1.目的/purpose：
规范与限制300系列不锈钢柠檬酸钝化作业流程，保证作业过程中的安全和作业后的产品品质/Stipulate Work Instruction of citric acid passivation on 300 series stainless steel. Make sure operation safety and parts quality。
2.范围/scope：
公司内部需要作柠檬酸钝化的300系列不锈钢产品（有其他特殊要求除外）/All the parts of 300 series stainless steel which needs citric acid passivation。
3.参考文件：reference documents
MIL-F-14072
ASTM A380
AMS QQ-P-35
AMS 2700
ASTM A967
   
4.相关设备：relative equipments
钝化槽、柠檬酸钝化液、去离子水passivaion container , citric acid solution , deionized water
钝化槽
槽体必须采用硬性PVC或 聚丙烯。辅助设备应采用塑料(PVC, PP) ，铁或其它金属禁止使用。
The material of container must be PVC or polypropylences, auxiliary equipments must be PVC ,PP, iron and other metal are not allow to use .
5. Ref. Inf. (参考资料)：
前处理
根据不同产品需要可能需增加以下前处理do below according the requirements of different products.
1. 预清洗precleaning
                               
预清洗就是在制造过程或最终清洗前去除油脂、油污、泥土、沙粒以及其他严重污染。预清洗并不像随后的清洗操作那么严格，一般也不那么彻底。材料都必须在热成型、退火以及其他高温操作前，在任何除锈处理前，在零件需要进入溶液进行最终清洗或是当清洗溶液需要重复使用时，材料应进行预清洗。产品需经过多次拉伸或一系列高温成型操作，其间需要退火处理的零件在每个加工程序后，在退火前都要进行清洗。预清洗可以通过蒸汽脱脂、浸泡、喷淋或用碱性或乳状洗调剂刷洗、压力蒸汽或高压水喷射清洗。Precleaning is the removal of grease ,oil,paint,soil,grit,and other gross contamination preparatory to a swabbingfabrication process or final cleaning.precleaning is not as critical and is generally not as thorough as subsequent cleaning operations .materials should be precleaned before hot-forming ,annealing ,or other high-temperature operation before any deacaling operation ,and before any finish-cleaning operations where the parts will be immersed or where the cleaning solutions will be reused ,items that are subject to several redraws or a serials of hot-forming operations ,with intermediate anneals ,must be cleaned after each forming operation, prior to annealing. Pre-cleaning may be accomplished by vapor degreasing ;immersion in ,spraying ,or swabbing with alkaline or emulsion cleaner ,steam ,or high-pressure water-jet.
   
2. 除锈de-scaling           
                           
2.1常规除锈——除锈就是去除那些因热成型、热处理、焊接以及其他高温操作而产生的紧密粘附的后氧化膜。因扎制产品通常以去除氧化皮状态供货，在设备制造或系统安装的过程中除锈（去除焊接产生的局部氧化皮除外）并不是必需的。如有必要，氧化皮可以通过以下的化学方法之一去除，或机械方法，（例如：研磨、喷砂、砂纸打磨、磨削、电刷），或是化学和机械方法相结合。General-de-scaling is the removal of heavy ,tightly adherent oxide films resulting from hot-forming ,heat-treatments, welding ,and other high-temperature operations because mill products are usually supplied in the de-scaled condition, de-scaling (except removal of localized scale resulting from welding )is generally not necessary during fabrication of equipments or erection of systems .when necessary ,scale may be removal by one of the chemical methods listed below ,by mechanical methods (for example ,abrasive blasting, sanding ,grinding ,power brushing ),or by a combination of these.
                               
