The Sphere has been placed in New York's Battery Park
The Sphere, created by German artist Fritz Koenig, had stood in the World Trade Center plaza as a monument to world peace through world trade since 1971.
But it was split and partially crushed by falling debris from the Twin Towers on 11 September.
It has now been restored and was dedicated to become a temporary memorial at 0846 local time (1346 GMT) - six months to the minute after the first plane hit.
'Beautiful corpse'
New York mayor Michael Bloomberg has said the $1m (£700,000) bronze and steel sculpture would probably also form the centrepiece of a permanent memorial.
Mr Koenig, now 77, will fly to New York to see the repaired Sphere be unveiled - despite originally saying it should not be restored.
He described it as "a beautiful corpse" at the time.
"It is lost, just like the World Trade Center," he said.
More recently, he said he still had mixed feelings about the globe's fate, but said: "I hope I will still be able to consider myself the creator of this work."
The restored sculpture, which weighs 45,000lb (2,041kg), will be surrounded by trees and park benches in Battery Park, close to Ground Zero.
Destroyed
It had originally sat on a fountain and served as a meeting place in the World Trade Centre's five-acre plaza.
The Sphere was one of the only salvageable works of art found in the wreckage after the attacks.
Artworks worth up to $100m (£70m) were destroyed after the planes hit.
Koenig has previously created memorials at a Nazi concentration camp in Austria and to Israeli athletes killed at the Munich Olympics in 1972.