How to calculate the length of high-pressure flange bolts
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Based on the flange bolt lengths specified in HG20613, the bolt lengths calculated at low pressures are similar to those specified in the standards; however, for pressures above PN63, the calculated bolt lengths are much shorter than those specified in the standards. Why is this? Installation requirements for high-pressure flanges
For high-pressure flanges, do the bolts need to be hydraulically stretched? If hydraulic stretching is required, the length of the bolts needed for the equipment must be considered, as it is longer than those used for low-pressure, non-hydraulic stretching.
I learned about it; I didn’t know such a term existed before. Our factory uses low-pressure flanges, and we know very little about high-pressure systems
Is PN63 63 bar or 63 MPa? If it’s 63 bar, it’s not considered very high pressure, so hydraulic stretching isn’t necessary
Hydraulic tensioning has not much to do with the load capacity; it is used when high torque values are required, and it also applies in cases of low torque values, as it ensures more even distribution of force on the bolts.