Questions regarding fasteners for low-temperature pipelines.
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In HG/T20592, it is required that 35CrMo fasteners undergo impact testing at low temperatures. How should this be represented when designing pipelines? Should I just switch to bolts made of a different material?
For bolts used in low-temperature environments during pipeline design, low-temperature impact tests are required according to this standard; during the design phase, it is sufficient to specify the required impact energy of the bolts at the design temperature.
May I ask, how should this be represented in the material list? How exactly do we write this information in the material list? Could you send a screenshot of the material list?
Either use low-temperature bolts A320 L7/A194 GR.7 directly. Either the bolts require an IT (impact test) at -46°C.
The 1997 version of the standard required that for materials designed for low temperatures, the letter L (LOW) be added after their grade designation; however, this requirement was removed in the 2009 version of the standard. Personally, I suggest adding a note in the material table specifying at what low temperature shock it can withstand.
This post was last edited by wswwsw3869 on 2022-8-9 08:45. Every design comes with a design specification, where the technical requirements can be listed and explained. And each major has a design description. Also, there are the standards cited. A section for referenced standards is always included in general design specifications. As long as the standard references are correct, it doesn’t matter if everything listed in the standards isn’t included in the technical specifications. After all, design is done according to standards, and construction is also carried out in accordance with standards. Design specifications generally do not list all the requirements already specified in standards; instead, they outline those that the designer deems important, serving as a reminder. Also, list the user’s special requirements. If it is a equipment manufacturing drawing, the designer’s requirements should be specified in the technical requirements section of the main diagram. If it is a pipeline to be purchased, the technical requirements for the pipeline must be specified in MRP. Clarifications should also be pulled out separately to be shown.
This requirement is also present in version 09, on page P213. I just don’t know how to express it.
May I ask, is a low-temperature shock test also required for the A320, L7?
May I ask, does the A320 and L7 also need to undergo low-temperature impact testing?
35CrMoL(30CrMoL)
No need, it’s already included in the standards.