What is the flexible expansion bonding process in the mechanical expansion bonding of heat exchangers?

Flexible expansion joining is in contrast to rigid expansion joining; mechanical expansion joining falls under the category of rigid expansion joining, as its expansion head is rigid and causes even expansion around the area being joined. The area to be joined must have a cylindrical surface； Hydraulic expansion belongs to the category of flexible expansion joining; it includes the commonly used liquid bag expansion and rubber expansion methods. The expansion head in this type is flexible, and its characteristic is that the pressure is distributed evenly in all directions. Elliptical holes can also achieve the effect of expansion joining. The characteristics of hydraulic expansion joining are: high efficiency in tube expansion, reliable connections, no mechanical damage, and low stress on the tube bundle. The \"hydraulic expansion joining\" process is particularly suitable for expanding tubes in deep holes as well as for expanding tubes connected to intermediate sheet plates.

Mechanical expansion causes the heat exchange tubes to elongate, and the inner surface of the tubes suffers from crushing damage； Flexible expansion jointing causes the heat exchange tubes to shorten. Pay attention in areas where stress issues need to be considered particularly.