The welding structure of stainless steel heat exchange tube and tube plate can be divided into front and back to form two kinds of weld. Choose which structure, need to see the specific conditions of use, that is, whether there is gap corrosion (stainless steel heat exchange tube and tube plate hole gap), as well as stainless steel heat exchange tube and tube plate material processing mechanical properties, welding metallurgical properties, and combined with processing equipment and technical ability comprehensive consideration.

The front of a tube plate forms a weld

Compared with the back welding, the front welding process and welding lead pair is simple, but whether it is expanded or not, the front welding has the stress concentration problem at the root of the weld, and the gap between the heat exchange tube and tube plate tube hole can not be completely eliminated, there are clearance corrosion conditions.

As shown in the above two screenshots, "weld forming on the front" can be divided into:

1. Front fillet weld type

The tube end of the heat exchange tube extends out of the tube plate, which can form a variety of weld feet height size. This solder foot size needs strength check, this type is easy to calculate and adjust.

This kind of structure can be welded manually and automatically. In multi-pass welding, visual inspection and PT can be carried out after the completion of backing welding to control the root weld quality.

In addition, this structure can be manufactured in advance of the tube end out of the tubesheet long enough, after the completion of welding, the tube end of the entire tubesheet can be machined, so that all the tube end is on the same level. This structure can be used for heat exchangers and condensers with vertical installation where uniform liquid film is formed on the inner wall of tubes in production process.

However, the disadvantage of this fillet weld is that, because the tube end protruding, compared with the entrance of the smooth heat exchange tube and tube plate, the structure of the tube end sinking, it will produce a large entrance section shrinkage rate (reference so, personal do not understand), there may be media erosion in the tube mouth.

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