1、Designation: B183 79 (Reapproved 2014)Standard Practice forPreparation of Low-Carbon Steel for Electroplating1This standard is issued under the fixed designation B183; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This practice is intended as an aid
3、 to electroplaters insetting up a suitable cleaning cycle preparatory to electroplat-ing of low-carbon steel (Note 1) containing less than 0.35mass % of carbon and to indicate some of the precautions thatmust be taken to maintain this cycle in good operatingcondition.NOTE 1The preparation of high-ca
4、rbon steel for electroplating iscovered in Guide B242.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
5、ibility 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 Documents2.1 ASTM Standards:2B242 Guide for Preparation of High-Carbon Steel for Elec-troplatingB322 Guide for Cleaning Met
6、als Prior to Electroplating3. Nature of Cleaning3.1 The preparation of low-carbon steel for electroplatinginvolves three basic steps in the following order:3.1.1 Removal of oil, grease, and caked-on dirt,3.1.2 Removal of scale and oxide films by “pickling,” and3.1.3 Removal of any smut left on the s
7、urface after step3.1.2 and activation of the steel.3.2 Removal from the steel of fabricating lubricants andfinishing compounds may have to be undertaken by “preclean-ing” before the articles reach the electroplating room. Theremainder of the operations should immediately precede theelectroplating. I
8、n some instances separate removal of smut maynot be necessary as in the case of parts which are barrel-electroplated and tumbled.4. Cleaning Solutions and Apparatus4.1 All solutions should be subject to chemical control,including determinations of the free acid and iron contents ofthe pickling solut
9、ions and acid dips, and such tests of thecleaning solutions as recommended by the manufacturer.4.2 Based on tests and experience, all solutions should bediscarded before they have lost their effectiveness.4.3 To conserve cleaning and pickling solutions and toensure continuous operation when heavy pr
10、oduction isinvolved, doubling of facilities in the same line of operationmay be desirable. This arrangement will result in a high degreeof contamination of the first of two solutions of the same kindwhile the second ones will be sufficiently clean to continue touse. It will also reduce the degree of
11、 contamination ofsubsequent solutions, for example, by oil and grease.4.4 As an alternative to the procedure described in 4.3, thecleaner and pickle tanks may be provided with a large damoverflow and a pump having its intake placed about half-waydown the overflow dam between the accumulated grease a
12、ndoil on top and the settled-out solid dirt at the bottom, andhaving its outlet placed near the bottom of the tank at the endopposite to the dam overflow.4.5 Separate tank electrodes, removable from the tank forinspection and cleaning, should be used. Contact hooks for theelectrodes should be of the
13、 inverted V-type for round tank barsand should be of sufficient size to carry the required current.4.6 Rinse tanks should be arranged with a dam overflow,and any water inlet other than a spray should be placed so asto ensure thorough circulation of the water and a large workingsurface free from grea
14、se accumulation. An adequate flow ofwater is essential.1This practice is under the jurisdiction of ASTM Committee B08 on Metallicand Inorganic Coatingsand is the direct responsibility of Subcommittee B08.02 onPre Treatment.Current edition approved Nov. 1, 2014. Published November 2014. Originallyapp
15、roved in 1943. Last previous edition approved in 2009 as B183 79(2009). DOI:10.1520/B0183-79R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Docume
16、nt Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.7 Heating coils should be placed on the work-piece side ofthe tank in order to assure a working surface free from greaseaccumulation.5. Procedure for
17、 Racked Parts5.1 The cycle described in 5.2 to 5.6 should be used for thepreparation of racked parts subsequently electroplated in stilltanks, agitated tanks, semi- and full-automatic equipment,except in those cases described in Section 6.5.2 PrecleaningIn general, it is necessary to removefabricati
18、ng lubricants, buffing compounds, and other soils byprecleaning. This precleaning may be accomplished withalkaline soak cleaners, cleaners designed to remove buffingcompounds (including the use of ultrasonic cleaners), alkalinespray cleaners, and the use of chlorinated solvents such astrichloroethyl
19、ene and perchloroethylene in vapor-type degreas-ing equipment, or by use of cold chlorinated solvents if vaporequipment is not available. Precleaning normally should beaccomplished as soon as possible after fabrication becausemany stamping lubricants and buffing compounds becomemuch more difficult t
20、o remove if allowed to age on the steelsurface and can chemically attack the substrate causing etch-ing.5.3 ElectrocleaningThe part to be cleaned should beanodically (reverse) electrocleaned in a solution of a suitablycompounded, free-rinsing, high-conductivity steelelectrocleaner, at a concentratio
21、n of about 45 to 90 g/L. Thecurrent density should preferably be between 5 and 6 A/dm2and the tank voltage about 6 V. The temperature should bebetween 60 and 90C. The time of cleaning following aneffective precleaning operation is usually between 1 and 4 min.If proprietary cleaners are used, the rec
22、ommendations of themanufacturer should be followed.5.4 Water RinseImmerse the part to be cleaned in clean,overflowing water for a minimum of 15 s. If possible, airagitation of the water rinse should be provided. If the water isvery cold, below 10C, slight warming is beneficial. A freshwater spray on
