1. Should the length of the pipe fitting with a flange be reduced by the wall thickness? 2. Which is better: a grounding plate or grounding bolts?
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This post was last edited by zhangjuhua on 2016-12-24 at 19:31. Two small questions: 1. When calculating the length of the flange fitting, one simply measures the distance from the lowest point of the root to the sealing surface. However, in the welding diagram for fittings and flanges according to HG20592, this distance needs to be reduced by (f2, i.e., at least the thickness of the fitting). For thick-walled pipes, the difference resulting from whether or not this amount is deducted can be ten to twenty units or even more. Could you please tell me what the correct way to do this is? 2. The saddle standard includes bolt holes for grounding, but stainless steel grounding plates are often used as shown in the drawings. What are the advantages of a grounding plate over grounding bolts? 3. Can fasteners specified in GB/T5782, GB/T901, or HG/T20613 be used for equipment flanges? Are there stainless steel bolts specified in NB/T47027?
1. For PL and SO flanges, when calculating the flange nozzle length, (f2, i.e., at least the nozzle thickness) + 1 must be subtracted. 2. The stainless steel ground plate on the saddle must have good electrical conductivity. 3. There are no bolts made of stainless steel in NB/T47027.
I remember that stainless steel doesn’t have very good electrical conductivity; it’s probably inferior to carbon steel. Is that because of its corrosion resistance?
The two bolt holes on the saddle are indeed not as good as a welded ground plate, but there’s no inspector who checks it every time, so it’s necessary to use one.
When calculating SW6, the distance to the sealing surface still needs to have (tube thickness + 1) subtracted from it, right?
Is this item included in the SW6 calculation?
1. Subtract (f2+1). 2. The foundation bolts cannot serve as a grounding element; a separate grounding wire must be connected to the grounding plate.
3. Stainless steel fasteners cannot meet the strength requirements.
The effective overhang height for takeover – in the past it was measured up to the flange sealing surface; so should (f2+1) not be subtracted?
We enter the length of the pipe extension based on the welding position outside the flange; for WN type it is a butt weld, while for PL and SO, the flange thickness is deducted...