Selection of welding materials for pressure vessels that require heat treatment
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In GB150.2-2024, Section 9.4: Welding materials for pressure vessel components used in post-weld heat treatment – The holding temperature for the weld metal during post-weld heat treatment should be the same as that used for the pressure vessel itself, and the holding time should be no less than 80% of the total holding time employed during the manufacturing process of the pressure vessel. Does this mean that for any pressure vessel that requires post-weld heat treatment – whether for stress relief or to restore the material’s properties – the welding materials used must have their deposited metal heat-treated before mechanical property tests are conducted? Example: Pressure vessels made from Q345R steel require post-weld stress-relief heat treatment at 620°C; therefore, welding materials such as J507R or H10Mn2 used must have their deposited metal subjected to heat treatment at 620°C as well. If other types of heat treatment are applied, the heat treatment of the deposited metal also changes accordingly. (I’m not sure if this is correct.) Question: If that’s the case, then it’s easier to talk about temperature levels; there are various insulation times available. It’s impossible for manufacturers to customize welding materials every time according to their own needs, right?
Yes, in accordance with the requirements of GB150.2-2024 standard, for pressure vessels that require post-weld heat treatment, the welding materials used must have undergone heat treatment tests at the same temperature as that of the pressure vessel itself. If the pressure vessel made of Q345R steel in your example requires post-weld stress relief treatment at 620°C, then the weld metal obtained from welding materials such as J507R or H10Mn2 should also be subjected to heat treatment testing at 620°C. As for the issue of holding time, it is indeed impossible for the manufacturer to customize welding materials for each individual case. Under normal circumstances, the holding time should, in accordance with standard requirements, be at least 80% of the total holding time during the manufacturing process of the pressure vessel. Therefore, weld material manufacturers provide heat treatment data within a certain range to meet the needs of most situations. In practice, the design and manufacturing companies of pressure vessels usually communicate closely with welding material suppliers to ensure that the welding materials used meet the corresponding heat treatment requirements. .
Special attention must be paid to this requirement during equipment manufacturing
The standard states that it is “recommended,” so it is not mandatory.