An apparatus for descaling an inner surface of a bending steel pipe, comprising:
- a support pallet configured to support a plurality of bending steel pipes of which first ends and second ends are opened, the plurality of bending steel pipes being disposed in one direction on the support pallet;
- a stopper part configured to stop the first ends and the second ends of the plurality of bending steel pipes;
- a shot ball supply part configured to supply shot balls to inner portions of the plurality of bending steel pipes through one of the first ends or the second ends of the plurality of bending steel pipes;
- and
- a high frequency vibration part on which the support pallet is seated and which performs high frequency vibrations to shot-peen the inner portions of the plurality of bending steel pipes supported by the support pallet;
- wherein the stopper part includes:
- a plurality of first stoppers configured to stop the first ends of the plurality of bending steel pipes;
- and
- a plurality of second stoppers configured to stop the second ends of the plurality of bending steel pipes;
- wherein the shot ball supply part is configured to supply the shot balls to the inner portions of the plurality of bending steel pipes through the second ends of the plurality of bending steel pipes after the first ends of the plurality of bending steel pipes are stopped by the plurality of first stoppers;
- wherein the high frequency vibration part shot-peens the inner portions of the plurality of bending steel pipes supported by the support pallet by vibrating the support pallet seated thereon at a high frequency after the second ends of the plurality of bending steel pipes are stopped by the plurality of second stoppers;
- wherein the plurality of bending steel pipes are in a heat-treated state and have a U-shape;
- wherein first ends and the second ends are supported by the support pallet;
- wherein the high frequency vibration part performs high frequency vibrations for 180 seconds to 240 seconds as vibrations at 500 Hz to 1000 Hz;
- wherein the support pallet includes:
- first guide pins configured to support the first ends of the plurality of bending steel pipes;
- and
- second guide pins configured to support the second ends of the plurality of bending steel pipes;
- and
- wherein the plurality of first guide pins each have a depressed shape configured to receive the first ends of the plurality of bending steel pipes, and the plurality of second guide pins each have a depressed shape configured to receive the second ends of the plurality of bending steel pipes.