Determine where you would like the piece of steel plate to bend. Draw a straight line in this location to mark the desired bend area.
Secure your piece of steel plate into the bench vise, lining up the bending line with the edge of the vise.
Put on a pair of welding gloves and a welding mask or a pair of welding goggles to protect your body. Make sure that your workspace is free of flammable materials.
Heat up the acetylene torch to a low flame. You can also use a rosebud torch tip, which is common for heating large areas of metal.
Apply the flame to the surface of the metal, along the bending line. Move the torch slowly along the line until the metal begins to turn red. Turn off the torch.
Hammer the plate metal over the vise with firm, even strokes. Stop hammering when the metal becomes resistant to bending.
Heat up the bending line again, and begin the hammering process. Continue heating and hammering the plate metal until you have the desired bend.
Let the steel plate metal cool completely. Remove the bent steel plate from the vise.