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AssigneeKawasaki Jukogyo Kabushiki Kaisha
InventorsHajimu Horiuchi, Akira Sakaguchi
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A method for preventing discoloration of the area around an indentation in spot welding is provided in which the weld zone and its surrounding area are masked with a non-oxidizing gas such as argon gas, helium gas, nitrogen gas or a mixture of argon gas and carbon dioxide gas from ambient atmospheric air and spot welding is carried out in the atmosphere of the non-oxidizing gas to prevent the discoloration from occurring at the weld zone of a metal sheet under the influence of heat during spot welding.
A method for preventing the discoloration of an area around an indentation formed in spot welding stainless steel, comprising masking a weld zone and its surrounding area from ambient atmospheric air with non-oxidizing gas, conducting spot welding in an atmoshpere of said non-oxidizing gas to thereby prevent the discoloration from occuring on the welded metal surface under the influence of heat during spot welding.
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Resistance welding; Severing by resistance heating: the welding zone being shielded against the influence of the surrounding atmosphere
Soldering or unsoldering
Term ended 30 Mar 2004 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
This invention relates to a method for preventing discoloration from occurring at the area around indentation in the welded zone of a sheet metal under the influence of heat during spot welding.
2. Description of the Prior Art
FIG. 1 is a schematic illustration of a conventional method for preventing the discoloration of the area around an indentation in spot welding.
FIGS. 2 to 4 are schematic illustrations of the three different modes of embodiments of the method according to this invention.
This invention will be described in detail below by way of its embodiments illustrated in the accompanying drawings.
The method of this invention is applicable to any known metal materials and other analogous materials that can be spot welded.
For practising the method of this invention, a spot welder is provided with a blow-out port(s) of an inert gas or non-oxidizing gas (such gas being hereinafter referred to as non-oxidizing gas) at a position(s) close to or in the neighborhood of electrodes so that said gas is ejected from said port(s) toward the area around the electrodes or said gas is effused so that the whole weld zone is masked with this gas from the ambient atmospheric air.