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Global Glass Balls

Global glass Balls are dimensionally stable, resistant to corrosion and chemical absorption and can withstand high temperatures up to 290°C.
Glass balls vary in density depending on the type of glass they are made from. They are widely used in applications that require balls of certain specific gravity. The surface can be alternatively polished or matte.

Soda-lime

Soda-lime Glass Balls are made from the most prevalent type of glass for
windows and containers. They are inexpensive, chemically stable, reasonably hard, and extremely workable. Soda-lime Glass Balls are resistant to high alkaline solutions and mainly used for applications not subjected to strong mechanical or thermal shocks, such as plastic bearings, flow meters, ink cartridges and ball-valves of sprayers in cosmetics and pharmaceutical sectors.

Physical Properties

Linear Thermal Expansion: Th (20-300°C) 9.2 •10-6 K-1
Transformation temperature: Tg 515 °C
Softening Point: 695 °C
Young’s Modulus: 72 Gpa
Hardness: (Moh's) 6
Density: ρ at 20 °C 2.52 g•cm-3
Refractive index: (λ = 587.6nm) nd 1.518

Chemical Composition (main components in approx. weight %)

SiO2 Na2O CaO K2O Al2O3 MgO
62—74% 12—16% 5—11% 1—2% 1—3% 1—2%
Chemical Properties
Hydrolytic Class (DIN ISO 719) HGB 3
Acidic Class (DIN 12116) S 2
Alkaline Class (DIN 695) A 2

Borosilicate Glass Balls

Borosilicate glass balls are made from the special glass of the first hydrolytic class, which is well-known for its stability and pressure resistance, good workability and high thermal shock resistance due to its low rate of thermal expansion.
Borosilicate glass balls are resistant to corrosion and remain absolutely neutral, even to aggressive chemicals in nearly all fields of chemistry. It is extremely resistant to water, acids, organic substances and halogens and it also has a high alkali resistance.
Borosilicate glass balls are particularly suitable for metering pumps and valves against strong oxidizing concentrations.

Physical Properties

Linear Thermal Expansion, Th (20-300°C) 3.3 •10-6 K-1
Transformation temperature Tg 530 °C
Softening Point 820 °C
Young’s Modulus 64 Gpa
Hardness (Moh's) 7
Density ρ at 20 °C 2.23 g•cm-3
Refractive index (λ = 587.6nm) nd 1.473

Chemical Composition

(main components in approx. weight %)
SiO2 B2O3 Na2O + K2O Al2O3
81% 13% 4% 2%

Chemical Resistance

Hydrolytic Class (DIN ISO 719) HGB 1
Acidic Class (DIN 12116) S 1
Alkaline Class (DIN 695) A 2

Quality and Tolerance

Standard Diameter Tolerance ± 0.02mm
Standard Roundness / Sphericity ≤0.02mm
Special Diameter Tolerance ± 0.01mm
Special Roundness / Sphericity ≤0.01mm
Surface Finish Matte / Polished