Summary of Technical Requirements for Pressure Vessels (19)

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Mandatory requirements for high-temperature vessels: The mandatory requirements for vessels operating at high temperatures (≥200°C) are as follows: 01 For austenitic steels, when the operating temperature is above 525°C, the carbon content in the steel must be ≥0.04%. 02 For Q370R steel plates designed for temperatures above 200°C, and for 18MnMoNiR, 13MnNiMoR, and 12Cr2Mo1VR steel plates designed for temperatures above 300°C, high-temperature tensile tests at the design temperature shall be conducted on the steel plates as required; the yield strength values are given in Appendix B. 03 For Grade III or Grade IV forgings of 20MnMoNb, 20MnNiMo, 12Cr2Mo1V, and 12Cr3Mo1V designed for temperatures above 300°C, the design documents shall specify that high-temperature tensile tests at the design temperature be carried out in batches (for Grade III) or on a piece-by-piece basis (for Grade IV); the yield strength values are given in Appendix B. 04 For forged steels of 12Cr2Mo1, 12Cr2Mo1V, and 12Cr3Mo1V intended to meet the requirements regarding resistance to temper embrittlement, the technical documents shall specify the special requirements for their chemical composition and mechanical properties. 05 When the design temperature is greater than 300°C, a lining composite structure shall not be used. 06 When the design temperature is greater than 300°C, strength expansion joining shall not be used. 07 For tower-type vessels, when the design temperature of the lower head of the tower shell is ≥ 400°C, an air barrier should be installed at the upper part of the skirt near the head.