锅炉管道最小壁厚和壁温相关问题

teapaopao

锅炉过热器管道最小壁厚不同标准的计算公式不同，应该以哪个标准为准？
管道壁温是指管壁的平均温度么？

leehuahua

请知道的说说吧，宿便学习一下！

xiaoshugenliu

不知道你说的“不同标准的计算公式不同”是指的都是什么标准？ASME第I卷的preamble列出了第I卷的管辖范围，对照一下你的锅炉的用途、形式、参数范围在不在其中。
如果在第I卷的管辖范围内，可以按PG27，按管子的外径大小选用PG27.2.1或者PG27.2.2的公式计算；或者可以按A-317的公式计算。
确定最大许用应力时的管子(tubes)壁温是指预期的最高平均温度，指管子内外壁温度之和除以2；对于不受热的管子，可以取管内介质温度，但不小于其饱和温度。
PG-27.1 General. Unless the requirements of A-317 of Nonmandatory Appendix A are selected, the equations under this paragraph shall be used to determine the minimum required thickness or the maximum allowable working pressure of piping, tubes, drums, Shells, and headers in accordance with the appropriate dimensional categories as given in PG-27.2.1, PG-27.2.2, and PG-27.2.3 for temperatures not exceeding those given for the various materials listed in Section II, Part D, Subpart 1, Tables 1A and 1B.
PG-27.2.1 Tubing — Up to and Including 5 in. (125 mm) Outside Diameter.
PG-27.2.2 Piping, Drums, Shells, and Headers.
PG-27.4.2 The temperature of the metal to be used in selecting the S value for tubes shall not be less than the maximum expected mean wall temperature, i.e., the sum of the outside and inside tube surface temperatures divided by 2. For tubes that do not absorb heat, the metal temperature may be taken as the temperature of the fluid within the tube but not less than the saturation temperature.
A-317 CYLINDRICAL COMPONENTS UNDER INTERNAL PRESSURE
A-317.1 General. The requirements of this Appendix may be used in place of the requirements of PG-27 to determine the minimum required thickness or the maximum allowable working pressure of piping, tubes, drums, shells, and headers for temperatures not exceeding those given for the various materials listed in Section II, Part D, Subpart 1, Tables 1A and 1B.

Hadeshine

感谢楼主的分享！

hfmzx

不同标准确实计算公式不同，许用应力也不同。
应该按哪个标准为准，取决于你要按哪个标准去设计或者检验。
也就是说，如果你的锅炉是按ASME标准去设计制造（这个在锅炉技术协议里面有体现），那么就要遵循ASME标准的壁厚计算公式和许用应力；如果你们的锅炉是号称按国标16507设计制造，那么就要遵循16507的许用应力和壁厚计算公式。
如果您只是关心安全问题，那么满足哪一份标准都是安全的