2.2 化学除锈（酸洗）——化学除锈剂包括硫酸、硝酸和水溶液，溶融碱和盐浴以及各种专用配方。
Chemical de-scaling (pickling )-chemical de-scaling agents include aqueous solutions of sulfuric ,nitric ,and hydrofluoric acid ,molten alkali or salt baths ,and various proprietary formulations .                               
2.2.1酸洗——硝酸-混合溶液是不锈钢制造厂最广泛使用的，可同时去除金属污染及焊接和热处理氧化皮。    使用时应该谨慎控制，不推荐用于敏化奥氏体不锈钢或硬化马氏体不锈钢零件的除锈，或是可能与碳钢零件、组件、设备或系统接触的地方。单一的硝酸溶液去除厚的氧化皮通常无效。                            Acid picking –nitric –hydrofluoric acid solution is most widely used by fabricators of stainless steel equipments and removal both metallic contamination ,and welding and heat-treating scales .its use should be care fully controlled and is not recommended for de-scaling sensitized austenitic stainless steels or hardened martensite stainless steels or where it can come into contact with carbon steel parts ,assemblies ,equipment ,and systems .solutions of nitric acid alone are usually not effective for removing heavy oxide scale.
2.2.2欲除锈的表面通常化学处理前要预清洗。当产品的尺寸和形状许时，建议全部进入酸洗溶液中。当完全进入    不切实际时，除锈可以用下面方法进行：（1）用刷式或喷淋方法浸湿表面；（2）用酸洗溶液部分充满产品，经转动或摇动使所有表面都得到要求的化学处理。表面应保持与搅动的溶液接触大概15至30分钟，或直到检验表明已经完全去除氧化皮。没有搅动，可能需要增加曝露在酸洗溶液中的时间。如果摇动或搅动是不切实际的，酸洗溶液可以循环流经产品或系统，直到检验表明已经完全去除氧化皮。Surface to be de-scaled are usually pre-cleaned prior to chemical treatments. When size and shape permit, total immersion in the picking solution is preferred; where immersion is impractical, de-scaling may be accomplished by (1)wetting the surface by  swabbing or spraying ;or (2)by partially filling the item with picking solution and rolating or rocking to slosh the solution so that all surface receive the required chemical treatments .the surface should be kept in contact with agitated solution for about 15 to 30 min or until inspection shows that complete scale removal has been accomplished .without agitation ,additional exposure time may be required .if rocking or rotation are impracticable, picking solution may be circulated through the item or system until inspection show that de-scaling has been accomplished.
2.2.3 过渡酸洗必须避免。能否用酸洗均匀去除氧化皮取决于所用的酸、酸浓度、溶液温度和接触时间。连续曝露在酸洗溶液中超过30分钟是不推荐的。30分钟后，产品应排空并冲洗，检验处理的效果。可能需要额外的处理时间。大多数酸洗溶液会松动焊接和热处理氧化皮，但不能完全去除氧化皮。用不锈钢刷或毛刷不断地刷洗，接合酸洗或最初的冲洗，助于去除氧化皮和化学反应的产物（即酸污垢）。                        Over-picking must avoided ,uniform removal of scale with acid picking depends on the acid used ,acid concentration, solution temperature, and contact time .continuous exposure to picking solutions for more than 30 minis not recommended .the item should be drained and rinsed after 30 minutes examined to check the effectiveness of the treatment. additional treatments may be required .most picking soluions will loosen weld and heat-treating scale but may not remove them completely ,intermittent scrubbing with stainless steel brush or fiber-bristle brush, in conjunction with picking ir initial rinse ,may facilitate the removal of scale particles and products of chemical reaction .(that is ,pickling smut)   
