An analysis of the reasons for the reduction in reliability of machinery structures under low temperature climate conditions

The influence of low temperature on the reliability of machine parts and on the characteristics of strength of steels and their weld joints is analyzed. It is established that a drop in temperature in impact cyclic loading causes a decrease in fatigue resistance of weld joints of low-alloy steels and a corresponding increase in relative frequency of crack formation in them. A comparison of experimental and service data shows that the increase in service relative frequency of crack formation in welded machine parts at reduced temperature is an indication of their fatigue origin. It was concluded that the increase in the frequency of failures of welded machine parts with a reduction in temperature observed under service conditions is caused by a reduction in their fatigue resistance and an increase in the tendency of their materials toward brittle fracture.