General flame correction, according to the shrinkage principle, the baking direction should be the direction you want the component to bend (most baking shapes are triangular, and the correction in the thickness direction generally needs to bake through 1/3 of the thickness of the plate, and it should not be all red, and the baking temperature should not be too high to prevent the material from changing).

The correction of section steel is different, but unfortunately the picture can't be sent.