ASTM C1350M Viscosity of Glass by Beam Bending (Metric)

Scope:

Finding the density of glass by ASTM C1350M is essential for measuring the viscosity of glass in ranges higher than those covered by parallel plate and rotational viscometry. This test method helps provide information related to the behavior of glass when it has been changed into an object of business and in research and development. It is also used in experimental procedures that emphasize non-equilibrium conditions.

Test Procedure:

In ASTM C1350M, a sapphire or alumina specimen is used to generate a curve of background deflection against temperature. The deflection of the test specimen is then determined by subtraction of this background curve from the measured curve and the dimensions of the test beam are measured to the nearest 0.01 mm. A thin platinum foil is placed between the loading rod and the specimen to reduce friction. Weight to the hook is applied on the end of the extensometer, adjusting the total applied load to obtain a deflection rate.

Specimen Size : 

The platinum foil must be 25 µm thick. The samples can weigh in the range of 1 to 500 g.

Data:

In ASTM C1350M, viscosity is calculated using the viscosity (Ŋ) equation using the parameters Pa·s, M (applied load + loading train), g (acceleration of gravity) and other required parameters like c (cross-sectional moment of inertia), r (the density of glass), A (the cross-sectional area of the beam) and L (the support span).

Conclusion:

ASTM C1350M measures the viscosity of glass from approximately 10⁸ Pa·s to approximately 10¹³ Pa·s by determining the rate of viscous bending of a purely loaded glass beam.