1、Designation: C694 90a (Reapproved 2016)Standard Test Method forWeight Loss (Mass Loss) of Sheet Steel During Immersionin Sulfuric Acid Solution1This standard is issued under the fixed designation C694; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONIn the manufacture of porcelain-enameled ware, some formed steel articles are pretreate
3、d with acidand a nickel deposit to ensure one coat enamel adherence. The pretreatment comprises, in part, ofetching the steel surface with sulfuric acid solution and in depositing nickel on the steel surface froma nickelous sulfate solution. Conditions are maintained to provide a minimum amount of m
4、etalremoval (weight loss) (mass loss) in the acid solution and a minimum amount of nickel deposition.These minimums are particularly critical in direct-on enameling in which the ground-coat enamel withits adherence promoting oxides is omitted.1. Scope1.1 This test method covers the evaluation of the
5、 weight-loss (mass loss) characteristics 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
6、the standard. The values in parentheses are 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 appli
7、ca-bility of regulatory limitations prior 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 spec
8、imens are selected,measured, cleaned, and weighed prior to immersion for mea-sured periods in a bath of dilute sulfuric acid that has beenpreconditioned by controlled solution of panels of the samesheet steel. The specimens are rinsed, dried, and reweighedafter the timed exposure.3.2 Values of weigh
9、t loss (mass loss) per unit area arecalculated 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) charact
10、eristics of a given lotof sheet steel in 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
11、sys-tem in preparing the steel for porcelain 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) an
12、d an outside depth of about 11 in.(280 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 5.3.1This test method is
13、under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatingsand is the direct responsibility of Subcommittee B08.12 onMaterials for Porcelain Enamel and Ceramic-Metal Systems.Current edition approved Nov. 1, 2016. Published November 2016. Originallyapproved in 1971. Last previous ed
14、ition approved in 2011 as C694 90a (2011).DOI: 10.1520/C0694-90AR16.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.6 Stainless Steel Jig, for support of test specimens (seeFig. 1, Fig. 2, and Fig. 3).6. Reagents and Materials6.1 Di
15、stilled Water.6.2 Isopropyl Alcohol (CH3)2CHOH).6.3 Methyl Alcohol (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 s
16、teel sheet of 6.4. Use these panels in the precondi-tioning in accordance 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), Ameri
17、can Chemical Society(ACS) reagent grade.6.6 Trisodium Phosphate(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
18、 identification stamp.7.1.2 Identify the specimens by steel die 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 testsp
19、ecimens to the nearest 0.01 in. (nearest 1 mm).8.1.3 Thoroughly 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 (ma
20、ss), W1, of each testspecimen to the nearest 0.01 g.8.2.1 Store 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.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 JigC694 90a (2016)29.1.1 Control the cleaner temperature at 190 to 195F (88 to91C).9.2 Cleaner RinseAt least 19 L of tap water.9.2.1 Control the rinse temperature at 170
22、 6 5F (77 63C).9.3 Sulfuric Acid SolutionAdd 765 mL of ACS reagentgrade 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 immersio
23、n heater.9.3.2 Control the acid temperature at 155 6 1F (68 6 1C).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 solutio
24、n todissolve a total of 15 to 30 g of iron. Do not add iron powderor 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
25、 not in use.9.4 Acid RinseAt least 19 L of tap water.9.4.1 Adjust 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 f
26、or com-plete immersion of two panels.9.6.1 Maintain the alcohol 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
27、 accordance with 10.3.2.10.3 Transfer the eight specimens to the 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
28、 10.2 and 10.3.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 JarC694 90a (2016)310.3.2 If water breaks are observed after repeating 10.2 and10.3 three times, prepare a new cleaner solution and repeat10.2 10.3
29、.1.10.3.3 Discard the cleaner rinse after processing each groupof 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
30、 of two specimens from the acid solution(Fig. 3) to the acid rinse 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 s
31、pecimens for 30 s.10.6.2 Discard the final rinse after processing 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
32、.10 Determine the final weight (mass), Wf, of eachspecimen to 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 72Wi2 Wf!/L 3W! (1)where:Wi= initial panel weight (mass), g,Wf= final panel weight (mass), g,L = length of
33、panel, in., andW = width of panel, in.11.2 Calculate the weight loss (mass loss) in grams persquare decimetre of surface, Y, using Eq 2:Y 5 5Wi2 Wf!103!/L 3W! (2)where:Wi= initial panel weight (mass), g,Wf= final panel weight (mass), g,Metric Equivalentsin.145165834 212 35612(mm) (6.4) (8) (16) (19)
34、 (63.5) (76) (127) (165)FIG. 3 Panels Being Removed from Acid Solution After 5-min ImmersionC694 90a (2016)4L = length of panel, mm, andW = width of panel, mm.12. Report12.1 The report shall include the following:12.1.1 Calculated weight loss (mass loss) per unit area andimmersion time for each of t
35、he eight panels,12.1.2 Average weight loss (mass loss) per unit 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
36、 3.99 6 0.255 g/ft2(55.42 6 3.54 g/m2) for repeatability and 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
37、 prior to the testing of the samples and its source,and (2) the 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
38、 minimize them.ASTM International takes no position respecting 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 s
39、uch rights, are entirely their own responsibility.This standard 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 add
40、itional standardsand should be addressed to ASTM International 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 t
41、he ASTM Committee on Standards, at the address shown below.This 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 th
42、e aboveaddress 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:/ 90a (2016)5
