| 摘要 |
The present invention relates to processes and apparatus for welding or joining metal parts which comprises moving a welding torch in a direction along a joint between said parts, causing a molten pool of metal with said welding torch along the joint and directing a laminar flow of inert fluid toward a freshly welded area behind said welding torch in the form of a trailing shield whereby said freshly welded area is protected from the surrounding air during its solidification. The laminar flow or inert fluid may also be directed along the joint ahead of said welding torch in the form of a leading shield such that turbulence in and around the joint caused by a high welding speed is reduced, thereby preventing oxygen entrainment in said molten pool of metal. The laminar flow of inert fluid is usually provided through at least one diffuser having at least one porous diffusing surface which is generally provided with a screen and/or a spatter shield.
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