2.2.4化学除锈后，表面必须彻底清洗，去除残留的化学剂；最终冲洗前有时必须经中和阶段。为尽可能减少污染，在相继的两个阶段酸洗除锈和冲洗过程之间不许干燥，并继最终水冲洗后马上进行彻底干燥。化学除锈方法的选择，应在零件处于其尽可能最简单的几何形状时，在后续制造或安装阶段产生内部缝隙或不能完全排空空间前进行，这些缝隙或空间可能截留除锈剂、污泥、粉末或污染的冲洗水，可能导致产品在投用后的最终腐蚀或对产品产生负作用。   
    After chemical de-scaling, surface must be thoroughly rinse to remove residual chemical ,a neutralization step is sometimes necessary before final rinsing. to minimize staining ,surface must not be permitted to dry between successive steps of the acid de-scaling and rinsing producer, and thorough drying should follow the final water rinse .chemical de-scaling methods ,factors in their selection ,when chemical de-scaling is necessary ,it should be done while the parts is in its simplest possible geometry, before subsequent fabrication ir installation steps create internal crevices or undrainable spaces that may trap de-scaling agents ,sludge ,particles ,or contaminated rinse water that might either result in eventual corrosion or adversely affect operation of the items after it is placed in service.                   
2.3机械除锈——机械除锈方法包括喷砂、电刷、砂纸打磨、磨削和铲削。机械除锈的方法的优点是不会产生晶间腐蚀、点蚀、氢脆、裂纹或污垢沉积。对于某些材料，特别是处于敏化状态的奥氏体不锈钢和硬化状态的马氏体不锈钢，机械除锈是唯一适合的方法。磨削通常是去除像焊接产生的局部氧化皮的最好方法。机械除锈方法的缺点是与化学除锈相比成本高，表面缺陷（如。褶皱，麻孔，毛刺）可能模糊不清，使其难以检测。    Mechanical descaling-mechanical descaling methods include abrasive blasting, power brushing ,sanding ,grinding, and chipping .Mechanical descaling methods has the advantage that they do not produce  such physical or chemical conditions ad intergranular attack, pitting ,hydrogen embrittlement,crack, or smut deposits. For some materials, in particular the austenitic stainless steels when in the sensitized condition and the martensitic stainless steels when in the hardened condition, mechanical descaling may be only suitable method. Grinding is usually the most effective means of removing localized scale such as that which result from welding .Disadvantages of mechanical descaling are cost ,as compared to chemical descaling ,and the fact that surface (for example ,laps,pits,slivers)may be obscured ,making them difficult to detect.
2.3.1要除锈的表面可能不得不进行预清洗。当对薄壁零件、抛光表面和接近公差的零件进行除锈时，必须特别小心，避免被机械方法损害。机械除锈后，表面应用热水和毛刷刷洗干净，接着用清浩的热水冲洗。    Surfaces to be descaled may have to be precleaned .particular care must be taken to avoid damage by mechanical methods when descaling thin sections, polished surfaces. And close-tolerance parts .after mechanical descaling, surface should be cleaned by scrubbing with hot water and fiber brushes, followed by rinsing with clean , hot water.                           
2.3.2砂轮和砂纸打磨材料不应含有铁、氧化铁、锌或其它可能引起金属表面污染的有害材料。在其它材料上用过的砂轮、砂纸打磨材料及钢丝刷不得应用于不锈钢。钢丝刷应用不锈钢制造，应与将要加工的材料有相同的耐腐蚀性能。Grinding wheels and sanding materials should not contain iron ,iron oxide ,zinc ,or other undersirable materials that may cause contamination of the metal surface .grinding wheels ,sanding materials ,and wire brushes previously used on other metals should not be used on stainless steel. wire brushes should be of a stainless steel which is equal in corrosion resistance to the material being worked on..
                               
