Combination Beading Expanders
![Combination beading expander](https://tubetools.ca/wp-content/uploads/2024/01/com_720-1.jpg)
Why Tubes are Beaded.
We bead tubes for one reason, to transfer the heat from the tube end into the tube sheet—a dissipation of heat. Usually, at the first pass, otherwise known as the hot pass, tubes welded will transfer the heat to the tube sheet. Temperatures on the hot pass can be 1800-1900 degrees. If not welded cracking or burn back would occur. This in turn would cause the tube joint to fail. On the next pass, the tubes rolled and beaded pass the heat back to the sheet. The heat then transfers to the larger mass, albeit the tube sheet.
To achieve formed tube joints with beads we must follow certain specific requirements. This applies to both procedures, manual beading or using combination beading expanders. A required protrusion, or stick-out, of the tube from the tube sheet to form the bead. For the combination expander, this protrusion, listed as found in the specifications.
![Tube tools for Retubing on a boiler using the combination tool.](https://tubetools.ca/wp-content/uploads/2024/01/bg_05.jpg)
Conventional Way of Beading
- Secure the tube with the correct stick out on the end being rolled.
- Roll the joint with a flaring expander (114 Series).
- Using a power hammer and beading chisel. form the bead back onto the tube sheet. Experience needed.
- Re-roll the joint with either a Collins Expander or an A Series Expander.
Collins Roller or V Series
Manual Beading Tool
![manual beading tool 1](https://tubetools.ca/wp-content/uploads/2024/08/manual-beading-tool-1-225x300.webp)
Combination Beading
- Secure the tube with the correct stick out on the end being rolled.
- Roll the tube and bead in one operation.
![Combination Beading Expanders](https://tubetools.ca/wp-content/uploads/2024/01/combo-1-1.jpg)