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Development of GMAW consumable test method

An analysis of I/U-characteristics and automated welding, regarding new quantifying measurables and stability

Anton Denzler ; Jonas Henrikson
Göteborg : Chalmers tekniska högskola, 2014. 75 s. Diploma work - Department of Materials and Manufacturing Technology, Chalmers University of Technology; 130, 2014.
[Examensarbete på avancerad nivå]

This project investigates the possibility to find measurable values based on the current and voltage characteristics of the GMAW, Gas Metal Arc Welding, process that may be correlated to process parameters and/or geometrical measurements of weld beads. Such quantites may have the potential to replace or complement existing subjective and qualitative charcterisation and validation methods of the welding process. Existing characterisation methods of the performance of welding consumables consist, at least partly, of an experienced welder/engineer that uses his/her experience to evaluate the welding process. Finding other more objective and quantitative measures that correlates to aspects of the welding process may enable more systematic and efficient methods of development and validation of welding consumbles. Also, a replacement of manual welding with automated welding may further contribute to the efficiency of the methods. This work will focus on two aspects during two experiments. The first experiment performed aimed on deriving possible quantitative measurables from the I/U characteristics from welds acquired with varying voltage and wire feed speed. An automated GMAW process were used. The I/U data was then analysed in a computer software to find possible characteristic measurables, which have the potential of correlating to the welding process. Examples of calculated characteristic quantities are; amount of short-circuiting, quantities from Fourier transformation analysis and deviation in current, voltage and power. A discussion are made about how these aspects of the I/U characteristic are linked to the process and different transfer modes. The I/U characteristics analysis revealed that some of the calculated characteristic quantities showed possible trends or indications of correlations to the weld process. The Fourier transformation showed a unexpected peak in the frequency span of 300- 900 Hz, which could be of future interest but it needs further analysis to draw any conclusions. In the second experiment, a number fillet welds were made in order to demonstrate the effectiveness and stabillity of the automated setup. These welds are also made with varying wire feed speed and voltage with an automated GMAW process. Geometry measurements were performed on the weld bead profile, in terms of throat thickness, leg length, penetration, etc. The result from the geometrical measurements and their correlation with the input parameters are shown to be in good agreement with theory and the automated setup being promising as a standard method for consumable characterisation.

Nyckelord: Automated GMAW, I/U characteristics, MIG/MAG Welding

Publikationen registrerades 2015-06-30. Den ändrades senast 2015-06-30

CPL ID: 219132

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