The object was found around 9.30pm on Sunday evening, resting in a grassy courtyard in the middle of a residential area.
Twenty-one homes were evacuated and the area was blocked off. All the evacuees were able to arrange alternate housing, Lars Engström of the Norrköping police told the TT news agency.
Shortly before four o’clock on Monday morning, bomb experts used a specially equipped vehicle to transport the suspicious pipe to a secure area for detonation.
Early Monday morning it remained unclear whether the pipe actually contained explosive material, but further analysis will be used to make the determination.