DN600 pipeline
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For 24\", that is, low-pressure pipes of DN600, what type of pipe is generally chosen? Our carbon dioxide compressor intake pipeline has a pressure of 0.17 MPaA and a diameter of 24 inches; it is made of stainless steel and features longitudinal welds, and it seems to have been fabricated from stainless steel sheets. Is that the case? I would appreciate your advice.
We are in the same situation: for the atmospheric pressure intake pipes of DN600, we use seamless steel tubes of 630*10 dimensions, but the procurement department usually orders straight-seam welded pipes; it seems to be a common practice. . . .
I remember that pipes with a diameter larger than a certain value are made by rolling steel plates; in other words, many tower-type equipment components are also fabricated from rolled steel plates. I wonder if this is the right way to understand it?
Reply to 2#: For the atmospheric pressure inlet pipeline of 3051Hart DN600, we use seamless steel pipes with dimensions of 630*10; however, the purchasing department usually opts for straight-seam welded pipes – it seems to be a common practice. . . . Dude, do you know how much the cost difference is between DN600 seamless pipes and welded pipes? This isn’t a habit; it’s something you should take into account when providing the parameters for procurement. It’s a pipeline under normal pressure – how can you ignore the costs in that case? There’s no sense of cost at all. Speaking of which, what’s wrong with large-diameter welded pipes? It can be used as a substitute entirely, provided that the welding coefficient of the weld is maintained. Don’t get upset at what was said above, hehe.
Hehe, we design everything in accordance with the technical specifications. Since those specifications require GB8163 standard pipes, we can only use seamless steel pipes; otherwise, the drawing review won’t be approved. . . The users will say that they have already paid for it, so changes aren’t allowed arbitrarily. . . However, they purchase straight-seam welded pipes for procurement, and users generally haven’t said anything about it. . . Perhaps the people on site think it’s sufficient or haven’t noticed yet. . . Hehe
The original design was seamless steel pipe of 20# grade. Considering the carbonic corrosion of carbon dioxide at low temperatures, the material has been changed to stainless steel. Switching to straight-seam welded pipes was probably due to cost considerations.
It seems there aren’t many manufacturers in China capable of producing seamless pipes of size 20x600. Generally, large-diameter steel pipes either have straight seams or spiral welds; in any case, they are welded pipes. Half of the steel pipes on the 20th series are of small diameter; those of large diameter are presumably made by rolling 325-grade steel plates. It’s not cost that should be considered, but rather the manufacturing process. Stainless steel is not much more expensive than carbon steel