Should ear supports on chromium-molybdenum steel pressure vessels indeed be equipped with shims?
Thread Content
On page 391, section 21.4.3 of our commonly used blue book, \"Training Manual for Pressure Vessel Design Engineers,\" it states that lugs with gaskets should not be used, as this can lead to cracks and make it impossible to detect internal defects. ” But our jbt4712.3 already comes with 15CrMo lugs. It also does not state that 15CrMo lugs cannot be fitted with gussets, and the standard further recommends the use of gussets for containers with a temperature rating of ≥900.
Is the \"Training Manual for Pressure Vessel Design Engineers\" a textbook or does it hold a higher status as a standard? Of course, the standards related to supports are also recommended; whether shims should be used depends on whether the local stresses in the cylinder have been properly evaluated. The support pad should not be placed at the weld site; this is a requirement specified in our design. It is necessary to consider the appropriate placement location during the design phase, and the manufacturing factory must also pay attention to this when cutting the materials.
On the roof, avoiding welds is definitely the right approach
Note the prerequisite that \"brackets with shims cannot be used\": \"When the diameter of vertical containers is small, …, attention must be paid to … in such cases.\" ” With a small diameter of the container, the lugs are relatively large; coupled with the gussets, these may cover most of the cylinder body, including the longitudinal seams. Chromium-molybdenum steel welds have a relatively high risk of cracking, and non-destructive testing may be required for type A and type B welds during subsequent regular inspections. On the other hand, containers with a small diameter usually have sufficient rigidity without gaskets.