As the experimenter explains in the comments section two things are happening simultaneously.  Inside the surface of the pipe  a current is created (and the same effect would happen if was aluminum too or even a different metals).  On the outside of the pipe there is a magnetic field so the two forces somewhat counteract each other and create this cool effect.  And what is interesting is the movement of the magnet creates the levitating force.  However if the force got strong enough to actually suspend the magnet in mid air, the force would stop because of lack of movement hence the magnet would start moving again.