Discussion on the maximum opening diameter without additional reinforcement
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This post was last edited by Unity of knowledge and action_JRKZ on 2018-1-17 at 18:54. Design parameters: design pressure of 2 MPa, design temperature of 190°C, diameter of 1700 mm, material of 316L, and corrosion margin of 2 mm. Problem description: As shown in the diagram, the pipe openings D1-D2 (89X7) are located 450 mm away from the equipment’s centerline, which meets all the requirements for no additional reinforcement at a distance of 150 mm; however, the software calculations indicate that this requirement is not satisfied. Reinforcement using forgings needs to be considered. There are several issues here, and I would appreciate everyone’s opinions on them. 1. GB150 does not specify any restrictions on the location of the nozzles that do not require additional reinforcement, but SW6 requires the distance between the inlet nozzle and the equipment’s centerline to be specified. How should this situation be handled? 2. Can this case be understood as follows: when the nozzle opening D is 450 mm away from the equipment’s centerline, its diameter is larger than the outer diameter of the pipe fitting, which is 89 mm (the shape of the opening is no longer circular); it is also larger than the maximum opening diameter of 150 mm for which no additional reinforcement is required. Therefore, reinforcement of the forging is necessary.
Your item fails all the requirements of not needing additional reinforcement if it doesn’t reach 150! The diameter of the opening after eccentricity adjustment is required to be larger than the standard value; sw6 does not apply to nozzles that meet the requirement of 150 without additional reinforcement! The software will make a judgment!
Just change the structure to radially arranged tubes bent in the axial direction.
This takeover no longer meets the requirement of not requiring additional drilling for reinforcement; it was correct of you to opt for a fully forged component.
The clause in 6.1.3 of GB/T 150.3 that specifies no additional reinforcement is applicable to radial nozzles only; it is not applicable to non-radial nozzles. In fact, the provision in GB/T150.3 regarding the need for no additional reinforcement is based on extensive experimental data, which show that the stress concentration factor decreases as the diameter decreases. Therefore, relevant constraints are given. The maximum diameter of the pipe connections that do not require additional reinforcement here should actually be referred to as the \"diameter of openings without additional reinforcement.\" In non-radial pipe connections, especially those with tangential or oblique cuts, the length-to-diameter ratio of the openings increases, sometimes even exceeding 2; as a result, the stress concentration factor in such cases is **higher than that of conventional radial pipe connections.** At this point, hole reinforcement calculations must be performed separately
The maximum diameter of the pipe connection that does not require additional reinforcement should actually be referred to as the \"diameter of the opening without additional reinforcement.\" In non-radial pipe connections, especially those with tangential or oblique cuts, the length-to-diameter ratio of the opening increases, sometimes exceeding 2; as a result, the stress concentration factor in such cases is **higher than that of conventional radial pipe connections.** At this point, hole reinforcement calculations must be performed separately
In the designer’s specifications, the corrosion margin is set at 2.0, which means that the requirements of GB150.3 regarding additional reinforcement are not applicable. As can be seen from the diagram, the diameter of the openings in the circumferential direction has not increased; it remains equal to the diameter of the pipe fitting.
This issue was discussed some time ago. Illegally taken over; the opening size is already greater than 89.
I agree with the friend on the sixth floor; the no-reinforcement requirement for connections of 150 size applies to radial connections, while reinforcement should be considered for eccentric connections. However, our reviewer said there is no restriction on the position of connections for 150 size, and SW6 requires the input of the distance between the centerline of the connection and the center of the equipment. In this case, it may not be necessary to calculate for that connection port. So, should I sign or not?
This post was last edited by zjq1962 on 2018-1-19 at 08:37. For the two calculation results shown in the attached figures, all conditions are the same except for the eccentricity; in both cases it is an axial connection. This indicates that non-radial connections can still be used for strengthening openings in the head, as long as the calculated diameter of the opening remains within the limits specified by GB150. In Table 6-1 of GB150.3, for a given thickness of the fitting, there is more than one diameter; when it comes to the fitting with the smaller diameter, as long as the eccentricity remains within a certain range, the need for reinforcement calculations can be waived. Similarly, on the cylinder, it is also applicable as long as the eccentricity remains within a certain range; see Calculation Sheet 3