Pressure vessels, cylinders, fittings – Welding procedure qualification: Methods and scope of application

This post was last edited by cxd11888 on 2016-7-5 08:54. Welding methods, welding materials, and the base material of the test piece (including nozzles and cylinders; if there is a large difference in thickness between the nozzles and cylinders, two evaluations are required). All of these aspects must comply with NB/T47014-2011. For the base material of the welded joint, a butt weld evaluation is sufficient.

Is it also necessary to create a type test specimen for the tube sheet, in order to evaluate it in combination with the butt-welded test specimens?

My idea is to use two assessments to cover the Class D welded joints of the cylinder and the fittings

I understand what you mean, but currently NB/T47014-2011 does not require the creation of type test specimens. (This requirement was in place for JB4708.)

Could you explain it in more detail? Are there any examples?

Example: For a container with a cylinder wall thickness of 10 mm made of Q345R material, and nozzles made of 20# steel with dimensions of φ76×6, only one type of weld is required – a butt weld using Q245R+Q345R steel plates with a thickness of 6 mm (the welding range being 6–12 mm). The welding material E4315 is sufficient to handle both materials and the two different thicknesses； However, if the cylinder is made of Q345R material with a thickness of 18 mm, and the nozzles are made of 20# steel with dimensions of φ76×6, then it is necessary to carry out a butt welding of Q245R+Q345R plates with a thickness of 6 mm (coverage range: 6–12), as well as another butt welding of Q245R+Q345R plates with a thickness of 16 mm (coverage range: 16–32). (If heat treatment is not considered, Q245R+Q345R plates with a thickness of 38 mm can also be used, with a coverage range of 16–200.) This is just an example; when conducting process evaluations, it’s best to perform as few tests as possible while still ensuring broad coverage.