The heat exchanger tube sheet flange is a butt-welded ring loose-flange type; is the thickness of the tube sheet shell the same as that of the butt-welded ring (material: Ti)?
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This post was last edited by zhyongcun on 2011-5-25 at 22:05. The heat exchanger is a small one with a DN350 size; the tube sheet flanges are butt-welded ring loose-flange types, with the loose flanges being made of 16Mn steel and the butt-welding rings made of Ti. The thickness of these butt-welding rings corresponds to the thickness of the tube sheet shell. It is planned to use 6mm thick titanium plates to fabricate the shell, which will then be welded to an 8mm thick titanium ring serving as the sealing surface. Steel tube flanges of type HG20592 DN350-1.6 loose-flange type are to be used. According to standards, the minimum thickness for such butt-welding rings should be 7.1mm; is it acceptable to use 6mm (since 2mm is sufficient based on strength calculations)? How is the thickness of the butt weld ring specified in this standard?
I don’t understand. According to the specifications in HG20592-2009 DN350-1.6 for loose-flange connections, the thickness of the weld ring neck is specified as 8 mm; this is the thickness used when the customer does not specify any particular requirements. Generally, the thickness of the weld ring neck is the same as that of the steel pipe. When the customer does not choose the dimensions listed in the table, the thickness must be at least 0.875 times the size of the neck
The question is great! ! It’s unknown how the thickness specified in the standards was determined! But it’s best for you to refer to the standards; in our field, it’s ideal to have something to back things up! ! If your 6mm calculation passes, I think it’s fine; it’s acceptable to have a slight error in the ring peak values as well! !
Are you sure: the shear stress at the loop has been passed! ! ! Based on my experience, it’s impossible to determine the thickness required for 2mm Ti. By 2mm, you are referring only to the wall thickness needed to handle the internal pressure in the tube sheet, right? I suggest the original poster take a close look at the calculation documents to confirm the minimum thickness required
I think the thickness of the butt weld ring specified in HG20592 is set taking into account the more complex forces exerted on the nozzles welded to the cylinder, such as those from external pipelines connected to it, as well as local stress or stiffness issues. But when the butt weld ring is used for the cylinder of a tube box flange, is it not necessary to use such a thick thickness if the SW6 calculation shows that the tube box cylinder meets the requirements? (For example, the standard here should be 8mm, but it’s actually 6mm.) Sigh~~ Does anyone know the person who sets these standards?