Questions about the operating temperature of 20# steel
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I found on the Internet that netizens say the minimum operating temperature for 20# steel is -20 degrees, and it is stated to be specified in the relevant standards. I checked the GB150 standard but couldn’t find any relevant provisions; could netizens help me identify where these standards clauses can be found? It can be seen that the provisions in Appendix C of GB150 regarding low temperatures state that such temperatures refer to situations where the design temperature or ambient temperature is not greater than -20 degrees; here, the ambient temperature refers to the monthly average lowest temperature (calculated by adding up the lowest temperatures for each day of the month and dividing by the number of days in that month). So, does the minimum operating temperature of 20# steel, which is mentioned by everyone to be -20 degrees, refer to the same temperature as the ambient temperature? Please make it clear; thank you
GB50316, the \"Code for Design of Industrial Metal Piping\", specifies that the design temperature should be no lower than -20
-Temperatures below 20°C fall within the range suitable for low-temperature steel, while ordinary special steel can be used at temperatures above -20°C.
Bro, the minimum operating temperature specified in the standards, as you said, generally refers to the situation where the temperature of the fluid flowing through the pipeline designed is likely to remain below 20 degrees for an extended period of time; if the design temperature chosen is lower than 20 degrees, then steel grade 20# cannot be used.
Internal temperature and external temperature are not the same concept. The external temperature is temporary, and when the internal temperature is high, the temperature of the pipes is also high; it’s not necessary for the temperature to be low in order for cracks to occur, as this can lead to leaks and accidents
The friend on the 3rd floor mentioned that Chapter 4 and Appendix A of GB50316, the \"Code for Design of Industrial Metal Piping\", contain relevant provisions. As I understand it, the operating temperature mentioned in the code refers to the actual temperature of the medium. Could everyone please share whether this is indeed the case, as explained by the friend on the 5th floor?
It must be related to the material; below -20 degrees, low-temperature steel is required, otherwise problems will occur due to the material’s brittle transition temperature
The strength decreases due to low-temperature cold brittleness and high-temperature creep; in my opinion, this is simply a matter of the material’s applicable range
Note: Under conditions of low temperature and low stress, do not choose materials indefinitely!
There is no need to be restricted by the requirements of GB50316 \"Code for Design of Industrial Metal Piping\". 20# steel is roughly equivalent to A106 according to the American standards; it can also be used in low-temperature and low-stress conditions down to temperatures below -20 degrees, and for example, it can be utilized at -40 degrees as well. Refer to the explanation on page 569 of \"Industrial Pipeline Layout Design and Engineering Applications\".