulate on the ceiling or cover of the chamber shall not be permitted to fall on the specimens being exposed.1This practice is under the jurisdiction of ASTM Committee G01on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05on LaboratoryCorrosion Tests.Current edition approved October1,2003.Published October2003.Originallyapproved st previous edition approved in2002as B117–02.2Annual Book of ASTM Standards,V ol02.05.3Annual Book of ASTM Standards,V ol06.01.4Annual Book of ASTM Standards,V ol11.01.5Annual Book of ASTM Standards,V ol15.05.6Annual Book of ASTM Standards,V ol14.02.7Annual Book of ASTM Standards,V ol03.02.1Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.4.3Drops of solution which fall from the specimens shall not be returned to the solution reservoir for respraying.4.4Material of construction shall be such that it will not affect the corrosiveness of the fog.4.5All water used for this practice shall conform to Type IV water in Specification D1193(except that for this practice limits for chlorides and sodium may be ignored).This does not apply to running tap water.All other water will be referred to as reagent grade.5.Test Specimens5.1The type and number of test specimens to be used,as well as the criteria for the evaluation of the test results,shall be defined in the specifications covering the material or product being exposed or shall be mutually agreed upon between the purchaser and the seller.6.Preparation of Test Specimens6.1Specimens shall be suitably cleaned.The cleaning method shall be optional depending on the nature of the surface and the contaminants.Care shall be taken that specimens are not recontaminated after cleaning by excessive or careless handling.6.2Specimens for the evaluation of paints and other organic coatings shall be prepared in accordance with applicable specification(s)for the material(s)being exposed,or as agreed upon between the purchaser and the supplier.Otherwise,the test specimens shall consist of steel meeting the requirements of Practice D609and shall be cleaned and prepared for coating in accordance with the applicable procedure of Practice D609.6.3Specimens coated with paints or nonmetallic coatings shall not be cleaned or handled excessively prior to test.6.4Whenever it is desired to determine the development of corrosion from an abraded area in the paint or organic coating, a scratch or scribed line shall be made through the coating with a sharp instrument so as to expose the underlying metal before testing.The conditions of making the scratch shall be as defined in Test Method D1654,unless otherwise agreed upon between the purchaser and the seller.6.5Unless otherwise specified,the cut edges of plated, coated,or duplex materials and areas containing identification marks or in contact with the racks or supports shall be protected with a suitable coating stable under the conditions of the practice.N OTE1—Should it be desirable to cut test specimens from parts or from preplated,painted,or otherwise coated steel sheet,the cut edges shall be protected by coating them with paint,wax,tape,or other effective media so that the development of a galvanic effect between such edges and the adjacent plated or otherwise coated metal surfaces,is prevented.7.Position of Specimens During Exposure7.1The position of the specimens in the salt spray chamber during the test shall be such that the following conditions are met:7.1.1Unless otherwise specified,the specimens shall be supported or suspended between15and30°from the vertical and preferably parallel to the principal direction offlow of fog through the chamber,based upon the dominant surface being tested.7.1.2The specimens shall not contact each other or any metallic material or any material capable of acting as a wick.7.1.3Each specimen shall be placed to permit unencum-bered exposure to the fog.7.1.4Salt solution from one specimen shall not drip on any other specimen.N OTE2—Suitable materials for the construction or coating of racks and supports are glass,rubber,plastic,or suitably coated wood.Bare metal shall not be used.Specimens shall preferably be supported from the bottom or the side.Slotted wooden strips are suitable for the support offlat panels.Suspension from glass hooks or waxed string may be used as long as the specified position of the specimens is obtained,if necessary by means of secondary support at the bottom of the specimens.8.Salt Solution8.1The salt solution shall be prepared by dissolving561 parts by mass of sodium chloride in95parts of water conforming to Type IV water in Specification D1193(except that for this practice limits for chlorides and sodium may be ignored).Careful attention should be given to the chemical content of the salt.The salt used shall be sodium chloride with not more than0.3%by mass of total impurities.Halides (Bromide,Fluoride,and Iodide)other than Chloride shall constitute less than0.1%by mass of the salt content.Copper content shall be less than0.3ppm by mass.Sodium chloride containing anti-caking agents shall not be used because such agents may act as corrosion inhibitors.See Table1for a listing of these impurity restrictions.Upon agreement between the purchaser and the seller,analysis may be required and limits established for elements or compounds not specified in the chemical composition given above.TABLE1Maximum Allowable Limits for Impurity Levels inSodium Chloride A,BImpurity Description Allowable Amount Total Impurities#0.3% Halides(Bromide,Fluoride and Iodide)excluding Chloride#0.1% Copper<0.3ppmAnti-caking Agents0.0%A A common formula used to calculate the amount of salt required by mass to achieve a5%salt solution of a known mass of water is:.053X Mass of Water5Mass of NaCl requiredThe mass of water is1g per1mL.To calculate the mass of salt required in grams to mix1L of a5%salt solution,multiply.053by1000g(35.27oz.,the mass of 1L of water).This formula yields a result of53g(1.87oz.)of NaCl required for each liter of water to achieve a5%salt solution by mass.The0.053multiplier for the sodium chloride used above is derived by the following:1000g~mass of a full L of water!divided by0.95~water is only95%of the total mixture by mass!yields1053gThis1053g is the total mass of the mixture of one L of water with a5%sodium chloride concentration.1053g minus the original weight of the L of water,1000g, yields53g for the weight of the sodium chloride.53g of total sodium chloride divided by the original1000g of water yields a0.053multiplier for the sodium chloride.As an example:to mix the equivalent of200L(52.83gal)of5%sodium chloride solution,mix10.6kg(23.37lb)of sodium chloride into200L(52.83gal)of water. 