Why do flange bolts and flange nuts need to add an angle to the plane

There is an angle of 0.75±0.75 degrees on the flange surface of the flange surface bolt and the flange surface nut, which is equivalent to installing a tapered spring washer to achieve installation reliability. If it is a flat surface, the outer ring may not be pressed in place after the installation force is applied, which reduces the force-bearing area and reduces the installation reliability.
Flange bolts, the common flange bolts are external hexagon bolts plus a flange under the hexagon head. The flange surface has some regular teeth (the hexagon head and the flange are fixed together, not It can be separated like a gasket.) There are some flange bolts that have no teeth on the flange plate. At present, almost all customers of the flange bolts in the business need to be toothed, and the following are introduced with toothed flange bolts. , At the end, there will be a flange bolt without teeth.

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