Doc No. 740048
19
MODEL 96
TUBE TO TUBESHEET WELD HEAD
OPERATION MANUAL
10.0 CLEANING AND MAINTENANCE
CAUTION, DO NOT USE AIR PRESSURE
ABOVE 20 PSI (139 Kp) (1.38 Bar)
10.3 To clean the weld head, use a lint-free cloth and alcohol to wipe
down all surfaces.
11.0 STORAGE
11.1 Attach the dust cap to the electrical connector, and store the weld
head in a clean, dust-free area.
11.2 Do not store the weld head for more than 1 month without first
draining the coolant from the weld head and hoses. Refer to chapter
10.0 for coolant draining instructions.
12.0 TUBE & TUBESHEET PREPARATION CONSIDERATIONS
As with all welding applications, regardless of the welding process or the
material being welded, cleanliness of the materials being welded is of
upmost importance. Dirt, oil, paint, hydraulic fluid, oxidation, or any other
contaminant must be removed from both the tube and the tubesheet prior
to installing the tube into the tubesheet. Cleaning the joint after the tube
has been installed will not be adequate, as contaminants trapped between
the tube and tubesheet cannot be removed, and will cause weld defects
and/or porosity. Additionally, contaminants can adhere to the electrode
and contaminate it.
Fit up between the tube O.D. and the tubesheet hole I.D. is also very
important. If the tube is not in good contact with the tubesheet, weld
repeatability will suffer. Weld puddle characteristics will not be consistent
if the fit up is not consistent. In order to get repeatable thermal transfer
between the tube and the tubesheet, they must be in good contact with
each other.
