Visit you near by Hardware Store and ask them for their recommendation. Take care to avoid painted or galvanized metal poles. Bare steel can be used with an occasional application of corn oil or like natural oil products. Aluminum is another possible metal that could be used.
Why not just replace it with a like wood product? Your Parrot appears to be enjoying the activity. And after all, if the choice is having your Parrot chew the pole or something far more expensive; I would choose to provide a chewable wood pole. But that is just me.