Regarding the issue of the scope of qualification for the hot pressure welding process of simulated heads
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Taking Q345R as an example, let’s conduct a welding process evaluation. For plates with a thickness of 20 mm, heat treatment in the form of simulated head hot pressing (normalizing) is applied; according to JB4708-2000, the applicable range is 5–22 mm. If I use a test plate with a thickness of 40 mm, then the applicable range becomes 5–44 mm. With the same welding process and the same heat treatment, just one such test plate is sufficient to cover almost all thickness ranges for heads. Is this feasible?
Yes, so for weld evaluations at temperatures above the upper transition temperature, it is best to use thick plates in order to cover as wide a range of thicknesses as possible
I completely agree with Clover’s view; it’s economical and legal.
The standards allow this approach, but for some reason some inspection personnel do not agree with it; they believe that an impact test is necessary, so the lower limit should be 0.7 times the thickness of the plate. I wonder if you have encountered such a problem as well
Section 5.3.4.1 of JB4708 explains this clearly: if the test specimen undergoes post-weld heat treatment at a temperature higher than the upper transformation temperature, the original regulations shall still be followed. Our inspection personnel agree with this; I discussed this issue with them specifically, and there are no problems