Steel to steel stuck is simple rust. Dip the front end in Evaporust or a solution of oxalic acid for a day or two. Should do the job.
Also, the shape of the stem and that it is on a Bianchi says Ambrosio, not Cinelli.
I agree with this approach with a small caveat. What material is the headset made of? If it's alu, I might be cautious of the oxalic acid for a long period of time.
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I'm not one for fawning over bicycles, but I do believe that our bikes communicate with us, and what this bike is saying is, "You're an idiot." BikeSnobNYC