What is the inner diameter of the cylinder to consider double-sided welding?
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For a cylinder with an inner diameter of 700mm and a length of 1300mm, the design drawing requires double-sided welding. When I compiled the welding process, I really didn’t want the master to climb in for welding. I would like to ask, what is the minimum inner diameter of the cylinder that everyone generally considers when considering double-sided welding?
The minimum inner diameter of the cylinder is based on the worker's operation* Usually, like our unit, double-sided welding can be achieved even with a minimum cylinder inner diameter of 500mm.
Our units generally use double-sided welding when the diameter is greater than 600mm.
Generally, double-sided welding is used when the diameter is greater than 600mm, and it is also possible when the diameter is 300-600mm and the length is less than 500mm. There are regulations in HG20583
It is worth advocating that the poster consider the operating environment of the master welder. However, it is better to use the process of welding the inside of the DN700 cylinder, gouging and cleaning the outside, and then automatically welding, forming and capping.
If possible, try to weld according to the drawings. In addition to the old masters, there should be immortal masters, right?
Single-sided welding and double-sided molding can be used.
It's quite hard, but if there are regulations, you have to follow them. It's better to work harder than to have problems, right?
Generally, it should be no less than 700. Now that conditions are better and there are more fat people, the standard should be revised according to the actual situation.
Single-sided welding or double-sided welding mainly depends on the individual* Customary, double-sided welding butt groove processing quality and matching requirements, welder skills, etc. are relatively low ； Depending on the length of the cylinder structure, double-sided welding is generally considered if it is above 800. Small-diameter short cylinders can also be double-sided welded.
Double-sided welding cannot be used if people cannot get in to perform welding. Single-sided welding and double-sided forming with argon arc welding can be used. Generally, the manhole is at least DN400. Considering the space for people to enter for welding, the cylinder must be at least 500mm. It should be noted that double-sided welding has requirements on the thickness of the cylinder.
You should still decide which welding plan to adopt based on the verification results!
Don't consider whether the workers are working hard, but consider which one is better in terms of ensuring the welding quality. Obviously, the effect of double-sided welding is better than that of single-sided welding.
The quality of double-sided welding is easier to ensure. Our units generally consider double-sided welding for diameters above 700mm.
As long as people can get in, double-sided welding can be achieved. However, double-sided welding does not necessarily require people to enter. Single-sided welding and double-sided molding can be achieved.
Do things according to standards. Pressure vessel design is not a humane design. If something happens, no one can afford it. The diameter of the tube must be considered. As mentioned above, the material and medium must also be considered. It's better to consider it all.
Generally, anything larger than DN400 can be double-sided welded, but it cannot be measured based on the diameter alone. It also depends on the strength calculation. Although the barrel is small, the strength is calculated based on double-sided welding. If you use single-sided welding, it is not very dangerous.
If the manhole is 400mm, according to the opening requirement of 150mm, the diameter of the cylinder must be greater than twice the opening diameter, which is 852mm. It does not agree with the diameter of 500mm.
According to the recommendations in HG20583-1998, double-sided welding is generally used when the diameter is greater than 600mm.