Material substitution: SA516-70 in place of Q345R
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What are the requirements or issues regarding the use of SA516-70 instead of Q345R for the pre-welded components inside pressure vessels?
No problem,,, GB/T150 references this material
It can be used; the non-compressed elements connected to the compressed elements only need to have good weldability
The pre-welded components inside the container are generally non-compressive components; as long as there is a weld assessment for the welds connecting them to the compressive components, that is sufficient.
The allowable stress values differ; although it is a pre-welded component, calculations are generally required for supporting equipment with large diameters. Pay attention to the allowable stress
According to the scope of GB/T150, \"non-pressure components directly connected to the vessel\" also fall within the scope of this standard. The SA516-70 material has been added to the amendment to GB/T150.2; this material can be used directly in pressure vessels and pressure-bearing equipment in China, provided that its C, S, P contents as well as A and KV2 values meet the requirements of Q345R. However, the material used by the poster for welding internal components is a non-compressive element; in my opinion, S516-70 can be used, but the contents of C, S, and P should meet the requirements specified in TSG21-2016 for these elements in materials used for welding.