Welding process
Thread Content
Containers made of 16MnDR require post-weld heat treatment to relieve stress. There is a S30408 fitting on the equipment cylinder; what type of welding rod should be used to weld this fitting to the 16MnDR main body of the equipment?
Use the transition welding electrode 307 made of low-alloy steel and austenitic stainless steel.
Note in Table 3 on page 99 of NB47015 states: To be used when no post-weld heat treatment is performed. The key is that I need post-weld heat treatment
47015 is recommended, but not mandatory. A weld evaluation is carried out; if the weld evaluation confirms that the process is suitable, then that’s sufficient
Under normal circumstances, welding with A307 electrodes followed by heat treatment poses no problems. However, post-weld heat treatment can have an impact on the properties of these welds. Moreover, given the different thermal expansion coefficients of stainless steel and carbon steel, heat treatment can also cause issues, including the formation of cracks. If the wall thickness of the container is large, the local welding stress on the nozzles is high; in such cases, it is possible to first weld a transition layer at the openings of the nozzles, then subject the container to heat treatment. After that, the stainless steel nozzles can be welded without undergoing any further heat treatment.
The handling on the 9th floor was proper; I’ve learned from it
My equipment is 14 MM thick – can I simply use A307 or A312 welding rods for the welding process? Is it a serious problem?