Minimum thickness of the butt joint cylinder for necked butt-welded flanges
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The data for welded flanges with necks includes a minimum thickness requirement for the butt joint cylinder; what should be done if the cylinder does not reach this thickness?
According to the JB/T4700 standard, the flange height can be adjusted; the thickness of the butt joint cylinder can be reduced, or a transition section can be used.
Increase the height of the straight edge, then thin it out according to the specified slope! Make corrections in accordance with Table 3 (JB T4703). Or add a transitional short section to the connecting cylinder.
Add a short section as required by the standards; the length calculated according to flange standards might be a bit short, and there is also a 300 limit for values above 150.
If none of the above methods are used, then design a custom flange; considering that the allowable stress of forgings is lower than that of sheets, the smaller end of the flange when connecting to the cylinder should be 1–2 mm thicker than the cylinder.
A gentle slope at the transition is sufficient; it’s best if it can be machined, and the straight edges at the transition should have a smooth curve.
I haven’t encountered this kind of problem before; I hope the experts here can give me some advice. I’m learning, haha
In JB4703, WN1000-2.5 specifies that the minimum thickness of the socket cylinder is 14; if any corrections are needed, then the thickness of the flange’s neck portion must also be at least 14 – it cannot be less than that (is that what it means? I’m not quite sure). This flange is connected to the tube box, which has a thickness of only 8 mm and a length of just 300 mm; it will be difficult to use excessive short sections in this case
Does 6# lnfszn008 refer to cutting bevels on the flange neck?
1. When the flange connected to the cylinder is a JB/T4703 long-neck butt-weld flange of the container type, and if the minimum thickness of the cylinder is less than the specified minimum value, 1) it can be corrected using the correction values in Table 3; 2) if no corresponding value is available in the table, the flange must be calculated using SW6, typically by increasing the H value (flange height) or adjusting the number of bolts in order to meet the strength requirements. 2. When the flange connected to the cylinder is a steel pipe flange (HG20592 long-diameter butt-weld flange), and if the minimum thickness of the cylinder does not meet the minimum S value specified in the flange tables, the S value must be indicated when specifying the flange