2.3.3喷沙推荐使用清洗、未曾使用过的磨料，例如玻璃珠或无铁硅砂或氧化铝砂。因为金属微粒可能嵌入表面，不推荐使用金属丸或颗粒。使用不锈钢丸或颗粒降低生锈和铁污染的风险，但不能完全排除氧化铁的嵌入残留。    Clean ,previously unused abrasives ,such as glass beads or iron-free silica or alumina sand ,are recommended for abrasive blasting ,steel shot or grit is generally not recommended because of the possibility of  embedding iron particles .the use of stainless steel shot or grit reduces the danger of rusting and iron contamination, but can not completely eliminate the possibility of embedding residues of iron-oxide scale.
                           
2.3.4如果要求完全没有铁和氧化皮，最好在喷砂后接着做短时间的酸浸。                               
If a totally iron and scale free surface is required ,most abrasive blasting may be followed by a brief acid dip.
运行步骤
1.目视——清洗后的产品应无油漆、油、脂、焊剂、焊渣、热处理和热成型氧化皮（在某些表面焊接产生的紧密粘合氧化皮是允许的）、灰尘、垃圾、金属和磨料颗粒和废屑及其它严重污染。易引起沉积的大气尘土通常会存在与外表面，但不允许存在与内表面。目视检验应在一定光照下进行，包括通常的和补充的照明，至少为100尺烛光（10761x），最好在被检表面达到250尺烛光（26901x）。当必要时目视检验应辅以管道镜、镜子和其它辅助工具实地检查不可接近或难以看到的表面。灯的放置应防止被检验表面强光眩目。
Visual-items cleaned in accordance with this practice should be free of paint ,oil ,grease ,welding flux, slag, heat-treating and hot-forming scale (tightly adherent scale resulting from welding may be permissible on some surfaces),dirt, trash ,metal and abrasive particles and chips, and other gross contamination. Some deposited atmospheric dust will normally be present on exterior surfaces but should no be present on interior surfaces. Visual insperction should be carried out under a lighting level, including both general and supplementary lighting ,of at least 100 footcandles (1076lx),and preferably 250 footcandles (2690lx) on the surface being inspected. Visual inspection should be supplemented with borescopes, mirrors, and other aids, as necessary, to properly examine inaccessible or difficult-to-see surfaces, Lights should be positioned to prevent glare on the surfaces being inspected.
2.擦拭试验——用清洁、不掉绒的白棉布、商用纸或滤纸，以高纯度的溶剂润湿（但不要饱和），可以用于评价不可接近目视检验的表面洁净度。小直径管的擦拭试验，可以用清洁、干燥、过滤的压缩空气将一个清洁白的直径略大于管内径的毛毡球吹过管子。擦拭试验的洁净度抹布或毡球上擦下的污染类型来评价。抹布上的污迹表明污染存在。在对污染的有害性存在争议时，小污点的抽样可以送到清洁的显微镜水晶载物玻璃片上做红外分析。擦拭试验有时增加用黑布重复试验以检出白布上无法看到的污染。
Wipe test-rubbing of a surface with a clean,lint-free,white cotton cloth ,commercial paper product, or filter paper moistened (but not saturated) with high-purity solvent, may be used for evaluating the cleanness of surface  not accessible for direct visual inspection, Wipe tests of small diameter tubing are made by blowing a clean white felt plug, slightly larger in diameter than the inside diameter of tube, through the tube with clean ,dry, filtered compressed air cleanness in wipe tests is evaluated by the type of contamination rubbed off on the swab or plug, the present of a smudge on cloth is evidence of contamination .In case of dispute concerning the harmful nature of the contamination ,a sample of the smudge may be transferred to a clean quartz microscope slide for infrared analysis. The wipe test is sometimes supplemented by repeating the test with a black cloth to disclose contaminants that would be invisible on a white cloth.
开槽
1．加柠檬酸钝化液到槽中/add citric acid solution into the container。
2．加热到工作温度/heat the solution to required temperature。
3．检查运行条件，如果需要可以调整/Check all the requirements。
使用条件/operation requirements
参数如下/Parameter reference：                       
浓度/consistency:            4~10%                                 
温度/temperature:            21~49 ℃（70~120 ℉）                               
浸泡处理时间dip time:      30 min;   
2.3.5钝化后用去离子水清洗，按去离子水清洗作业指导书/clean the parts per SEN-075-A0；
2.3.6按烘干作业指引进行烘干/dry the parts per SEN-076-A0
6. BE Tanks Passivation Procedures/工序流程
1. 除锈/Descaling
  1.1 Bead blasting machine
1.2 #40 glass bead
1.3 Plug holes (SS plugs) to prevent entering of beads
1.4 Remove plugs after bead blasting
2. 超声除油/Ultrasonic Degreasing
  2.1 Cleaner– ZY-21 weak alkaline type cleaning detergent, 1:200 ratio by wt.
    2.2 Ultrasonic degreasing tank
    2.3 Parts completely immersed for 1 minutes min.,
3. 自来水洗/Water Rinsing
  3.1 overflowing water tanks
    3.2 use soft water conduit to rinse tank inside for 30 seconds min.
4. 去离子水洗/Deionized water rinsing
  4.1 overflowing water tanks
    4.2 use soft water conduit to rinse tank inside for 30 seconds min.
    4.3 no visible water bead on surface, if seen, degrease again
5.  柠檬酸钝化/Citric acid passivation
  5.1 Passivation tanks
5.2 Parameters
浓度/concentration:            4~10%                                 
温度/temperature:            21~49 ℃（70~120 ℉）                               
浸泡处理时间dip time:      30 minutes min.;   
6. 自来水洗/Water Rinsing
  6.1 overflowing water tanks, rinse outside for 30 sec. min.
    6.2 use soft water conduit to rinse tank inside for 30 seconds min.
7. 去离子水洗/Deionized water rinsing
  7.1 overflowing water tanks, rinse outside for 30 sec. min.
    7.2 use soft water conduit to rinse tank inside for 30 seconds min.
8. 烘干/Drying
  8.1 按烘干作业指引进行烘干/dry the parts per SEN-076-A0
7.操作全/operation safety:
飞溅事故或与皮肤或眼睛接触可能引起灼烧/splash on skin or eye may cause scorch。
万一接触到皮肤，马上用水冲洗然后用2.5%葡萄糖酸钙胶体按摩几分钟/If contact skin; Clean the skin with water, them use 2.5% calglucon to massage。
万一飞溅到眼睛里，马上用干净水冲洗，然后使用2％三乙醇胺滴眼液，马上就医/If splash to eyes, wash with water, then go to see doctor。
操作时建议戴手套，防护眼镜，防护服，安全鞋/Suggest to wear gloves, glasses, exposure suit and safety shoes。
不要使用玻璃或含硅的容器The glass contianers or silicic containers can’t be used。
8.检验标准/inspection standard：
检验方法参见《不锈钢件钝化的检测作业指引》 SQU-045/refer spec SQU-045。

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