Tube sheet opening roughness
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What is the approximate range of the roughness of the tube sheet opening used for expansion joints? Are there any standards to check? Is 12.5 suitable?
Article 6.4.6 of GB151-1999: Tube hole surface roughness a) When the heat exchange tube is welded to the tube plate, the tube hole surface roughness Ra value shall not be greater than 25 μm. ； b) When the heat exchange tube is expanded and connected to the tube plate, the surface roughness Ra value of the tube hole shall not be greater than 12.5 μm. ； However, our expansion joints generally take 6.3μm, which is slightly higher than the standard.
Yes, the tube hole surface roughness is introduced in GB151 and other related books. a) When the heat exchange tube is welded to the tube plate, the tube hole surface roughness Ra value shall not be greater than 25 μm.； b) When the heat exchange tube is expanded and connected to the tube plate, the surface roughness Ra value of the tube hole shall not be greater than 12.5 μm. ；