1、Designation: C 536 83 (Reapproved 2004)e1Standard Test Method forContinuity of Coatings in Glassed Steel Equipment byElectrical Testing1This standard is issued under the fixed designation C 536; 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 (e) indicates an editorial change since the last revision or reapproval.e1NOTEKeywords were added editorially in September 2004.1. Scope1.1 This test method covers the detection
3、 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 to (1) provide a manufacturing and inspection test ofglassed-steel equipment desi
4、gned 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 equipmentis described in Test Method C 537.1.2 This standard does not purport to address al
5、l 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 to use.2. Referenced Document2.1 ASTM Standards:2C 537 Test Method for
6、 Reliability of Glass Coatings onGlassed Steel Reaction Equipment by High Voltage3. Summary of Test 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 suitab
7、le probe electrically connected to the other side ofthe generator. Wherever a discontinuity exists, 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.
8、 Abuilt-in current limiting device ensures electrical safety for theoperator.4. Significance and 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 co
9、ating. The test is adaptable for manufac-turing inspection in the processing of equipment and for 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,
10、or specification.5. Definition5.1 glassed steel (glass-lined steel or glass-coated steel)designations 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 nec
11、essary to havea good ground connection between the instrument and themetal 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 give an indication of a “contact” over a
12、 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 apparatus comprises a voltage stabilizing tr
13、ans-former, a step-up transformer, a current-limiting resistance, a1This test method is under the jurisdiction of ASTM 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 ap
14、proved Aug. 1, 2004. Published September 2004. Originallyapproved in 1964. Last previous edition approved in 1998 as C 536 83 (1998).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume infor
15、mation, refer to the standards Document Summary page onthe ASTM website.3When requesting information, specific reference should be made to the ASTMdesignation number.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.voltmeter and pilot
16、 light, along with a suitably insulated cableand probe handle equipped with interchangeable wire brush-type and point electrodes (see Fig. 1 for a schematic wiringdiagram). The current output is limited to 2.5 mA. The wirebrush-type electrode is designed for sweeping larger areas ofglass coating whi
17、le the point electrode is better adapted tocorners and the more restricted areas.7.2 A portable 5000-volt d-c tester may be used in this testmethod.8. Safety Precautions8.1 The equipment being tested should be well grounded aswell as electrically connected to the ground side of the testingapparatus.
18、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 Turn the switch off and ground the electrode beforechanging probe heads. Although the current is low enough tobe electric
19、ally safe, the involuntary reaction to a surprisedischarge can cause injury.9. Procedure9.1 Using a 14-gage (1.63-mm) (or heavier) wire, connectthe ground connection of the tester to the cleaned metalsubstrate of the equipment to be tested. A similar connectionshould be made to a suitable external g
20、round.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, oruse a portable 5000-volt d-c unit.9.4 While holding the probe by the plastic handle move theswitch to the on position. A red pilot lig
21、ht 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 interferences are not too great, a spark should alsobe seen and heard as it arcs between the electrode and the metalsubstra
22、te.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 or changing the elec-trodes on the probe.10. Report10.1 The report shall include the following:10.1.1 Date of test,10.
23、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 theprecision and bias of this test method because it is designed forapplication to full-size production vessels and reactor
24、s with theresult that variables due to design, metal composition, fabrica-tion, and metal processing, as well as porcelain enameling, areintroduced into the results.12. Keywords12.1 continuity of coating; discontinuities; glass coated steelequipment; glass coating; high voltage test; porcelain ename
25、lFIG. 1 Circuit Diagram, 5000 V A-C TesterC 536 83 (2004)e12ASTM 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 pa
26、tent rights, and the riskof infringement of such 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 ei
27、ther for revision of this standard or for additional 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
28、 hearing you shouldmake your views known to the 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 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 536 83 (2004)e13
