Under long-term exposure to high temperatures, the creep-rupture strength of a material is significantly lower than its short-term tensile strength; furthermore, the corrosive effect of the internal medium (such as oxidation) is intensified by the high temperature. Materials for high-temperature pressure vessels are selected based on operating temperatures and media-typically utilizing high-temperature strength steels or heat-resistant steels, and in some cases, superalloys.
High-temperature pressure vessels generally require a design life exceeding 100,000 hours, necessitating appropriate material selection and stress analysis during the design phase. To ensure safe operation, industry standards have been issued for critical components-such as "Surface Temperature Detectors for High-Temperature Pressure Vessels" (JB/T 15306-2025), which came into effect on November 1, 2025. Since a certain degree of change in shape and dimensions is typically permissible during service, material selection relies primarily on high-temperature creep-rupture strength and corrosion resistance. Stress analysis for these vessels is complex, making theoretical solutions difficult to derive; however, modern practice has demonstrated that the finite element method is a viable approach. If the vessel is subjected to cyclic loading (such as repeated pressurization and depressurization), the interaction between fatigue (see fatigue strength design) and creep must also be considered. In recent years, progress has been made in technologies for preventing and controlling creep-fatigue damage in welded structures of high-temperature pressure vessels and piping; these technologies have formed a comprehensive system covering design, manufacturing processes, and life prediction, and have been successfully applied to major pressure-bearing equipment in key sectors.
