When you say 2cm think, do you actually mean thickness or width?
I have no idea what you would need 20mm thick steel for on a turbo setup, unless it's for flanges, spacer plates, or your making some brackets to hold a turbine off a 747?
If it is infact 20mm thick, as said previously, cut and weld. If it's only a few millimetres thick, either put it in a vice and hit with hammer, or take it down to a fabrication shop and get them to press bend it to required angle. Would cost you next to nothing to have it bent. Infact if they charged you, imo their tightasses