Is a washer required when connecting flanges with bolts and nuts?
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Is a washer required when connecting flanges with bolts and nuts?
It’s necessary; otherwise, the tightness won’t be good. Moreover, without gaskets, it’s also difficult to disassemble.
In the presence of vibration, it is advisable to use spring washers. The reality is that it’s not needed in most situations.
Bolts with washers have not been seen in petrochemical plants.
This post was last edited by Chow Tai Fook on 2015-8-4 16:42. High-pressure pipes are not required. At high temperatures, bolts experience stress relaxation; the difference in thermal expansion coefficients between the bolts and the flanges during heating and cooling cycles can lead to leaks. There doesn’t seem to be any specific standard regarding the temperature; from what I’ve seen, those with butterfly washers are used at temperatures above around 500 degrees.
The washer you mentioned is commonly used in insulating gasket assemblies, and so is the sleeve.
It’s generally not added, unless it’s on the items right after they leave the factory
Rather than saying there are regulations requiring it to be included, it’s more accurate to say that there are no regulations requiring it to be omitted
Carbon steel flanges can be used without gaskets, while plastic flanges definitely require screw gaskets; when installed vertically, the nuts are on top, allowing any looseness to be detected promptly. For components that vibrate, use spring washers or butterfly washers; in highly corrosive environments, apply butter. Stainless steel bolts and nuts must not be made of the same material (otherwise they will become hardened and stuck during installation and removal).
This issue should be determined depending on the circumstances, taking into account the medium flowing through the pipeline and the operating conditions at the site. It doesn’t really matter much whether a gasket is used or not.
It is usually not necessary to use them, but if the hardness of the flange material is much lower than that of the bolts – for example, when the bolts and nuts are made of alloy steel while the flange is made of aluminum, copper, fiberglass, PVC, etc. – washers are used to increase the load-bearing area