200L of water weighs200,000g.200,000g of water x.053(sodium chloride multiplier)=10,600g of sodium chloride,or10.6kg.B In order to ensure that the proper salt concentration was achieved when mixing the solution,it is recommended that the solution be checked with either a salimeter hydrometer or specific gravity hydrometer.When using a salimeter hydrometer,the measurement should be between4and6%at25°C(77°F).When using a specific gravity hydrometer,the measurement should be between1.0255and1.0400at 25°C(77°F).8.2The pH of the salt solution shall be such that when atomized at35°C(95°F)the collected solution will be in the pH range from6.5to7.2(Note3).Before the solution is atomized it shall be free of suspended solids(Note4).The pH measurement shall be made at25°C(77°F)using a suitable glass pH-sensing electrode,reference electrode,and pH meter system in accordance with Test Method E70.N OTE3—Temperature affects the pH of a salt solution prepared from water saturated with carbon dioxide at room temperature and pH adjust-ment may be made by the following three methods:(1)When the pH of a salt solution is adjusted at room temperature,and atomized at35°C(95°F),the pH of the collected solution will be higher than the original solution due to the loss of carbon dioxide at the higher temperature.When the pH of the salt solution is adjusted at room temperature,it is therefore necessary to adjust it below6.5so the collected solution after atomizing at35°C(95°F)will meet the pH limits of6.5to 7.2.Take about a50-mL sample of the salt solution as prepared at room temperature,boil gently for30s,cool,and determine the pH.When the pH of the salt solution is adjusted to6.5to7.2by this procedure,the pH of the atomized and collected solution at35°C(95°F)will come within this range.(2)Heating the salt solution to boiling and cooling to35°C(95°F)and maintaining it at35°C(95°F)for approximately48h before adjusting the pH produces a solution the pH of which does not materially change when atomized at35°C(95°F).(3)Heating the water from which the salt solution is prepared to35°C (95°F)or above,to expel carbon dioxide,and adjusting the pH of the salt solution within the limits of6.5to7.2produces a solution the pH of which does not materially change when atomized at35°C(95°F).N OTE4—The freshly prepared salt solution may befiltered or decanted before it is placed in the reservoir,or the end of the tube leading from the solution to the atomizer may be covered with a double layer of cheesecloth to prevent plugging of the nozzle.N OTE5—The pH can be adjusted by additions of dilute ACS reagent grade hydrochloric acid or sodium hydroxide solutions.9.Air Supply9.1The compressed air supply to the Air Saturator Tower shall be free of grease,oil,and dirt before use by passing through well-maintainedfilters.(Note6)This air should be maintained at a sufficient pressure at the base of the Air Saturator Tower to meet the suggested pressures of Table2at the top of the Air Saturator Tower.N OTE6—The air supply may be freed from oil and dirt by passing it through a suitable oil/water extractor(that is commercially available)to stop any oil from reaching the Air Saturator Tower.Many oil/water extractors have an expiration indicator,proper preventive maintenance intervals should take these into account.9.2The compressed air supply to the atomizer nozzle or nozzles shall be conditioned by introducing it into the bottom of a towerfillwed with water.A common method of introduc-ing the air is through an air dispersion device(X1.4.1).The level of the water must be maintained automatically to ensure adequate humidification.It is common practice to maintain the temperature in this tower between46and49°C(114–121°F)to offset the cooling effect of expansion to atmospheric pressure during the atomization process.Table2in9.3of this practice shows the temperature,at different pressures,that are com-monly used to offset the cooling effect of expansion to atmospheric pressure.9.3Careful attention should be given to the relationship of tower temperature to pressure since this relationship can have a direct impact to maintaining proper collection rates(Note7). It is preferable to saturate the air at temperatures well above the chamber temperature as insurance of a wet fog as listed in Table2.N OTE7—If the tower is run outside of these suggested temperature and pressure ranges to acheive proper collection rates as described in10.2of this practice,other means of verifying the proper corrosion rate in the chamber should be investigated,such as the use of control specimens (panels of known performance in the test conducted).It is preferred that control panels be provided that bracket the expected test specimen performance.The controls allow for the normalization of test conditions during repeated running of the test and will also allow comparisons of test results from different repeats of the same test.(Refer to Appendix X3, Evaluation of Corrosive Conditions,for mass loss procedures).10.Conditions in the Salt Spray Chamber10.1Temperature—The exposure zone of the salt spray chamber shall be maintained at35+1.1−1.7°C (95+2−3°F).Each set point and its tolerance represents an operational control point for equilibrium conditions at a single location in the cabinet which may not necessarily represent the uniformity of conditions throughout the cabinet.The tempera-ture within the exposure zone of the closed cabinet shall be recorded(Note8)at least twice a day at least7h apart(except on Saturdays,Sundays,and holidays when the salt spray test is not interrupted for exposing,rearranging,or removing test specimens or to check and replenish the solution in the reservoir)N OTE8—A suitable method to record the temperature is by a continu-ous recording device or by a thermometer which can be read from outside the closed cabinet.The recorded temperature must be obtained with the salt spray chamber closed to avoid a false low reading because of wet-bulb effect when the chamber is open.10.2Atomization and Quantity of Fog—Place at least two clean fog collectors per atomizer tower within the exposure zone so that no drops of solution will be collected from the test specimens or any other source.Position the collectors in the proximity of the test specimens,one nearest to any nozzle and the other farthest from all nozzles.A typical arrangement is shown in Fig.1.The fog shall be such that for each80 cm2(12.4in.2)of horizontal collecting area,there will be collected from1.0to2.0mL of solution per hour based on an average run of at least16h(Note9).The sodium chloride concentration of the collected solution shall be561mass% (Notes9-11).The