How is the welding thickness at the stuffing box location of a valve support calculated?
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I would like to ask the experienced colleagues: it is difficult to perform surfacing welding at the location of the gland for this type of valve support. A rod made of the material suitable for surfacing welding is inserted and welded first, after which further processing is carried out. How much should be welded on the upper and lower parts (the dimension indicated by “7” in the diagram) to ensure strength? How is this calculated?
Weld width: The width of the weld is primarily determined by the thickness of the base material and the type of groove. Under normal circumstances, the weld width should exceed 2–3 mm on each side of the groove to ensure the strength and sealing performance of the weld. For the surfacing at the position of the valve support stuffing box, if the base material is thick or needs to withstand high pressures, the weld width should be increased accordingly. Weld bead height: Weld bead height refers to the portion of the weld surface that is above the surface of the base material. It has a certain impact on the strength and corrosion resistance of the weld. Generally, the weld bead height should be controlled between 1.5 and 3 mm, with the specific value depending on the requirements for weld strength and sealing.
Why not consider processing the core rod made of surfacing material into a stepped shaft in advance and then inserting it from the flange side? This would significantly reduce the strength of the weld. Additionally, looking at the screenshot, it seems that these are die-forged valve bodies with small openings; the quantity is not large and the material is already forged, so it would be better to use a single-piece material. The cost of surfacing might even be higher in such cases