Why in the pipe material grade table provided by the design institute is the temperature corresponding to a lower pressure value higher in the extreme condition column?
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Why in the pipe material grade table provided by the design institute is the temperature corresponding to a lower pressure value higher in the extreme condition column?
The properties of the material determine that as the temperature rises, its pressure-bearing capacity decreases. If the temperature column and the pressure column are swapped in position, there will be no misunderstandings. Attached is a partial screenshot of our material grade table: https://bbs.hcbbs.com/forum.php?mod=image&aid=1810564&size=300x300&key=84251c7bf573a157&nocache=yes&type=fixnone
Isn’t that normal? At over 1,000 degrees it turns into molten steel – how can it still withstand any pressure?
On one hand, there is the temperature and pressure at the flange, and on the other hand, there is the wall thickness of the pipe. It is recommended that the original poster take a look at HG20592, and also check out 20801. It becomes clear then
That’s right; under normal circumstances, it’s not possible for both pressure and temperature to be very high at the same time, as this would require extremely high standards for the material used.
This post was last edited by Liu Jiajia on 2019-4-30 at 10:34. It is determined based on the temperature-pressure values of the flange; as the temperature rises, the strength of the material decreases, and thus its capacity to bear pressure also drops. For example, when iron is heated red, it becomes soft; it’s the same principle.
As the temperature rises, the pressure-bearing capacity decreases – something that anyone who has worked in a chemical plant knows. I just want to ask: why is the format of this table such a mess? The first row indicates the medium, the second row the pressure, the third row the temperature, the fourth row the limit conditions, and the fifth row the pipe specifications. Is there any correlation between these different rows?
The grade tables for each design institute vary slightly, probably due to differences in the conservatism of their designs.
This post was last edited by lupg on 2019-5-4 11:12. 1 Do not treat this table as a whole, especially regarding the correspondence of columns. 2 This table shows that “part” has several distinct meanings: 2.1. Grade code (1 row) ； 2.2. Temperature and pressure conditions for different media (3 lines) ； 2.3. Limit temperature-pressure relationship of materials (2 lines) ； 2.4. Pipe specifications (3 lines)