Brittle fracture of heat exchanger tube sheet
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The fillet weld at the tube-sheet joint has suddenly fractured. What could be the cause? The shell side is under 45 bar of steam pressure, while the tube side is under negative pressure. And what is the typical size of the empty gaps on the tubes and tube sheets? From the fracture site, the gap is at least 2 mm. Additionally, the fillet weld is not high; it is even lower than the tube sheet. Is the manufacturing standard acceptable? Thank you!
That’s quite a problem; I’ll hold things up for you
What is the temperature of the vapor in the shell side? What medium is a pipe routine?
45 bar steam, at a temperature of around 250 degrees; it is a product used in pipeline systems and is non-corrosive to carbon steel. I forgot to mention the material: the shell side is made of 16MnR, while the tubes are made of 20#.
This temperature is not suitable for 20# steel
It’s probably a problem with the source material of the tube sheet itself; it shouldn’t be a big issue. Just grind it using a grinder or similar tool, repair it with the appropriate welding rod, and then polish it smooth
There are problems with the tube sheet material itself, as well as issues with its manufacturing.
Judging solely from the appearance of the weld, the welder is definitely an expert. Problems with tube sheet processing? Is there a problem with the tube sheet material? Is there still a problem with the welding material? Analysis can start from these aspects.
A similar brittle fracture occurred in a similar device 2 years ago, with steam at 45 bar in the shell side as well.
The 2 devices were manufactured by the same manufacturer.