The overall local detection coefficient is 0.85; the coefficient is set to 1 when calculating external pressure instability. Is this related to the flaw detection grade of level II?

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Dear teachers, I recently read an article on a public account (Figure 1), which mentioned that when performing overall and local inspections of the equipment, a coefficient of 1 can be used for calculating external pressure. This value of 1 is applied because what is at issue here is instability, not strength, and it has nothing to do with defects; therefore, it is not necessary to take into account the coefficient related to welding joints. The key point mentioned there is that \"for external pressure instability, the joint coefficient is not considered, so 1 is used.\" Extending this idea, when the overall scale of the equipment is within the range of 20%-III-0.85, according to GB/T150.3-7.6.4.3.2, a coefficient of 1 is used for the calculations related to the shell and the large-end reinforcements. Taking into account the provisions of 7.6.4.3.1 and 7.6.1.2, if 100% inspection is carried out on the circumferential seams at both the large and small ends, what should be the inspection level – Level II or Level III? (Figures 2, 3, 4) First, two issues need to be clarified here: 1) Is the concept of the weld joint coefficient applicable to the instability calculation under compressive stress? When defects in the weld of a device are in a closed state under compressive stress and show no tendency to expand or crack, is it still necessary to introduce a weld joint factor to assess the degree of weakening of the weld, in order to adjust the allowable stress in calculations? As shown in Figure 4: Here, defect closure is calculated based on compressive stress; setting the value to 1 to eliminate the influence of defects. Is this the same as setting the value to 1 to account for the reduction in defect expansion and tearing under tensile stress? 2) If the weld joint coefficient is not applicable for external pressure calculations, is the value of 1 used for the weld joint coefficient in such calculations still related to the flaw detection level? Given that the overall equipment meets the 20%-Grade III criteria, the coefficient is set at 0.85. Although the ring seam at the larger end of the cone is calculated using Φ=1, this value is used on the assumption that the external pressure calculation is independent of the joint coefficient. Since it has been clearly stated that the external pressure calculation is unrelated to the joint coefficient, then a 100% inspection is carried out on the larger end; in such a case, is the acceptance standard still tied to Φ=1 for the ring seam at the larger end, and is Grade II still required? It is still Grade III for the main body, but here 1 is used based on external pressure calculations; therefore, the qualified grade remains 100% for the main body, Grade III? ——Since the defect did not expand under external pressure, is it still necessary to evaluate the weakening effect of this defect on the weld using the conventional 100%-II-1 approach? In this case, with 100% inspection, should the flaw detection grade still be linked to the joint coefficient calculated based on the external pressure?