The issue of temperature during hydrotesting of pressure vessels
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As the title suggests, when designing vessels with Q345R shells, what are the requirements regarding water temperature during hydrostatic testing? Is it not less than 5 degrees Celsius, or not less than 15 degrees Celsius? Should we consider other materials such as those for the pipes and flanges, and then make a comprehensive decision?
Based on the material of the main shell, don’t overthink it; 5°C is sufficient.
If the material being used for the take over is grade 20 steel, then considering it as carbon steel, the temperature should be no lower than 15 degrees Celsius. Can we consider only the shell material? Is there any clear evidence?
Consider the shell material. Clause 11.4.9.3 of GB/T150.4 makes it very clear.
Although the standards do not specify exactly what type of material is to be used for manufacturing the components, based on stress analysis, it should be a material capable of withstanding overall film stress; this refers to the material used for the housing
Thank you all for your responses. I actually also think that only the material of the shell should be taken into consideration, but during a lecture on the D-class inspection for pressure vessels in Henan, a teacher emphasized the need to consider other materials as well. I didn’t find any clear statements on this in the standards either, so I posted it on the forum to see what others think.
There is a saying that the appropriate water test temperature for other stressed components needs to be taken into consideration as well
It is generally considered based on the main stressed components; those with a DN250 size or less are not taken into account, and this is just my personal opinion
Based on the material of the main shell
This post was last edited by Benjamin_ENDF on 2018-7-27 22:02. Not only the main housing should be considered, but also other materials. The reason is as follows: The purpose of specifying the temperature for hydrostatic testing is to prevent brittle fracture accidents. The hydrostatic test temperature here should be adjusted upward based on the lowest design temperature of the container. GB/T150 defines MDMT as the minimum temperature of the metal components of a vessel under various possible conditions to which it is exposed during operation. Please note that here, not only are \"various operating conditions\" emphasized, but also \"individual components\" are specifically highlighted; in other words, the lowest temperature at which the container can operate should be set at the highest value that each component can withstand under various operating conditions. The hydrostatic test falls under the special operating conditions for vessels; under design stress, a certain margin should be added to the minimum design temperature to serve as the test temperature. The current method specified in GB/T150 for determining the minimum design temperature of materials is entirely empirical; therefore, the provisions regarding the hydrostatic test temperature in the manufacturing section are also based on experience, which means that only general statements can be made. The discussions above are covered by relevant provisions in EN13445 as well as in ASME VIII. Taking ASME VIII-1 as an example, it specifies that the MDMT indicated on the nameplate should be based on the highest temperature among all the components of the vessel.