23、 the part as it enters and leaves the rinse tankhelps ensure complete rinsing.5.5 Acid PicklingPickle the part in a solution of 150 to500 mL of concentrated, 31 mass %, hydrochloric acid (density1.16 g/mL) diluted to 1 L, 100 mL of concentrated, 93 mass %,sulfuric acid (density 1.83 g/L) diluted to
24、1 L, or a solution ofproprietary acid salts at room temperature, for a sufficientlength of time to remove all oxides, rust, or scale. (WarningThe acid should be added to the approximate amount of waterrequired and then after thorough mixing, diluted to exactvolume.)5.6 Alkaline DescalingIn place of
25、acid pickling (5.5)itissometimes found that alkaline descaling may be more practi-cal. Such solutions are operated at about 40C and averagecurrent density of 2 to 5 A/dm2. A typical bath compositionmay be as follows:Sodium hydroxideSodium cyanideChelating agent180g/L120 g/L(EDTA-NTA gluconates) 80 g
26、/LWhen using this method it must be followed by a water rinse(5.4), an acid dip (5.5), and water rinse (5.4).5.7 Water RinseRinse the part again, as described in 5.4but in a separate tank.6. Variations in Procedure for Racked Parts6.1 Consideration should be given to separate precleaningbetween manu
27、facturing operations; for example, between gear-cutting and deburring operations, and between drawing orstamping and buffing operations.6.2 Vapor phase degreasing with chlorinated solvents is anexcellent way to remove mineral oil form recesses such asoverlapping joints that cannot be cleaned by any
28、other method.6.3 Plants with limited facilities sometimes omit preclean-ing especially with work that is not too heavily soiled. This ispermissible; however, electrocleaning time may have to beincreased and it is almost always necessary to change electro-cleaners more frequently. Likewise, close con
29、trol is necessaryto ensure proper electrocleaner concentration at all times.6.4 While pickling in strong hydrochloric acid or acid saltsin accordance with 5.5 is suitable for most oxide conditions,including heavy annealing scale, welding marks, or wheelburns, it may sometimes be preferable to use ho
30、t sulfuric acid(about 100 mL of concentrated, 93 mass %, sulfuric acid(density 1.83 g/mL) diluted to 1 L) containing a suitableinhibitor to protect the steel from over pickling (see Warningin 5.5). The acid temperature may vary between 50 and 70C.When inhibitors are used, a second alkaline cleaning
31、operation,preferably electrocleaning, should follow pickling to removeany adsorbed inhibitor.6.5 Heavy scale may be removed more rapidly by makingthe part to be pickled either anodic or cathodic in a 50 to 100mL of concentrated, 93 mass %, sulfuric acid (density 1.83g/mL) diluted to 1 L or proprieta
32、ry acid salt solution at atemperature of 50 to 65C and an average current density ofabout 4 A/dm2(see Warning in 5.5). Anodic pickling avoidshydrogen embrittlement. Cathodic pickling provides a brightersurface provided the acid is not contaminated with heavymetals such as copper, tin or lead.6.6 In
33、addition to acid pickling, scale may be removed byshot-blasting, tumbling, or sandblasting. These methods avoidhydrogen embrittlement but may work-harden the surface.6.7 When there is a lapse of time between the final rinsingoperation (5.6) of the preparatory cleaning process andelectroplating, arra
34、ngements should be made for temporarystorage of parts. Those which are to be electroplated in acyanide solution may be stored in a solution of 15 to 30 g/L ofsodium cyanide and an equal amount of sodium hydroxide atroom temperature. Those which are to be electroplated in analkaline solution such as
35、alkaline tin, should be stored in asolution containing 8 g/L of sodium hydroxide at roomtemperature. Storage time for parts to be nickel electroplatedshould be minimized but, if necessary, they may be held inclean cold water for a very short time (3 or 4 min, dependingon water quality).B183 79 (2014
36、)27. Procedure for Parts in Bulk7.1 The cycle described in 7.2 to 7.5 should be used forcleaning part to be electroplated in barrels, hand-operated orautomatic, except in those cases described in Section 8.7.2 Alkaline CleaningClean the parts by tumbling with orwithout current, in a solution of 30 t
37、o 60 g/L of a suitablealkaline cleaner at 60 to 90C. Anodic electrocleaning at about2 to 4 A/dm2may supplement tumbling for more effectivecleaning.7.3 Water RinseRinse the parts in clean, overflowingwater. Air agitation of the rinse water is beneficial. If the wateris very cold, rinsing is improved
38、by some warming.7.4 Acid PicklingPickle in a solution of 150 to 500 mL ofconcentrated, 31 mass %, hydrochloric acid (density 1.16g/mL) diluted to 1 L at room temperature. Other suitablepickling solutions are proprietary acid salts and 50 to 150 mLof concentrated, 93 mass %, sulfuric acid (density 1.
39、83 g/mL)diluted to 1 L (see Warning in 5.5).7.5 Water RinseRinse the parts again as described in 7.3,using a separate tank.8. Variations in Procedure for Bulk Parts8.1 Two water rinses after both cleaning and acid picklingare beneficial in many barrel electroplating operations. Thisserves to ensure
40、more complete rinsing and thus preventcarry-over of cleaners or acids into subsequent tanks.8.2 Heavily scaled parts such as heat-treated nuts and boltsmay require pickling in strong inhibited sulfuric acid (see 6.4).Tumble-pickling is preferred to immersion-pickling in bulkbecause the tumbling acti
41、on increases the rate of scale andoxide removal.8.3 StorageIf parts must be stored after cleaning andpickling prior to electroplating, the procedure described in 6.7should be followed.NOTE 2Additional information on procedures for cleaning of low-carbon steel prior to electroplating may be found in
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46、oveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 79 (2014)3
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