The hardness of silicone sealing rings is an important parameter when selecting and applying them, usually expressed in Shore A hardness. The following is a detailed analysis of the hardness of silicone sealing rings:
1. Hardness Range
Silicone sealing rings have a wide range of hardness, usually ranging from 25 to 90 Shore A. Silicones of different hardness are suitable for different application scenarios:
Low hardness (25-40°A): Suitable for occasions requiring high elasticity and softness, such as children's toys or soft gaskets.
Medium hardness (40-60°A): Commonly used in electronic product housings or protective cases, with both elasticity and strength.
High hardness (60-90°A): Suitable for making wear-resistant and high-temperature resistant sealing rings or molds, such as automotive seals or injection molds.
2. Relationship between hardness and performance
Elasticity and compressibility: Low hardness silicone has higher elongation and lower tensile strength, suitable for applications that require bending or stretching; high hardness silicone has better wear resistance and deformation resistance.
Tear resistance: The lower the hardness, the better the tear resistance; the higher the hardness, the relatively weaker the tear resistance.
Abrasion resistance and fatigue resistance: High hardness silicone has better wear resistance in long-term use, but fatigue may decrease.
3. Application scenarios and recommended hardness
Y-type sealing ring: The recommended hardness is 85±2°A, suitable for high pressure environment.
O-type sealing ring: The recommended hardness is 75±5°A, suitable for general sealing needs.
Special environment: In low or high temperature environment, silicone sealing ring can still maintain good performance, with a minimum tolerance of -100°C and a maximum tolerance of more than 200°C.
4. Precautions for selecting hardness
Use environment: Select the appropriate hardness according to temperature, pressure and medium.
Sealing performance: High hardness silicone is not easy to leak under high pressure, but may lack elasticity; low hardness silicone is the opposite.
Cost and Quality: High-quality silicone seals are usually made of pure silicone, with stable hardness and excellent performance; inferior products may have uneven hardness and are easy to deform.
