On longitudinal flaw detection of three types of pressure vessels
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What are the requirements for longitudinal weld inspection of Class 3 pressure vessels? What is the percentage? Are cross welds allowed?
Cross welds are not allowed at all in pressure vessels; they should be avoided intentionally during the cutting and assembly of the equipment, mainly to prevent stress concentration
For the three types of containers, 100% compliance with Grade II radiographic inspection or 100% compliance with Grade I ultrasonic testing is required. Cross joints are not allowed in the longitudinal and transverse welds of the container’s upper sections; such cross joints should generally be avoided. Refer to GB150 for details
The longitudinal welds of category three pressure vessels, also known as category A welds, have a defect detection rate that is typically determined by factors such as the material grade, thickness, degree of hazard posed by the medium, and welding joint factors; generally, this is specified by the designer in the drawings. Specifically, you can take a look at GB150 and the tolerance standards. Cross welds are not allowed; generally, the gap between two longitudinal seams should be at least 100 mm.
There are no regulations specifying the proportion of seam weld inspections for the three types of containers; the relevant provisions of GB150-1998 and the Container Code shall be followed.
100% flaw detection by radiography or ultrasound. Cross welds should be avoided in all pressure vessels, and they are absolutely not permitted in category III vessels.
100% RT grade II qualified or 100% UT grade I qualified; cross joints are not allowed for the longitudinal and transverse welds of the cylinder sections
Requirements for longitudinal weld inspection of Class 3 pressure vessels: The proportion is the same as that for Classes 1 and 2. Cross welds are not allowed; they are prohibited! ! ! ! !
There’s clearly something wrong upstairs. Article 85 of the regulations specifies clearly that Category III pressure vessels must undergo 100% flaw detection, and the results must be at grade II or above.
100% flaw detection; cross welds are not allowed
100% RT + 20% UT; cross welds are not allowed.
According to Article 85 of the Code, 100% flaw detection is required; cross welds are not allowed, with a minimum offset of 100 mm. Last edited by Yajiong on 2009-2-25 08:50.]
Inspection requirements: Refer to Article 10.8 of GB150; the standard specifies that cross welds are not allowed, and this is also basic common sense in container design and manufacturing.
According to the regulatory requirements, category III containers must meet the grade II criteria for radiographic inspection 100% of the time, or meet the grade I criteria for ultrasonic testing 100% of the time. Cross joints are not allowed in the longitudinal and transverse welds of the vessel sections of category III containers; such cross joints must be avoided
Note: 100%RT+20%UT or 100%UT+20%RT
Cross welds are not allowed, but it seems there is no such requirement according to ASME
This requirement is used only in cases where the standards are quite high. :lol
100% RT grade III compliance or 100% UT grade I compliance; cross-stitching is not allowed, with the two longitudinal seams separated by at least 100 mm
For longitudinal weld inspection of category three pressure vessels, 100% RT at grade II or 100% UT at grade I is required. For thick-walled vessels, 100% RT + 20% UT or 100% UT + 20% RT is applicable; the grade to be used is the corresponding one. Cross seams are not permitted.