What is the minimum diameter of a cylinder that allows for internal grooving and welding inside?
Thread Content
As the title suggests, I would like to ask: what is the minimum diameter of a cylinder for which an internal groove can be created for welding inside it?
It is related to the length of the cylinder. For cylinders with a length of 300 mm or less, the minimum diameter can be as high as 250 mm. For cylinders with a length of over 300 mm, the minimum diameter must be at least 500 mm (to ensure that a person can fit inside).
I generally agree with the comments above, but a diameter of 500 seems too small; 700 mm or more would be better. Submerged arc welding is the preferred method, as manual arc welding is quite difficult to operate.
This standard is not mandatory; it is actually intended to meet the requirements regarding the operating space. On the one hand, the equipment needs to be considered; on the other hand, the personnel situation also matters (for example, in the northeastern regions during winter, with a 700-tank structure, it’s impossible for welders to get inside even when wearing thick cotton coats, right, haha)
There are no mandatory requirements; provided that welding quality is ensured, in cases with poor conditions it is still possible to use a structure with shims, or if technical support is available, single-sided welding for double-sided formation is no longer a difficult task either.
Here, we generally use DN600 as the boundary
DN500 versions that are shorter can also be welded