Arc welding

About: Arc welding is a research topic. Over the lifetime, 25393 publications have been published within this topic receiving 168182 citations.

Weld-pool image centroid algorithm for seam-tracking vision model in arc-welding process

Abstract: Visual sensing is an attractive approach to detect the weld position in an arc-welding process, which provides information for seam tracking However, it is difficult to accurately detect the weld position adjacent to a molten pool because of strong arc disturbances A novel algorithm based on the weld-pool image centroid is presented to improve the seam-tracking ability The molten pool images are taken by a camera arranged ahead of the welding torch and the centroid is extracted as a parameter to detect the weld position It is worth noting that the centroid corresponds to the thermal distribution of the molten pool affected by the offset between the arc and the seam centreline Therefore the offset between the arc and the seam centreline can be estimated by this centroid The least square linear regression method is employed to correlate the relationship between the centroid and the offset under different welding conditions For further analysis of the centroid characteristics, a non-linear neural network is designed with three input variables which are the position, displacement and moving velocity of the centroid, respectively This neural network model shows higher accuracy of weld detection In comparison with directly detecting the weld position, the centroid can be measured and computed easily This algorithm is expected to provide a promising vision model to improve the accuracy of seam tracking in real time, and subsequently to ensure good welding quality

Metal-core weld wire for welding galvanized steels

Abstract: A metal-core weld wire usable for gas shielded arc welding gapless joints on low carbon and low alloy galvanized and galvanealed steels. The metal-core weld wire includes a low carbon steel sheath surrounding a core composition. In one embodiment, the low carbon steel sheath includes, by total weight of the metal-core weld wire, between approximately 0.01-0.03% C, and the core composition includes, by total weight of the metal-core weld wire, between approximately 0.05-0.20% Ti, between approximately 0.05-1.00% Nb, Fe powder, and Mn to the extent that the metal-core weld wire includes between approximately 0.1-1.0% Mn wherein the metal-core weld wire includes between approximately 0.1-1.0% Si. The core composition is, by total weight of the metal-core weld wire, between approximately 0.001-12.0%. The metal-core weld wire provides, at weld rates up to 150 cm/min, reduced arc ionization potential and spatter, and improved arc stability and shielding. The metal-core weld wire produces, at weld rates up to 150 cm/min, weld deposits having reduced blow holes and porosity, no liquid metal embrittlement, and reduced weld pool surface tension resulting in an improved wetting characteristic.

System and process for video monitoring a welding operation

Abstract: The invention is both a system and method for video monitoring a metal working process which involves the generation of an intense point source of light near or on a workpiece, such as an electric arc welding process. The system comprises a lens assembly for projecting an image of the point source of light and the area of the workpiece being worked onto the image sensing circuit of a television camera, a filter assembly having at least one filter element that includes both a central region of low light transmission for dimming the image of the point source of light projected onto the image sensing circuit, and a peripheral region of high light transmission for freely transmitting the image of the background surrounding the point source, and a mechanism for adjusting the apparent size of the central region of low light transmission relative to the image. In the preferred embodiment, an iris disposed within the lens assembly is used to adjust the apparent size of the central region so that it just barely covers the bright arc generated by the torch assembly so that the weld puddle and surrounding area of the workpiece is clearly visible and brightly illuminated in the resulting video image. The system provides a clear, bright and well balanced image of a welding operation without the severe and obscuring contrasts associated with prior art monitoring devices.

Grounding component for electric welding systems and methods

Abstract: A variety of work stands and support assemblies for supporting workpieces such as pipes, are described. The work stands include a base plate and a welding stand-off or grounding lug, at which an electrical grounding cable can be readily attached.