pH of the collected solution shall be6.5to 7.2.The pH measurement shall be made as described in8.2 (Note3).N OTE9—Suitable collecting devices are glass or plastic funnels with TABLE2Suggested Temperature and Pressure guideline for the top of the Air Saturator Tower for the operation of a test at35°C(95°F)Air Pressure,kPa Temperature,°C Air Pressure,PSI Temperature,°F 83461211496471411711048161191244918121the stems inserted through stoppers into graduated cylinders,or crystal-lizing dishes.Funnels and dishes with a diameter of 10cm (3.94in.)have an area of about 80cm 2(12.4in.2).N OTE 10—A solution having a specific gravity of 1.0255to 1.0400at 25°C (77°F)will meet the concentration requirement.The sodium chloride concentration may also be determined using a suitable salinity meter (for example,utilizing a sodium ion-selective glass electrode)or colorimetrically as follows.Dilute 5mL of the collected solution to 100mL with distilled water and mix thoroughly;pipet a 10-mL aliquot into an evaporating dish or casserole;add 40mL of distilled water and 1mL of 1%potassium chromate solution (chloride-free)and titrate with 0.1N silver nitrate solution to the first appearance of a permanent red coloration.A solution that requires between 3.4and 5.1mL of 0.1N silver nitrate solution will meet the concentration requirements.N OTE 11—Salt solutions from 2to 6%will give the same results,though for uniformity the limits are set at 4to 6%.10.3The nozzle or nozzles shall be so directed or baffled that none of the spray can impinge directly on the test specimens.11.Continuity of Exposure11.1Unless otherwise specified in the specifications cover-ing the material or product being tested,the test shall be continuous for the duration of the entire test period.Continu-ous operation implies that the chamber be closed and the spray operating continuously except for the short daily interruptions necessary to inspect,rearrange,or remove test specimens,to check and replenish the solution in the reservoir,and to make necessary recordings as described in Section 10.Operations shall be so scheduled that these interruptions are held to a minimum.12.Period of Exposure12.1The period of exposure shall be as designated by the specifications covering the material or product being tested or as mutually agreed upon between the purchaser and the seller.N OTE 12—Recommended exposure periods are to be as agreed upon between the purchaser and the seller,but exposure periods of multiples of 24h are suggested.13.Cleaning of Tested Specimens13.1Unless otherwise specified in the specifications cover-ing the material or product being tested,specimens shall be treated as follows at the end of the test:13.1.1The specimens shall be carefully removed.13.2Specimens may be gently washed or dipped in clean running water not warmer than 38°C (100°F)to remove salt deposits from their surface,and then immediately dried.14.Evaluation of Results14.1A careful and immediate examination shall be made as required by the specifications covering the material or product being tested or by agreement between the purchaser and the seller.15.Records and Reports15.1The following information shall be recorded,unless otherwise prescribed in the specifications covering the material or product being tested:15.1.1Type of salt and water used in preparing the salt solution,15.1.2All readings of temperature within the exposure zone of the chamber,15.1.3Daily records of data obtained from each fog-collecting device including the following:15.1.3.1V olume of salt solution collected in millilitres per hour per 80cm 2(12.4in.2),15.1.3.2Concentration or specific gravity at 35°C (95°F)of solution collected,and15.1.3.3pH of collectedsolution.N OTE —This figure shows a typical fog collector arrangement for a single atomizer tower cabinet.The same fog collector arrangement is also applicable for multiple atomizer tower and horizontal (“T”type)atomizer tower cabinet constructions as well.FIG.1Arrangement of FogCollectors15.2Type of specimen and its dimensions,or number or description of part,15.3Method of cleaning specimens before and after testing, 15.4Method of supporting or suspending article in the salt spray chamber,15.5Description of protection used as required in6.5, 15.6Exposure period,15.7Interruptions in exposure,cause,and length of time, and15.8Results of all inspections.N OTE13—If any of the atomized salt solution which has not contacted the test specimens is returned to the reservoir,it is advisable to record the concentration or specific gravity of this solution also.16.Keywords16.1controlled corrosive environment;corrosive condi-tions;determining mass loss;salt spray(fog)exposureAPPENDIXES(Nonmandatory Information)X1.CONSTRUCTION OF APPARATUSX1.1CabinetsX1.1.1Standard salt spray cabinets are available from several suppliers,but certain pertinent accessories are required before they will function according to this practice and provide consistent control for duplication of results.X1.1.2The salt spray cabinet consists of the basic chamber, an air-saturator tower,a salt solution reservoir,atomizing nozzles,specimen supports,provisions for heating the cham-ber,and suitable controls for maintaining the desired tempera-ture.X1.1.3Accessories such as a suitable adjustable baffle or central fog tower,automatic level control for the salt reservoir, and automatic level control for the air-saturator tower are pertinent parts of the apparatus.X1.1.4The size and shape of the cabinet shall be such that the atomization and quantity of collected solution is within the limits of this practice.X1.1.5The chamber shall be made of suitably inert mate-rials such as plastic,glass,or stone,or constructed of metal and lined with impervious plastics,rubber,or epoxy-type materials or equivalent.X1.1.6All piping that contacts the salt solution or spray should be of inert materials such as plastic.Vent piping should be of sufficient size so that a minimum of back pressure exists and should be installed so that no solution is trapped.The exposed end of the vent pipe should be shielded from extreme air currents that may causefluctuation of pressure or vacuum in the cabinet.X1.2Temperature ControlX1.2.1The maintenance of temperature within the salt chamber can be accomplished by several methods.It is generally desirable to control the temperature of the surround-ings of the salt spray chamber and to maintain it as stable as possible.This may be accomplished by placing the apparatus in a constant-temperature room,but may also be achieved by surrounding the basic chamber of a jacket containing water or air at a controlled temperature.X1.2.2The