Why is the service life of the aluminum pressure cooker limited to 8 years?

After the pressure cooker is used for many years, the structure of the aluminum alloy crystal will undergo certain changes after high temperature and high pressure. The material becomes loose and causes a decrease in strength. However, these changes are very subtle and are generally difficult to detect by the naked eye. In response to the above situation, the country has conducted long-term testing and testing of more than 3,000 pressure cookers, and released statistical results. It has established that the service life of the pressure cooker is calculated as 1 hour per day, and its service life is 8 years. The user's service life should be much less than 8 years due to the high intensity of use, which is higher than 1 hour per day.