Under what circumstances should the minimum design metal temperature be indicated on the drawings?

It seems to be available only on ASME standards; for GB standards, it seems to be the design temperature at low temperatures

The foreigners were also puzzled as to how it had become a low-temperature container

The minimum design metal temperature is generally determined based on the material’s temperature at which plasticity ceases to occur. Since this temperature varies among different materials, the minimum design temperature also differs. Making the most of the material properties is something that will continue to be improved in the future. However, in our country, it is currently determined artificially, that is, the minimum operating temperature of the material. The design temperature specified in the design drawings must not be lower than the minimum operating temperature of the material; this is a mandatory requirement in China. (The above is the official view; I’m just repeating it.)

I think the reasonable sequence for determining the minimum design metal temperature is: wall temperature calculation → calculated minimum metal wall temperature → minimum design temperature → selection of material → determination of the minimum design metal temperature? In actual design, wall temperature calculations are generally not performed, and it is easy to confuse the minimum design temperature with the Minimum Design Metal Temperature (MDMT). The former is determined based on the process design conditions, while the latter is determined by the selected material grade and its dimensions. For the latter, GB150 specifies an empirical lower limit for the operating temperature of the material; the minimum design metal temperature must not be lower than this allowable lower limit for the material’s use. GB150 and the relevant regulations do not explicitly state when the minimum design metal temperature should be specified; according to GB150.1 §4.3.4a), it can be understood that the minimum design metal temperature should be indicated when the metal temperature is below 0°C. ASME VIII-1 is based on fracture mechanics theory; the MDMT is determined using the properties of the material itself and its dimensions, in accordance with the requirements of UG20 and UCS66. The calculations performed must be listed in the strength calculation report, and they should be indicated on the product label along with the maximum allowable working temperature (MAWP). In other words, MDMT should always be indicated under any circumstances.