Summary of Technical Requirements for Pressure Vessels (15)

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Mandatory requirements for low-temperature vessels: The mandatory requirements for low-temperature vessels (≤ -20°C) are as follows: 01 For low-alloy steel low-temperature pressure vessels designed for temperatures below -40°C, the surfaces of their welded joints must be inspected using magnetic particle or penetrant testing. 02 For low-temperature vessels made of carbon steel or low-alloy steel, the length for detecting surface defects during periodic inspections shall be not less than 20% of the length of the butt welds. 03 Low-temperature vessels made of carbon steel and low-alloy steel must not have weld undercutting. 04 For pressure vessels storing media at temperatures below 0°C, anti-frost level gauges should be used. 05 For level gauges used outdoors in cold areas, jacketed or insulated types should be selected. 06 It is used for designing steel plates intended for temperatures below -40°C; a drop hammer test can be conducted, in accordance with GB/T6803, using P-2 type specimens. The acceptance criteria regarding the temperature at which plasticity transformation occurs are specified in the design documents. 07 Steel pipes intended for use at temperatures below -20°C shall not have their normalizing heat treatment replaced by hot rolling, whose final rolling temperature corresponds to the normalizing temperature. 08 Steel pipes designed for temperatures below -40°C must undergo secondary refining outside the furnace.