[Discussion Post 41] The maximum value of the sum of the diameters of the openings on the same cross-section on the flat cover d+d2... (mm)

The answer to the second item has been found: I would like to ask: What is the theoretical reason why input cannot be performed when a single hole is opened?

2. Will the flat cover be exempted from reinforcement calculation after entering the cross-section opening calculation? Is there any basis and source? The answer to the second item has been found: I would like to ask: What is the theoretical reason why a single opening cannot be input? The software requires the input of "the maximum value of the sum of the diameters of openings on the same section d1+d2..." when calculating the flat cover, which corresponds to the multiple openings of the 150.3-6.4.3 flat cover. In fact, it is calculating the reinforcement. ； 6.4.3 corresponds to "multiple" openings, and a single opening should be calculated according to 6.3. 3. Can a reinforcing ring be added to the opening on the flat cover? (When reinforcing, is the thickness of the flange cover also limited to 38mm?) Yes, as long as the conditions for using the reinforcing ring are met, but I have never seen it before.

The sum of the cross-section openings should not contain bolt holes.

For 2, it can be understood that it is not suitable for single hole calculation.

After thinking about it, the threaded holes of the flat cover should not be included in the reinforcement calculation.

1. In terms of stress, the bolt hole belongs to the flange connection part, and the flat cover part should be the inner diameter part of the connecting cylinder, so it is not included. 2. The openings on the largest input section are already reinforced as a whole, so there is no need to perform reinforcement calculations. (6.4.3) 3. Reinforcement circles can be added, but they are rarely used. 4. The conditions for not reinforcing the flat cover and the conditions for using the reinforcing ring are the same as those for the cylinder and head.

The second point is that the single hole in SW6 is not applicable and the openings indicated in GB150 should have the same meaning.

This post was last edited by zjq1962 on 2019-4-19 09:50. I have always had this question, why does GB150 distinguish between single opening and multiple openings. In fact, you can understand it after reading the restriction requirements on the center distance of any two hole openings in GB150.3 6.4.3. Multiple openings must meet the conditions for joint reinforcement. If they do not meet the conditions, they can only be calculated as a single opening. My understanding is that even if there are two openings on the same section of the flat cover (the two holes are relatively far apart and the openings do not affect each other), if the conditions for joint reinforcement are not met, they can only be calculated as 6.3.4.1 Individual openings are calculated separately.

I calculated a piece of equipment, and after inputting the opening size, the standard flange cover calculation passed. According to the opening reinforcement calculation, if the reinforcement circle is not met, an extra 16mm will be added to the flange cover when the pipe is φ133x8 (GB/T8163-2018). If forgings are used, the standard flange cover can be used when φ163x21 is used, without increasing the thickness. So if you can’t explain the GB150 sentence, you should comprehensively choose small forged pipes.