When forming tube-to-tubesheet expansion joints, everyone knows the rule of thumb guidelines published by tube expanding equipment suppliers and in text books, but do they know why that range is proposed, and what happens if it is exceeded? If the joint doesn’t seal within the range what do you do? Pull the tube and try another one, potentially damaging the tubesheet and tube hole? Or do you keep going into an unknown region and hope for the best?
Allied Heat Transfer is often performing R&D projects with a recent one conducting tube pull-out tests as per ASME to further our understanding of the affect different expansion magnitudes have on the joint strength and what the acceptable limits for various materials are. We expanded a range of tubes with several wall thicknesses to different levels of wall thickness reduction, then ran tests to determine the force required to break the joint, as well as mechanical tests such as tube wall hardness to determine whether the expansion had damaged the tube. The results of these tests have been used to refine our tube expansion procedure.
You can be sure when dealing with Allied Heat Transfer for your shell and tube and air cooled heat exchangers that we understand the design and fabrication processes intimately, providing you with the best product.