On-site welding issues for gas storage tanks

The original poster should provide a more detailed and professional description; some parts are hard to understand, making it difficult to respond.

For shell assembly, it is first necessary to align and adjust them using pins, after which spot welding is carried out at the symmetrical points in sections to connect everything together. Manufacture the pins, align the edges, weld them to the housing simultaneously, and lock them in place; work in a symmetrical manner.

First of all, thank you for your enthusiastic reply. 1. In our factory, which manufactures gas storage tanks, the usual procedure is to wait until the head has been pressed into shape, after which the operator measures the outer perimeter of the head using a tape measure; this perimeter is then used as the dimension for cutting the cylinder body (theoretical values suggest that this dimension should be about 10 mm smaller). The problem now is that when using 16MnDR material and following the previous methods, there is a large mismatch in dimensions between the head and the cylinder. (16MnDR deforms significantly during welding; how to address this?) ) The second issue is that since elliptical end caps are all formed by spinning, there is a discrepancy between the surface shape and the theoretical values. When creating cylindrical supports, I followed the theoretical specifications for the designs, but the actual height and surface fit differed significantly from those expectations. Do anyone have any good suggestions?

From the poster’s description, it seems there are deeper issues at play here. Firstly, the welding deformation of 16MnDR is not very different from that of ordinary 16MnR. The significant deformation mentioned by the original poster is likely due to the fact that the cold-formed head was not subjected to stress-relief heat treatment, which caused the head to expand outward as it was heated during welding. Secondly, the spin-formed 16MnDR head must undergo stress-relief heat treatment; otherwise, its impact toughness will be reduced. There’s not much that can be done regarding the second issue; since the surface formed by spinning differs significantly from the theoretical value, standard templates should be used for inspection, and those that don’t meet the standards should be returned

:Lol, fixing it bit by bit. . .

Question 1: After the head is pressed into shape and returned to the factory, measure the outer perimeter of the head’s straight edges. The diameter of the cylinder is then determined based on this outer perimeter, thereby reducing variations. This approach ensures the best possible fit between the head and the cylinder during spot welding. Question 2: After the curved surface of the leg-type support (circular tube type) gasket is fitted to the head, the tolerance for the cutting of the circular tube can actually be increased slightly; the tube can be made a bit longer and then the excess part cut off.

It should be fine if the shims for your support legs are cut to size and sent to the head manufacturing plant together with the head material for pressing at the same time