CWEng
Materials
- Jul 18, 2015
- 146
We make a product that looks like a heat exchanger, but isn't. A customer is requiring us to do tube-to-tubesheet mock-ups, which have been problematic for us even though we don't make tubes or tubesheets. The product we make has tubes from .028" to .042" thick, but they are filled with an insulating powder and then rolled/compacted, so act similar a solid bar. However, due to customer requirements, we are doing the mock-up with hollow tubes. Even though our plate has a relief cut to even out the heat between the thick plate and thin tube, it is difficult in a manual weld to fuse the tube without burning through (despite the fact that ASME doesn't define "burning through"- AWS defines "burn through" as a concavity- so our customer has accepted some "melt through" that is not concave). What is the thinnest wall thickness you tube heat exchanger manufacturers manually weld without issues? Seems like typically I see references to 1/16" and greater, but I've not manufactured typical heat exchangers. Also note that our tube sticks out way past the joint, so melting the edge of the tube is not a possibility, as that seems like it would make it a lot easier. It has to be a true fillet weld.