-Material selection issues for equipment under 50℃ operating conditions
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I’ve encountered a problem in design recently and would like to hear everyone’s opinions. An external circulation cooler, with fluorine refrigerant at -50°C flowing in the shell side and a pressure of 1.4 MPa; the direct evaporation of this fluorine refrigerant is used to remove the heat from the material in the tube side ； The material used for the liquid storage tank of the chiller supplied in this project is 16MnR ； When selecting materials, I, as a person from the process engineering field, suggested that stainless steel should be used for the shell side; however, the client believed that 16MnR could be used for the refrigerant tank, so it was decided that 16MnR should also be used as the material for this heat exchanger ； So I would like to ask here whether 16MnR can be used in the operating conditions mentioned above. Do the above operating conditions fall within the category of low temperature and low stress?
I think it should work; I once read a paper on low-temperature and low-stress operating conditions that described a similar situation.
This paper should be helpful to you: http://bbs.hcbbs.com/viewthread.php?tid=9596&highlight=%B5%CD%CE%C2%B5%CD%D3%A6%C1%A6%B9%A4%BF%F6
No. According to Section 4.2.8 of GB150, the minimum impact test temperature for 16MnR is -20°C; therefore 16MnD should be used
:I was wrong; 16MnD doesn’t work either, -40
It is impossible to determine the wall thickness without information on whether it is under low-temperature and low-stress conditions.
The liquid storage tank is generally located on the high-pressure side, at a temperature of 40 degrees; using 16MnR is perfectly fine for this purpose. The evaporator is on the low-pressure side; at -50 degrees, the absolute pressure of the saturated vapor of R22 refrigerant is 0.6 kPa. You can calculate whether this represents a condition of low temperature and low stress.
It is recommended to use 09MnNiDR, a specialized low-temperature steel with an impact energy of over 34 J at -70 degrees Celsius. It is widely used in the manufacture of refrigeration equipment for liquid propylene (-47.7°C), liquid hydrogen sulfide (-61°C), Freon, and lithium bromide. This steel is already in mass production, with Wuhan Iron and Steel allowing a maximum thickness of 120 mm. Our company has some stock available. Please feel free to contact Pang Long from Wuhan Iron and Steel for inquiries: 13137747779, QQ57244114
Careful consideration must be given to the materials chosen during design; it is best to refer to the proven designs of existing projects. Otherwise, if there are design mistakes, one will have to bear the consequences themselves – ranging from financial losses to legal liability. Design is a crucial matter, and it is advised that everyone pay close attention to this.
The key is to determine whether it falls under the “low temperature and low stress” condition.
{:2_45:} It must be examined carefully 9# phy0001