Dünnwald-Turan had been on trial with United since last week, and played in the pre-season friendly at Watford on Saturday.
The forward has played in England before, when he was on the books of Bristol Rovers between 2017 and 2018, but most recently played back in his home country.
Speaking after joining, the 24-year-old said: “Obviously I’m very happy to join.
“The main decision for me when I came was that the gaffer had a proper plan and I like that. It’s nice to come to a club like this.
“I’ll give my best and dig deep. You can be sure I will always give 100 per cent for the team. I will try to bring other players into play and I want goals and assists, as I am a striker.
“I’ve had some pre-season in my home country with a local side at a good level, because I know the manager quite well.
“You can always improve, so that’s what I’ll be looking for. The target is to win as many games as possible.”
Scunthorpe’s odds on the app from Paddy Power, despite a decent amount of signings, still sit mid-way in the promotion rankings, at 7/1.
Despite that, Iron manager Neil Cox was happy to beat off competition from other clubs and secure the strikers signature.
“He’s trained really well and shown a lot of good things, and we’re glad to finally get him on a contract.
“He’s big, strong and has good movement. He likes to get the ball into his feet in and around the box, and can go both ways and strike with both feet. I’m looking forward to working with him and think he’ll have a good season.
“There were other clubs interested but we managed to get him in (on trial) last week and he’s enjoyed his time here. When we made him an offer, he was over the moon. He’s another good one to have in and we’re starting to look strong as an attacking force.”