Regarding weld bead smoothing
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Manufacturing equipment: coke towers, made of 15CrMoR+410S and 15CrMoR. It is required that the reinforcement height of all butt welds on the shell be completely removed so that they are level with the steel plate; in other words, the reinforcement height should be 0. My questions are: 1. Do the welds between the pipes and the pipe supports as well as flanges also need to be polished flat? 2. Do the welds on the skirt base not need to be smoothed?
It is believed that what the drawings require to be smoothed out is the excess height of the butt welds; there is no need to smooth out the leg thicknesses of fillet welds, as a certain height for those leg thicknesses is necessary. The welds on the skirt base do not need to be smoothed out, as the skirt base is not a primary load-bearing component. However, the welds that connect the skirt base to the equipment must be prepared in accordance with the drawing specifications. Those welds are combination welds of butt welds and fillet welds, and the requirement to smooth them out is aimed at reducing the stress resulting from the excess height of the welds, thereby ensuring a smooth transition between the welds and the base material
I’m not talking about grinding the fillet welds; I’m referring to the butt welds between the pipe fittings and the flanges, as well as between the pipe fittings and the pipe supports. In other words, are the butt welds during takeover included in the butt welds of the shell as specified in the technical requirements?
If it is explicitly specified that it is a shell, then there is no need to grind the joint seam between the pipe and the high-neck welding flange, as it can be difficult to flatten the excess material inside some small flanges; or in the case of pipe joints, it’s simply not possible to flatten that area at all. Since it is specified that it is a shell joint seam, only that seam needs to be ground – the other welds don’t matter. If you want to grind them, go ahead and do so
Since it is required that the housing have its weld seams smoothed, there are likely no such requirements for the welds between the pipes and the pipe mounts as well as the flanges. The pipe mounts are non-pressure-bearing components, and unless specified otherwise, there is no need to smooth them out, as that would be somewhat wasteful.
In my opinion, it should not be included within the shell range; what the shell should encompass are the head and the cylinder. However, this requirement should also apply to larger connections, such as manholes.
Personal opinion: The mating joints of the casing should be smoothed, while the connectors generally do not need to be smoothed unless there are special requirements.