Welding of stainless steel composite plates

Sure, in our company, we usually complete welding of all the layers at the base level first, and then conduct RT testing together, along with PT on the surface

I think it’s possible~ The processes I use generally follow these rules as well~ Typically, for composite plates, the base layer is welded first, followed by the addition of a overlay layer. When performing calculations, the base layer is intended to bear loads, while the overlay layer serves to provide corrosion resistance. The reason for using composite plates is usually to save on material costs; therefore, after welding the base layer, RT testing can be carried out to check for any defects in the load-bearing welds and ensure their strength. PT testing is then used on the overlay layer to ensure there are no cracks on its surface and to guarantee its corrosion resistance~ But it’s also possible to conduct RT testing after both layers have been welded together, followed by PT testing on the surface~ However, I think repairs would be rather complicated at that point~

Our company first welds the base layer, performs RT testing after welding, then welds the transition layer, and finally conducts re-inspection; for the clad layer, MT testing is carried out

Reply to 4# huanggang1987: Correction – the composite layer is PT, a non-ferromagnetic material

From a safety perspective, RT should be carried out after all the base and overlay layers have been welded (no one can guarantee that no internal defects such as cracks or lack of fusion will occur during the welding of the overlay layers), and at least the ASME codes specify that non-destructive testing must be performed after the overlay welds are completed. The domestic standard is not specified.

Reply to 4# huanggang1987: Does your company perform MT on stainless steel? What about austenitic stainless steel? :D

Generally, after the base layer is welded, RT testing is carried out; this way, any defects in the base layer can be detected early, allowing for timely correction. After the entire weld is completed, PT testing is performed on the cladding.

From a safety perspective, RT should be carried out after all the base and overlay layers have been welded (no one can guarantee that no internal defects such as cracks or lack of fusion will occur during the welding of the overlay layers), and at least the ASME codes specify that non-destructive testing must be performed after the overlay welds are completed. No one can guarantee that no internal defects such as cracks or lack of fusion will occur during the surfacing process. Domestic standards do not specify this clearly; in other words, in China it is possible to weld composite steel plates. When the surfacing layer does not contribute to the strength of the composite steel plate, RT testing can be performed on the base layer, while PT testing is sufficient for the surfacing layer.?????

Since the cladding, as part of stainless steel, can only be used for PT, it is only the base layer that can be used for RT. Whether the cladding does not bear load or not is not a factor that determines whether RT can be applied; I think you’re overthinking it – if the cladding could be used for RT, it would indeed be used for that purpose. After all, cracks are dangerous both in load-bearing and non-load-bearing areas. It is not allowed under regulations.