1 Scope
This part of GB/T 7962 specifies the test methods, test steps and data processing for the average linear thermal expansion coefficient, transformation temperature and yield point temperature of colourless optical glass.
This part is applicable to the tests on the average linear thermal expansion coefficient, transformation temperature and yield point temperature of colourless optical glass.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 7962, constitute provisions of this part. For dated references, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
GB/T 903 Colourless optical glass
3 Terms and definitions
For the purposes of this part, the following terms and definitions apply.
3.1
average linear thermal expansion coefficient
αL
elongation per unit length of the sample under test for each 1℃ increase in temperature within a certain temperature range
3.2
transformation temperature
Tg
temperature corresponding to the intersection between the extended straight line parts of the low-temperature area and the high-temperature area on the expansion curve of the sample under test
3.3
yield point temperature
Ts
temperature at which the structure of the sample under test yields and starts to collapse in the temperature rise process
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatus
6 Sample
7 Test steps
8 Data processing
