Wide range deployment device with shielding gas atmosphere

摘要

PROBLEM TO BE SOLVED: To prevent irregularity of thickness of a shield gas atmosphere around a welding part in performing welding by emitting a laser beam.SOLUTION: In this wide-area expansion device A of a shield gas atmosphere in a laser processing machine for inserting a pipe 1 in each of a plurality of holes 2a formed on an end plate 2 to laser-weld one-side end 1a of the pipe 1 to the end plate 2, a supply member 10 of shield gas is connected to the other-side end side of the pipe 1 inserted in each of the holes 2a formed on the end plate 2; the shield gas is supplied from the supply member 10 through the pipe 1; and thereby the circumference of a welding part 3 between the hole 2a formed on the end plate 2 and the one-side end 1a of the pipe 1 is brought into a shield gas atmosphere. A cover 15 covering a welding surface 2b where the plurality of holes 2a on the end plate 2 and the ends 1a of the pipes 1 each inserted in each of the respective holes 2a and welded to the holes are exposed is arranged. Outlets 16 for discharging the shield gas are formed above the welding parts 3 on the cover 15. A transparent lid body 17 is arranged above the welding parts 3 on the cover 15.