use of immersion heaters in an internal salt solution reservoir or within the chamber is detrimental where heat losses are appreciable because of solution evaporation and radiant heat on the specimens.X1.3Spray NozzlesX1.3.1Satisfactory nozzles may be made of hard rubber, plastic,or other inert materials.The most commonly used type is made of plastic.Nozzles calibrated for air consumption and solution-atomized are available.The operating characteristics of a typical nozzle are given in Table X1.1.X1.3.2It can readily be seen that air consumption is relatively stable at the pressures normally used,but a marked reduction in solution sprayed occurs if the level of the solution is allowed to drop appreciably during the test.Thus,the level of the solution in the salt reservoir must be maintained automatically to ensure uniform fog delivery during the test.8 X1.3.3If the nozzle selected does not atomize the salt solution into uniform droplets,it will be necessary to direct the spray at a baffle or wall to pick up the larger drops and prevent them from impinging on the test specimens.Pending a com-plete understanding of air-pressure effects,and so forth,it is important that the nozzle selected shall produce the desired 8A suitable device for maintaining the level of liquid in either the saturator tower or reservoir of test solution may be designed by a local engineering group,or may be purchased from manufacturers of test cabinets as an accessory.TABLE X1.1Operating Characteristics of Typical Spray Nozzle SiphonHeight,cmAir Flow,dm3/min Solution Consumption,cm3/hAir Pressure,kPa Air Pressure,kPa34691031383469103138 101926.531.5362100384045845256 201926.531.536636276037204320 301926.531.5360138030003710 401926.631.536078021242904SiphonHeight,in.Air Flow,L/minSolutionConsumption,mL/hAir Pressure,psi Air Pressure,psi51015205101520 41926.531.5362100384045845256 81926.531.536636276037204320 121926.531.5360138030003710 161926.631.536078021242904condition when operated at the air pressure selected.Nozzles are not necessarily located at one end,but may be placed in the center and can also be directed vertically up through a suitable tower.X1.4Air for AtomizationX1.4.1The air used for atomization must be free of grease, oil,and dirt before use by passing through well-maintainedfilters.Room air may be compressed,heated,humidified,and washed in a water-sealed rotary pump if the temperature of the water is suitably controlled.Otherwise cleaned air may be introduced into the bottom of a towerfilled with water through a porous stone or multiple nozzles.The level of the water must be maintained automatically to ensure adequate humidification.A chamber operated in accordance with this method and Appendix X1will have a relative humidity between95and 98%.Since salt solutions from2to6%will give the same results(though for uniformity the limits are set at4to6%),it is preferable to saturate the air at temperatures well above the chamber temperature as insurance of a wet fog.Table X1.2 shows the temperatures,at different pressures,that are required to offset the cooling effect of expansion to atmospheric pressure.X1.4.2Experience has shown that most uniform spray chamber atmospheres are obtained by increasing the atomizing air temperature sufficiently to offset heat losses,except those that can be replaced otherwise at very low-temperature gradi-ents.X1.5Types of ConstructionX1.5.1A modern laboratory cabinet is shown in Fig.X1.1. Walk-in chambers are usually constructed with a sloping ceiling.Suitably located and directed spray nozzles avoid ceiling accumulation and drip.Nozzles may be located at the ceiling,or0.91m(3ft)from thefloor directed upward at30to 60°over a passageway.The number of nozzles depends on type and capacity and is related to the area of the test space.An11 to19L(3to5-gal)reservoir is required within the chamber, with the level controlled.The major features of a walk-in type cabinet,which differs significantly from the laboratory type, are illustrated in Fig.X1.2.Construction of a plastic nozzle, such as is furnished by several suppliers,is shown in Fig.X1.3.TABLE X1.2Temperature and Pressure Requirements forOperation of Test at95°FAir Pressure,kPa8396110124 Temperature,°C46474849Air Pressure,psi12141618 Temperature,°F114117119121。
ASTM B117 －2011：操作盐雾测试机1 的标准实验方法本标准是在以固定称呼B117 来发行，而跟随在称呼之后的数字则表示为最早发行之年版或是最后发行年版，括号内之号码则表示该版本经确认之最后年版，如果后面又加上括号内并含一希腊字母时则代表在最后版本确认后还有编辑上的修改。
本标准已由国防部核准使用。
1. 范围1.1 本实验方法包含了仪器、程序以及为了建立与保持盐水喷雾试验环境所要求之条件。
附录X1描述可被使用之适合的试验机。
1.2 本实验没有指定试验样品的种类或者对于特定产品所需的曝露时间，也不对结果作说明。
1.3 以SI(国际公制单位)数据单位来表示被视为标准。
英吋-磅单位以括号表示是为了提供资讯且可能是相等的。
1.4 本标准并未指明试验方法上所产生之任何安全问题，该安全问题是引用本标准之使用者的责任。
使用者应自行建立适当之安全卫生操作方法，并且在使用前决定应有的使用限制规定。
2. 参考文件2.1 ASTM 标准B 368－醋酸铜盐水喷雾试验方法(CACC试验) . D 1193－试剂水4(Reagent Water)的规范.D 1654－涂漆或有镀层的试片在腐蚀环境3下之评估方法.E 70－使用玻璃电极5量测含水溶液的pH值之试验方法.E 691－决定试验方法的正确性6.G 85－修正盐水喷雾试验的实验73. 重要性以及使用3.1 本实验提供一个受控制之腐蚀环境，该环境被利用来让金属与镀金属的试件暴露于一特定试验室中而产生相关防腐蚀的讯息。
3.2 当使用独立的数据时，在自然环境中试验的预估很少与盐水喷雾的结果有所关连。
3.2.1 基于暴露于本实验所提供的试验环境，腐蚀发生的关系与推测并不常是可预料的。
3.2.2 只有在适当的确定长期环境暴露已被采用时，相互关系与推测应被考虑。
2/153.3 暴露于盐水喷雾结果的再现性是高度取决于试验试件的种类所选择的评估准则，以及操作变异的控制。
在任何试验程序中，在建立结果的变异应包括充分的复制。
名称：B117-03盐雾喷射（雾化）装置操作的标准实施规范本标准按固定名称B117发行；名称后的编号表示最初采用的年份，或者，如果是修订版，则是最新修订版的年份。
圆括号中的数字表示最新重新批准的年份。
上标ε表示自最新修订版或重新批准后的编辑性修改。
本标准已经被国防部的机构批准采用。
1 范围1.1 本规范规定了创建和维护盐雾喷射（雾化）试验环境所需的装置、程序和条件。
附录X1中说明了可以使用的合适装置。
1.2 本规范没有规定用于特定产品的试样类型或暴光时间；也没有对结果作出解释。
1.3 以国际单位制说明的数值被视作为标准。
圆括号中的英寸-磅单位制供参考并且是近似值。
1.4 本标准声明不处理所有的安全事务，如果有，只是与其用途相关的。
在使用之前，本标准的用户有责任制定相关的安全和健康规范并确定规章限制的适用范围。
2 参考文献2.1 ASTM标准B368铜加速的醋酸腐蚀盐喷雾试验(CASS试验)的标准试验方法D609涂料、清漆、转化涂层和相关覆层产品的测试用冷轧钢板制备的标准实施规范D1193试剂水的标准规范D1654腐蚀环境中涂漆或涂层试样评估的标准测试方法E70用玻璃电极测量水溶液pH值的标准试验方法E691为测定试验方法精密度开展的实验室间的研究的标准实施规范G85改进的盐喷雾(雾化)试验的标准实施规范3 意义和用途3.1 本规范提供了可控制的腐蚀环境，利用它来为暴光在特定试验舱中的金属和涂层金属的试样确定相关的抗腐性资料。
3.2 当将盐雾喷射结果作为独立数据时，自然环境中的性能预测几乎很少与此相关。
3.2.1 本规范提供的暴光在试验环境中的腐蚀性能的相关性和外延并不总是可以预测的。
3.2.2 相关性和外延应该只存在于进行进一步证实的长期大气暴露的情况下。
3.3 盐喷雾暴光试验中结果的再现性完全取决于试样类型和所选择的评估标准及操作变量的控制。
在任何测试项目中，必须包括足够的重复以确定结果的可变性。
