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3091 |
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Thursday, March 29, 2012, SuperC, Hall Ford 9:25 AM Weld Properties 1 |
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Reduction of weld residual stresses with the electron beam |
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Alexander Backhaus* / ISF - Welding and Joining Institute, RWTH Aachen University, Germany Uwe Reisgen / ISF - Welding and Joining Institute, RWTH Aachen University, Germany Simon Olschok/ ISF - Welding and Joining Institute, RWTH Aachen University, Germany Michael Rethmeier/ Federal Institute for Materials Research and Testing, Germany Andrey Gumenyuk/ Federal Institute for Materials Research and Testing, Germany Florian Tölle/ Federal Institute for Materials Research and Testing, Germany |
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High welding residual stresses can cause service life reducing consequences. Even though many processes have been developed to reduce these stresses, they are only applicable for wider welds and simple component geometries or are cost-intensive, respectively. This work introduces a possibility to reduce the weld residual stresses by means of the electron beam. The same tool is used for the production of the welded seam and the weld residual stresses are reduced touchless, in a multiple-process technique or in a second working step. Other process steps, spanning or shifting of the component or even additional machines are no longer required when this method is used. Via beam oscillation and multiple-process technique, the defocused electron beam produces thermal fields in transversal and lateral distance to the welded seam which impose compressive stress on the ambient material. With the help of adjusted distances, the residual stresses in the welded seam are, e.g. in the case of ferritic steel, reduced by up to 73%. In this work, the basic mechanism for stress relief is introduced and also the influence which different process parameters, e.g. beam power, deflection parameters, diameter of the defocused electron beam and work distances between thermal fields and welded seams exert on the reduction of residual stresses. Moreover, different results made with ferritic and austenitic steel are presented in the form of linear and circumferential welds. |