The use temperature is another important factor affecting the permanent deformation of the O-ring seal. High temperatures can accelerate the aging of rubber materials. The higher the working temperature, the greater the compression permanent deformation of the O-ring. When the permanent deformation exceeds 40%, the O-ring loses its sealing ability and leaks. The initial stress value formed in the rubber material of the O-ring due to compression deformation will gradually decrease and disappear with the relaxation process and temperature decrease of the O-ring. The initial compression of O-ring seals that operate at temperatures below zero may decrease or completely disappear due to a sharp decrease in temperature. At temperatures ranging from -50 to -60 ℃, rubber materials that are not resistant to low temperatures will completely lose their initial stress; Even for low-temperature resistant rubber materials, the initial stress at this time will not be greater than 25% of the initial stress at 20 ℃. This is because the initial compression of the O-ring depends on the coefficient of linear expansion. Therefore, when selecting the initial compression amount, it is necessary to ensure that there is still sufficient sealing capacity after the stress decreases due to the relaxation process and temperature drop.
For O-ring seals operating at temperatures below zero, special attention should be paid to the recovery index and deformation index of the rubber material

In summary, the design should try to ensure that the O-ring has a suitable working temperature, or choose O-ring materials that are resistant to high and low temperatures to extend its service life.