[Daily Question] Question 001
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Does the welding of the fixed-type nozzle to the cylinder constitute a fully penetrated joint of the cylinder? Briefly explain the reason? Valid for 24 hours
Not all welds need to be fully penetrated; refer to Article 3.14.2 of TSG R0004-2009. Welds between nozzles and cylinders/headings must be fully penetrated in the following situations: 1) When the medium is extremely or highly hazardous; 2) For vessels that require pneumatic testing or combined gas-liquid pressure testing; 3) Class III pressure vessels; 4) Cryogenic pressure vessels; 5) Pressure vessels subjected to fatigue analysis; 6) Pressure vessels directly exposed to flame heating; 7) As specified in the design drawings (direct answer to the knowledge point)
According to Appendix D of GB150.3, the structure shown in the figure can be used for welding the nozzle to the cylinder, and it should achieve full penetration
On regular weekdays, I should be able to keep creating questions, but it’s hard to guarantee it on weekends. Moreover, the questions are based on problems encountered in work, and the answers provided are not necessarily correct.
The welding of the inserted fitting to the cylinder does not necessarily result in a fully welded joint of the cylinder, as this varies depending on the welding method used.
The welding of the inserted fitting to the cylinder does not necessarily result in a fully penetrated joint. The key point is that the groove shape isn’t specified.
Fixed-type fittings have better stress resistance compared to inserted-type ones; they also offer higher precision in manufacturing, with smaller openings. The reduction factor is 1.0, meaning less reinforcement is required. However, ultrasonic testing is necessary at the opening site, and drilling may be needed. Fittings are often made from forged materials, which makes processing more difficult and increases costs, but the quality is guaranteed. It is generally used in high-voltage equipment.
Fixed-type fittings have better stress resistance compared to inserted-type ones; they also offer higher precision in manufacturing, with smaller openings. The reduction factor is 1.0, meaning less reinforcement is required. However, ultrasonic testing is necessary at the opening site, and drilling may be needed. Fittings are often made from forged materials, which makes processing more difficult and increases costs, but the quality is guaranteed. It is generally used in high-voltage equipment.
The conclusion reached by our company is that it does not meet the requirement of full penetration as specified in the regulatory standards. According to those standards, full penetration should be achieved in the cross-section of the openings in the cylinder, and full penetration should also be present in the cross-section of the inserted nozzles; however, the cross-section of the openings in the cylinder has not been welded