Diameter of the openings used for reinforcement
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Chapter 8, Clause 8.3 of GB150-1998 states that for nozzles with a diameter ranging from 20 to 80, it may not be necessary to carry out reinforcement by adding openings under full load conditions. However, Table 1 of JB/T4736-2002 \"Reinforcement Rings\" lists reinforcement rings for nozzles with diameters of 50, 65, and 80 as well. What is the explanation for this?
Is reinforcement needed when those conditions are not met?
There must be certain constraints; it’s likely restrictions on pressure and temperature.
Chapter 8, Article 8.3 of GB150-1998 states that for pipes with a diameter range of 20–80, it is not necessary to carry out hole-opening reinforcement. Has the original poster checked the requirements? There are requirements regarding pressure of 2.5 MPa, wall thickness, corrosion allowance, and so on. If these conditions cannot be met, reinforcement of the pipe is still required
The requirements of GB150 must be met: 1. The design pressure is less than or equal to 2.5 MPa； 2. The distance between the centers of two adjacent openings (for curved surfaces, this distance is calculated in terms of arc length) should be no less than twice the sum of the diameters of the two openings ； 3. The nominal outer diameter of the pipe to be taken over is less than or equal to 89 mm ； The minimum wall thickness for takeover meets the requirement of 3.5 mm for Φ25, 32, and 38 ； Φ45, 48 minimum wall thickness 4.0mm ； Φ57, 65 minimum wall thickness 5.0mm ； For Φ76 and 89, the minimum wall thickness is 6.0 mm. It should also be noted that: ① The steel’s σb value must be greater than 540 MPa, and a fully penetrative welding structure should be used for the connection between the pipe fittings and the shell ； ②The corrosion margin of the joint is 1 mm. The original poster is requested to read GB150 carefully; if the requirements are not met, calculations for reinforcement through opening must be carried out. If all reinforcement requirements are satisfied, no reinforcement rings are necessary, but if the requirements are not met, reinforcement rings must be added or an integral reinforcement structure should be used!
You need to understand the provisions in clause 8.3: a shell opening does not require additional reinforcement if it meets all of the following conditions (all four conditions must be satisfied); if not, reinforcement calculations for the opening are necessary
The original poster doesn’t read carefully; let alone follow the standards, they certainly can’t just read half of it.
Anything that does not meet the requirements needs to be reinforced; for pipelines of 25 mm in diameter at 16 MPa, reinforcement is necessary
When the requirements of clause 8.3 of GB150-1998 are not met, reinforcement rings need to be used
GB150 stipulates that no additional reinforcement is required for nozzles under certain conditions; as the others have already explained clearly, it means that for openings that do not meet the criteria for not requiring additional reinforcement, no reinforcement rings are needed either. PS: For the provisions of standards, it is necessary to understand their purpose and applicable conditions; they should not be interpreted in a one-sided manner by taking them out of context.
All regulatory provisions need to be carefully considered in order to reduce the chances of making mistakes^_^