1、Designation: C 694 90a (Reapproved 2006)Standard Test Method forWeight Loss (Mass Loss) of Sheet Steel During Immersionin Sulfuric Acid Solution1This standard is issued under the fixed designation C 694; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONIn the manufacture of porcelain-enameled ware, formed steel articles are pretreated
3、to ensureenamel adherence. The pretreatment comprises, in part, of etching the steel surface with sulfuric acidsolution and in depositing nickel on the steel surface from a nickelous sulfate solution. Conditions aremaintained to provide a minimum amount of metal removal (weight loss) (mass loss) in
4、the acidsolution and a minimum amount of nickel deposition. These minimums are particularly critical indirect-on enameling in which the ground-coat enamel with its adherence-promoting oxides is omitted.1. Scope1.1 This test method covers the evaluation of the weight-loss (mass loss) characteristics
5、of sheet steel in sulfuric acidsolution.1.2 This test method provides means of rating the effective-ness of in-plant pretreatment acid solutions in preparing steelsurfaces for porcelain enameling.1.3 The values stated in inch-pound units are to be regardedas the standard. The values in parentheses a
6、re for informationonly.1.4 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior
7、 to use.2. Terminology2.1 Definitions:2.1.1 quarter linesimaginary lines parallel to the directionof rolling, positioned at a distance from the sheet mill edgeequal to one quarter of the sheet width.3. Summary of Test Method3.1 Representative sheet-steel specimens are selected, mea-sured, cleaned, a
8、nd weighed prior to immersion for measuredperiods in a bath of dilute sulfuric acid that has been precon-ditioned by controlled solution of panels of the same sheetsteel. The specimens are rinsed, dried, and reweighed after thetimed exposure.3.2 Values of weight loss (mass loss) per unit area arecal
9、culated for the four acid immersion periods and, if desired,the rate of weight loss (mass loss) per unit area per unit time iscalculated.4. Significance and Use4.1 The results of this test method can be used to evaluatethe pickle weight-loss (mass loss) characteristics of a given lotof sheet steel i
10、n dilute sulfuric acid solution, and may enablethe enamel processor to select a pickling time that will providesatisfactory porcelain enamel bond.4.2 The results of this test method can be used to evaluatethe effectiveness of the enamel processors pretreatment sys-tem in preparing the steel for porc
11、elain enameling, and may aidthe processor in obtaining satisfactory porcelain enamel bond.5. Apparatus5.1 Analytical Balance, accurate to 0.01 g.5.2 Linear Measuring Device.5.3 Borosilicate Glass Container, having an inside diameterof about 1112 in. (290 mm) and an outside depth of about 11 in.(280
12、mm).5.4 Water Bath, heated, of sufficient size to immerse theglass container (5.3) to within about 1 in. (25 mm) of its top.5.5 Glass Plate or Acid-Resistant Porcelain-Enameled SteelSheet, sufficient to cover the container described in 5.3.5.6 Stainless Steel Jig, for support of test specimens (seeF
13、ig. 1, Fig. 2, and Fig. 3).1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 onMaterials for Porcelain Enamel and Ceramic-Metal Systems.Current edition approved April 1, 2006. Published April 200
14、6. Originallyapproved in 1971. Last previous edition approved in 2000 as C 694 90a (2000).1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Reagents and Materials6.1 Distilled Water.6.2 Isopropyl Alcohol (CH3)2CHOH).6.3 Methyl Alcoh
15、ol (CH3OH).6.4 Steel Sheet, sufficient in size to provide the panels andstrips described in 6.4.1 and 6.4.2, and to provide the testspecimens described in 7.1 and 7.1.1.6.4.1 Shear two to four 4 by 6-in. (102 by 152-mm) panelsfrom the steel sheet of 6.4. Use these panels in the precondi-tioning in a
16、ccordance with 9.3.3 and 9.3.4.6.4.2 Shear ten to twelve14 by 5-in. (6 by 127-mm) stripsfrom the steel sheet of 6.4. Fashion these strips into hooks forhanging test specimens from the stainless steel jig.6.5 Sulfuric Acid (H2SO4), American Chemical Society(ACS) reagent grade.6.6 Trisodium Phosphate(
17、Na3PO412H2O), granular,technical grade.7. Sampling7.1 Shear eight test specimens, each 4 by 6 in. (102 by 152mm), from within the quarter lines of the sheet or coil.7.1.1 Choose specimens from rust-free areas that do notcontain the mill identification stamp.7.1.2 Identify the specimens by steel die
18、stamping.8. Test Specimens8.1 File edges of the eight test specimens lightly to removeshearing burrs.8.1.1 Punch or drill a hole near one end, at the center of thespecimen width.8.1.2 Determine the width, W, and length, L, of the testspecimens to the nearest 0.01 in. (nearest 1 mm).8.1.3 Thoroughly
19、clean the specimens with methyl alcohol.(Thereafter, handle the specimens by the edges with cleanwhite gloves.)8.1.4 Dry in still air.8.1.5 Store the specimens in a desiccator until ready forweighing.8.2 Determine the initial weight (mass), W1, of each testspecimen to the nearest 0.01 g.8.2.1 Store
20、the specimens in a desiccator until ready to runthe test.9. Preparation of Solutions9.1 CleanerPrepare at least 19 L of 5 6 0.5 weight (mass)percent solution using 53 g of trisodium phosphate per litre oftap water.9.1.1 Control the cleaner temperature at 190 to 195F (88 to91C).Metric Equivalentsin.1
