1、Designation:C69490a(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 case o
2、f 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 pretreated with acidan
3、d 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 metalremoval(weigh
4、t 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 weight-loss(mass los
5、s)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 the standard.The values
6、 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 applica-bility of regulatory lim
7、itations 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 specimens are selected,measured,cl
8、eaned,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 weight loss(mass loss)per unit area arec
9、alculated 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 in di
10、lute 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 porcelain
11、 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 1112in.(290 mm)and an outside depth of about 11 in.(280 mm).5.4 Wate
12、r 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 under the jurisdiction ofASTM Committee B08 on Metallicand
13、 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 edition approved in 2011 as C694 90a(2011).DOI:10.1520/C0694-90AR
14、16.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.6 Stainless Steel Jig,for support of test specimens(seeFig.1,Fig.2,and Fig.3).6.Reagents and Materials6.1 Distilled Water.6.2 Isopropyl Alcohol(CH3)2CHOH).6.3 Methyl Alcohol(CH3OH).6.4
15、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 accordance with 9.3.3
16、 and 9.3.4.6.4.2 Shear ten to twelve14by 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(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