Showing papers by "Tracy W. Nelson published in 2007"

Torque based weld power model for friction stir welding

Abstract: For decades, models have been developed for predicting the size of the weld nugget and heat affected zones in fusion welded structures. The basis for these models is the welding heat input, which is fairly well understood for most arc welding processes. However, this traditional approach is not as straightforward for friction stir welding (FSW). To date, no definitive relationship exists to quantify the heat input for FSW. An important step to establish a heat input model is to identify how FSW process parameters affect weld power. This study details the relationship between FSW process parameters and torque for three different aluminium alloys: 7075, 5083 and 2024. A quantitative weld power and heat input model is created from the torque input. The heat input model shows that decreasing the spindle speed or increasing the feedrate significantly decreases the heat input at low feedrates. At high feedrates, the feedrate and spindle speed have little effect on the heat input. Process parameter v. he...

A look at the statistical identification of critical process parameters in friction stir welding

Abstract: Many fundamental physical relationships governing the friction stir welding (FSW) process remain largely unexplored. Recent studies have aided in the discovery and clarification of many process fundamentals. A 16-run fractional factorial experiment was used to analyze the effects of nine FSW input parameters on measured process outputs. It was confirmed that the most significant input parameters are spindle speed, feed rate, and tool depth. In addition, the distance between the weld and side of the plate had a significant effect on measured Z-force and shoulder depth, and thus should be considered in future studies.