Minimum thickness of the cylinder at the joint of long-neck butt weld flanges
Thread Content
Standard NB/T47023-2012 specifies a minimum thickness for the butt-welded flanges with long necks. It also provides a correction table for the total height of the flange when the thickness of the butt joint tube decreases. What I would like to know is: why does the standard specify a minimum thickness for the butt joint tube? What factors are taken into consideration? If the flange has been calculated according to standard flange dimensions in the design, does this minimum thickness still need to be followed? ?
On the minimum thickness of the butt joint cylinder for long-neck welded flanges: http://bbs.hcbbs.com/thread-1345335-1-1.html (Source: Haichuan Chemical Industry Forum)
Regarding the thickness and height of the flange, I also believe that it is possible to deviate from the standards as long as calculations are performed. However, I have some doubts regarding the minimum thickness required for the butt joint cylinder; this aspect is not covered in the calculations for the flange. So, does it still need to meet this minimum thickness requirement for the butt joint cylinder based on the calculations?
For the minimum thickness, it is not taken into account in the calculations for flanges; its requirement may be determined for structural reasons. Then, for custom flanges, if the design is reasonable, shouldn’t this minimum thickness also be considered? In my opinion, the minimum thickness still needs to be taken into consideration
Whether it is a standard flange or a custom flange, the minimum thickness of the butt joint cylinder must be taken into account. At the junction between the cylinder and the flange, there are both welding residual stresses and secondary stresses resulting from deformation coordination; these two types of stresses cannot be accounted for in conventional calculations. To avoid their accumulation, it is necessary to use some empirical values for a conservative assessment. Therefore, it is advisable to take a cautious approach in engineering terms; for large-scale equipment that has a significant impact on investment, stress analysis methods can be considered to conduct detailed calculations. :)