When are washers needed when using flange bolt fasteners?
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Under what circumstances are washers required for flange bolt fasteners, and under what circumstances are they not needed? What are the relevant standards and specifications?
Flange bolts require washers; a set of bolts consists of a screw rod, a nut, two flat washers (at both ends), and one spring washer. The function of a flat washer is to increase the average force-bearing area and reduce rotational resistance. A spring washer, also known as an anti-loosening washer, prevents bolts from loosening due to external vibrations. So it must be added.
Thank you, Xue*Xue*! :handshake
Add them all. Prevent vibration-seal tightening
Which specification states that?
The sources and formulation of standards are based on principles. Should you devote yourself to this when you have time free, or should you go back and look at the junior high school physics textbooks?
Pressure pipelines generally use HG/T20592~20635-2009 steel pipe flanges, gaskets, and fasteners
I checked on this, and it doesn’t clearly state that it’s necessary to add it
Generally, washers are used when connecting RPP plastic flanges, while carbon steel 304 flanges usually don’t require washers. As for fiberglass flanges, washers may or may not be used depending on the situation
Theoretically, there is nothing wrong with this statement, but it raises some concerns when included in standards and specifications for flange fasteners. HG/T20613-2009, Fasteners for steel pipe flanges; applicable to hex head bolts, equal-length double head bolts, fully threaded bolts and nuts. Clause 5.0.1 on the use of fasteners, whether for general-purpose or specialized use, specifies only bolts and nuts. 5.0.9 The selection of washers shall comply with the provisions of Appendix A of the standard. “The “” indicates that it is not mandatory. Additionally: The standards do not mention spring pads, nor do they reference any standards related to spring pads. In summary: For flange fasteners, flat washers and spring washers are not necessary.
Different perspectives lead to different requirements, that’s all. Don’t argue about this