How to ensure the flatness of the sealing surface of large flanges?
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I encountered such a problem at work: high-neck flanges with a nominal diameter of DN3000, after being machined to fit together, were welded to the cylinder respectively. When the two flanges were being installed, it was found that the sealing surface of one of them was severely distorted, with a deformation of over 10 mm. The operating pressure inside this cylinder is 1.6 MPa. It had to be scrapped, resulting in heavy losses. I hope everyone can discuss: what processing and welding techniques should be used to avoid similar phenomena from occurring? Thank you! This post was last edited by hehe2006 on 2008-1-21 00:43]
Due to its large size, the flange has very low stiffness relative to its diameter; not to mention welding, even transportation can cause deformation of the container. 1. Due to its large diameter, the stiffness of the flange becomes very low; as a result, the equipment (or pipeline) to which the flange is attached must have relatively high stiffness. In simple terms, both are soft materials and it’s difficult to ensure they won’t deform. 2. If the equipment (or pipeline) has high rigidity, then use the same welding parameters for symmetrical welding during the process; high energy levels are not recommended. During the welding process, adjust the welding parameters in a timely manner to correct the deformation of the flange. 3. Remove the temporary supports for the flange after welding is completed
And who has any clever solutions? One is the processing technique, and the other is the welding technique. Wait! This post was last edited by hehe2006 on 2008-1-28 at 14:18.]
We’ve encountered the same problem as well; currently, foreigners are working on finding a solution. How did you guys resolve it in the end upstairs?
Is it necessary to keep the welded parts insulated after welding to prevent cold-shrinkage deformation?
1. Before welding, tighten the bolts used for flange alignment and then proceed with welding. 2. Weld symmetrically during the welding process. 3. Take insulation measures after welding. 4. After cooling, remove the flange, add gaskets, and reinstall it.