Modification of manhole flanges
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The manhole flanges for low-temperature equipment in our company are made entirely of stainless steel, which makes them very expensive. But other companies have a lot of carbon steel products, using only stainless steel cladding ； There are even end caps that can be used as a direct replacement. I would like to ask about the advantages and disadvantages of each. If faceted carbon steel flanges can be used as a substitute, the cost will be significantly reduced. Thank you for the advice.
1. Stainless steel cladding or low-temperature composite steels (such as 16MnD or 09MnNiD) can be used to replace the original stainless steel material, but the design temperature must meet the requirements of the low-temperature steel, and low-temperature impact testing is essential. 2. A cover can also be used as a substitute, but the manhole must be located in a place where it can be easily removed by operators without posing a risk of injury (such as on the ground), and the weight of the flat cover for such a manhole should not be excessive. 3. If the process and medium conditions permit the use of low-temperature steel, it is recommended to use such steel for manholes, as it is both economical and effective. :) This post was last edited by c_m_1979 on 2007-12-8 17:24 ]
Thank you for the advice, but what I’m referring to are veneered flanges
What the poster is referring to as a lining is actually a gasket; in order to save costs, companies use stainless steel gaskets instead – of course, this still meets the requirements of safety design standards
What I mean is, aside from the cost differences, are there any deeper-level impacts?
We also use all-stainless steel versions; the cost is very high, but they basically don’t rust
Cost should be considered only after the functional requirements are met.
The first requirement regarding the manufacturing process is to determine the main material based on the process specifications. For example, in cases involving low temperatures, it’s important to consider whether low temperatures alone or both low and high temperatures are involved; if it’s the latter, I believe it’s better to use all-stainless steel. If only low temperatures are involved, then using low-temperature grade materials combined with stainless steel would also work!