Designation:B 117–03Standard Practice forOperating Salt Spray (Fog)Apparatus 1This standard is issued under the fixed designation B 117;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the 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.Scope1.1This practice covers the apparatus,procedure,and conditions required to create and maintain the salt spray (fog)test environment.Suitable apparatus which may be used is described in Appendix X1.1.2This practice does not prescribe the type of test speci-men or exposure periods to be used for a specific product,nor the interpretation to be given to the results.1.3The values stated in SI units are to be regarded as standard.The inch-pound units in parentheses are provided for information and may be approximate.1.4This standard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents 2.1ASTM Standards:B 368Method for Copper-Accelerated Acetic Acid-Salt Spray (Fog)Testing (CASS Test)2D 609Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint,Varnish,Conversion Coatings,and Related Coating Products 3D 1193Specification for Reagent Water 4D 1654Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments 3E 70Test Method for pH of Aqueous Solutions with the Glass Electrode 5E 691Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method 6G 85Practice for Modified Salt Spray (Fog)Testing 73.Significance and Use3.1This practice provides a controlled corrosive environ-ment which has been utilized to produce relative corrosion resistance information for specimens of metals and coated metals exposed in a given test chamber.3.2Prediction of performance in natural environments has seldom been correlated with salt spray results when used as stand alone data.3.2.1Correlation and extrapolation of corrosion perfor-mance based on exposure to the test environment provided by this practice are not always predictable.3.2.2Correlation and extrapolation should be considered only in cases where appropriate corroborating long-term atmo-spheric exposures have been conducted.3.3The reproducibility of results in the salt spray exposure is highly dependent on the type of specimens tested and the evaluation criteria selected,as well as the control of the operating variables.In any testing program,sufficient repli-cates should be included to establish the variability of the results.Variability has been observed when similar specimens are tested in different fog chambers even though the testing conditions are nominally similar and within the ranges speci-fied in this practice.4.Apparatus4.1The apparatus required for salt spray (fog)exposure consists of a fog chamber,a salt solution reservoir,a supply of suitably conditioned compressed air,one or more atomizing nozzles,specimen supports,provision for heating the chamber,and necessary means of control.The size and detailed con-struction of the apparatus are optional,provided the conditions obtained meet the requirements of this practice.4.2Drops of solution which accumulate on the ceiling or cover of the chamber shall not be permitted to fall on the specimens being exposed.1This practice is under the jurisdiction of ASTM Committee G01on Corrosion of Metals and is the direct responsibility of Subcommittee G01.05on Laboratory Corrosion Tests.Current edition approved October 1,2003.Published October 2003.Originally approved in st previous edition approved in 2002as B 117–02.2Annual Book of ASTM Standards ,V ol 02.05.3Annual Book of ASTM Standards ,V ol 06.01.4Annual Book of ASTM Standards ,V ol 11.01.5Annual Book of ASTM Standards ,V ol 15.05.6Annual Book of ASTM Standards ,V ol 14.02.7Annual Book of ASTM Standards ,V ol 03.02.1Copyright ©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,UnitedStates.4.3Drops of solution which fall from the specimens shall not be returned to the solution reservoir for respraying.4.4Material of construction shall be such that it will not affect the corrosiveness of the fog.4.5All water used for this practice shall conform to Type IV water in Specification D1193(except that for this practice limits for chlorides and sodium may be ignored).This does not apply to running tap water.All other water will be referred to as reagent grade.5.Test Specimens5.1The type and number of test specimens to be used,as well as the criteria for the evaluation of the test results,shall be defined in the specifications covering the material or product being exposed or shall be mutually agreed upon between the purchaser and the seller.6.Preparation of Test Specimens6.1Specimens shall be suitably cleaned.The cleaning method shall be optional depending on the nature of the surface and the contaminants.Care shall be taken that specimens are not recontaminated after cleaning by excessive or careless handling.6.2Specimens for the evaluation of paints and other organic coatings shall be prepared in accordance with applicable specification(s)for the material(s)being exposed,or as agreed upon between the purchaser and the supplier.Otherwise,the test specimens shall consist of steel meeting the requirements of Practice D609and shall be cleaned and prepared for coating in accordance with the applicable procedure of Practice D609.6.3Specimens coated with paints or nonmetallic coatings shall not be cleaned or handled excessively prior to test.6.4Whenever it is desired to determine the development of corrosion from an abraded area in the paint or organic coating, a scratch or scribed line shall be made through the coating with a sharp instrument so as to expose the underlying metal before testing.The conditions of making the scratch shall be as defined in Test Method D1654,unless otherwise agreed upon between the purchaser and the seller.6.5Unless otherwise specified,the cut edges of plated, coated,or duplex materials and areas containing identification marks or in contact with the racks or supports shall be protected with a suitable coating stable under the conditions of the practice.N OTE1—Should it be desirable to cut test specimens from parts or from preplated,painted,or otherwise coated steel sheet,the cut edges shall be protected by coating them with paint,wax,tape,or other effective media so that the development of a galvanic effect between such edges and the adjacent plated or otherwise coated metal surfaces,is prevented.7.Position of Specimens During Exposure7.1The position of the specimens in the salt spray chamber during the test shall be such that the following conditions are met:7.1.1Unless otherwise specified,the specimens shall be supported or suspended between15and30°from the vertical and preferably parallel to the principal direction offlow of fog through the chamber,based upon the dominant surface being tested.7.1.2The specimens shall not contact each other or any metallic material or any material capable of acting as a wick.7.1.3Each specimen shall be placed to permit unencum-bered exposure to the fog.7.1.4Salt solution from one specimen shall not drip on any other specimen.N OTE2—Suitable materials for the construction or coating of racks and supports are glass,rubber,plastic,or suitably coated wood.Bare metal shall not be used.Specimens shall preferably be supported from the bottom or the side.Slotted wooden strips are suitable for the support offlat panels.Suspension from glass hooks or waxed string may be used as long as the specified