Hanson had four consecutive birdies in one stretch and birdied four in a five-hole span of the second nine to get to 14-under 130 after 36 holes. World No. 1-ranked Rory McIlroy had a bogey-free 7-under 65 and is second at 12-under.
Robert Karlsson had six consecutive birdies in his 8-under 64 and is third at 9-under. Jamie Donaldson, who had a course record 62 Thursday, was 2-over Friday and slid back into a tie for fourth with Shane Lowry (64 Friday), Alexander Noren (68) and Justin Rose (68).
Hanson had a 5 at the par-4 first hole but later said, "It's amazing how many good rounds come together after a bogey at the first."
He got the stroke back at the third before stopping his second shot within 4 feet at No. 5, setting off a string of fourth consecutive birdies. His iron play stayed sharp on the second nine, allowing him short birdie putts on 11, 12 and 13 before he dropped a 20-foot putt at 15
"It's pretty soft so you can see yourself shooting some low scores here," Hanson said. "I'm happy with the way I played so far and I know it's going to be a tough one coming up against the World No. 1 these last couple of days on a golf course he obviously loves. He won here last year."