How you can make a steel pipe brittle?
If usability of the pipe is no issue, and you have the safety equipment, I suppose you could clean it off with soap, and then rinse it with HCl, and then scrape at it for a while. Alternatively, you could use liquid nitrogen to flash freeze it, and then strike it with a hammer. I have never personally tried either method, would use extreme caution in whatever manner you choose. This is purely theoretical, any damage you inflict is your own fault, do not attempt the above.
