Any chisel with a curved cutting edge is a gouge, and this defines a huge range of variants The bevel of the cutting edge may be situated on the inside of the curve (in-cannel) or the outside (out-cannel), and you need both For example, in working with moldings, you may want to rough in the hollows with an out-cannel gouge before shaping them with a plane, and then use an in-cannel gouge to trim the curved ends to fit together at an inside corner
Local damage caused by mechanical or forceful removal of metal from a local area on the surface of the pipe that may work harden the pipe and make it more susceptible to cracking