Resistance to
Thermal Shock |
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According to DIN ISO 718, the resistance to thermal shock is the
difference in temperature between the hot test sample and the cold
water bath (room temperature) at which 50 % of all test samples show
a tendency to crack when quickly immersed. Resistance to thermal shock
of tubing, capillary and rod is dependent on the wall thickness, the
shape and size of the quenched area, the state of the surface, the
stress which may be present and the end finish. Fast, uneven heating
or cooling can easily lead to breakage as a result of tensile strength.
It is recommended not to exceed a temperature difference of 120 ºC.
For large wall thicknesses, this temperature is limited to lower values.
Listed below are some measured values to illustrate the resistance
to thermal shock of DURAN Borosilicate Glass 3.3 tubing and rod. These
should be used only as reference values as considerable differences
between tubing/rod of the same dimensions are possible.
Tubes |
OD 50.5 / WT 5.00 mm: 220 ºC |
Rod |
Diam. 24.0 mm: 140 ºC |
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OD 133.0 / WT 7.00 mm: 180 ºC |
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OD 120.0 / WT 8.00 mm: 180 ºC |
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The following graph shows the resistance to thermal shock of the
tubes Duran, Durobax, Fiolax Clear, Fiolax Amber, Illax and AR-Glas: |
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