What should I do if the butt weld between the head and the cylinder is too misaligned?
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A newly manufactured Class III pressure vessel has a design pressure of 5.5MPa, a cylinder thickness of δ=48mm, a minimum designed head thickness of δ=30mm, and the manufacturer selected a head steel plate of δ=36mm. When the equipment was inspected on site, it was found that the 6mm misalignment of the cylinder and head welds exceeded the GB150 regulations. The head is large and the cylinder is small. How to deal with this situation?
Can the weld be extended and turned in the direction of the top of the arc to make it meet the thickness requirements? Suggestions for copycat versions ;P
This production plant is also a copycat. It is obvious that the cylinder needs to be trimmed. Now the equipment is probably too big and there is no machine tool that can process it. It will take some effort to grind out the trimmed edges. Be careful not to grind the welds and heat-affected zones thinner. It should be a little larger than 36, and the wrong edge will be fine if it meets the standards.
The cylinder steel plate δ=48mm, and the head steel plate thickness δ=36mm. If the edge is not trimmed or the edge is not trimmed enough, the cylinder side is higher, but the actual situation is that the head side is 6mm higher.
Cut the cylinder from the weld, add a cylinder plate with a width exceeding 144mm, measure it and cut off the excess part from the original cylinder plate. Then weld and round.
If the outside of the head is 6mm higher, shouldn't the inside edge of the container be 12mm, and the joint is 6mm less? If there is such a big difference, will the strength meet the requirements? In addition, the wrong edge will cause stress, and the weld is a place prone to problems. Is this equipment safe? Can the manufacturer make Class III containers in this way? Is there any product inspection? Check whether there is a manufacturing license, whether the company has a quality assurance system, and whether the quality assurance system is running? When you see this problem with this equipment, are there any major hidden dangers that have not been discovered? How many are there? Do you know what's going on? Is the equipment produced by such a company still a Class III container safe? Do you dare to use it? If it is really made like this, it is recommended to return the equipment, and then find a company that can really make Class III containers to make a new one. After all, it is a Class III container, and safety is still very important.
According to 150, the butt weld should be trimmed...if the hemispherical head is butt with the cylinder, the cylinder cannot be trimmed.
In this case, we probably have to rework it, cut it open and re-weld it.
If it is cut and re-welded, there will be a problem with the factory's quality assurance system. It is better to lose money than to have an accident. It’s better to listen to the advice of your peers and don’t mess around if you don’t have the ability.
Can this be understood according to Haiyou’s words?: If the elliptical head is connected to the cylinder, can the cylinder be thinned? Is there any basis for this?