Mechanical properties of pressure vessel plates
The failure of pressure vessels usually occurs when the mechanical stress generated by internal pressure reaches the strength limit of the vessel material. However, when the temperature decreases to a certain range, the stress in the container wall can also occur without reaching the yield limit, or even below the allowable stress.
The lower the temperature of a container of the same material and specification, the lower the bursting pressure of the container. This phenomenon is called low stress brittle failure. One of the main reasons for low stress damage of containers is that the impact energy value of steel at low temperatures decreases significantly.
Therefore, the quality of steel used at low temperatures largely depends on the impact energy value at the operating temperature. Pressure component materials in low-temperature vessels must undergo low-temperature Charpy (V-notch) impact testing, and steel should be subjected to impact testing and reinspection in batches. The steel used for pressure components of cryogenic vessels must be killed steel.
