Can the steel tubes specified in GB/T8163 be used for pressure vessel nozzles without vacuum treatment?

After the implementation of the new GB/T 150-2024 standard, the material requirements for pressure vessel shells (including nozzles) generally must comply with the relevant provisions in GB/T 150. In accordance with the requirements of GB/T150-2024, the steel used for pressure elements in pressure vessels should be killed steel, and it usually needs to be smelted or treated through (out-of-furnace refining or vacuum degassing) in order to improve the purity of the material and the stability of its properties. Seamless steel pipes in accordance with the GB/T8163 standard are used for the transportation of ordinary fluids, and there is no explicit requirement for vacuum treatment processes such as secondary refining or vacuum degassing. Therefore, if the steel pipes specified in standard GB/T8163 have not undergone vacuum treatment that meets the requirements of GB/T150-2024 (such as secondary refining and vacuum degassing), they generally cannot be used directly in pressure vessel shells and their connecting fittings, which are the main pressure-bearing components. Conclusion: After the implementation of GB/T150-2024, GB/T8163 pipes that have not undergone the corresponding vacuum treatment process do not meet the requirements of pressure vessel standards in principle; therefore, they cannot be used for the nozzles of actual pressure vessels. .

Clause 5.2.1 of GB/T8163-2018 states that \"Steel should be produced by using an electric arc furnace with post-furnace refining or an oxygen converter with post-furnace refining.\" The steel grades specified in GB/T8163-2018 for use in pipes already meet the requirements of GB/T150-2024

During the training on standard implementation, it seems that the training materials mentioned that secondary refining includes vacuum treatment. But for some reason, emphasis was placed once again on vacuum treatment in the end.