1、Designation: C536 83 (Reapproved 2014)1Standard Test Method forContinuity of Coatings in Glassed Steel Equipment byElectrical Testing1This standard is issued under the fixed designation C536; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, 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.1NOTEIntroduction added and units abbreviations corrected editorially in June 2014.INTRODUCTIONThis procedure
3、 is a high-voltage discharge test used to locate defects in glass-lined tanks bygrounding the base metal of the test specimen and brushing the test specimen with a probe connectedto the high-voltage side of the test instrument. If a discontinuity exists, a spark will discharge throughthe defect to t
4、he ground provided by the metal.1. Scope1.1 This test method covers the detection of discontinuitiesin the glass coating of glassed steel equipment where suchdiscontinuities would result in early failure due to the attack ofthe chemical contents of the vessel on the metal substrate. It isapplicable
5、to ( 1) provide a manufacturing and inspection testof glassed-steel equipment designed for relatively mild, low-temperature corrosive service, and (2) the field testing ofsimilar equipment used in more severely corrosive environ-ment.NOTE 1A manufacturing test method for the latter type of equipment
6、is described in Test Method C537.1.2 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 theresponsibility of the user o
7、f this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Document2.1 ASTM Standards:2C537 Test Method for Reliability of Glass Coatings onGlassed Steel Reaction Equipment by High Voltage3. Summary of T
8、est Method3.1 The test method consists essentially of grounding themetal structure of the equipment being tested to the ground sideof a voltage generator and sweeping the surface of the glasswith a suitable probe electrically connected to the other side ofthe generator. Wherever a discontinuity exis
9、ts, a discharge willgive a positive indication that such a discontinuity exists. Thevoltage is set at 5000 V in order to show existing discontinui-ties without breaking through the existing glass coating. Abuilt-in current limiting device ensures electrical safety for theoperator.4. Significance and
10、 Use4.1 This test method is designed to detect existing discon-tinuities in the glass coating of glassed steel equipment whilemaintaining a voltage low enough as to be unlikely to causebreakdown of the coating. The test is adaptable for manufac-turing inspection in the processing of equipment and fo
11、r fielduse to find existing defects which can be “plugged” or repairedbefore serious damage is done to the equipment. As a means ofpositive detection, it is applicable to process studies, qualitycontrol, or specification.5. Definition5.1 glassed steel (glass-lined steel or glass-coated steel)designa
12、tions generally applied to a class of porcelain enamelsthat have high resistance to chemical attack at elevatedtemperatures and pressures.6. Interferences6.1 Since the test method is electrical, it is necessary to havea good ground connection between the instrument and the1This test method is under
13、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 May 1, 2014. Published June 2014. Originallyapproved in 1964. Last previous edition appro
14、ved in 2009 as C536 83 (2009).DOI: 10.1520/C0536-83R14E1.2For 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 Document Summary page onthe ASTM website.Copy
15、right ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1metal substrate of the equipment being tested. It is alsonecessary that the surfaces of the glass be reasonably clean anddry. A wet surface will conduct enough voltage to any exposedmetal to
16、 give an indication of a “contact” over a large areainstead of at a specific area of discontinuity. Such a capacitancedischarge can be distinguished from a true failure by extendingover a large area instead of at local spots that could beidentified and marked for repair.7. Apparatus37.1 The test app
17、aratus comprises a voltage stabilizingtransformer, a step-up transformer, a current-limitingresistance, a voltmeter and pilot light, along with a suitablyinsulated cable and probe handle equipped with interchange-able wire brush-type and point electrodes (see Fig. 1 for aschematic wiring diagram). T
18、he current output is limited to 2.5mA. The wire brush-type electrode is designed for sweepinglarger areas of glass coating while the point electrode is betteradapted to corners and the more restricted areas.7.2 A portable 5000 V dc tester may be used in this testmethod.8. Safety Precautions8.1 The e
19、quipment being tested should be well grounded aswell as electrically connected to the ground side of the testingapparatus.8.2 The probe should be handled only by the insulatingplastic handle.8.3 Keep the probe electrode away from personnel and fromconducting surfaces that might lead to personnel.8.4
20、 Turn the switch off and ground the electrode beforechanging probe heads. Although the current is low enough tobe electrically safe, the involuntary reaction to a surprisedischarge can cause injury.9. Procedure9.1 Using a 14 gauge (1.63 mm) (or heavier) wire, connectthe ground connection of the test
21、er to the cleaned metalsubstrate of the equipment to be tested. A similar connectionshould be made to a suitable external ground.9.2 Attach the probe cable to the tester and the desired probeelectrode to the end of the probe handle.9.3 Connect the input to a 115 to 120 V, 60 Hz source, or usea porta
22、ble 5000 V dc unit.9.4 While holding the probe by the plastic handle move theswitch to the on position. A red pilot light indicates that thetester is in operation.9.5 Apply the test probe lightly to the surface of the glasscoating in a sweeping motion to cover the whole area to betested. If the inte
23、rferences are not too great, a spark should alsobe seen and heard as it arcs between the electrode and the metalsubstrate.9.6 Mark each area where a contact is found using suitablycolored chalk or crayon.9.7 Turn the switch off and ground the electrode to the metalground before laying the probe down
24、 or changing the elec-trodes on the probe.10. Report10.1 The report shall include the following:10.1.1 Date of test,10.1.2 Description or identification of equipment beingtested, and10.1.3 Number and location of failures.11. Precision and Bias11.1 No justifiable statements can be made regarding thep
25、recision and bias of this test method because it is designed forapplication to full-size production vessels and reactors with theresult that variables due to design, metal composition,fabrication, and metal processing, as well as porcelainenameling, are introduced into the results.12. Keywords12.1 c
26、ontinuity of coating; discontinuities; glass coated steelequipment; glass coating; high voltage test; porcelain enamel3When requesting information, specific reference should be made to the ASTMdesignation number.FIG. 1 Circuit Diagram, 5000 V ac TesterC536 83 (2014)12ASTM International takes no posi
27、tion 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 such rights, are entirely their own responsibili
28、ty.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 additional standardsand should be addressed to AST
29、M 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 the ASTM Committee on Standards, at the address
30、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 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).C536 83 (2014)13
