Why does the boiler standard allow a thickness exemption for heat treatment in 15CrMo, while pressure vessels do not permit such an exemption?
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Dear teachers, according to the boiler standard GB/T16507, heat treatment after welding can be waived for Fe-4-1 material at certain thicknesses; however, GB/T150 requires heat treatment after welding for 15CrMoR regardless of its thickness. Why is there a threshold thickness at which heat treatment after welding can be exempted in the boiler standard for the same material, while such an exemption is not allowed in the pressure vessel standard?
The heat treatment types are different. Boilers undergo high-temperature tempering, while pressure vessels are annealed.
Are different media, structures, and thicknesses (sizes) considered, given that the inside of the boiler is mostly composed of water and steam?
This question should be asked to the standards-setting body.
This post was last edited by qqsbig001 on 2022-11-8 15:27; it’s not part of a unified system. American-style and Soviet-style.
Experts in the container industry are gradually taking control of the boiler industry; who knows, it might be the same in the future.
It should be considered from the perspective of the operating medium; many heat treatment processes are determined by factors related to the medium.
In my opinion, the selection criteria for materials in boilers and pressure vessels are different; boilers are designed to prevent damage caused by high temperatures and creep, while pressure vessels focus on strength
This post was last edited by Li Hongwei on 2022-11-11 08:10. The ambient temperature of the materials is used as the basis for calculations; the materials used in boilers are exposed to high temperatures, while pressure vessels differ in that they may operate within a wider range of temperatures. The risk of brittle fracture that may occur is also more severe.