Selection of bolts for refineries
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For a company, the most important thing is to make the best use of available resources, so as to avoid waste and reduce risks. This is where confusion arises: since the requirements vary across different workshops within the company – for example, wastewater treatment units have low requirements in terms of temperature and pressure, while pressure vessels such as heat exchangers have specific requirements regarding these parameters – it can be difficult to source the necessary bolts. When exactly and which criteria should be chosen? That expert could give some advice! Thank you
Seeing that everyone is just observing without offering their opinions, I’ll share my own views first: For the oil pipelines within distillation units, bolts for flange connections should be selected in accordance with HG20613-97 \"Fasteners for Steel Pipe Flanges (European System)\" and HG20614-97 \"Specifications for Steel Pipe Flanges, Gaskets, and Fasteners (European System)\". But there is a question: should one choose the commercial grade or the professional grade. For pipelines such as sewage and water supply and drainage systems, bolts of grade B according to GB/901-88 for long double-ended bolts can be selected. Which professional can provide comments and answers? ! ! ! ! !
When the pressure is below 600#, classification can be made based on the material of the device: for carbon steel devices, the ratio of material for studs and nuts is 35CrMoA/45#, and these components are subjected to blackening treatment; when the device is made of stainless steel, both studs and nuts are made of stainless steel； When the pressure is above 600#, both the stud and nut materials are 35CrMoA/45#, and they are subjected to blackening treatment. Relevant standards can refer to HG20613 and HG20634. This post was last edited by summer54 on 2009-2-3 at 19:54.]
Preparations for maintenance have started again, yet this issue still hasn’t received a definitive answer. Are there any colleagues from design firms who can share how they choose bolts when designing new systems? I believe that although bolts may seem unimportant, there is a huge difference in their quality, and their impact on the entire system must also be significant. I’m raising this question again, hoping to get guidance from professionals. Thank you!