ASTM F428-2003a Standard Test Method for Intensity of Scratches on Aerospace Glass Enclosures《航空航天用玻璃外壳抗划痕硬度的标准试验方法》.pdf
《ASTM F428-2003a Standard Test Method for Intensity of Scratches on Aerospace Glass Enclosures《航空航天用玻璃外壳抗划痕硬度的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM F428-2003a Standard Test Method for Intensity of Scratches on Aerospace Glass Enclosures《航空航天用玻璃外壳抗划痕硬度的标准试验方法》.pdf(4页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: F 428 03aStandard Test Method forIntensity of Scratches on Aerospace Glass Enclosures1This standard is issued under the fixed designation F 428; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the visual inspection ofscratches on the glass surface of aerospace transparent enclo-sures.1.2 This stand
3、ard may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicabi
4、lity of regulatory limitations prior to use.2. Referenced Documents2.1 Other Standards:Glass Scratch Visual Comparison Standard23. Summary of Test Method3.1 A visual comparison is made between a set of gradedscratch standards and the scratch on the glass aerospacetransparency to determine the relati
5、ve intensity of the scratch.4. Significance and Use4.1 Scratches exist on all glass surfaces. Often there are veryfine scratches from cleaning operations that are not visiblewhen looking through the glass. Visible scratches may bedistracting to the observer looking through the enclosure.Therefore, a
6、 procedure to define scratches is useful. A visualstandard is used because it is not practical to measure thedimensions of the fine scratches in the scope of this testmethod.5. Reference Materials5.1 Glass Scratch Visual Comparison Standard consists of aset of six hermetically sealed glass plates 38
7、 mm (1.5 in.)square with scratches of graded intensity on the inside surface.The lightest scratch is identified as ASTM F 428-3 and theheaviest as ASTM F 428-8.36. Procedure6.1 Place the part in a suitable inspection position. This maybe horizontal on a padded table, vertical against a neutral todar
8、k background, or at an angle simulating the installedposition. The scratched surface shall be toward the observer.The light level shall be a minimum of 80 lux. Either natural orartificial light may be used. If possible, move the light until thescratch has the highest contrast against the background.
9、 Placethe scratch in the visual comparison standard beside andparallel to the scratch in question. Rotate the part or viewingangle to get the best definition of the scratch. Disregarding thelength of the scratch on the part and on the standard, select andrecord the standard that most closely matches
10、 the appearanceof the scratch on the part. Measure and record the length of thescratch to the nearest 1 mm (or 0.05 in.).7. Interpretation7.1 Customer specifications for aerospace glass surfacedtransparent enclosures may detail allowable frequency, loca-tion, length, and standard number for scratche
11、s and they mayassign maximum scratch limits for critical and noncriticaloptical viewing areas.8. Report8.1 For each scratch within the scope of the glass scratchstandard, report its standard number, length, frequency, andlocation.9. Precision and Bias49.1 Precision:9.1.1 The repeatability of judging
12、 the intensity of a scratchwithin one scratch value, for the same observer, is 90 % orbetter.9.1.2 The reproducibility (between observers) of judgingthe intensity of a scratch within two scratch values is 87 % orbetter.1This test method is under the jurisdiction of ASTM Committee F07 onAerospace and
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