Glass beads do not have a fixed melting point because glass is an amorphous non-crystalline solid. Instead, it has a softening temperature range—as temperature rises, glass beads gradually soften, decrease in viscosity, and eventually turn into a molten state, rather than melting abruptly at a specific temperature.
The softening and melting temperature ranges of glass beads vary significantly depending on their chemical composition. The key parameters for common types are as follows:
- Soda-lime glass beads (the most widely used, for sandblasting, filling, daily use)
- Softening temperature range: 500–600°C
- When the temperature exceeds 600°C, the viscosity drops rapidly, and the beads gradually become viscous fluid. They fully melt into a liquid state at 1400–1500°C.
- Borosilicate glass beads (heat-resistant type, for laboratory use, high-temperature filling)
- Softening temperature range: 800–900°C
- It has better heat resistance and lower thermal expansion coefficient than soda-lime glass, and is not easy to deform at high temperatures.
- Fused silica glass beads (high-purity heat-resistant type, for high-end optics, semiconductor manufacturing)
- Softening temperature range: 1600–1700°C
- With ultra-high purity (SiO₂ ≥ 99.9%), it has the best heat resistance among common glass types, and its full melting temperature can reach above 2000°C.
In practical applications, the so-called “melting point” of glass beads usually refers to their softening temperature or full melting temperature, which needs to be selected according to specific usage scenarios.