Please help me by providing your opinion on the following issue:

While cutting a replaceable pipe inside furnace, a cut mark by gas cutting tool is found on adjacent good pipe. A cut mark of 3 mm depth and 6 mm diameter is created on a 3 inch (originally 5.49 mm thickness) A335 Gr. P5 pipe. Should I replace the pipe or locally repair the mark by welding. It is mentionable that overall thickness of the pipe is satisfactory.