Glass - Double liner method for determination of coefficient of linear thermal expansion
1 Scope
This standard specifies the double liner method for determining the coefficient of linear thermal expansion of glass.
This standard is applicable to the determination of coefficient of linear thermal expansion of glass and glass containers that have compositions similar to the reference standard glass.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 16920 Glass - Determination of coefficient of mean linear thermal expansion
3 Principle
In this method, the reference standard glass with the known coefficient of linear thermal expansion is burnt together with the glass to be tested for the coefficient of linear thermal expansion in an overlapped way, and then they are drawn into thin filaments. As these two kinds of glass have different coefficients of linear thermal expansion, the thin filaments will bend, and the coefficient of linear thermal expansion of the glass to be tested can be determined according to the bending degree of thin filaments.
4 Appliance
4.1 Blowtorch, fueled by gas, liquefied petroleum gas, or natural gas, with compressed air or oxygen for combustion support.
4.2 Micrometer and support, with a minimum graduation value of 0.01mm.
4.3 Special clip, made of steel strap approximately 200mm long, 20mm wide, and 1mm thick. To prevent hand scalding, two insulating plates shall be inserted at the positions 100mm away from the front ends, as shown in Figure 1.
Foreword II
1 Scope
2 Normative references
3 Principle
4 Appliance
5 Test procedures
6 Test report
