Serving our customers and the industry with quality light pole products since 1973
NAFCO Heat Treating Procedures
Age Hardening
To maintain the strict structural design criteria of AASHTO, it is absolutely necessary for aluminum light poles to be age hardened after welding on the base casting. At our facility, the entire pole is placed in an oven and age hardened at 355° F for nine hours to restore the structural integrity of the weld area to a T6 temper. See photos 1 and 2 for the welding and oven heat treating processes.
Destructive Testing
Photos 3, 4 and 5 show a new base design in the process of destructive testing.
Photo 3 shows the welded pole base with the age hardening. Photo 4 shows the welded pole base without the age hardening.
Photo 5 shows an age hardened 6S30E pole with a dead load of approximately 700 pounds placed on the pole 25 feet from the base. The shaft deflected 46" and remained in that condition for three days. No failures occurred during the testing process. The same test was performed on a pole that was not age hardened. At approximately 400 pounds and 25 feet, the shaft ripped from the base just above the weld.
The results of this test demonstrate the purpose of age hardening and our intolerance for field-welding of bases to light poles.