position of the specimens is obtained,if necessary by means of secondary support at the bottom of the specimens.8.Salt Solution8.1The salt solution shall be prepared by dissolving561 parts by mass of sodium chloride in95parts of water conforming to Type IV water in Specification D1193(except that for this practice limits for chlorides and sodium may be ignored).Careful attention should be given to the chemical content of the salt.The salt used shall be sodium chloride with not more than0.3%by mass of total impurities.Halides (Bromide,Fluoride,and Iodide)other than Chloride shall constitute less than0.1%by mass of the salt content.Copper content shall be less than0.3ppm by mass.Sodium chloride containing anti-caking agents shall not be used because such agents may act as corrosion inhibitors.See Table1for a listing of these impurity restrictions.Upon agreement between the purchaser and the seller,analysis may be required and limits established for elements or compounds not specified in the chemical composition given above.TABLE1Maximum Allowable Limits for Impurity Levels inSodium Chloride A,BImpurity Description Allowable Amount Total Impurities#0.3% Halides(Bromide,Fluoride and Iodide)excluding Chloride#0.1% Copper<0.3ppmAnti-caking Agents0.0%A A common formula used to calculate the amount of salt required by mass to achieve a5%salt solution of a known mass of water is:.053X Mass of Water5Mass of NaCl requiredThe mass of water is1g per1mL.To calculate the mass of salt required in grams to mix1L of a5%salt solution,multiply.053by1000g(35.27oz.,the mass of 1L of water).This formula yields a result of53g(1.87oz.)of NaCl required for each liter of water to achieve a5%salt solution by mass.The0.053multiplier for the sodium chloride used above is derived by the following:1000g~mass of a full L of water!divided by0.95~water is only95%of the total mixture by mass!yields1053gThis1053g is the total mass of the mixture of one L of water with a5%sodium chloride concentration.1053g minus the original weight of the L of water,1000g, yields53g for the weight of the sodium chloride.53g of total sodium chloride divided by the original1000g of water yields a0.053multiplier for the sodium chloride.As an example:to mix the equivalent of200L(52.83gal)of5%sodium chloride solution,mix10.6kg(23.37lb)of sodium chloride into200L(52.83gal)of water. 200L of water weighs200,000g.200,000g of water x.053(sodium chloride multiplier)=10,600g of sodium chloride,or10.6kg.B In order to ensure that the proper salt concentration was achieved when mixing the solution,it is recommended that the solution be checked with either a salimeter hydrometer or specific gravity hydrometer.When using a salimeter hydrometer,the measurement should be between4and6%at25°C(77°F).When using a specific gravity hydrometer,the measurement should be between1.0255and1.0400at 25°C(77°F).8.2The pH of the salt solution shall be such that when atomized at35°C(95°F)the collected solution will be in the pH range from6.5to7.2(Note3).Before the solution is atomized it shall be free of suspended solids(Note4).The pH measurement shall be made at25°C(77°F)using a suitable glass pH-sensing electrode,reference electrode,and pH meter system in accordance with Test Method E70.N OTE3—Temperature affects the pH of a salt solution prepared from water saturated with carbon dioxide at room temperature and pH adjust-ment may be made by the following three methods:(1)When the pH of a salt solution is adjusted at room temperature,and atomized at35°C(95°F),the pH of the collected solution will be higher than the original solution due to the loss of carbon dioxide at the higher temperature.When the pH of the salt solution is adjusted at room temperature,it is therefore necessary to adjust it below6.5so the collected solution after atomizing at35°C(95°F)will meet the pH limits of6.5to 7.2.Take about a50-mL sample of the salt solution as prepared at room temperature,boil gently for30s,cool,and determine the pH.When the pH of the salt solution is adjusted to6.5to7.2by this procedure,the pH of the atomized and collected solution at35°C(95°F)will come within this range.(2)Heating the salt solution to boiling and cooling to35°C(95°F)and maintaining it at35°C(95°F)for approximately48h before adjusting the pH produces a solution the pH of which does not materially change when atomized at35°C(95°F).(3)Heating the water from which the salt solution is prepared to35°C (95°F)or above,to expel carbon dioxide,and adjusting the pH of the salt solution within the limits of6.5to7.2produces a solution the pH of which does not materially change when atomized at35°C(95°F).N OTE4—The freshly prepared salt solution may befiltered or decanted before it is placed in the reservoir,or the end of the tube leading from the solution to the atomizer may be covered with a double layer of cheesecloth to prevent plugging of the nozzle.N OTE5—The pH can be adjusted by additions of dilute ACS reagent grade hydrochloric acid or sodium hydroxide solutions.9.Air Supply9.1The compressed air supply to the Air Saturator Tower shall be free of grease,oil,and dirt before use by passing through well-maintainedfilters.(Note6)This air should be maintained at a sufficient pressure at the base of the Air Saturator Tower to meet the suggested pressures of Table2at the top of the Air Saturator Tower.N OTE6—The air supply may be freed from oil and dirt by passing it through a suitable oil/water extractor(that is commercially available)to stop any oil from reaching the Air Saturator Tower.Many oil/water extractors have an expiration indicator,proper preventive maintenance intervals should take these into account.9.2The compressed air supply to the atomizer nozzle or nozzles shall be conditioned by introducing it into the bottom of a towerfillwed with water.A common method of introduc-ing the air is through an air dispersion device(X1.4.1).The level of the water must be maintained automatically to ensure adequate humidification.It is common practice to maintain the temperature in this tower between46and49°C(114–121°F)to offset the cooling effect of expansion to atmospheric pressure during the atomization process.Table2in9.3of this practice shows the temperature,at different pressures,that are com-monly used to offset the cooling effect of expansion to atmospheric pressure.9.3Careful attention should be given to the relationship of tower temperature to pressure since this relationship can have a direct impact to maintaining proper collection rates(Note7). It is preferable to saturate the air at temperatures well above the chamber temperature as insurance of a wet fog as listed in Table2.N OTE7—If the tower is run outside of these suggested temperature and pressure ranges to acheive proper collection rates as described in10.2of this practice,other means of verifying the proper corrosion rate in the chamber should be investigated,such as the use of control specimens (panels of known performance in the test conducted).It is preferred that control panels be provided that bracket the expected test specimen performance.The controls allow for the normalization of test conditions during repeated running of the test and will also allow comparisons of test results from different repeats of the same test.