Flange structure
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As shown in the picture: The flange structure of GB150 is different from that of HG20592 and NB/T 47020. 1. What is the applicable scope of the flange structure in Figures 7-1~7-2 in Chapter 7.4 of GB150? 2. With the same flange structure, why are the weld heights and positions different in 150 and 20592? 3. If the flange in GB150 requires post-weld processing, is it easy to process if it is of large diameter? Have you ever experienced this in actual production? 4. The structure of the arbitrary flange in Figure 7-2 of Chapter 7.4 of GB150 is also different from that of the NB/T 47020 Type A flange. 5. Now we need to design a non-standard pipe flange. Because the design is an arbitrary structure (same as Type A flange) due to other factors, should it be designed directly according to the requirements of Type A flange in NB/T 47020? It is still necessary to meet the size (A, B, C) requirements of the arbitrary flange in Figure 7-2 of Chapter 7.4 of GB150.
Sorry, I didn't understand what you meant.
1. What is the applicable scope of the flange structure in Figures 7-1~7-2 in Chapter 7.4 of GB150? GB/T150.3 provides the calculation method for non-standard flanges, which does not involve the scope of application. Selecting according to flange standards can avoid calculation. The non-standard design meets the structural size requirements of 150. If you choose a standard flange, you don’t have to worry about the 150 regulations. 2. With the same flange structure, why are the weld heights and positions different in 150 and 20592? In the figure, the distance between the weld end and the flange surface is ≥3, which is the allowance for secondary processing of the flange sealing surface.
There are many domestic flange standards. What standard flange should be selected during design? The rest of the requirements should be implemented according to the selected standard. Don't screw together several standard requirements.