Selection of saddle material for low-temperature horizontal pressure vessels
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For a horizontal single-layer gas storage tank designed for a temperature of -30°C, must the saddle material be Q345R? According to the standards for container supports, the material of the saddle is determined by taking into account both the ambient temperature and the design temperature.
Can you use the lower limit temperature for using the steel plate that you want to check? The minimum operating temperature for Q345R is -20°C, and the lowest operating temperature of the steel plate should also be taken into account when designing the supports. If your device is used under conditions of low temperature and low stress, then it is not necessary to follow the design requirements for low-temperature pressure vessels.
If the saddle is equipped with a gasket, then only the low-temperature load-bearing capacity of the gasket material needs to be carefully considered; specifically, the welds between the gasket and the cylinder must be supported by weld evaluations showing compliance with impact tests under MDMT conditions.
Mm-hmm, the shims are made from the same low-temperature steel plate as the cylinder body; it’s a bit difficult to determine the material suitable for the saddle based on the standards.
Verify whether it is in a low-temperature and low-stress operating condition. If calculation is not desired, and the entire saddle is enclosed for heat insulation, then the saddle should be made of the same material as the housing. If it cannot be enclosed, choose a material of one lower grade than that of the cylinder. Generally, there’s no problem
The shims are made of the same material as the cylinder; if insulation is used to cover the entire saddle, then materials suitable for low temperatures should be chosen； If insulation is not applied around the saddle, the materials for the saddle itself can be selected based on an average monthly minimum temperature plus 20°C, for reference only.
The design temperature in the saddle standards refers to the designed temperature of the saddle, which is determined by taking into account both the designed temperature of the container and the ambient temperature. This requires taking into account the ambient temperature at the location of use. Since the ambient temperature is not provided, it is possible to choose either Q235B or Q345R for the owner’s situation.
We just use Q345R for the saddle pad, while the rest use 235B
When the ambient temperature reaches -25°C, is it necessary to use Q345R steel plates?
The ambient temperature is considered based on the lowest average monthly minimum temperature; if it is below -20 degrees, Q345R should be used as the material for the supports.
The ambient temperature is considered based on the lowest average monthly minimum temperature; if it is below -20 degrees, Q345R should be used as the material for the supports.