Seeking advice on the material for a manhole
Thread Content
In HG21521-2014, pressure-bearing components such as the flange sections of manholes are specified to be made of low-temperature materials like 16MnDR, while accessories such as handles and hooks are made of Q235B. Is such a material selection appropriate at an ambient temperature of minus 30 degrees?
If there are problems, low-temperature steel must be used at the very least; it is best to choose a material that is similar to that of the equipment itself.
The standards specify that \"compressed components\" should be made of materials resistant to low temperatures, while the hook handle is a non-compressed component and is not exposed to low-temperature conditions.
In such an environment, can non-compressive components such as container supports and pipeline brackets also be made of Q235B material?
There is no issue with the material selection for manhole standards. The material requirements for stressed components are different from those for unstressed components. The selection of saddle material is governed by the following requirements: the gasket material for the container supports welded to the cylinder must be compatible with the cylinder material. The design temperature of the saddle should be determined by taking into account both the design temperature of the container and the ambient temperature. When selecting the saddle material, consideration should be given to the container’s design temperature (in low-temperature conditions), the ambient temperature, as well as economic feasibility.
Hooks, handles, etc. of manholes are non-compressive components, and they are used only when the manhole is opened for equipment maintenance; therefore, low-temperature conditions need not be considered when selecting materials for them.