Excessively long protrusion of flange bolts affects the preload
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Hello, everyone who is into the sea. I saw a discussion about a device issue: after the flange bolts were tightened, their heads protruded too much, and it was said that prolonged operation affected the bolt preload. I don’t know what the basis for this is? With too long a length, many specifications state that it should not be greater than 1/2 of the screw diameter or 2-3 threads; so how does a longer length affect the preload?
If the length of the flange bolt that protrudes is too great, the bolt may have more room to deform after being tightened due to vibrations or thermal expansion and contraction, which can lead to a decrease in preload over time. Generally, the tightening length of bolts should be kept within a certain range to ensure stability and reduce elastic deformation caused by overly long bolts. If the bolt protrudes too far, its free length increases, making the bolt more susceptible to external influences and thus causing changes in the preload. .
I’ve only heard that a shorter length affects the preload, but I haven’t heard that a longer length also has an impact on it. However, it’s true that being too long can be problematic; if it extends too far, there might not be enough length in the sleeve when using a torque wrench
There is indeed an impact, but the specific explanation is unclear