In the case of O rings, the first thing to pay attention to is its specifications, but there is another factor that is easier to ignore, that is, the hardness of the O rings. How much hardness should be selected for the O rings? In fact, it depends on the pressure in the sealing system of the product itself.
Among the products sealed by the O ring seal, according to the pressure in the sealing system, rubber materials with different hardnesses are designed for the O ring seal. For high pressure, high-hardness rubber should be used, and for low pressure, medium-hardness or medium-hardness or Low hardness compound.
In order to improve product quality and service life, the rubber hardness has been serialized in national standards. For example: nitrile rubber used in hydraulic systems, except for special requirements, the rubber hardness is divided into 60°±5°, 70°±5 °, 80°±5°, 88°±5° (Shore a) four hardnesses to meet the requirements of different pressures.
Generally 60-70 is low hardness, 80 is medium hardness, 88 is high hardness, the sealing pressure is in the range of 30-60mpa, and the hardness of O ring seal is 85-90.
Therefore, whether it is material or hardness, it needs to be determined according to the working conditions of the product itself.