Charpy V-notch test on welded joints
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The drawings specify that the pressure-bearing components and weld joints of this equipment must undergo Charpy V-notch impact tests at -20 degrees Celsius... Does this requirement mean that the welding process evaluation for the equipment should cover this impact value, or is it necessary to create welding specimens and then take samples from those specimens for impact testing?
Please provide the context of this paragraph. At present, first of all, for raw materials, an impact test at -20 degrees Celsius is required. It is very likely that the designed operating temperature for this equipment is -20 degrees Celsius, and it uses Q345R and 16Mn forgings; hence this requirement is specified. A welded joint should refer to the welding procedure qualification.
First, the quality certification document for the raw materials must state that a shock test at -20°C has been conducted; second, the manufacturing unit should have carried out a welding procedure qualification test at -20°C.
What is the difference between welding procedure qualification and welding test pieces? Isn’t weld procedure qualification based on test pieces? Please give me some advice; I really don’t understand
In my understanding, it is necessary to prepare welded specimens and then conduct low-temperature impact tests. Welding procedure qualification covers the compatibility between the base material and welding materials, as well as the welding method. The -20°C low-temperature impact test is mainly a re-inspection of the base material of steel plates such as Q345R at an operating temperature of -20°C, while the focus of the other test is different.
For the longitudinal seam strip test plates, an impact test at -20 degrees is required.
I believe that welding test pieces are required for low-temperature containers; this is not necessary in this case. However, the base material needs to have an impact value, and for the welded joint, a welding procedure qualification is sufficient.