Steel Bicycle Frames

I installed the seat pin with copper grease to avoid this problem. I tried to turn with a wrench, but he was afraid of damaging the frame.

There is an easier and faster too.

Remove the bolt from the frame, then drip a little ammonia (ammonia real, not cleaner with ammonia inside) around the area frame seatpin /. Continue to drip into ammonia until it is completely saturated. Wait about one hour.

Keep up on the saddle seatpin and use it to wring seatpin rather than a key.

Once seatpin is out be sure to wipe the ammonia from the frame and seatpin. When fat LITHIUM reinstall use inside the frame rather than the fat of copper on the seatpin.

Try some WD40 can penetrate 1 / 2 hour, then press the framework in the field with a soft mallet or screwdriver handle, plastic head twisting as you go.
After he was released from the PTFE grease smears on the stem, then wipe this should prevent a recurrence.

If you have any bolts for a bottle of water in the seat tube, remove, turn the bike upside down, spray penetrating oil into the hole and leave overnight. This may also help to free the seatpost all the other useful suggestions given.

He is seized because of cold weather and the fact that aluminum and steel expand and contract at different rates. Try to warm it with a hairdryer. If this does not remove anything flammable and use a torch.

You may need to be there for your bike shop where they need to heat the part to remove the safety pin. I do not know another way, I'm sorry.

the heat with a torch and hold it firmly in handles mole or Stillson and rotate until it loosens,

Try ...

penetrating oil