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สหรัฐอเมริกา
ASTM
C978-04(2019)
Standard Test Method for Photoelastic Determination of Residual Stress in a Transparent Glass Matrix Using a Polarizing Microscope and Optical Retardation Compensation Procedures
2019
10
ASTM Vol.15.02 (2022)
The quality and performance of an article of glassware may be affected not only by the presence of residual stresses due to heat treatment above the strain point in the ware, but also by additional residual stresses caused by differences in thermal expansion between the glass substrate, and either cord, fired-on vitreous enamel, or ACL decoration.
The effects of those additional residual cord, enamel, or ACL stresses and the resulting performance of such items may be evaluated by performance test procedures. Such evaluations of enamel or ACL stresses may also be accomplished through the determination of appropriate physical properties of the decoration and matrix glass, or by analytical methods.
This test method offers a direct and convenient means of determining the magnitudes and spatial distributions of residual stress systems in glass substrates. The test method is simple, convenient, and quantitatively accurate.
This test method is useful in evaluating the degree of compatibility between the coefficient of thermal expansion of an enamel or ACL applied to a glass substrate.