(Refer to Appendix X3, Evaluation of Corrosive Conditions,for mass loss procedures).10.Conditions in the Salt Spray Chamber10.1Temperature—The exposure zone of the salt spray chamber shall be maintained at35+1.1−1.7°C (95+2−3°F).Each set point and its tolerance represents an operational control point for equilibrium conditions at a single location in the cabinet which may not necessarily represent the uniformity of conditions throughout the cabinet.The tempera-ture within the exposure zone of the closed cabinet shall be recorded(Note8)at least twice a day at least7h apart(except on Saturdays,Sundays,and holidays when the salt spray test is not interrupted for exposing,rearranging,or removing test specimens or to check and replenish the solution in the reservoir)N OTE8—A suitable method to record the temperature is by a continu-ous recording device or by a thermometer which can be read from outside the closed cabinet.The recorded temperature must be obtained with the salt spray chamber closed to avoid a false low reading because of wet-bulb effect when the chamber is open.10.2Atomization and Quantity of Fog—Place at least two clean fog collectors per atomizer tower within the exposure zone so that no drops of solution will be collected from the test specimens or any other source.Position the collectors in the proximity of the test specimens,one nearest to any nozzle and the other farthest from all nozzles.A typical arrangement is shown in Fig.1.The fog shall be such that for each80 cm2(12.4in.2)of horizontal collecting area,there will be collected from1.0to2.0mL of solution per hour based on an average run of at least16h(Note9).The sodium chloride concentration of the collected solution shall be561mass% (Notes9-11).The pH of the collected solution shall be6.5to 7.2.The pH measurement shall be made as described in8.2 (Note3).N OTE9—Suitable collecting devices are glass or plastic funnels with TABLE2Suggested Temperature and Pressure guideline for the top of the Air Saturator Tower for the operation of a test at35°C(95°F)Air Pressure,kPa Temperature,°C Air Pressure,PSI Temperature,°F 83461211496471411711048161191244918121the stems inserted through stoppers into graduated cylinders,or crystal-lizing dishes.Funnels and dishes with a diameter of 10cm (3.94in.)have an area of about 80cm 2(12.4in.2).N OTE 10—A solution having a specific gravity of 1.0255to 1.0400at 25°C (77°F)will meet the concentration requirement.The sodium chloride concentration may also be determined using a suitable salinity meter (for example,utilizing a sodium ion-selective glass electrode)or colorimetrically as follows.Dilute 5mL of the collected solution to 100mL with distilled water and mix thoroughly;pipet a 10-mL aliquot into an evaporating dish or casserole;add 40mL of distilled water and 1mL of 1%potassium chromate solution (chloride-free)and titrate with 0.1N silver nitrate solution to the first appearance of a permanent red coloration.A solution that requires between 3.4and 5.1mL of 0.1N silver nitrate solution will meet the concentration requirements.N OTE 11—Salt solutions from 2to 6%will give the same results,though for uniformity the limits are set at 4to 6%.10.3The nozzle or nozzles shall be so directed or baffled that none of the spray can impinge directly on the test specimens.11.Continuity of Exposure11.1Unless otherwise specified in the specifications cover-ing the material or product being tested,the test shall be continuous for the duration of the entire test period.Continu-ous operation implies that the chamber be closed and the spray operating continuously except for the short daily interruptions necessary to inspect,rearrange,or remove test specimens,to check and replenish the solution in the reservoir,and to make necessary recordings as described in Section 10.Operations shall be so scheduled that these interruptions are held to a minimum.12.Period of Exposure12.1The period of exposure shall be as designated by the specifications covering the material or product being tested or as mutually agreed upon between the purchaser and the seller.N OTE 12—Recommended exposure periods are to be as agreed upon between the purchaser and the seller,but exposure periods of multiples of 24h are suggested.13.Cleaning of Tested Specimens13.1Unless otherwise specified in the specifications cover-ing the material or product being tested,specimens shall be treated as follows at the end of the test:13.1.1The specimens shall be carefully removed.13.2Specimens may be gently washed or dipped in clean running water not warmer than 38°C (100°F)to remove salt deposits from their surface,and then immediately dried.14.Evaluation of Results14.1A careful and immediate examination shall be made as required by the specifications covering the material or product being tested or by agreement between the purchaser and the seller.15.Records and Reports15.1The following information shall be recorded,unless otherwise prescribed in the specifications covering the material or product being tested:15.1.1Type of salt and water used in preparing the salt solution,15.1.2All readings of temperature within the exposure zone of the chamber,15.1.3Daily records of data obtained from each fog-collecting device including the following:15.1.3.1V olume of salt solution collected in millilitres per hour per 80cm 2(12.4in.2),15.1.3.2Concentration or specific gravity at 35°C (95°F)of solution collected,and15.1.3.3pH of collectedsolution.N OTE —This figure shows a typical fog collector arrangement for a single atomizer tower cabinet.The same fog collector arrangement is also applicable for multiple atomizer tower and horizontal (“T”type)atomizer tower cabinet constructions as well.FIG.1Arrangement of FogCollectors15.2Type of specimen and its dimensions,or number or description of part,15.3Method of cleaning specimens before and after testing, 15.4Method of supporting or suspending article in the salt spray chamber,15.5Description of protection used as required in6.5, 15.6Exposure period,15.7Interruptions