What do the various defects in pressure vessel welds actually look like? What standards should be applied for inspecting welds during acceptance?

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Upon the arrival of pressure vessels such as reactors, heat exchangers, and towers, we conduct inspections to assess their appearance. I was only able to find standards regarding weld inspection in GB 150.4, sections 6.2.1 and 7.3; the standards NB/T47014 (JB/T4708) \"Welding Procedure Qualification for Pressure Vessels\", NB/T47015 (JB/T4709) \"Welding Rules for Pressure Vessels\", NB/T47016 (JB/T4744) \"Mechanical Property Testing of Welded Test Pieces for Pressure Vessels\", and NB/T47018 (JB/T4747) \"Technical Requirements for Welding Materials Used in Pressure Vessels\". None of these standards contain requirements related to on-site visual inspections. According to GB 150.4, “7.3.3 The surface of welded joints shall be inspected visually in accordance with relevant standards; there shall be no surface cracks, lack of penetration, lack of fusion, surface pores, arc pits, unfilled areas, slag inclusions, or spatter ； The weld seam should transition smoothly into the base material ； The shape of the fillet weld should have a concave, smoothly transitioning profile. ” 1. I would like to ask everyone: what do various defective welds actually look like? Surface cracks and surface pores are easy to understand, but after searching on Baidu for a long time, I still can’t clearly figure out which defect corresponds to which one. I hope my friends from Sichuan can help by sending me some pictures so I can learn from them* 2. If a weld has been repaired, but the manufacturer has failed to record this in the product quality certification documents as required, I would like to know whether it is possible to detect this through visual inspection, and how 3. Are there any other standards applicable to the inspection of the appearance and welds of pressure vessels? Thank you!