Expanding of heat exchange tubes
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When is hydraulic expansion and mechanical expansion used for expanding heat exchange tubes, and what are the requirements regarding how far the tubes extend beyond the tube sheet?
This is related to the material of the heat exchange tubes used and the tube expansion equipment; it is best to make adjustments with reference to the recommendations in GB151
Each case must be analyzed on its own merits. If there is no relevant process experience, it is best to conduct experiments to determine it. Generally speaking, the mechanical expansion ratio is slightly longer than that of hydraulic expansion.
It depends on the specific requirements; the protrusion length can be set at 151, but there are variations during actual manufacturing. The final protrusion length at both ends can be controlled through expansion joining. Some heat exchangers require no inward contraction, while others require it