21、4 456(mm) (6) (102) (127) (127)NOTE 1All materials are of Type 316 stainless steel.FIG. 1 Specimens Suspended from Stainless-Steel JigC 694 90a (2006)29.2 Cleaner RinseAt least 19 L of tap water.9.2.1 Control the rinse temperature at 170 6 5F (77 63C).9.3 Sulfuric Acid SolutionAdd 765 mL of ACS reag
22、entgrade H2SO4to 16 900 mL of distilled water in the glasscontainer described in 5.3.9.3.1 Immerse the acid container to within about 1 in. (25.4mm) of its top in the heated water bath described in 5.4.Donotheat the acid with an immersion heater.9.3.2 Control the acid temperature at 155 6 1F (68 6 1
23、C).9.3.3 Process the two to four panels in 6.4.1 through thecleaner (9.1) and cleaner rinse (9.2) so that the panels arethoroughly cleaned, as evidenced by freedom from waterbreaks.9.3.4 Immerse the two to four panels in the acid solution todissolve a total of 15 to 30 g of iron. Do not add iron pow
24、deror chemicals such as ferrous sulfate (FeSO47H2O) to the acidto obtain the required dissolved iron.9.3.5 To avoid evaporation, place the glass plate or acid-resistant porcelain-enameled steel sheet on the acid containerwhen the acid is not in use.9.4 Acid RinseAt least 19 L of tap water.9.4.1 Adju
25、st the rinse to a pH of 2.5 to 3.0 with H2SO4.9.4.2 Maintain the acid rinse at room temperature.9.5 Final RinseAt least 19 L of tap water.9.5.1 Maintain the final rinse at room temperature.9.6 Isopropyl Alcohol RinseSufficient quantity for com-plete immersion of two panels.9.6.1 Maintain the alcohol
26、 rinse at room temperature.10. Procedure10.1 Suspend the eight specimens on the stainless steel jig(Fig. 1) using hooks made of metal strips (6.4.2).10.2 Immerse the specimens in the cleaner (9.1) for 10 min.10.2.1 Discard the cleaner in accordance with 10.3.2.10.3 Transfer the eight specimens to th
27、e cleaner rinse (9.2),and immerse the specimens for five 15-s periods (momentarilyremove the specimens from the rinse after each immersionperiod).10.3.1 If water breaks are observed on the specimens afterthe last immersion period, repeat 10.2 and 10.3.10.3.2 If water breaks are observed after repeat
28、ing 10.2 and10.3 three times, prepare a new cleaner solution and repeat10.2-10.3.1.Metric Equivalentsin.18145814 13(mm) (3.2) (6.4) (16) (19) (330)FIG. 2 Panels Immersed in Acid Solution with Jig Seated on Rim of Battery JarC 694 90a (2006)310.3.3 Discard the cleaner rinse after processing each grou
29、pof eight specimens.10.4 Transfer the eight specimens to the H2SO4solutiontaking care not to agitate the solution or the specimens (Fig. 2).10.4.1 Discard the acid solution after processing each groupof eight specimens.10.5 Transfer a set of two specimens from the acid solution(Fig. 3) to the acid r
30、inse at successive 5 min 6 5-s intervals.10.5.1 Agitate each set of two specimens for 1 min.10.5.2 Discard the rinse after processing each group of eightspecimens.10.6 Transfer each set of specimens to the final rinse.10.6.1 Agitate the specimens for 30 s.10.6.2 Discard the final rinse after process
31、ing each group ofeight specimens.10.7 Transfer the specimens to the isopropyl alcohol.10.7.1 Agitate the specimens for 30 s.10.8 Dry the specimens in still air.10.9 Place the specimens in the desiccator until they areready for weighing.10.10 Determine the final weight (mass), Wf, of eachspecimen to
32、the nearest 0.01 g.11. Calculation11.1 Calculate the weight loss (mass loss) in grams persquare feet of surface, X, using Eq 1:X 5 72Wi Wf!/L 3 W! (1)where:Wi= initial panel weight (mass), g,Wf= final panel weight (mass), g,L = length of panel, in., andW = width of panel, in.11.2 Calculate the weigh
33、t loss (mass loss) in grams persquare decimetre of surface, Y, using Eq 2:Y 5 5Wi Wf!103!/L 3 W! (2)where:Wi= initial panel weight (mass), g,Wf= final panel weight (mass), g,L = length of panel, mm, andW = width of panel, mm.12. Report12.1 The report shall include the following:12.1.1 Calculated wei
34、ght loss (mass loss) per unit area andimmersion time for each of the eight panels,Metric Equivalentsin.145165834 212 35612(mm) (6.4) (8) (16) (19) (63.5) (76) (127) (165)FIG. 3 Panels Being Removed from Acid Solution After 5-min ImmersionC 694 90a (2006)412.1.2 Average weight loss (mass loss) per un
35、it area foreach set of two panels at each immersion time, and12.1.3 Amount of iron dissolved in the acid solution (9.3.4).13. Precision and Bias13.1 PrecisionThe 95 % reproducibility limits showingthe difference between two test results is 3.99 6 0.255 g/ft2(55.42 6 3.54 g/m2) for repeatability and
36、3.99 6 0.581 g/ft2(55.42 6 8.07 g/m2) for reproducibility, where 3.99 g/ft2(55.42g/m2) is the weight (mass) loss.13.2 BiasThe major known sources of bias in this testmethod are: (1) the amount of iron dissolved in the sulfuricacid solution prior to the testing of the samples and its source,and (2) t
37、he requirement that the surface of the sheet steelsamples be clean and show no water break before they areimmersed in the sulfuric acid. Both of these sources of biashave been pointed out in this test method and the procedure isdesigned to minimize them.ASTM International takes no position respectin
38、g the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standa
39、rd is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Internationa
40、l Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.Th
41、is standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C 694 90a (2006)5
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