Testing Methodology to Characterize GMA Welds for use in FEA Simulation******

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Automotive producers would like to increase use of advanced high strength steel (AHSS) in gas metal arc welded (GMAW) frame applications. This would allow parts to be made from thinner gauges of steel than are currently used, reducing part weight, and improving vehicle fuel economy, while maintaining or increasing vehicle safety. However, when AHSS are GMAW, many AHSS exhibit heterogeneous properties exhibiting local areas of high and low hardness due to their complex chemical composition and microstructures. This hardness variation leads to variations in results during strength testing so that the data cannot be used to inform numerical simulation models needed for part design.****This project will develop a testing methodology to characterize the tensile weld strength of lap shear joints, which may be used as input for the models needed to design automotive parts. The method will be designed so that it may be implemented using standard testing methods available to industry. The test method will be improved by increasing the symmetry of the tested joint, and then validated by comparing test results to welds made in a butt joint configuration, which is the ideal case, and local stress-strain data from various areas of the HAZ, calculated using instrumented hardness test data.****Implementing the results of this project is the first step to integrating heavy (>2 mm) AHSS into frame applications. Increasing use of AHSS in frame application will allow thinner materials to be used for automotive designs decreasing vehicle weight and reducing their environmental impact. This will benefit Canada by: reducing the environmental footprint of new vehicles, providing manufacturing know-how to Canadian companies, such as Martinrea, to manufacture new grades of steel, and provide a market for Canadian steelmakers such as Stelco and ArcelorMittal Dofasco to sell their new AHSS grades.