in exposure,cause,and length of time, and15.8Results of all inspections.N OTE13—If any of the atomized salt solution which has not contacted the test specimens is returned to the reservoir,it is advisable to record the concentration or specific gravity of this solution also.16.Keywords16.1controlled corrosive environment;corrosive condi-tions;determining mass loss;salt spray(fog)exposureAPPENDIXES(Nonmandatory Information)X1.CONSTRUCTION OF APPARATUSX1.1CabinetsX1.1.1Standard salt spray cabinets are available from several suppliers,but certain pertinent accessories are required before they will function according to this practice and provide consistent control for duplication of results.X1.1.2The salt spray cabinet consists of the basic chamber, an air-saturator tower,a salt solution reservoir,atomizing nozzles,specimen supports,provisions for heating the cham-ber,and suitable controls for maintaining the desired tempera-ture.X1.1.3Accessories such as a suitable adjustable baffle or central fog tower,automatic level control for the salt reservoir, and automatic level control for the air-saturator tower are pertinent parts of the apparatus.X1.1.4The size and shape of the cabinet shall be such that the atomization and quantity of collected solution is within the limits of this practice.X1.1.5The chamber shall be made of suitably inert mate-rials such as plastic,glass,or stone,or constructed of metal and lined with impervious plastics,rubber,or epoxy-type materials or equivalent.X1.1.6All piping that contacts the salt solution or spray should be of inert materials such as plastic.Vent piping should be of sufficient size so that a minimum of back pressure exists and should be installed so that no solution is trapped.The exposed end of the vent pipe should be shielded from extreme air currents that may causefluctuation of pressure or vacuum in the cabinet.X1.2Temperature ControlX1.2.1The maintenance of temperature within the salt chamber can be accomplished by several methods.It is generally desirable to control the temperature of the surround-ings of the salt spray chamber and to maintain it as stable as possible.This may be accomplished by placing the apparatus in a constant-temperature room,but may also be achieved by surrounding the basic chamber of a jacket containing water or air at a controlled temperature.X1.2.2The use of immersion heaters in an internal salt solution reservoir or within the chamber is detrimental where heat losses are appreciable because of solution evaporation and radiant heat on the specimens.X1.3Spray NozzlesX1.3.1Satisfactory nozzles may be made of hard rubber, plastic,or other inert materials.The most commonly used type is made of plastic.Nozzles calibrated for air consumption and solution-atomized are available.The operating characteristics of a typical nozzle are given in Table X1.1.X1.3.2It can readily be seen that air consumption is relatively stable at the pressures normally used,but a marked reduction in solution sprayed occurs if the level of the solution is allowed to drop appreciably during the test.Thus,the level of the solution in the salt reservoir must be maintained automatically to ensure uniform fog delivery during the test.8 X1.3.3If the nozzle selected does not atomize the salt solution into uniform droplets,it will be necessary to direct the spray at a baffle or wall to pick up the larger drops and prevent them from impinging on the test specimens.Pending a com-plete understanding of air-pressure effects,and so forth,it is important that the nozzle selected shall produce the desired 8A suitable device for maintaining the level of liquid in either the saturator tower or reservoir of test solution may be designed by a local engineering group,or may be purchased from manufacturers of test cabinets as an accessory.TABLE X1.1Operating Characteristics of Typical Spray Nozzle SiphonHeight,cmAir Flow,dm3/min Solution Consumption,cm3/hAir Pressure,kPa Air Pressure,kPa34691031383469103138 101926.531.5362100384045845256 201926.531.536636276037204320 301926.531.5360138030003710 401926.631.536078021242904SiphonHeight,in.Air Flow,L/minSolutionConsumption,mL/hAir Pressure,psi Air Pressure,psi51015205101520 41926.531.5362100384045845256 81926.531.536636276037204320 121926.531.5360138030003710 161926.631.536078021242904condition when operated at the air pressure selected.Nozzles are not necessarily located at one end,but may be placed in the center and can also be directed vertically up through a suitable tower.X1.4Air for AtomizationX1.4.1The air used for atomization must be free of grease, oil,and dirt before use by passing through well-maintainedfilters.Room air may be compressed,heated,humidified,and washed in a water-sealed rotary pump if the temperature of the water is suitably controlled.Otherwise cleaned air may be introduced into the bottom of a towerfilled with water through a porous stone or multiple nozzles.The level of the water must be maintained automatically to ensure adequate humidification.A chamber operated in accordance with this method and Appendix X1will have a relative humidity between95and 98%.Since salt solutions from2to6%will give the same results(though for uniformity the limits are set at4to6%),it is preferable to saturate the air at temperatures well above the chamber temperature as insurance of a wet fog.Table X1.2 shows the temperatures,at different pressures,that are required to offset the cooling effect of expansion to atmospheric pressure.X1.4.2Experience has shown that most uniform spray chamber atmospheres are obtained by increasing the atomizing air temperature sufficiently to offset heat losses,except those that can be replaced otherwise at very low-temperature gradi-ents.X1.5Types of ConstructionX1.5.1A modern laboratory cabinet is shown in Fig.X1.1. Walk-in chambers are usually constructed with a sloping ceiling.Suitably located and directed spray nozzles avoid ceiling accumulation and drip.Nozzles may be located at the ceiling,or0.91m(3ft)from thefloor directed upward at30to 60°over a passageway.The number of nozzles depends on type and capacity and is related to the area of the test space.An11 to19L(3to5-gal)reservoir is required within the chamber, with the level controlled.The major features of a walk-in type cabinet,which differs significantly from the laboratory type, are illustrated in Fig.X1.2.Construction of a plastic nozzle, such as is furnished by several suppliers,is shown in Fig.X1.3.TABLE X1.2Temperature and Pressure Requirements forOperation of Test at95°FAir Pressure,kPa8396110124 Temperature,°C46474849Air Pressure,psi12141618 Temperature,°F114117119121。
