Issues with container flange verification using SW6-2011
Thread Content
When performing the stress verification for the container, its design pressure is 1.6 MPa, with a DN600 size. 1. Type A flat welding flanges rated for 1.6 MPa and DN600 were selected, but the verification did not pass； 2. The flange selected is a Type B flat-weld flange with a pressure rating of 2.5 MPa and a diameter of DN600; theoretically, this is one full grade higher, so it should be more than sufficient for use. However, when using SW6 to check the equipment flange separately (it’s unclear why it isn’t possible to perform the check together with the cylinder, head, etc.), it is indicated that the area of the bolts required is insufficient. After choosing 35CrMoA bolts, the bolt area became sufficient, but then it was shown that the flange thickness is not adequate. . . They were all selected according to the standards, so how could there be a situation where they fail the verification? Using a long-neck butt weld flange at 1.6 MPa is sufficient to pass the verification. Can’t the Type B flat welding flange be used?
Since standard flanges are being used, no calculations are necessary; the specifications for equipment flanges provide details on this. If you calculate it, it generally won’t pass.
Well, thank you. What is your major? I’ll ask you for advice more often in the future
What’s the relationship? I chose an asbestos-wrapped gasket. Could you give me more details?
The m and y values vary for different gaskets. Let’s see if a non-metallic gasket will work; asbestos materials are hardly used these days.
There are many posts on the forum regarding the calculation of equipment flanges; you can search for them. Some of those posts also explain why the calculations for standard equipment flanges fail http://bbs.hcbbs.com/thread-1430372-1-1.html
I’m not sure what your design temperature is; it’s related to temperature. Furthermore, it is related to corrosion margin and the material. . . . . . . . . . . .
1. Standard flanges should be used; if the maximum allowable pressure for such flanges is satisfied, no calculation is required； 2. When selecting standard flanges, be sure to pay attention to the compatibility of bolts, nuts, gaskets, and the flange material; refer to NB/T47020
Looking at the selection table for flange standards, Type A flanges come with corresponding gasket materials as well as bolt and nut materials. If the materials specified in the table are not used, it may be impossible to carry out the calculations correctly. Different material gaskets have different coefficient values, which means that the required preload varies; all of this ultimately affects the bolt area and the thickness of the flange